- Email: [email protected]
Monoclonal antibodies in the characterization of human T and large granular lymphocytes
Monoclonal Antibodies in the Characterization of Human T and Large Granular Lymphocytes* Fernando Aiuti, M.D. Franco Pandolfi, M.D. Department of Clinical bnmunology, Universitd delia Sapienza, Rome 00161, Italy In recent years, the development of monoclonal antibodies against human lymphocytes has brought considerable insight into the complex network of different subpopulations which interact and are required for a proper immunological response. The quantity of data thus obtained has elucidated the relationship pattern between discrete subpopulations present in normal donors and alterations observed in many pathological conditions. A careful interpretation of these results is required. For instance, the most frequent erroneous assumption is that of considering the expansion of a given antigen as strictly related to the capacity of the positive cell of performing a given function. Several antigens that are identified by monoclonal reagents have been described on human T cells, and T-cell subpopulations are capable of mediating different regulatory functions such as helper, suppression, or B-cell differentiation. Helper T cells are included in subpopulations identified by some monoclonal reagents (i.e., Leu 3a or OKT4), but this does not necessarily mean that all the normal Leu 3a + or OKT4 + cells are helper cells. In addition, the issue is complicated by the fact that in pathological conditions (such as lymphoproliferative disorders or in primary immunodeficiencies) the expression of these antigens or the ability to perform a given function may be altered by the disease. With such limitations, however, monoclonal antibodies are helpful reagents for basic and clinical immunologists. In this review we will * Supported by a grant from the "Ministero della Pubblica Istruzione, Ricerca Scientifica" 1981.
32
focus on human T cells and large granular lymphocytes (LGL) as identified by monoclonal reagents in normal donors and in some pathological conditions.
Identification of T Cells and Large G r a n u l a r L y m p h o c y t e s in Normal Donors Current terminology refers to the cells of thymic origin situated in the secondary lymphoid organs as peripheral T lymphocytes, and thymic cells are usually referred to as thymocytes. Large granular lymphocytes are medium to large size lymphocytes with azurophilic granules in their cytoplasm which mediate natural killer activity. Thus far, no conclusive evidence has been obtained demonstrating that LGL belong to any of the known hemic lineages. Since these cells share some surface markers with T lymphocytes and monocytes, it has been postulated that they may belong to the T lineage, the myelomonocytic lineage, or to a separate cell lineage. T Lymphocytes Three main groups of monoclonal reagents directed against antigens expressed by T cells have been devel-
oped (Table I). The first group includes antigens expressed by all the thymocytes and peripheral T cells. Some reagents in this group (9.6 and OKTI 1) (2) are directed against the membrane receptor for sheep erythrocytes which mediates the function of E-rosettes by T ceils. Others (10.2 and Leu 1) identify a separate antigen. The second group consists of monoclonal antibodies that identify antigens expressed on many thymocytes and on a subpopulation of peripheral T cells. These reagents are of particular importance because among these subpopulations are restricted ceils with immunoregulatory functions. Thus, helper T cells are comprised among OKT4, 9.3, and Leu 3a cells, whereas suppressor T cells are restricted to OKT5, OKT8, and Leu 2a cells. Another commonly used is reagent 3A1. Among 3A1 cells are comprised helper and inducible suppressor T cells. A different issue is represented by antigens expressed by T cells at early differentiation stages. For instance, OKT6 recognizes an antigen present on thymocytes but not on mature peripheral T lymphocytes.
