- Email: [email protected]
The plausibility of Helicobacter pylori-related infertility in Japan
The plausibility of Helicobacter pylori-related infertility in Japan The aim of the present study was to confirm the seropositive rate of Helicobacter pylori to which antibodies cross-react with spermatozoon flagella in patients with infertility. Of the 204 patients in whom the anti-H. pylori IgG antibody in serum and follicular fluids were measured, 45 (22.1%) were seropositive for H. pylori and the seropositive percentage of infertile patients without any possible cause was higher than that of patients with one or more known infertility factors [8 of 21 patients (38.3%) vs. 37 of 183 patients (20.2%), respectively], which suggests a new concept: H. pylori-related infertility. (Fertil Steril 2008;90:866–8. 2008 by American Society for Reproductive Medicine.)
The bacterium Helicobacter pylori is known as an important cause of gastric diseases, including peptic ulcers and stomach cancer (1, 2). Helicobacter pylori infection may also affect extradigestive diseases, including idiopathic thrombocytopenic purpura (3, 4) and chronic urticaria (5, 6). Figura et al. (7) have hypothesized an antigenic mimicry between bacterial flagella of H. pylori and spermatozoa, the only flagellated human cells, and that the antibodies produced against H. pylori flagella may cross-react with spermatozoon flagella. They have reported that the levels of the anti-H. pylori antibody in serum samples was significantly higher in patients with reproductive disorders than in age-matched control subjects and suggested that H. pylori infection may increase the risk of infertility. For the comparative control group in a case-control study, fertile women are preferable, whose risk factors for H. pylori infection such as year of birth, sanitary conditions during childhood, and social class are known. Because such control women were not available, we compared the seropositivity between infertile women with and without known infertility causes to investigate how much H. pylori infection links with unknown infertility using available retrospective samples. This was a retrospective study including 204 women undergoing infertility treatment at the Department of Obstetrics and Gynecology at Nagoya University Graduate School of Medicine between February 2001 and December 2004. The screening examination for infertility included transvaginal ultrasound, seminal fluid analysis including sperm concentration, motility, and morphology, hysterosalpingography, anti-Chlamydia trachomatis antibodies, antinuclear antibodies, thyroid function test, and determination of FSH, LH, androgen, P, and PRL concentrations. Male factor infertility was diagnosed according to standard World Health Organization semen analyses. If these were within the Received February 6, 2007; revised and accepted June 28, 2007. Reprint requests: Akira Iwase, M.D., Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466–8550, Japan (FAX: 81-52-744-2268; E-mail: [email protected]).
866
normal range, the patients were considered to have unknown etiology. The study was approved by the ethics committee of Nagoya University School of Medicine. A commercially available direct ELISA kit (E Plate Eiken H. Pylori Antibody; Eiken Kagaku, Tokyo, Japan) was used to determine the serum IgG level for H. pylori infection (8–10). The positive status of H. pylori infection was defined as H. pylori IgG antibodies over 10 U/mL in serum. Serum and follicular fluids were obtained during ovarian stimulation and IVF treatment, respectively. The procedures of ovarian stimulation, oocyte retrieval, and standard IVF were performed according to routine protocols as described previously (11). The data were analyzed using the Mann–Whitney U test and Fisher exact test with the software Statistics Package for Social Sciences (SPSS) version 11.0J for Windows (SPSS Japan, Tokyo, Japan). All tests were two-tailed, and significance was accepted at P<.05. Odds ratios were calculated by a logistic regression model using the software Stata version 7 (Stata Corp., College Station, TX). The demographic data for all subjects who received infertility treatment were obtained from the medical records (Table 1). The diagnosed one or two main causes of infertility were as follows (number of patients, percentage): hormonal dysfunction (104, 51.0%), male factor (55, 27.0%),
TABLE 1 Demographic data of the study group. Characteristic Age (yrs) Mean SD Range Primary infertility [n (%)] Secondary infertility [n (%)] Duration of infertility (yrs) Mean SD Range
34.5 5.4 24–44 135 (66.2) 69 (33.8) 3.8 3.7 1–20
Kurotsuchi. Helicobacter pylori and infertility. Fertil Steril 2008.
Fertility and Sterility Vol. 90, No. 3, September 2008 Copyright ª2008 American Society for Reproductive Medicine, Published by Elsevier Inc.
