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Reactions of human endometrium to the intrauterine device
volume
106 March
number 6 15, 1970
JOU~Iof Obstetrics and Gynecology
Ametican
GYNECOLOGY Reactions of human endometrium
to the
intrauterine device I. Correlation of the endometrial histology with the bacterial environment OFthe uterus following short-term insertion of the IUD
DEAN
L.
MOYER,
M.D.
DANIEL
R.
MISHELL,
JAMES
BELL,
M.D.
Las Angeles,
JR.,
M.D.
California
The introduction of an intrauterine device through the endocervical canal produces a transient endometrial infection as the result of contamination with bacteria from the cervical mucus. These bacteria are nearly always of low virulence. The response of endometrial tissue to the bacteria and to the polyethylene device is similar to a foreign body reaction in other tissues of the body. In this study a correlation has been established between the length of time following the insertion of an IUD and the intensity and incidence of cell types (plasma cells, mononuclear cells, and neutrophils) found in the endometrium. During the first 6 days following IUD insertion, only neutrophils and mononuclear cells (lymphocytes and monocytes) were present in the endometrial stroma. The period of 7 through 49 days was characterized by the presence of neutrophils, plasma cells, and increasing numbers of mononuclear cells. Even though the bacteria are killed shortly after IUD insertion by the endometrial fluids and cells, the inftammatory cell infiltrates persist for many months in response to the IUD itself. The presence of plasma cells in the endometrium is not pathognomonic of an active bacterial infection, but more commonly represents the residual of a previous endometritis.
AT THE TIME OF insertion of an intrauterine device, bacteria present in cervical mucus are introduced into the uterine cavity, and immediately thereafter a tranGent bacterial contamination of the endometrium occmxl The resulting endometrial
From the Section of Experimental Pathology and Section of Reproductive Biology, Department of Pathology, and Department of Obstetrics and Gynecology, University of Southern California School of Medicine. This Ford
research was supported Foundation.
by The 799
800
Moyer,
Mishell,
and Bell
infection is nearly always asymptomatic, clinically insignificant, and of short duration. Although earlier studies2 using transcervical methods of obtaining endometrial cultures with an IUD in place demonstrated that the incidence of positive cultures was high, a study using a transfrmdal method revealed the actual incidence to be considerably 1ower.l During the 24 hour period immediately following insertion of the IUD, positive endometrial cultures were obtained from all of the uteri studied using the transfundal method. The incidence of positive cultures diminished rapidly after 24 hours, so that in the second 24 hour period 80 per cent of the cultures were sterile and by the time 30 days had elapsed after insertion none of the uteri contained viable bacteria. In addition, when the endometrium was sterile, sterile cultures were obtained from all portions of the device itself and from portions of the thread within the uterine cavity. In the present report the histologic alterations of the endometrium are correlated with the results of the bacteriologic cultures. In addition, a detailed evaluation of the histologic changes are presented together with analysis of the relationship of these alterations to the time interval following insertion of the IUD. The detailed bacteriologic analyses were presented in a previous communicati0n.l
Materials and methods Representative samples of endometrium were obtained from uteri removed by means of elective vaginal hysterectomy from 75 patients who had symptomatic uterine and vaginal relaxation. The majority of these women were Caucasian and were between 25 and 35 years of age. The majority of patients had from 3 to 7 children and were between 2 and 7 months post partum at the time of IUD insertion. At intervals ranging from 4 hours to 7 months prior to hysterectomy, a Lippes Loop D, sterilized in benzalkonium solution for a minimum of 24 hours, was aseptically placed into a sterile inserter and then introduced into the endometrial cavity. No special cleansing of the cervix
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March 15, 1970 J. Obstet. Gynec.
or vagina was performed prior to the insertion. Immediately following hysterectomy the uterus was placed on a sterile towel and taken directly to the bacteriologic laboratory. There, using the method previously described,l approximately 100 mg. of endometrial tissue was aseptically obtained through a transfundal incision of myometrium and incubated in 8 different culture media. The endocervical mucus from the hysterectomy specimens was also cultured in the same media to serve as control of the culture method. After the removal of the endometrial tissue through the sterile incision, the uterus was dissected in a frontal plane and the IUD removed. Two strips of endometrium extending from the fundus through the endocervical canal in both the anterior and posterior portions of the uterus were removed with a scapel and placed in Technicon fixative. A minimum of six sections, measuring at least 1 cm. in length, were taken from each hysterectomy specimen. The sections were taken mainly from the strips, but in some uteri additional samples of endometrium were obtained from other areas. Following 24 hours of fixation, these sections were studied with the light microscope (usually 6 to 8 sections of 1 to 1.5 cm. each in length). All sections were stained with hematoxylin and eosin, and some selected sections were stained with pyronine-methylene green. Eliminated from the study were 2 specimens from which negative cervical mucus cultures were obtained and thus did not conform to the bacteriologic standards of the study. Also eliminated were all 3 specimens showing menstrual endometrium. Thus representative samples of endometria from 70 hysterectomy specimens are included. The terminology used in the paper includes the following : Severe plasma cell infiltration. Plasma cells present in at least one half of the sections of the endometrium studied and more than 4 or more plasma cells per high-power field (~400) in focal areas in one quarter of the sections. In all these sections large numbers of mononuclear cells and/or neutrophils were
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Fig. 1. Plasma cells (arrows)
Endometrial
in the endometrial
stroma of a patient wearing
reaction
to IUD
801
an intrauterine
device. (x800.)
aho present in association with the plasma cells (Fig. 1) . Minimal to moderate plasma cell infiltration. Plasma cell infiltrations of lessthan 4 plasma cells per high-power field in more than 75 per cent of the sectionsexamined. Mononuclear cell infiltration. Mononuclear cells in the endometrial stroma present in quantities of 4 mononuclear cells or more per, high-power field. If plasma cells were present in addition to the mononuclear cells the specimen was included in either of the two categories listed above. No pathology. The absenceof plasma cells, and lessthan 4 mononuclear cells per highpower field. Because of the well-recognized naturally occurring stromal infiltration of mononuclear cells in the latter part of the
luteal phase (9 through 12 days after ovulation) , those specimens containing mononuclear cells without plasma cells at this time of the cycle were placed in this “no pathology” category. Studies of inflammation using histologic sections stained with hematoxylin and eosin do not give adequate morphologic detail to accurately distinguish between lymphocytes, blood-borne monocytes, tissuehistiocytes, and mast cells. Therefore, our previous description3 has been revised and the term “mononuclear cell infiltration” has been substituted for “stromal lymphocytosis.” The precise identification of these mononuclear cells by electron microscopy is the subject of a subsequent communication.4 Although they were commonly associated with superficial
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ulcerations, the presence or absence of neutrophils was not included in the above classification. The ‘quantity of neutrophils present, as well as their significance, can more accurately be determined by other methods.5
specimens showed marked plasma cell infiltration. It is noteworthy that the specimens containing the plasma cell infiltrations were obtained from uteri removed toward the end of this period, i.e., on the fifth and sixth days after insertion. During this period, viable bacteria were present within the endometrial tissue in 100 per cent of the endometria during the first 24 hours, and in 20 per cent of the endometria obtained from the second through the sixth day following IUD insertion. No plasma cells were noted in any of the bacteriologically positive endometria during this 6 day period. In 2 specimens (24 and 43 hours after IUD insertion) ulcerations of the superficial epithelium underlying the IUD showed focal accumulations of neutrophils and mononuclear cells beneath the ulcerations.