Table 1
Antigens Recognized by Monoclonal Antibodies Expressed by Human T Cells Designation
Molecular Weight
% Thymocytes
%'Peripheral T Cells
First group (all thymocytes and peripheral T cells) 9.6 50,000 100 100 OKT I 1 I0.2 67,000 100 100 Leu 1 66,000 100 I00 Second group (minority of thymoeytes and all peripheral T cells) Leu 4 20-30,000 80 95 OKTI 65,000 10 100 OKT3 19,000 20 95 UCTH 1 -40 95 Third group (many thymocytes and a subpopulation of T cells) OKT4 62,000 90 65 9.3 44,000 40 65 Leu 3a 55,000 80 50 OKT5 32,000 90 20 OKT8 33,000 90 30 Leu 2a 32-42,000 80 25 3AI 40,000 100 85
Notes Sheep receptor
Helper T cells
Suppressor T cells Helper and inducible T cells
ClinicalImmunologyNewsletter
Large Granular Lymphocytes Human LGL are characterized by the following criteria (8): By light and electrbn microscopy they appear as medium to large size lymphocytes with cytoplasmic azurophilic granules. They are positive for acid hydrolases and negative for peroxidase. Functionally, these cells mediate natural killer (NK) activity, while being nonphagocytic. The characterization of these cells by surface markers (1 I) is an intriguing issue since LGL are a heterogeneous population. The vast majority of LGL have receptors for the Fc portion of IgG and about half of them form E-rosettes. A study with monoclonal antibodies has demonstrated that these cells share reactivity with some T-7 cell reagents (OKT8, Leu 2a, OKT10, 3A1) and some myelomonocytic reagents (OKM1), and that they are positive with monoclonal antibodies directed against antigens apparently specific for LGL (Leu 7) (1). The Role of Monoclonal Antibodies in Clinical Immunology In recent years, the possibility of identifying functionally active T-cell subpopulations in humans has raised considerable interest in the study of several clinical conditions. Imbalances, abnormal proliferations, or re-
duction of a given T-cell subset may represent an important step in the pathogenesis of some diseases. Furthermore, immunological monitoring may help in the diagnosis or in the follow-up of a number of patients. Thus, the application of monoclonal antibodies in the monitoring of patients with different diseases has encountered an increasing use and abuse. While the correct indication of when to perform the study of T-cell subsets with monoclonal antibodies is the aim of this article, we would like to focus briefly on two main disorders in which monoclonal reagents against T-cell subpopulations are chiefly applied, i.e., lymphoproliferative disorders and primary immunodeficiencies.
T- and LGL-Lymphoproliferative Disorders It is well demonstrated that lymphoid malignancies may be classified on the basis of the immunological characterization of neoplastic cells. The advent of monoclonal antibodies to T-cell subsets has greatly increased our knowledge of these diseases and permits a careful definition of the maturity of proliferating cells. Thus, it has been shown that T acute lymphoblastic leukemia (T-ALL) and T lymphoblastic lymphoma (T-LL) are characterized by immature T cells
with a thymic phenotype (7). All the degrees of T-cell differentiation have been shown in different patients and may be summarized in three main groups (Table 2): early, common, and late thymic cells. These diseases have an aggressive clinical course and a bad prognosis. T chronic leukemias, although rare, have raised considerable interest since these diseases are characterized by the proliferation of mature T-lymphocytes often capable of functional activities. In this group are included: a) adult T-cell leukemia (ATL) (15), originally described in Japan, an aggressive disease originated by OKT3 ÷, OKT4 ÷, and OKT8- cells which usually have in vitro suppressor activity. Recently, these patients have been shown to have some antibodies against a new type-C retrovirus which may be implicated in the pathogenesis of the disease (10). b) T chronic lymphocytic leukemia (T-CLL) often shows persistent bone marrow and T lymphocytosis as its main manifestation and a quite favorable and extremely chronic course. Since monoclonality of the expanded population is difficult to prove, its recognition as a malignant condition has lately been questioned. However, monoclonal antibodies have shown the proliferation of some populations of T helper or T suppressor phenotype cells
Table 2 Pattern of Reactivity wP.h Monoclonal Antibodies of Human Leukemic T Cells OKT3
T acute lymphoblastic leukemia (T-ALL) and T lymphoblastic lymphoma (T-LL) Early Common Late Form a* Form bt Adult T cell leukemia (ATL) T chronic lymphocytic leukemia (T-CLL) Form a Form b Cutaneous T cell lymphoma (CTCL) T Prolymphocytic leukemia (T-PLL) Form a Form b * a = f o r m w i t h O K T 4 proliferating cells.
O 1983 by Elsevier Science Publishing Co., Inc.
OKT4
OKT8
OKT6
3A1
+ +
+ +
+
+ +
+ + +
+ -+
-+ -
_ -_
+ + .9
+ + +
+ +
+ -
_
+ or + or +
+
d~.