0015-0282/08/$34.00 doi:10.1016/j.fertnstert.2007.06.097
TABLE 2 Cause of infertility and H. pylori status. Cause of infertility Known Unknown Total
H. pylori infected, n
H. pylori uninfected, n
Total, n
37 8 45
146 13 159
183 21 204
P value
0.091
Kurotsuchi. Helicobacter pylori and infertility. Fertil Steril 2008.
uterine factor (37, 18.1%), tubal factor (30, 14.7%), endometriosis (28, 13.7%), and unknown etiology (21, 10.3%). The H. pylori–seropositive rate was 22.1% (45 out of 204 women). The causes of infertility and H. pylori status are summarized in Table 2. The seropositivity was higher in the group of patients who did not have any known causes of infertility (unknown group) than in those who had one or more known causes of infertility (known group), although the difference was not statistically significant (38.3% [8 of 21 patients] vs. 20.2% [37 of 183 patients]; P¼.091). The odds ratio of the seropositivity adjusted for year of birth was 2.16 (95% confidence interval 0.82– 5.70). The titer of anti-H. pylori antibody was not significantly different between the two groups; the median (range) was 48 (11–297) U/mL in the known group and 55.5 (12–154) U/mL in the unknown group (P¼.314). In the titers of anti-H. pylori antibody of serum and follicular fluids in 11 patients who received IVF treatment, the median (range) was 36 (13–297) U/mL and 21 (3–232) U/mL, respectively. Among the 11 seropositive (>10 U/mL) patients, seven had anti-H. pylori antibodies over 10 U/mL in the follicular fluid. In the present study, the H. pylori seropositive rate was 22.1% (45 out of 204 women). Figura et al. (7) reported that the presence of the anti-H.pylori antibody was 60 out of 118 male patients (50.8%) and 22 out of 49 female patients (44.8%) with infertility. The lower incidence in the present study might reflect the improved sanitary conditions for the Japanese subjects in their childhood. Shimatani et al. (12) reported that H. pylori-infected individuals among healthy Japanese born in the 1970s accounted for 73 out of 371 men (19.7%) and 14 out of 159 women (8.8%). Fukui et al. (13) reported that H. pylori infection was found in 29 out of 120 pregnant women (24.2%) in their study regarding platelet counts during pregnancy. These infection rates indicate that the infection rates were slightly different among different Japanese groups with similar age distribution. The seropositivity among patients with infertility at our university hospital was within the range. Because the patients at our university clinic may have been living under higher socioeconomical conditions, which influences seropositivity through good sanitary conditions, control subjects from the general population could not be used in this study. Fertility and Sterility
Figura et al. (7) found that the equatorial zone of spermatozoa, which is a structure that reacts with the oocyte, was particularly reactive with antibodies against H. pylori and that the anti-H. pylori antibody was found in the follicular fluids in all seropositive patients. Therefore, they considered that the anti-H. pylori antibody may prevent spermatozoa from fertilizing the oocyte. In the present study the presence of the anti-H. pylori antibody in the patients without known causes tended to be higher than in the patients with known infertility. The anti-H. pylori antibody over 10 IU/mL was detected in the follicular fluid among 7 out of 11 seropositive patients who received IVF treatment. Therefore, the seven patients could have fertilization problems due to the antibody. Assuming that the antibodies are associated with the mechanism of infertility, seronegative status resulting from H. pylori eradication might lead to improved fertility. Although the present epidemiologic study failed to detect a significant association between H. pylori infection and infertility, it is plausible that H. pylori-related infertility occurs in infertile couples with unknown infertility causes. Because the biologic data support this plausibility, some infertility cases with unknown causes could be due to the H. pylori antibody. As well as a more precise analysis of the link between H. pylori infection and unknown infertility, further biologic studies on the mechanism are needed. Shozo Kurotsuchi, M.D.a Hisao Ando, M.D.a Akira Iwase, M.D.a Yoshiko Ishida, MSb Nobuyuki Hamajima, M.D., Ph.D., M.P.H.b Fumitaka Kikkawa, M.D.a a Department of Obstetrics and Gynecology and Department of Maternal and Perinatal Medicine; and b Department of Preventive Medicine/Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, Nagoya, Japan
REFERENCES 1. Labenz J, Borsch G. Evidence for the essential role of Helicobacter pylori in gastric ulcer disease. Gut 1994;35:19–22. 2. International Agency for Research on Cancer. Infection with Helicobacter pylori. IARC Monogr Eval Carcinog Risks Hum 1994;61: 177–240.