Results
Correlation of histologic findings with the time interval following insertion of the IUD. Four hours through 6 days (16 specimens). Minimal to moderate plasma cell infiltrations, together with mononuclear cells and neutrophils were seen in 25 per cent of the specimens. An additional 25 per cent of the specimens showed mononuclear cells scattered throughout the stroma, but without plasma cells. The remaining 50 per cent of the specimens contained neither mononuclear cells nor plasma cells. None of the
Fig. 2. Ulceration of superficial cated in the surrounding stroma.
epithelium (~88.)
March 15, 1970 J. Obstet. Gynec.
and
stroma
with
multiple
inflammatory
cells
lo-
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Seven through 21 days (25 specimens). Marked plasma cell infiltration was seen in 20 per cent of the hysterectomy specimens and 44 per cent showed a minimal to moderate plasma cell infiltration An additional 36 per cent of the specimens contained stroma1 mononuclear cells. None of the endometrial specimens were without cellular infiltrates. Focal accumulations of abundant numbers of plasma cells, neutrophils, and mononuclear cells were present beneath the ulcerations of the superficial epithelium
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803
underlying the IUD in specimens of 14, 16, 17, and 20 days following IUD insertion (Fig. 2). In addition, the specimen with Neisseria gonorrhoeae (10 days after IUD insertion) showed numerous and extensive ulcerations of the superficial epithelium in all sections studied. Twenty-two through 35 days (12 specimens). A marked plasma cell infiltration was noted in 17 per cent of the specimens and 50 per cent showed a slight to moderate plasma cell infiltration. The remaining 33
Fig. 3. Clusters of chromic inflammatory cells (arrows) metrium (M) from the basilar portion of the endometrium
extending
(E). (x275.)
into
the superficial
myo-
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per cent of specimens contained stromal mononuclear cells. All of the hysterectomy specimens showed cellular infiltrates, although the relative quantities of cells were variable. Thirty-six through 49 days (8 specimens). Slight to moderate plasma cell infiltration was seen in 63 per cent of the specimens. None of these specimens revealed marked plasma cell infiltrates. The remaining 37 per cent of the hysterectomy specimens showed mononuclear cells diffusely scattered throughout the stroma. One specimen (40 days) showed plasma cells, neutrophils, and mononuclear cells underlying the superficial ulcerations produced by contact with the IUD. None of the endometria contained viable bacteria after the thirtieth day following insertion. Fifty through 201 days (9 specimens). None of the specimens showed a marked plasma cell infiltration, however, 33 per cent showed a slight to moderate plasma cell infiltration. Of the remainder, 56 per cent of the specimens contained stroma mononuclear cells and 11 per cent showed no pathology. One specimen at 102 days following IUD insertion showed focal accumulations of plasma cell, neutrophils, and mononuclear cells beneath the IUD produced ulcerations.
Correlation of positive bacterial cultures with superf%a.l ulcerations, myometrial cellular infiltrates, and stromal mononuclear cell follicles. Of the specimens with superficial ulcerations and underlying infiltrates, only 2 (24 hours and 10 days following IUD insertion) had positive cultures (Staphylococcus epidermidis and Neisseria gonorrhoeae, respectively). In the remaining 7 specimens with superficial ulcerations (43 hours, 14, 16, 17, 20, 40, and 102 days) the cultures were negative for bacteria. In 9 of the 70 specimens studied, the inflammatory cellular infiltrates extended into the superficial myometrium along the course of the lymphatics (Fig. 3). In one specimen (48 hours after IUD insertion) the infiltrate consisted of neutrophils and mononuclear cells, however, in the remaining 8 specimens (9, 10, 13, 14, 14, 20, 28, and 40 days after IUD insertion) the infiltrate consisted pri-
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March 15, 1970 J. Obstet. Gym.
marily of mononuclear cells with only rare plasma cells and neutrophils. In all of these specimens the endometrial cultures were negative for bacteria. Mononuclear cell follicles were present in the stroma, usually in the basalis, in 4 specimens (Fig. 4). These were removed 9, 23, 30, and 44 days after IUD insertion. Of these specimens, 3 were negative for bacteria while one (30 days after IUD insertion) grew Staphylococcus epidermidis on culture. In all 4 specimens the prominent cell type was mononuclear cells spread diffusely in the stroma with no, or very rare, plasma cells present.
Correlation of the histologic responsewith the bacterial speciesin those specimenswith positive cultures. During the first 6 days following insertion of the IUD, 7 uteri contained viable bacteria in the endometrium. The organisms were identical to those isolated from the cervical mucus. Two of the endometrial specimens contained 2 organisms each. These were Streptococcus sanguis and diphtheroids (4 hours after insertion) and Streptococcus equisimilis and diphtheroids (11 hours after insertion). Both of these specimens were removed in the late luteal phase and had only occasional mononuclear cells in the stroma. This finding was consistent with the physiologic mononuclear cell response accompanying pseudodecidualization of the stroma. Rare leukocytes, but no plasma cells, were present. Of the remaining 5 specimens obtained within the first 6 days following insertion, one contained Alcaligenes faecalis (18 hours after insertion), 2 contained Staphylococcus epidermidis (each 24 hours after insertion), one contained Haemophilus vaginalis (47 hours), and one contained diphtheroids (6 days after insertion). It is possible that these endometria may have harbored additional bacterial species immediately following insertion, but because of the length of time from insertion to culture ( 12 hours or later), it is likely that one species became dominant and was the only species recovered on culture. The endometrium harboring the Alcaligenes faecalis was in the late luteal phase and showed only a physiologic mononuclear
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Fig. 4. A endometrium.
Endometrial
periglandular (~422.)
follicle
(arrows)
composed
cell infiltration. Of the 2 endometria harboring StaphyZococcus epidermidis, one specimen in the proliferative phaseshowed rare mononuclear cells scattered throughout the stroma. The other specimensshowed an early luteal phase endometrium, consistent with that seen 3 to 4 days after ovulation, and contained few mononuclear and neutrophilic cells in the stroma. However, a focal area of superficial ulceration showed dense accumulations of neutrophils and mononuclear cells lying beneath the ulcerated epithelium. The endometrium harboring Haemophilus
of mononuclear
cells
reaction
located
in
to IUD
805
basilar
vaginalis was in the proliferative phase, and showed moderate numbers of mononuclear cells in the superficial and basilar layers of endometrium together with neutrophils in focal superficial areas.The endometrial specimen harboring diphtheroids was in the proliferative phase and showed rare neutrophils and very few mononuclear cells in the stroma. No plasma cells were present in the endometrium of this specimen. In those endometrial specimensharboring bacteria after 6 days, viable bacteria were cultured at 10 days (A’. gonorrhoeac), 18
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days (Streptococcus sang&s), and at 30 days (Staphylococcus epidermidis). The endometrium harboring Neisseria gonorrhoeae was in the proliferative stage and showed many plasma cells, mononuclear cells, and neutrophils in the glands and throughout all layers of the endometrial stroma (Fig. 3 in Ref. 6). Occasional glands were destroyed by the inflammatory exudate and the majority of superficial epithelium was ulcerated. This amount was much greater than the epithelium in contact with the intrauterine device. Due to the fact that this patient had a negative cervical mucus culture of Neisseria gonorrhoeae at the time of insertion of the IUD, it is likely that the patient acquired the infection at some time after the IUD was inserted. The endometrium harboring the Streptococcus sanguis was in the proliferative phase and showed a diffuse infiltration of mononuclear cells and few superficial neutrophils. No plasma cells were present. The endometrium harboring the Staphylococcus epidermidis (30 days) was in the proliferative phase and showed only moderate numbers of mononuclear cells in the upper half of the endometrium and occasional mononuclear cells in the basalis. Rare mononuclear cell follicles were seen. Except for the endometrium containing Neisseria gonorrhoeae, the morphologic findings of these specimens could not be distinguished from those endometria studied at the same time intervals following IUD insertion in which no bacteria were cultured from the endometrium.