M
-I-
--
+
+ +
? .9
t b = form with OKT8 proliferatingcells.
33
(12). c) In cutaneous T-cell lymphoma, the malignant cell is a mature OKT3 +, OKT4 +, OKT8-, or 3A1 ÷ T lymphocyte with a characteristic marked convoluted nucleus. These ceils often exert in vitro helper activity (9). d) T prolymphocytic leukemia (T-PLL) is characterized by the presence of T ceils with a prominent nucleus in the presence of some degrees of peripheral nuclear chromatic condensation. Clinically, these patients have spleen involvement and short survival. The immunological characterization shows a rather immature T cell (5). Cases of leukemia-lymphoma sustained by LGL have been recently described and reflect the heterogeneity of this subpopulation (12, 14).
A
HAEMATOPOIETIC STEM CELLS
COMPLETE $CID
B SCID WITH B-LYMPHOCYTES AND MONOCYTES
IMMATURE THYMOCY;E /-.,T "~-:~-7,',f ~ 6 ,l
"T"
C - SCID WITH IMMATURE THYMOCYTES
-~'.T 9 ' 1 : . T 10 .i.t
COMMON THYMOCYTE
: T
D SCID WITH COMMON THYMOCYTES
~ T I0 :~:
T-Cell Differentiation and P r i m a r y T - C e l l Defects In Figure 1 we report a modification of a proposed scheme (4) of human T-cell differentiation. This scheme is based on normal T-cell differentiation (6) and reported cases of T-cell defects. Possible levels of block (arrows) that have been described in the literature or observed in our laboratory are shown. According to this model, T-cell subsets are characterized by a block of the normal T-cell differentiation at a given step. The first block may occur at the stem cell level, where the defect causes the lymphoreticular dysgenesia and classical severe combined immunodeficiency (SCID) with absence of both T and B cells (level A). Subsequent levels of possible T-cell defects are indicated at the different steps of Tcell maturation. Three forms of SCID may be thus identified: with B cells and monocytes, with immature thymocytes, and with common thymocytes (3). From this point the subsequent maturation takes two clear-cut routes. On one hand, cells lose the T5-8 antigens and express the T4 phenotype of ;mmature (T10 +) or mature (TI0-) helper phenotype T cells; on the other hand, a loss of the T4 antigen or T5-8 + cells indicates the phenotype of immature (Tl0-) or
34
EFG
MATURE THYMOCYTE
VARIABLE T C E L L DEFECTS (DI George - p a r t i a l n i G e o r g e or Nezelof)
H PERIFERAL
FUNCTIONAL T CELL D AND OR UNBALANCE OF T- SUBPOPULATIONS
BLOOD
LYMPHOCYTE
H Figure 1. Proposed scheme of human T-cell differentiation.
mature T10- cytotoxic suppressor T cells. A selective defect of T4 + or T8 ÷ cells has been reported in patients with DiGeorge syndrome or with other forms of immunodeficiency (E, F, G). Another point which may be relevant is the functional balance of T-cell subpopulations as identified by monoclonal antibodies (H). It has been shown that about one-third of the patients with common variable hypogammaglobulinemia have a consistent reversal of the physiological. ratio between OKT4 and OKT8 cells (13) and this immunoregulatory disturbance may be relevant in the pathogenesis of the disease at least in some patients. In conclusion, we believe that the study of patients with lympho-
proliferative or with primary immunodeficiency has been of extraordinary importance in our understanding of how normal systems differntiate and operate. These new findings may also provide insight for new approaches in the reconstitution of the immunologic system especially in patients with primary immune defects (Aiuti et al., in preparation).
References I. Abo, T., and C. M. Balch. 1981. A differentiation antigen of human NK and K cells identified by a monoclonal antibody (HNK-1). J. Immunol. 127:1024-1029. 2. Aiuti, F. 1982. Gli anticorpi monoclonali nella caratterizzazione delle cellule mononucleate umane. Immunol. Clin. Sper. 1:11-34.