867
3. Fujimura K. Helicobacter pylori infection and idiopathic thrombocytopenic purpura. Int J Hematol 2005;81:113–8. 4. Franchini M, Veneri D. Helicobacter pylori–associated immune thrombocytopenia. Platelets 2006;17:71–7. 5. Moreira A, Rodrigues J, Delgado L, Fonseca J, Vaz M. Is Helicobacter pylori infection associated with chronic idiopathic urticaria? Allergol Immunopathol (Madr) 2003;31:209–14. 6. Federman DG, Kirsner RS, Moriarty JP, Concato J. The effect of antibiotic therapy for patients infected with Helicobacter pylori who have chronic urticaria. J Am Acad Dermatol 2003;49:861–4. 7. Figura N, Piomboni P, Ponzetto A, Gambera L, Lenzi C, Vaira D, et al. Helicobacter pylori infection and infertility. Eur J Gastroenterol Hepatol 2002;14:663–9. 8. Kawai T, Kawakami K, Kudo T, Ogiahara S, Handa Y, Moriyasu F. A new serum antibody test kit (E plate) for evaluation of Helicobacter pylori eradication. Intern Med 2002;41:780–3. 9. Sasazuki S, Inoue M, Iwasaki M, Otani T, Yamamoto S, Ikeda S, et al. Effect of Helicobacter pylori infection combined with CagA and pep-
868
Kurotsuchi et al.
Correspondence
10.
11.
12.
13.
sinogen status on gastric cancer development among Japanese men and women: a nested case-control study. Cancer Epidemiol Biomarkers Prev 2006;15:1341–7. Fukuda S, Shimoyama T, Umegaki N, Mikami T, Nakano H, Munakata A. Effect of Helicobacter pylori eradication in the treatment of Japanese patients with chronic idiopathic urticaria. J Gastroenterol 2004;39:827–30. Iwase A, Ando H, Kuno K, Mizutani S. Use of follicle-stimulating hormone test to predict poor response in in vitro fertilization. Obstet Gynecol 2005;105:645–52. Shimatani T, Inoue M, Iwamoto K, Hyogo H, Yokozaki M, Saeki T, et al. Prevalence of Helicobacter pylori infection, endoscopic gastric findings and dyspeptic symptoms among a young Japanese population born in the 1970s. J Gastroenterol Hepatol 2005;20: 1352–7. Fukui O, Shimoya K, Shimizu T, Fukuda H, Wasada K, Murata Y. Helicobacter pylori infection and platelet counts during pregnancy. Int J Gynaecol Obstet 2005;89:26–30.
Vol. 90, No. 3, September 2008
The bacterium Helicobacter pylori is known as an important cause of gastric diseases, including peptic ulcers and stomach cancer (1, 2). Helicobacter pylori infection may also affect extradigestive diseases, including idiopathic thrombocytopenic purpura (3, 4) and chronic urticaria (5, 6). Figura et al. (7) have hypothesized an antigenic mimicry between bacterial flagella of H. pylori and spermatozoa, the only flagellated human cells, and that the antibodies produced against H. pylori flagella may cross-react with spermatozoon flagella. They have reported that the levels of the anti-H. pylori antibody in serum samples was significantly higher in patients with reproductive disorders than in age-matched control subjects and suggested that H. pylori infection may increase the risk of infertility. For the comparative control group in a case-control study, fertile women are preferable, whose risk factors for H. pylori infection such as year of birth, sanitary conditions during childhood, and social class are known. Because such control women were not available, we compared the seropositivity between infertile women with and without known infertility causes to investigate how much H. pylori infection links with unknown infertility using available retrospective samples. This was a retrospective study including 204 women undergoing infertility treatment at the Department of Obstetrics and Gynecology at Nagoya University Graduate School of Medicine between February 2001 and December 2004. The screening examination for infertility included transvaginal ultrasound, seminal fluid analysis including sperm concentration, motility, and morphology, hysterosalpingography, anti-Chlamydia trachomatis antibodies, antinuclear antibodies, thyroid function test, and determination of FSH, LH, androgen, P, and PRL concentrations. Male factor infertility was diagnosed according to standard World Health Organization semen analyses. If these were within the Received February 6, 2007; revised and accepted June 28, 2007. Reprint requests: Akira Iwase, M.D., Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466–8550, Japan (FAX: 81-52-744-2268; E-mail: [email protected]).