Correlation of the phase of the menstrual cycle to the inflammatory reaction. No correlation was noted between the bacteriologic findings and the stage of the menstrual cyc1e.l Similarly, there was no correlation between the histologic finding of plasma cell or mononuclear cell infiltrations and the menstrual phase. Over-all, 42 specimens out of the 70 total specimens showed plasma cell infiltrations. Of these 42, 30 (71 per cent) were in the proliferative phase and 12 (29 per cent) in the luteal phase. This incidence corresponds well to the total number of spec-
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imens studied (70) which included 50 (71 per cent) in the proliferative phase and 20 (29 per cent) in the luteal phase. In addition, there was no discernible difference in the quantity of inflammatory response when subdivided into the 2 menstrual phases.
Correlation of the inllarnmatory response with intervening menstrual periods. Of the patients studied, 95 per cent had at least one menses between the time of IUD insertion and hysterectomy. The menstrual cycles ranged from 25 through 38 days in duration. Of those patients who had no menstrual bleeding between the time of insertion and the vaginal hysterectomy, the uteri were removed within 10 days following insertion of the device in nearly all patients. None of these specimens showed plasma cell infiltrations, while about half showed varying numbers of stromal mononuclear cells. Of these patients having only one menstrual period between the time of insertion and the vaginal hysterectomy, 80 per cent of the patients showed plasma cell infiltration and mononuclear cells, and the remaining 20 per cent contained stromal mononuclear cells only. In this group the median time following insertion to hysterectomy was 30 days. Of the patients with 2 or more menstrual periods, 45 per cent showed plasma cell infiltration and 45 per cent showed stromal mononuclear cells, with 10 per cent containing no inflammatory cells. There was no relationship between the severity of the inflammatory cell response, either plasma cells or lymphocytes, with the clinical symptomatology. None of the patients in this study, although small in number, showed signs of fever, leukocytosis, or abdominal pain prior to hysterectomy. Comment Whenever an object such as an IUD is inserted through the endocervical canal, cervical mucus is introduced into the intrauterine cavity.’ The cervical mucus normally contains several species of bacteria, of which the most common are the staphylococci, streptococci, and diphtheroids. In general, these organisms are of low virulence, and normally
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the host defenses localize these viable organisms to the cervical OS and vaginal cavity. These physiologic conditions are disturbed when an intrauterine device containing cervical mucus and bacteria is inserted through the endocervical canal into the uterine cavity. In some, if not all patients, the superficial epithelium of the endometrium is denuded by the mechanical trauma of the IUD, and, as a result, bacteria have easier access to the superficial endometrial stroma. Usually, the defenses of the endometrium can adequately cope with infections of low virulence within a relatively short time.’ Even though most of the bacterial species found in this study were of low pathogenicity, the dosage of the initial infecting agent as well as the quality of the host tissue response is of importance in the bactericidal response. The capacity of the endometrial secretions to kill bacteria is usually rapid in the majority of patients; however, in the 3 uteri still harboring viable bacteria at 10, 18, and 30 days, the latter 2 showed only stromal mononuclear cells without plasma cells. This finding may be indicative of an inadequate inflammatory cellular and biochemical response to deal with the invading bacteria. Infections with organisms of higher virulence, such as Neisseria gonorrhoeae, usually undergo a different course, and even the presence of large numbers of inflammatory cells does not eliminate the invaders as effectively when compared to the low-virulence organisms. Although only one of the specimens in this study showed Neisseria gonorrhoeae on culture, it occurred late (10 days) following IUD insertion, and the intensity of the cellular infiltrate was marked. Potts and using electron microscopic techPearson,’ niques, demonstrated rod-shaped bacteria in the process of being phagocytosed by leukocytes adherent to the IUD. In addition, they showed that multiple bacteria may adhere to the surface of the IUD itself. Evaluation of inflammatory cell infiltrates in the endometrium is complicated due to the presence of neutrophils and mononuclear cells normally occurring in the stroma during specific phases of the menstrual period.
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Therefore, it is important to define precisely the type of cells present and the timing of their presence in the menstrual cycle. Observations have been made on normal human endometrium for decades, and the original descriptions of Hitschmann and Adler8 in 1908, and later by Noyes, Hertig, and Rock0 have accurately described the presence of endometrial inflammatory cells in the various periods of the cycle. Noyes, Hertig, and Rock stated, “A few scattered lymphocytes may be found in proliferative and early secretory stroma, but the differentiation of predecidua is accompanied by a sharp increase in lymphocytic infiltration.” From these studies it becomes apparent that neutrophils and mononuclear cells are abundant in endometrial tissue during the menstrual flow and that mononuclear cells increase in association with the pseudodecidual stromal reaction occurring in the late luteal phase (9 through 14 days after ovulation). Except for a few scattered mononuclear cells in the stroma, inflammatory cells present in the endometrium at any time other than the late luteal and menstrual phase should be considered an abnormal occurrence. The inflammatory cells found in the late postpartum endometria, as stated by Sharman,lO are the result of a noninfective physiologic restorative process. Plasma cells present in endometrium at any time of the cycle are abnormal although the significance of these cells remains in doubt. Myometrial cellular infiltrates at any stage of the menstrual cycle should be considered abnormal. Endometrial tissue responds to infection with the same defense mechanisms as do other tissues in the body. Following insertion of the IUD, inflammatory infiltrates vary in intensity and incidence of cell type (plasma cells, mononuclear cells, and neutrophils) . In this study multiple sections of endometrium from both the anterior and posterior walls of the uteri removed at hysterectomy were obtained and carefully examined. It was apparent that during the first few days following insertion, only small numbers of mononuclear cells and neutrophils and no plasma cells were present in the stroma of
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the endometrium. This period was followed by increased numbers of mononuclear cells and few plasma cells. The plasma cell infiltration reached maximal numbers during the period from 7 through 35 days but persisted in smaller numbers in excess of 50 days. Thus, the cellular infiltrates continued to accumulate in the endometrial stroma after the vast majority of specimens contained no viable bacteria, and in the case of plasma cells and mononuclear cells reached maximal numbers several weeks after the original infection had subsided. The gradual increase in the numbers of the chronic inflammatory cells and their persistence for an indefinite time following IUD insertion despite intervening menstrual periods is probably related to both the transitory infection as well as the continual presence of a foreign body in direct contact with the tissue. In general, cellular response to infection occurs in 2 stages. The emigration of neutrophils from vessels into the inflamed area usually takes place within one hour and the emigration of mononuclear cells takes place within 3 hours.ll Using a special histologic technique, Kolough12 has shown that the majority of mononuclear cells in the perivascular areas during the first few hours of an inflammatory response were morphologically indistinguishable from peripheral blood lymphocytes. Several bacterial species elaborate factors which excite the appearance of neutrophils.13 Additional factors chemotactic for neutrophils include those generated by the sequential interaction of the complement system14* I5 and the plasmin-split fragment of the third component of complement.16 Experimental studies have shown that the presence of neutrophils at the site of inflammation stimulates lymphocytic emigration and that substances arc released which induce circulating lymphocytes to transform into macrophages which in turn may participate in the inflammatory reaction.ll The long life-span of lymphocytes and their ability to undergo mitosis in tissue’? contribute to their prolonged residence in the endometrium when appropriate stimuli are present. Assuming that no new bacterial infections
March 15, 1970 Amer. J. Obstet. Gym.