Clinical Immunology Newsletter
3. Aiuti, F., et al. 1983. Monoclonal antibody analysis of T cell subsets in 40 patients with immunodeficiencies. J. Clin. Immunol. (in press). 4. Aiutl, F., and F. Pandolfi. 1982. The role of T lymphocytes in the pathogenesis of primary immunodeficiencies. Thymus 4:257-264. 5. Costello C., et al. 1980. Chronic T-cell leukemias. I. Morphology, cytochemistry and ultrastructure. Leukemia Res. 4:463-476. 6. Ellis, L., et al. 1980. Human immunodeficiency states resulting from disorders of T cell maturation and regulation, pp. 109-117. h~ M. Seligmann and W. H. Hitzig (eds.), Inserm Symposium N. 16. Elsevier/ North Holland Biomedical Press, Amsterdam. 7. Greaves M. F., et al. 1981. Phenotypic heterogeneity and cellular
8.
9.
I0.
11.
origins of T cell malignancies. Leukemia Res. 5:281-299. Grossi, C. E., et al. 1982. Large granular lymphocytes in human peripheral blood. Ultrastruetural and cytochemieal characterization of the granules. Blood 59:277-283. Haynes, B. F., et ai. 1981. Phenotypie characterization of cutaneous T cell lymphoma. Use of monoclonal antibodies to compare with other malignant T cells. N. Engl. J. Med. 304:1319-1323. Hinuma, Y., et ai. 1981. Adult Tcell leukemia: antigen in an ATL cell line and detection of antibodies to the antigen in human sera. Proc. Natl. 78:6476-6480. Ortaldo, J. R., et al. 1981. Determination of surface antigens of highly purified human NK cells by flow cytometry with monoclonal antibodies. J. Immunol. 127:2400-2409.
12. Pandolfi, F., et al. 1982. Immunologic evaluation of T chronic lymphocyte leukemia ceils: correlations among phenotype, functional activities and morphology. Blood 4:688-695. 13. Pandolfi, F., et al. 1982. Abnormalities of regulatory T-cell subpopulations in patients with primary immunoglobulin deficiencies. Clin. Immunol. Immunopathol. 22:323-330. 14. Pandolfi, F., et al. 1982. A population of sheep rosetting cells lacking T- and monocytie-specific antigens, as detected by monoclonal antibodies. Clin. Immunol. Immunopathol. 22:331-339. 15. Uchiyama, T., et al. 1977. Adult T-cell leukemia: clinical and hematologic features of 16 cases. Blood 50:481-492.
Editors' Corner
It is anticipated that every issue of the Clinical Immunology Newsletter for 1983 will consist of articles revolving around a central theme. Among areas of interest which will be covered in future issues are diabetes, legionellosis, acquired immunodeficiency syndrome as well as interferons, transplantation, cancer, inflammation, immunomodulation, and many others. Each of these areas will deal with theoretical as well as practical aspects of clinical immunology including, if at all possible, recent reports of international meetings and workshops and pertinent clinical case studies. The basic concept that threads the three major articles appearing in this issue of the Newsletter is that of using specific reagents for the identification of mononuclear leukocyte subpopulations. Although the present vogue of recombinant DNA technology has somewhat overshadowed hybridoma technology, the latter represents a development of equal promise. The recent commercial availability of monoclonal antibodies brings them to
(~) 1983 by ElsevierScience PublishlngCo., Inc.
the reach of clinical immunologists for research, diagnostic, and therapeutic purposes. Doctors Si and Whiteside describe the merits of the avidin-biotinperoxidase technique as applied to the immunophenotyping of lymphoid cells in situ. They emphasize, without exaggeration, the need for establishing a correlation between the numbers of mononuclear cell subpopulations depicted in tissues and those observed in the peripheral circulation as well as the value of interpreting pertinent findings to confirm a histopathologic diagnosis. Doctors Aiuti and Pandolfi discuss the use of monoclonal antibodies in the characterization of human T and large granular lymphocytes. They go one step further and provide us with a word of caution when assuming that the expression of a given antigen on the surface of a certain lymphoid cell subpopulation is strictly related to its regulatory function. In contrast, Dr. Kleinman has contributed greatly in reviving an old observation on bacterial adherence.