866
normal range, the patients were considered to have unknown etiology. The study was approved by the ethics committee of Nagoya University School of Medicine. A commercially available direct ELISA kit (E Plate Eiken H. Pylori Antibody; Eiken Kagaku, Tokyo, Japan) was used to determine the serum IgG level for H. pylori infection (8–10). The positive status of H. pylori infection was defined as H. pylori IgG antibodies over 10 U/mL in serum. Serum and follicular fluids were obtained during ovarian stimulation and IVF treatment, respectively. The procedures of ovarian stimulation, oocyte retrieval, and standard IVF were performed according to routine protocols as described previously (11). The data were analyzed using the Mann–Whitney U test and Fisher exact test with the software Statistics Package for Social Sciences (SPSS) version 11.0J for Windows (SPSS Japan, Tokyo, Japan). All tests were two-tailed, and significance was accepted at P<.05. Odds ratios were calculated by a logistic regression model using the software Stata version 7 (Stata Corp., College Station, TX). The demographic data for all subjects who received infertility treatment were obtained from the medical records (Table 1). The diagnosed one or two main causes of infertility were as follows (number of patients, percentage): hormonal dysfunction (104, 51.0%), male factor (55, 27.0%),
TABLE 1 Demographic data of the study group. Characteristic Age (yrs) Mean SD Range Primary infertility [n (%)] Secondary infertility [n (%)] Duration of infertility (yrs) Mean SD Range
34.5 5.4 24–44 135 (66.2) 69 (33.8) 3.8 3.7 1–20
Kurotsuchi. Helicobacter pylori and infertility. Fertil Steril 2008.
Fertility and Sterility Vol. 90, No. 3, September 2008 Copyright ª2008 American Society for Reproductive Medicine, Published by Elsevier Inc.
0015-0282/08/$34.00 doi:10.1016/j.fertnstert.2007.06.097
TABLE 2 Cause of infertility and H. pylori status. Cause of infertility Known Unknown Total
H. pylori infected, n
H. pylori uninfected, n
Total, n
37 8 45
146 13 159
183 21 204
P value
0.091
Kurotsuchi. Helicobacter pylori and infertility. Fertil Steril 2008.
uterine factor (37, 18.1%), tubal factor (30, 14.7%), endometriosis (28, 13.7%), and unknown etiology (21, 10.3%). The H. pylori–seropositive rate was 22.1% (45 out of 204 women). The causes of infertility and H. pylori status are summarized in Table 2. The seropositivity was higher in the group of patients who did not have any known causes of infertility (unknown group) than in those who had one or more known causes of infertility (known group), although the difference was not statistically significant (38.3% [8 of 21 patients] vs. 20.2% [37 of 183 patients]; P¼.091). The odds ratio of the seropositivity adjusted for year of birth was 2.16 (95% confidence interval 0.82– 5.70). The titer of anti-H. pylori antibody was not significantly different between the two groups; the median (range) was 48 (11–297) U/mL in the known group and 55.5 (12–154) U/mL in the unknown group (P¼.314). In the titers of anti-H. pylori antibody of serum and follicular fluids in 11 patients who received IVF treatment, the median (range) was 36 (13–297) U/mL and 21 (3–232) U/mL, respectively. Among the 11 seropositive (>10 U/mL) patients, seven had anti-H. pylori antibodies over 10 U/mL in the follicular fluid. In the present study, the H. pylori seropositive rate was 22.1% (45 out of 204 women). Figura et al. (7) reported that the presence of the anti-H.pylori antibody was 60 out of 118 male patients (50.8%) and 22 out of 49 female patients (44.8%) with infertility. The lower incidence in the present study might reflect the improved sanitary conditions for the Japanese subjects in their childhood. Shimatani et al. (12) reported that H. pylori-infected individuals among healthy Japanese born in the 1970s accounted for 73 out of 371 men (19.7%) and 14 out of 159 women (8.8%). Fukui et al. (13) reported that H. pylori infection was found in 29 out of 120 pregnant women (24.2%) in their study regarding platelet counts during pregnancy. These infection rates indicate that the infection rates were slightly different among different Japanese groups with similar age distribution. The seropositivity among patients with infertility at our university hospital was within the range. Because the patients at our university clinic may have been living under higher socioeconomical conditions, which influences seropositivity through good sanitary conditions, control subjects from the general population could not be used in this study. Fertility and Sterility