develop in the endometrium after the initial contamination,l it is likely that inflammatory cell stimuli other than the bacterial products are produced in the endometrium under sterile conditions. The persistence of the endometrial mononuclear cells in stroma throughout the entire study (up to 201 days) suggests that such mediators are continually being produced even though bacterial products have disappeared. It is not unlikely that contact of the IUD with the superficial tissues may produce such mediators, of which the focal superficial ulceration of epithelium and stroma may be only one of several mechanisms. The findings in this study would indicate that the presence of plasma cells in the endometrial stroma have less specific diagnostic implications than previously realized. Previous literature correlated the presence of plasma cells with an active infectious process in association with viable bacteria.* The finding in this study of the association in 3 patients with endometrial cells together with viable bacteria (N. gonorrhoeae, S. sanguis, S. epidermidis) would confirm this previous report. However, the majority of the specimens containing plasma cells in the endometrial stroma were associated with negative bacterial cultures. This finding, together with the fact that all endometria cultured within 24 hours after IUD insertion contained bacteria but were without plasma cells, would indicate that plasma cells usually appear after the bacteria have been killed. Plasma cells first appeared at the fifth day following IUD insertion, reached maximal numbers from the twelfth to thirty-fifth day, and decreased quantitatively several months after insertion. It is likely that the plasma cells continued to increase in response to the degradative bacterial products present during the first weeks after insertion, and as this stimulus diminished, the numbers of plasma cells also decreased. The presence of plasma cells in association with negative endometrial cultures raises a question regarding the use of the term “chronic endometritis” whenever plasma cells are found in the endometrium. In our opinion the descriptive term “plasma cell infiltra-
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tion” should be utilized instead of “endometritis” if plasma cells are found in the endometrium and if the transfundal culture is negative or if no such culture is obtained. Transcetical cultures are not adequate for this purpose and will usualIy produce faIse positive result+ 2y I8 due to the contamination by bacteria in the cervical mucus. endometritis” However, the term “chronic should be used only if there is a positive bacterial culture which has been taken from endometrium through the serosa and myometrium under sterile conditions and if plasma cells, mononuclear cells, and leukocytes are present in the endometrium. The loss of endometrial tissue during menstruation does not compietely eliminate the inflammatory cell infiltrates seen following insertion of the IUD. The incidence of inflammatory cell infiltrates within the endomet&m in relation to the number of intervening menses paralleled the incidence found
with the increasing time intervals previously noted. After at least one menstrual period had occurred, the majority of specimens still showed plasma cells and mononuclear cells. This would indicate that the sloughing of tissue and the biochemical events associated with menstruation does not in itself eliminate these chronic inflammatory cells. The basalis of endometrium as well as focal areas of superficial endometrium may remain during menstruation,lg and it is likely that foci of chronic inflammatory cells may remain in the endometrial tissue which does not slough at menstruation. The results of this study demonstrate the early histologic changes following insertion of an IUD and the correlation with the initial bacterial infection. All of the hysterectomy specimens were obtained in a relatively short time after insertion of the IUD. Longterm alterations in endometrial histology will be presented in a subsequent communication.
REFERENCES Mishell, D. R., Jr., Bell, J. H., Good, R. G., and Moyer, D. L.: AMER. J. OBSTET. GYNEC. 96: 119, 1966. J, H., Freeman, 2. Mishell, D. R., Jr., Bell, R. K., and Moyer, D. L.: Studies of the Endometrium in Patients Using Intrauterine Contraceptive Devices. II. Evaluation of Bacteriolorric Methods in Culturinrr Endometrial Tjssue, Proceedings of the- Second Conference on Intrauterine Contraceptive Devices, New York, 1964, Excerpta Medica International Congress Series No. 86. D. 166. D. L., and Mishell D. R., Jr.: Stud3. Moyer, ies of the Endometrium in Patients Using Intrauterine Contraceptive Devices, I. Histologic Changes in the Uterus, Proceedings of the Second Conference on Intrauterine Contraceptive Devices, New York, 1964, Excerpta Medica International Congress Series No. 86, p. 159. D. L., and Mishell, D. R., Jr.: 4. Moyer, Reactions of Human Endometrium to the Intrauterine Device. III. Electron Microscopy Study of the Endometrium in Contact with the Intrauterine Device. 5. Moyer, D. L., and Mishell, D. R., Jr.: Reactions of Human Endometrium to the Intrauterine Device. II. Light Microsconv Studv of Hysterectomy and-Biopsy Spec&ens of Endometrium. 6. Moyer, D. L.: The Endometrium in Infer-
tility, in Kistner, R., and Behrman, R., editors: Progress in Infertility, Boston, 1968, Little, Brown & Company. Potts, M., and Pearson, R. M.: J. Obstet. Gynaec. Brit. Comm. 74: 129, 1967. Hitschmann, F., and Adler, L.: Mschr. Geburtsh. Gynaek. 27: 1, 1908. Noyes, R. W., Hertig, A. T., and Rock, J.: Fertil. Steril. 1: 3, 1950. Sharman, A.: Reproductive Physiology of the Postpartum Period, Edinburgh, 1966, E. & S. Livingstone, Ltd. Page, A. R.: Ann. N. Y. Acad. Sci. 116: 950, 1964. Kolough, F., Jr.: Amer. J. Path. 15: 413, 1939. Ward, P. A., Lepow, I. H., and Newman, L. J.: Amer. J. Path. 52: 725, 1968. Ward, P. A., Cochrane, C. G., and MullerEberhard, H. J.: J. Exper. Med. 122: 327, 1965. Ward, P. A., Cochrane, C. G., and MullerEberhard, H. J.: Immunology 11: 141, 1966. Ward, P. A.: J. Exp. Med. 126: 189, 1967. Little, J. R., Brecher, G., Bradley, T. R., and Rose, S.: Blood 19: 236, 1962. Willson, J. R., Bollinger, C. C., and Ledger, W. J. AMER. J. OBSTET. GYNEC. 90: 726, 1964. McLennan, C. E., and Rydell, A. H.: Obstet. Gynec. 26:605,1965.