Thanks to the present knowledge which has emerged as a result of giant strides in the field of hybridoma technology it is now possible, as demonstrated by Dr. Kleinman, to assess the value of bacteria as tools for the identification of human lymphocytes and in probing host natural resistance. We hope that subsequent developments along these lines will not only contribute to a basic understanding of normal immune functions and immunopathologic mechanisms, but will also be of practical importance to the clinical laboratory immunologist. M.R.E.
35
32
focus on human T cells and large granular lymphocytes (LGL) as identified by monoclonal reagents in normal donors and in some pathological conditions.
Identification of T Cells and Large G r a n u l a r L y m p h o c y t e s in Normal Donors Current terminology refers to the cells of thymic origin situated in the secondary lymphoid organs as peripheral T lymphocytes, and thymic cells are usually referred to as thymocytes. Large granular lymphocytes are medium to large size lymphocytes with azurophilic granules in their cytoplasm which mediate natural killer activity. Thus far, no conclusive evidence has been obtained demonstrating that LGL belong to any of the known hemic lineages. Since these cells share some surface markers with T lymphocytes and monocytes, it has been postulated that they may belong to the T lineage, the myelomonocytic lineage, or to a separate cell lineage. T Lymphocytes Three main groups of monoclonal reagents directed against antigens expressed by T cells have been devel-
oped (Table I). The first group includes antigens expressed by all the thymocytes and peripheral T cells. Some reagents in this group (9.6 and OKTI 1) (2) are directed against the membrane receptor for sheep erythrocytes which mediates the function of E-rosettes by T ceils. Others (10.2 and Leu 1) identify a separate antigen. The second group consists of monoclonal antibodies that identify antigens expressed on many thymocytes and on a subpopulation of peripheral T cells. These reagents are of particular importance because among these subpopulations are restricted ceils with immunoregulatory functions. Thus, helper T cells are comprised among OKT4, 9.3, and Leu 3a cells, whereas suppressor T cells are restricted to OKT5, OKT8, and Leu 2a cells. Another commonly used is reagent 3A1. Among 3A1 cells are comprised helper and inducible suppressor T cells. A different issue is represented by antigens expressed by T cells at early differentiation stages. For instance, OKT6 recognizes an antigen present on thymocytes but not on mature peripheral T lymphocytes.
Table 1
Antigens Recognized by Monoclonal Antibodies Expressed by Human T Cells Designation
Molecular Weight
% Thymocytes
%'Peripheral T Cells
First group (all thymocytes and peripheral T cells) 9.6 50,000 100 100 OKT I 1 I0.2 67,000 100 100 Leu 1 66,000 100 I00 Second group (minority of thymoeytes and all peripheral T cells) Leu 4 20-30,000 80 95 OKTI 65,000 10 100 OKT3 19,000 20 95 UCTH 1 -40 95 Third group (many thymocytes and a subpopulation of T cells) OKT4 62,000 90 65 9.3 44,000 40 65 Leu 3a 55,000 80 50 OKT5 32,000 90 20 OKT8 33,000 90 30 Leu 2a 32-42,000 80 25 3AI 40,000 100 85
Notes Sheep receptor
Helper T cells
Suppressor T cells Helper and inducible T cells
ClinicalImmunologyNewsletter
Large Granular Lymphocytes Human LGL are characterized by the following criteria (8): By light and electrbn microscopy they appear as medium to large size lymphocytes with cytoplasmic azurophilic granules. They are positive for acid hydrolases and negative for peroxidase. Functionally, these cells mediate natural killer (NK) activity, while being nonphagocytic. The characterization of these cells by surface markers (1 I) is an intriguing issue since LGL are a heterogeneous population. The vast majority of LGL have receptors for the Fc portion of IgG and about half of them form E-rosettes. A study with monoclonal antibodies has demonstrated that these cells share reactivity with some T-7 cell reagents (OKT8, Leu 2a, OKT10, 3A1) and some myelomonocytic reagents (OKM1), and that they are positive with monoclonal antibodies directed against antigens apparently specific for LGL (Leu 7) (1). The Role of Monoclonal Antibodies in Clinical Immunology In recent years, the possibility of identifying functionally active T-cell subpopulations in humans has raised considerable interest in the study of several clinical conditions. Imbalances, abnormal proliferations, or re-
duction of a given T-cell subset may represent an important step in the pathogenesis of some diseases. Furthermore, immunological monitoring may help in the diagnosis or in the follow-up of a number of patients. Thus, the application of monoclonal antibodies in the monitoring of patients with different diseases has encountered an increasing use and abuse. While the correct indication of when to perform the study of T-cell subsets with monoclonal antibodies is the aim of this article, we would like to focus briefly on two main disorders in which monoclonal reagents against T-cell subpopulations are chiefly applied, i.e., lymphoproliferative disorders and primary immunodeficiencies.