Figura et al. (7) found that the equatorial zone of spermatozoa, which is a structure that reacts with the oocyte, was particularly reactive with antibodies against H. pylori and that the anti-H. pylori antibody was found in the follicular fluids in all seropositive patients. Therefore, they considered that the anti-H. pylori antibody may prevent spermatozoa from fertilizing the oocyte. In the present study the presence of the anti-H. pylori antibody in the patients without known causes tended to be higher than in the patients with known infertility. The anti-H. pylori antibody over 10 IU/mL was detected in the follicular fluid among 7 out of 11 seropositive patients who received IVF treatment. Therefore, the seven patients could have fertilization problems due to the antibody. Assuming that the antibodies are associated with the mechanism of infertility, seronegative status resulting from H. pylori eradication might lead to improved fertility. Although the present epidemiologic study failed to detect a significant association between H. pylori infection and infertility, it is plausible that H. pylori-related infertility occurs in infertile couples with unknown infertility causes. Because the biologic data support this plausibility, some infertility cases with unknown causes could be due to the H. pylori antibody. As well as a more precise analysis of the link between H. pylori infection and unknown infertility, further biologic studies on the mechanism are needed. Shozo Kurotsuchi, M.D.a Hisao Ando, M.D.a Akira Iwase, M.D.a Yoshiko Ishida, MSb Nobuyuki Hamajima, M.D., Ph.D., M.P.H.b Fumitaka Kikkawa, M.D.a a Department of Obstetrics and Gynecology and Department of Maternal and Perinatal Medicine; and b Department of Preventive Medicine/Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, Nagoya, Japan
REFERENCES 1. Labenz J, Borsch G. Evidence for the essential role of Helicobacter pylori in gastric ulcer disease. Gut 1994;35:19–22. 2. International Agency for Research on Cancer. Infection with Helicobacter pylori. IARC Monogr Eval Carcinog Risks Hum 1994;61: 177–240.
867
3. Fujimura K. Helicobacter pylori infection and idiopathic thrombocytopenic purpura. Int J Hematol 2005;81:113–8. 4. Franchini M, Veneri D. Helicobacter pylori–associated immune thrombocytopenia. Platelets 2006;17:71–7. 5. Moreira A, Rodrigues J, Delgado L, Fonseca J, Vaz M. Is Helicobacter pylori infection associated with chronic idiopathic urticaria? Allergol Immunopathol (Madr) 2003;31:209–14. 6. Federman DG, Kirsner RS, Moriarty JP, Concato J. The effect of antibiotic therapy for patients infected with Helicobacter pylori who have chronic urticaria. J Am Acad Dermatol 2003;49:861–4. 7. Figura N, Piomboni P, Ponzetto A, Gambera L, Lenzi C, Vaira D, et al. Helicobacter pylori infection and infertility. Eur J Gastroenterol Hepatol 2002;14:663–9. 8. Kawai T, Kawakami K, Kudo T, Ogiahara S, Handa Y, Moriyasu F. A new serum antibody test kit (E plate) for evaluation of Helicobacter pylori eradication. Intern Med 2002;41:780–3. 9. Sasazuki S, Inoue M, Iwasaki M, Otani T, Yamamoto S, Ikeda S, et al. Effect of Helicobacter pylori infection combined with CagA and pep-
868
Kurotsuchi et al.
Correspondence
10.
11.
12.
13.
sinogen status on gastric cancer development among Japanese men and women: a nested case-control study. Cancer Epidemiol Biomarkers Prev 2006;15:1341–7. Fukuda S, Shimoyama T, Umegaki N, Mikami T, Nakano H, Munakata A. Effect of Helicobacter pylori eradication in the treatment of Japanese patients with chronic idiopathic urticaria. J Gastroenterol 2004;39:827–30. Iwase A, Ando H, Kuno K, Mizutani S. Use of follicle-stimulating hormone test to predict poor response in in vitro fertilization. Obstet Gynecol 2005;105:645–52. Shimatani T, Inoue M, Iwamoto K, Hyogo H, Yokozaki M, Saeki T, et al. Prevalence of Helicobacter pylori infection, endoscopic gastric findings and dyspeptic symptoms among a young Japanese population born in the 1970s. J Gastroenterol Hepatol 2005;20: 1352–7. Fukui O, Shimoya K, Shimizu T, Fukuda H, Wasada K, Murata Y. Helicobacter pylori infection and platelet counts during pregnancy. Int J Gynaecol Obstet 2005;89:26–30.
Vol. 90, No. 3, September 2008