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7. 8. 9. 10.
11. 12. 13. 14.
15. 16. 17. 18.
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106 March
number 6 15, 1970
JOU~Iof Obstetrics and Gynecology
Ametican
GYNECOLOGY Reactions of human endometrium
to the
intrauterine device I. Correlation of the endometrial histology with the bacterial environment OFthe uterus following short-term insertion of the IUD
DEAN
L.
MOYER,
M.D.
DANIEL
R.
MISHELL,
JAMES
BELL,
M.D.
Las Angeles,
JR.,
M.D.
California
The introduction of an intrauterine device through the endocervical canal produces a transient endometrial infection as the result of contamination with bacteria from the cervical mucus. These bacteria are nearly always of low virulence. The response of endometrial tissue to the bacteria and to the polyethylene device is similar to a foreign body reaction in other tissues of the body. In this study a correlation has been established between the length of time following the insertion of an IUD and the intensity and incidence of cell types (plasma cells, mononuclear cells, and neutrophils) found in the endometrium. During the first 6 days following IUD insertion, only neutrophils and mononuclear cells (lymphocytes and monocytes) were present in the endometrial stroma. The period of 7 through 49 days was characterized by the presence of neutrophils, plasma cells, and increasing numbers of mononuclear cells. Even though the bacteria are killed shortly after IUD insertion by the endometrial fluids and cells, the inftammatory cell infiltrates persist for many months in response to the IUD itself. The presence of plasma cells in the endometrium is not pathognomonic of an active bacterial infection, but more commonly represents the residual of a previous endometritis.
AT THE TIME OF insertion of an intrauterine device, bacteria present in cervical mucus are introduced into the uterine cavity, and immediately thereafter a tranGent bacterial contamination of the endometrium occmxl The resulting endometrial
From the Section of Experimental Pathology and Section of Reproductive Biology, Department of Pathology, and Department of Obstetrics and Gynecology, University of Southern California School of Medicine. This Ford
research was supported Foundation.
by The 799
800
Moyer,
Mishell,
and Bell
infection is nearly always asymptomatic, clinically insignificant, and of short duration. Although earlier studies2 using transcervical methods of obtaining endometrial cultures with an IUD in place demonstrated that the incidence of positive cultures was high, a study using a transfrmdal method revealed the actual incidence to be considerably 1ower.l During the 24 hour period immediately following insertion of the IUD, positive endometrial cultures were obtained from all of the uteri studied using the transfundal method. The incidence of positive cultures diminished rapidly after 24 hours, so that in the second 24 hour period 80 per cent of the cultures were sterile and by the time 30 days had elapsed after insertion none of the uteri contained viable bacteria. In addition, when the endometrium was sterile, sterile cultures were obtained from all portions of the device itself and from portions of the thread within the uterine cavity. In the present report the histologic alterations of the endometrium are correlated with the results of the bacteriologic cultures. In addition, a detailed evaluation of the histologic changes are presented together with analysis of the relationship of these alterations to the time interval following insertion of the IUD. The detailed bacteriologic analyses were presented in a previous communicati0n.l
Materials and methods Representative samples of endometrium were obtained from uteri removed by means of elective vaginal hysterectomy from 75 patients who had symptomatic uterine and vaginal relaxation. The majority of these women were Caucasian and were between 25 and 35 years of age. The majority of patients had from 3 to 7 children and were between 2 and 7 months post partum at the time of IUD insertion. At intervals ranging from 4 hours to 7 months prior to hysterectomy, a Lippes Loop D, sterilized in benzalkonium solution for a minimum of 24 hours, was aseptically placed into a sterile inserter and then introduced into the endometrial cavity. No special cleansing of the cervix
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or vagina was performed prior to the insertion. Immediately following hysterectomy the uterus was placed on a sterile towel and taken directly to the bacteriologic laboratory. There, using the method previously described,l approximately 100 mg. of endometrial tissue was aseptically obtained through a transfundal incision of myometrium and incubated in 8 different culture media. The endocervical mucus from the hysterectomy specimens was also cultured in the same media to serve as control of the culture method. After the removal of the endometrial tissue through the sterile incision, the uterus was dissected in a frontal plane and the IUD removed. Two strips of endometrium extending from the fundus through the endocervical canal in both the anterior and posterior portions of the uterus were removed with a scapel and placed in Technicon fixative. A minimum of six sections, measuring at least 1 cm. in length, were taken from each hysterectomy specimen. The sections were taken mainly from the strips, but in some uteri additional samples of endometrium were obtained from other areas. Following 24 hours of fixation, these sections were studied with the light microscope (usually 6 to 8 sections of 1 to 1.5 cm. each in length). All sections were stained with hematoxylin and eosin, and some selected sections were stained with pyronine-methylene green. Eliminated from the study were 2 specimens from which negative cervical mucus cultures were obtained and thus did not conform to the bacteriologic standards of the study. Also eliminated were all 3 specimens showing menstrual endometrium. Thus representative samples of endometria from 70 hysterectomy specimens are included. The terminology used in the paper includes the following : Severe plasma cell infiltration. Plasma cells present in at least one half of the sections of the endometrium studied and more than 4 or more plasma cells per high-power field (~400) in focal areas in one quarter of the sections. In all these sections large numbers of mononuclear cells and/or neutrophils were
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Fig. 1. Plasma cells (arrows)
Endometrial
in the endometrial
stroma of a patient wearing
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an intrauterine
device. (x800.)
aho present in association with the plasma cells (Fig. 1) . Minimal to moderate plasma cell infiltration. Plasma cell infiltrations of lessthan 4 plasma cells per high-power field in more than 75 per cent of the sectionsexamined. Mononuclear cell infiltration. Mononuclear cells in the endometrial stroma present in quantities of 4 mononuclear cells or more per, high-power field. If plasma cells were present in addition to the mononuclear cells the specimen was included in either of the two categories listed above. No pathology. The absenceof plasma cells, and lessthan 4 mononuclear cells per highpower field. Because of the well-recognized naturally occurring stromal infiltration of mononuclear cells in the latter part of the
luteal phase (9 through 12 days after ovulation) , those specimens containing mononuclear cells without plasma cells at this time of the cycle were placed in this “no pathology” category. Studies of inflammation using histologic sections stained with hematoxylin and eosin do not give adequate morphologic detail to accurately distinguish between lymphocytes, blood-borne monocytes, tissuehistiocytes, and mast cells. Therefore, our previous description3 has been revised and the term “mononuclear cell infiltration” has been substituted for “stromal lymphocytosis.” The precise identification of these mononuclear cells by electron microscopy is the subject of a subsequent communication.4 Although they were commonly associated with superficial
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ulcerations, the presence or absence of neutrophils was not included in the above classification. The ‘quantity of neutrophils present, as well as their significance, can more accurately be determined by other methods.5
specimens showed marked plasma cell infiltration. It is noteworthy that the specimens containing the plasma cell infiltrations were obtained from uteri removed toward the end of this period, i.e., on the fifth and sixth days after insertion. During this period, viable bacteria were present within the endometrial tissue in 100 per cent of the endometria during the first 24 hours, and in 20 per cent of the endometria obtained from the second through the sixth day following IUD insertion. No plasma cells were noted in any of the bacteriologically positive endometria during this 6 day period. In 2 specimens (24 and 43 hours after IUD insertion) ulcerations of the superficial epithelium underlying the IUD showed focal accumulations of neutrophils and mononuclear cells beneath the ulcerations.