T- and LGL-Lymphoproliferative Disorders It is well demonstrated that lymphoid malignancies may be classified on the basis of the immunological characterization of neoplastic cells. The advent of monoclonal antibodies to T-cell subsets has greatly increased our knowledge of these diseases and permits a careful definition of the maturity of proliferating cells. Thus, it has been shown that T acute lymphoblastic leukemia (T-ALL) and T lymphoblastic lymphoma (T-LL) are characterized by immature T cells
with a thymic phenotype (7). All the degrees of T-cell differentiation have been shown in different patients and may be summarized in three main groups (Table 2): early, common, and late thymic cells. These diseases have an aggressive clinical course and a bad prognosis. T chronic leukemias, although rare, have raised considerable interest since these diseases are characterized by the proliferation of mature T-lymphocytes often capable of functional activities. In this group are included: a) adult T-cell leukemia (ATL) (15), originally described in Japan, an aggressive disease originated by OKT3 ÷, OKT4 ÷, and OKT8- cells which usually have in vitro suppressor activity. Recently, these patients have been shown to have some antibodies against a new type-C retrovirus which may be implicated in the pathogenesis of the disease (10). b) T chronic lymphocytic leukemia (T-CLL) often shows persistent bone marrow and T lymphocytosis as its main manifestation and a quite favorable and extremely chronic course. Since monoclonality of the expanded population is difficult to prove, its recognition as a malignant condition has lately been questioned. However, monoclonal antibodies have shown the proliferation of some populations of T helper or T suppressor phenotype cells
Table 2 Pattern of Reactivity wP.h Monoclonal Antibodies of Human Leukemic T Cells OKT3
T acute lymphoblastic leukemia (T-ALL) and T lymphoblastic lymphoma (T-LL) Early Common Late Form a* Form bt Adult T cell leukemia (ATL) T chronic lymphocytic leukemia (T-CLL) Form a Form b Cutaneous T cell lymphoma (CTCL) T Prolymphocytic leukemia (T-PLL) Form a Form b * a = f o r m w i t h O K T 4 proliferating cells.
O 1983 by Elsevier Science Publishing Co., Inc.
OKT4
OKT8
OKT6
3A1
+ +
+ +
+
+ +
+ + +
+ -+
-+ -
_ -_
+ + .9
+ + +
+ +
+ -
_
+ or + or +
+
d~.
M
-I-
--
+
+ +
? .9
t b = form with OKT8 proliferatingcells.
33
(12). c) In cutaneous T-cell lymphoma, the malignant cell is a mature OKT3 +, OKT4 +, OKT8-, or 3A1 ÷ T lymphocyte with a characteristic marked convoluted nucleus. These ceils often exert in vitro helper activity (9). d) T prolymphocytic leukemia (T-PLL) is characterized by the presence of T ceils with a prominent nucleus in the presence of some degrees of peripheral nuclear chromatic condensation. Clinically, these patients have spleen involvement and short survival. The immunological characterization shows a rather immature T cell (5). Cases of leukemia-lymphoma sustained by LGL have been recently described and reflect the heterogeneity of this subpopulation (12, 14).