Results
Correlation of histologic findings with the time interval following insertion of the IUD. Four hours through 6 days (16 specimens). Minimal to moderate plasma cell infiltrations, together with mononuclear cells and neutrophils were seen in 25 per cent of the specimens. An additional 25 per cent of the specimens showed mononuclear cells scattered throughout the stroma, but without plasma cells. The remaining 50 per cent of the specimens contained neither mononuclear cells nor plasma cells. None of the
Fig. 2. Ulceration of superficial cated in the surrounding stroma.
epithelium (~88.)
March 15, 1970 J. Obstet. Gynec.
and
stroma
with
multiple
inflammatory
cells
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Seven through 21 days (25 specimens). Marked plasma cell infiltration was seen in 20 per cent of the hysterectomy specimens and 44 per cent showed a minimal to moderate plasma cell infiltration An additional 36 per cent of the specimens contained stroma1 mononuclear cells. None of the endometrial specimens were without cellular infiltrates. Focal accumulations of abundant numbers of plasma cells, neutrophils, and mononuclear cells were present beneath the ulcerations of the superficial epithelium
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underlying the IUD in specimens of 14, 16, 17, and 20 days following IUD insertion (Fig. 2). In addition, the specimen with Neisseria gonorrhoeae (10 days after IUD insertion) showed numerous and extensive ulcerations of the superficial epithelium in all sections studied. Twenty-two through 35 days (12 specimens). A marked plasma cell infiltration was noted in 17 per cent of the specimens and 50 per cent showed a slight to moderate plasma cell infiltration. The remaining 33
Fig. 3. Clusters of chromic inflammatory cells (arrows) metrium (M) from the basilar portion of the endometrium
extending
(E). (x275.)
into
the superficial
myo-
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per cent of specimens contained stromal mononuclear cells. All of the hysterectomy specimens showed cellular infiltrates, although the relative quantities of cells were variable. Thirty-six through 49 days (8 specimens). Slight to moderate plasma cell infiltration was seen in 63 per cent of the specimens. None of these specimens revealed marked plasma cell infiltrates. The remaining 37 per cent of the hysterectomy specimens showed mononuclear cells diffusely scattered throughout the stroma. One specimen (40 days) showed plasma cells, neutrophils, and mononuclear cells underlying the superficial ulcerations produced by contact with the IUD. None of the endometria contained viable bacteria after the thirtieth day following insertion. Fifty through 201 days (9 specimens). None of the specimens showed a marked plasma cell infiltration, however, 33 per cent showed a slight to moderate plasma cell infiltration. Of the remainder, 56 per cent of the specimens contained stroma mononuclear cells and 11 per cent showed no pathology. One specimen at 102 days following IUD insertion showed focal accumulations of plasma cell, neutrophils, and mononuclear cells beneath the IUD produced ulcerations.
Correlation of positive bacterial cultures with superf%a.l ulcerations, myometrial cellular infiltrates, and stromal mononuclear cell follicles. Of the specimens with superficial ulcerations and underlying infiltrates, only 2 (24 hours and 10 days following IUD insertion) had positive cultures (Staphylococcus epidermidis and Neisseria gonorrhoeae, respectively). In the remaining 7 specimens with superficial ulcerations (43 hours, 14, 16, 17, 20, 40, and 102 days) the cultures were negative for bacteria. In 9 of the 70 specimens studied, the inflammatory cellular infiltrates extended into the superficial myometrium along the course of the lymphatics (Fig. 3). In one specimen (48 hours after IUD insertion) the infiltrate consisted of neutrophils and mononuclear cells, however, in the remaining 8 specimens (9, 10, 13, 14, 14, 20, 28, and 40 days after IUD insertion) the infiltrate consisted pri-
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marily of mononuclear cells with only rare plasma cells and neutrophils. In all of these specimens the endometrial cultures were negative for bacteria. Mononuclear cell follicles were present in the stroma, usually in the basalis, in 4 specimens (Fig. 4). These were removed 9, 23, 30, and 44 days after IUD insertion. Of these specimens, 3 were negative for bacteria while one (30 days after IUD insertion) grew Staphylococcus epidermidis on culture. In all 4 specimens the prominent cell type was mononuclear cells spread diffusely in the stroma with no, or very rare, plasma cells present.
Correlation of the histologic responsewith the bacterial speciesin those specimenswith positive cultures. During the first 6 days following insertion of the IUD, 7 uteri contained viable bacteria in the endometrium. The organisms were identical to those isolated from the cervical mucus. Two of the endometrial specimens contained 2 organisms each. These were Streptococcus sanguis and diphtheroids (4 hours after insertion) and Streptococcus equisimilis and diphtheroids (11 hours after insertion). Both of these specimens were removed in the late luteal phase and had only occasional mononuclear cells in the stroma. This finding was consistent with the physiologic mononuclear cell response accompanying pseudodecidualization of the stroma. Rare leukocytes, but no plasma cells, were present. Of the remaining 5 specimens obtained within the first 6 days following insertion, one contained Alcaligenes faecalis (18 hours after insertion), 2 contained Staphylococcus epidermidis (each 24 hours after insertion), one contained Haemophilus vaginalis (47 hours), and one contained diphtheroids (6 days after insertion). It is possible that these endometria may have harbored additional bacterial species immediately following insertion, but because of the length of time from insertion to culture ( 12 hours or later), it is likely that one species became dominant and was the only species recovered on culture. The endometrium harboring the Alcaligenes faecalis was in the late luteal phase and showed only a physiologic mononuclear
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Fig. 4. A endometrium.
Endometrial
periglandular (~422.)
follicle
(arrows)
composed
cell infiltration. Of the 2 endometria harboring StaphyZococcus epidermidis, one specimen in the proliferative phaseshowed rare mononuclear cells scattered throughout the stroma. The other specimensshowed an early luteal phase endometrium, consistent with that seen 3 to 4 days after ovulation, and contained few mononuclear and neutrophilic cells in the stroma. However, a focal area of superficial ulceration showed dense accumulations of neutrophils and mononuclear cells lying beneath the ulcerated epithelium. The endometrium harboring Haemophilus
of mononuclear
cells
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basilar
vaginalis was in the proliferative phase, and showed moderate numbers of mononuclear cells in the superficial and basilar layers of endometrium together with neutrophils in focal superficial areas.The endometrial specimen harboring diphtheroids was in the proliferative phase and showed rare neutrophils and very few mononuclear cells in the stroma. No plasma cells were present in the endometrium of this specimen. In those endometrial specimensharboring bacteria after 6 days, viable bacteria were cultured at 10 days (A’. gonorrhoeac), 18
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days (Streptococcus sang&s), and at 30 days (Staphylococcus epidermidis). The endometrium harboring Neisseria gonorrhoeae was in the proliferative stage and showed many plasma cells, mononuclear cells, and neutrophils in the glands and throughout all layers of the endometrial stroma (Fig. 3 in Ref. 6). Occasional glands were destroyed by the inflammatory exudate and the majority of superficial epithelium was ulcerated. This amount was much greater than the epithelium in contact with the intrauterine device. Due to the fact that this patient had a negative cervical mucus culture of Neisseria gonorrhoeae at the time of insertion of the IUD, it is likely that the patient acquired the infection at some time after the IUD was inserted. The endometrium harboring the Streptococcus sanguis was in the proliferative phase and showed a diffuse infiltration of mononuclear cells and few superficial neutrophils. No plasma cells were present. The endometrium harboring the Staphylococcus epidermidis (30 days) was in the proliferative phase and showed only moderate numbers of mononuclear cells in the upper half of the endometrium and occasional mononuclear cells in the basalis. Rare mononuclear cell follicles were seen. Except for the endometrium containing Neisseria gonorrhoeae, the morphologic findings of these specimens could not be distinguished from those endometria studied at the same time intervals following IUD insertion in which no bacteria were cultured from the endometrium.
Correlation of the phase of the menstrual cycle to the inflammatory reaction. No correlation was noted between the bacteriologic findings and the stage of the menstrual cyc1e.l Similarly, there was no correlation between the histologic finding of plasma cell or mononuclear cell infiltrations and the menstrual phase. Over-all, 42 specimens out of the 70 total specimens showed plasma cell infiltrations. Of these 42, 30 (71 per cent) were in the proliferative phase and 12 (29 per cent) in the luteal phase. This incidence corresponds well to the total number of spec-
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imens studied (70) which included 50 (71 per cent) in the proliferative phase and 20 (29 per cent) in the luteal phase. In addition, there was no discernible difference in the quantity of inflammatory response when subdivided into the 2 menstrual phases.
Correlation of the inllarnmatory response with intervening menstrual periods. Of the patients studied, 95 per cent had at least one menses between the time of IUD insertion and hysterectomy. The menstrual cycles ranged from 25 through 38 days in duration. Of those patients who had no menstrual bleeding between the time of insertion and the vaginal hysterectomy, the uteri were removed within 10 days following insertion of the device in nearly all patients. None of these specimens showed plasma cell infiltrations, while about half showed varying numbers of stromal mononuclear cells. Of these patients having only one menstrual period between the time of insertion and the vaginal hysterectomy, 80 per cent of the patients showed plasma cell infiltration and mononuclear cells, and the remaining 20 per cent contained stromal mononuclear cells only. In this group the median time following insertion to hysterectomy was 30 days. Of the patients with 2 or more menstrual periods, 45 per cent showed plasma cell infiltration and 45 per cent showed stromal mononuclear cells, with 10 per cent containing no inflammatory cells. There was no relationship between the severity of the inflammatory cell response, either plasma cells or lymphocytes, with the clinical symptomatology. None of the patients in this study, although small in number, showed signs of fever, leukocytosis, or abdominal pain prior to hysterectomy. Comment Whenever an object such as an IUD is inserted through the endocervical canal, cervical mucus is introduced into the intrauterine cavity.’ The cervical mucus normally contains several species of bacteria, of which the most common are the staphylococci, streptococci, and diphtheroids. In general, these organisms are of low virulence, and normally
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the host defenses localize these viable organisms to the cervical OS and vaginal cavity. These physiologic conditions are disturbed when an intrauterine device containing cervical mucus and bacteria is inserted through the endocervical canal into the uterine cavity. In some, if not all patients, the superficial epithelium of the endometrium is denuded by the mechanical trauma of the IUD, and, as a result, bacteria have easier access to the superficial endometrial stroma. Usually, the defenses of the endometrium can adequately cope with infections of low virulence within a relatively short time.’ Even though most of the bacterial species found in this study were of low pathogenicity, the dosage of the initial infecting agent as well as the quality of the host tissue response is of importance in the bactericidal response. The capacity of the endometrial secretions to kill bacteria is usually rapid in the majority of patients; however, in the 3 uteri still harboring viable bacteria at 10, 18, and 30 days, the latter 2 showed only stromal mononuclear cells without plasma cells. This finding may be indicative of an inadequate inflammatory cellular and biochemical response to deal with the invading bacteria. Infections with organisms of higher virulence, such as Neisseria gonorrhoeae, usually undergo a different course, and even the presence of large numbers of inflammatory cells does not eliminate the invaders as effectively when compared to the low-virulence organisms. Although only one of the specimens in this study showed Neisseria gonorrhoeae on culture, it occurred late (10 days) following IUD insertion, and the intensity of the cellular infiltrate was marked. Potts and using electron microscopic techPearson,’ niques, demonstrated rod-shaped bacteria in the process of being phagocytosed by leukocytes adherent to the IUD. In addition, they showed that multiple bacteria may adhere to the surface of the IUD itself. Evaluation of inflammatory cell infiltrates in the endometrium is complicated due to the presence of neutrophils and mononuclear cells normally occurring in the stroma during specific phases of the menstrual period.
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Therefore, it is important to define precisely the type of cells present and the timing of their presence in the menstrual cycle. Observations have been made on normal human endometrium for decades, and the original descriptions of Hitschmann and Adler8 in 1908, and later by Noyes, Hertig, and Rock0 have accurately described the presence of endometrial inflammatory cells in the various periods of the cycle. Noyes, Hertig, and Rock stated, “A few scattered lymphocytes may be found in proliferative and early secretory stroma, but the differentiation of predecidua is accompanied by a sharp increase in lymphocytic infiltration.” From these studies it becomes apparent that neutrophils and mononuclear cells are abundant in endometrial tissue during the menstrual flow and that mononuclear cells increase in association with the pseudodecidual stromal reaction occurring in the late luteal phase (9 through 14 days after ovulation). Except for a few scattered mononuclear cells in the stroma, inflammatory cells present in the endometrium at any time other than the late luteal and menstrual phase should be considered an abnormal occurrence. The inflammatory cells found in the late postpartum endometria, as stated by Sharman,lO are the result of a noninfective physiologic restorative process. Plasma cells present in endometrium at any time of the cycle are abnormal although the significance of these cells remains in doubt. Myometrial cellular infiltrates at any stage of the menstrual cycle should be considered abnormal. Endometrial tissue responds to infection with the same defense mechanisms as do other tissues in the body. Following insertion of the IUD, inflammatory infiltrates vary in intensity and incidence of cell type (plasma cells, mononuclear cells, and neutrophils) . In this study multiple sections of endometrium from both the anterior and posterior walls of the uteri removed at hysterectomy were obtained and carefully examined. It was apparent that during the first few days following insertion, only small numbers of mononuclear cells and neutrophils and no plasma cells were present in the stroma of
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the endometrium. This period was followed by increased numbers of mononuclear cells and few plasma cells. The plasma cell infiltration reached maximal numbers during the period from 7 through 35 days but persisted in smaller numbers in excess of 50 days. Thus, the cellular infiltrates continued to accumulate in the endometrial stroma after the vast majority of specimens contained no viable bacteria, and in the case of plasma cells and mononuclear cells reached maximal numbers several weeks after the original infection had subsided. The gradual increase in the numbers of the chronic inflammatory cells and their persistence for an indefinite time following IUD insertion despite intervening menstrual periods is probably related to both the transitory infection as well as the continual presence of a foreign body in direct contact with the tissue. In general, cellular response to infection occurs in 2 stages. The emigration of neutrophils from vessels into the inflamed area usually takes place within one hour and the emigration of mononuclear cells takes place within 3 hours.ll Using a special histologic technique, Kolough12 has shown that the majority of mononuclear cells in the perivascular areas during the first few hours of an inflammatory response were morphologically indistinguishable from peripheral blood lymphocytes. Several bacterial species elaborate factors which excite the appearance of neutrophils.13 Additional factors chemotactic for neutrophils include those generated by the sequential interaction of the complement system14* I5 and the plasmin-split fragment of the third component of complement.16 Experimental studies have shown that the presence of neutrophils at the site of inflammation stimulates lymphocytic emigration and that substances arc released which induce circulating lymphocytes to transform into macrophages which in turn may participate in the inflammatory reaction.ll The long life-span of lymphocytes and their ability to undergo mitosis in tissue’? contribute to their prolonged residence in the endometrium when appropriate stimuli are present. Assuming that no new bacterial infections
March 15, 1970 Amer. J. Obstet. Gym.
develop in the endometrium after the initial contamination,l it is likely that inflammatory cell stimuli other than the bacterial products are produced in the endometrium under sterile conditions. The persistence of the endometrial mononuclear cells in stroma throughout the entire study (up to 201 days) suggests that such mediators are continually being produced even though bacterial products have disappeared. It is not unlikely that contact of the IUD with the superficial tissues may produce such mediators, of which the focal superficial ulceration of epithelium and stroma may be only one of several mechanisms. The findings in this study would indicate that the presence of plasma cells in the endometrial stroma have less specific diagnostic implications than previously realized. Previous literature correlated the presence of plasma cells with an active infectious process in association with viable bacteria.* The finding in this study of the association in 3 patients with endometrial cells together with viable bacteria (N. gonorrhoeae, S. sanguis, S. epidermidis) would confirm this previous report. However, the majority of the specimens containing plasma cells in the endometrial stroma were associated with negative bacterial cultures. This finding, together with the fact that all endometria cultured within 24 hours after IUD insertion contained bacteria but were without plasma cells, would indicate that plasma cells usually appear after the bacteria have been killed. Plasma cells first appeared at the fifth day following IUD insertion, reached maximal numbers from the twelfth to thirty-fifth day, and decreased quantitatively several months after insertion. It is likely that the plasma cells continued to increase in response to the degradative bacterial products present during the first weeks after insertion, and as this stimulus diminished, the numbers of plasma cells also decreased. The presence of plasma cells in association with negative endometrial cultures raises a question regarding the use of the term “chronic endometritis” whenever plasma cells are found in the endometrium. In our opinion the descriptive term “plasma cell infiltra-
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tion” should be utilized instead of “endometritis” if plasma cells are found in the endometrium and if the transfundal culture is negative or if no such culture is obtained. Transcetical cultures are not adequate for this purpose and will usualIy produce faIse positive result+ 2y I8 due to the contamination by bacteria in the cervical mucus. endometritis” However, the term “chronic should be used only if there is a positive bacterial culture which has been taken from endometrium through the serosa and myometrium under sterile conditions and if plasma cells, mononuclear cells, and leukocytes are present in the endometrium. The loss of endometrial tissue during menstruation does not compietely eliminate the inflammatory cell infiltrates seen following insertion of the IUD. The incidence of inflammatory cell infiltrates within the endomet&m in relation to the number of intervening menses paralleled the incidence found
with the increasing time intervals previously noted. After at least one menstrual period had occurred, the majority of specimens still showed plasma cells and mononuclear cells. This would indicate that the sloughing of tissue and the biochemical events associated with menstruation does not in itself eliminate these chronic inflammatory cells. The basalis of endometrium as well as focal areas of superficial endometrium may remain during menstruation,lg and it is likely that foci of chronic inflammatory cells may remain in the endometrial tissue which does not slough at menstruation. The results of this study demonstrate the early histologic changes following insertion of an IUD and the correlation with the initial bacterial infection. All of the hysterectomy specimens were obtained in a relatively short time after insertion of the IUD. Longterm alterations in endometrial histology will be presented in a subsequent communication.
REFERENCES Mishell, D. R., Jr., Bell, J. H., Good, R. G., and Moyer, D. L.: AMER. J. OBSTET. GYNEC. 96: 119, 1966. J, H., Freeman, 2. Mishell, D. R., Jr., Bell, R. K., and Moyer, D. L.: Studies of the Endometrium in Patients Using Intrauterine Contraceptive Devices. II. Evaluation of Bacteriolorric Methods in Culturinrr Endometrial Tjssue, Proceedings of the- Second Conference on Intrauterine Contraceptive Devices, New York, 1964, Excerpta Medica International Congress Series No. 86. D. 166. D. L., and Mishell D. R., Jr.: Stud3. Moyer, ies of the Endometrium in Patients Using Intrauterine Contraceptive Devices, I. Histologic Changes in the Uterus, Proceedings of the Second Conference on Intrauterine Contraceptive Devices, New York, 1964, Excerpta Medica International Congress Series No. 86, p. 159. D. L., and Mishell, D. R., Jr.: 4. Moyer, Reactions of Human Endometrium to the Intrauterine Device. III. Electron Microscopy Study of the Endometrium in Contact with the Intrauterine Device. 5. Moyer, D. L., and Mishell, D. R., Jr.: Reactions of Human Endometrium to the Intrauterine Device. II. Light Microsconv Studv of Hysterectomy and-Biopsy Spec&ens of Endometrium. 6. Moyer, D. L.: The Endometrium in Infer-
tility, in Kistner, R., and Behrman, R., editors: Progress in Infertility, Boston, 1968, Little, Brown & Company. Potts, M., and Pearson, R. M.: J. Obstet. Gynaec. Brit. Comm. 74: 129, 1967. Hitschmann, F., and Adler, L.: Mschr. Geburtsh. Gynaek. 27: 1, 1908. Noyes, R. W., Hertig, A. T., and Rock, J.: Fertil. Steril. 1: 3, 1950. Sharman, A.: Reproductive Physiology of the Postpartum Period, Edinburgh, 1966, E. & S. Livingstone, Ltd. Page, A. R.: Ann. N. Y. Acad. Sci. 116: 950, 1964. Kolough, F., Jr.: Amer. J. Path. 15: 413, 1939. Ward, P. A., Lepow, I. H., and Newman, L. J.: Amer. J. Path. 52: 725, 1968. Ward, P. A., Cochrane, C. G., and MullerEberhard, H. J.: J. Exper. Med. 122: 327, 1965. Ward, P. A., Cochrane, C. G., and MullerEberhard, H. J.: Immunology 11: 141, 1966. Ward, P. A.: J. Exp. Med. 126: 189, 1967. Little, J. R., Brecher, G., Bradley, T. R., and Rose, S.: Blood 19: 236, 1962. Willson, J. R., Bollinger, C. C., and Ledger, W. J. AMER. J. OBSTET. GYNEC. 90: 726, 1964. McLennan, C. E., and Rydell, A. H.: Obstet. Gynec. 26:605,1965.
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