A
HAEMATOPOIETIC STEM CELLS
COMPLETE $CID
B SCID WITH B-LYMPHOCYTES AND MONOCYTES
IMMATURE THYMOCY;E /-.,T "~-:~-7,',f ~ 6 ,l
"T"
C - SCID WITH IMMATURE THYMOCYTES
-~'.T 9 ' 1 : . T 10 .i.t
COMMON THYMOCYTE
: T
D SCID WITH COMMON THYMOCYTES
~ T I0 :~:
T-Cell Differentiation and P r i m a r y T - C e l l Defects In Figure 1 we report a modification of a proposed scheme (4) of human T-cell differentiation. This scheme is based on normal T-cell differentiation (6) and reported cases of T-cell defects. Possible levels of block (arrows) that have been described in the literature or observed in our laboratory are shown. According to this model, T-cell subsets are characterized by a block of the normal T-cell differentiation at a given step. The first block may occur at the stem cell level, where the defect causes the lymphoreticular dysgenesia and classical severe combined immunodeficiency (SCID) with absence of both T and B cells (level A). Subsequent levels of possible T-cell defects are indicated at the different steps of Tcell maturation. Three forms of SCID may be thus identified: with B cells and monocytes, with immature thymocytes, and with common thymocytes (3). From this point the subsequent maturation takes two clear-cut routes. On one hand, cells lose the T5-8 antigens and express the T4 phenotype of ;mmature (T10 +) or mature (TI0-) helper phenotype T cells; on the other hand, a loss of the T4 antigen or T5-8 + cells indicates the phenotype of immature (Tl0-) or
34
EFG
MATURE THYMOCYTE
VARIABLE T C E L L DEFECTS (DI George - p a r t i a l n i G e o r g e or Nezelof)
H PERIFERAL
FUNCTIONAL T CELL D AND OR UNBALANCE OF T- SUBPOPULATIONS
BLOOD
LYMPHOCYTE
H Figure 1. Proposed scheme of human T-cell differentiation.
mature T10- cytotoxic suppressor T cells. A selective defect of T4 + or T8 ÷ cells has been reported in patients with DiGeorge syndrome or with other forms of immunodeficiency (E, F, G). Another point which may be relevant is the functional balance of T-cell subpopulations as identified by monoclonal antibodies (H). It has been shown that about one-third of the patients with common variable hypogammaglobulinemia have a consistent reversal of the physiological. ratio between OKT4 and OKT8 cells (13) and this immunoregulatory disturbance may be relevant in the pathogenesis of the disease at least in some patients. In conclusion, we believe that the study of patients with lympho-
proliferative or with primary immunodeficiency has been of extraordinary importance in our understanding of how normal systems differntiate and operate. These new findings may also provide insight for new approaches in the reconstitution of the immunologic system especially in patients with primary immune defects (Aiuti et al., in preparation).
References I. Abo, T., and C. M. Balch. 1981. A differentiation antigen of human NK and K cells identified by a monoclonal antibody (HNK-1). J. Immunol. 127:1024-1029. 2. Aiuti, F. 1982. Gli anticorpi monoclonali nella caratterizzazione delle cellule mononucleate umane. Immunol. Clin. Sper. 1:11-34.
Clinical Immunology Newsletter
3. Aiuti, F., et al. 1983. Monoclonal antibody analysis of T cell subsets in 40 patients with immunodeficiencies. J. Clin. Immunol. (in press). 4. Aiutl, F., and F. Pandolfi. 1982. The role of T lymphocytes in the pathogenesis of primary immunodeficiencies. Thymus 4:257-264. 5. Costello C., et al. 1980. Chronic T-cell leukemias. I. Morphology, cytochemistry and ultrastructure. Leukemia Res. 4:463-476. 6. Ellis, L., et al. 1980. Human immunodeficiency states resulting from disorders of T cell maturation and regulation, pp. 109-117. h~ M. Seligmann and W. H. Hitzig (eds.), Inserm Symposium N. 16. Elsevier/ North Holland Biomedical Press, Amsterdam. 7. Greaves M. F., et al. 1981. Phenotypic heterogeneity and cellular
8.
9.
I0.
11.
origins of T cell malignancies. Leukemia Res. 5:281-299. Grossi, C. E., et al. 1982. Large granular lymphocytes in human peripheral blood. Ultrastruetural and cytochemieal characterization of the granules. Blood 59:277-283. Haynes, B. F., et ai. 1981. Phenotypie characterization of cutaneous T cell lymphoma. Use of monoclonal antibodies to compare with other malignant T cells. N. Engl. J. Med. 304:1319-1323. Hinuma, Y., et ai. 1981. Adult Tcell leukemia: antigen in an ATL cell line and detection of antibodies to the antigen in human sera. Proc. Natl. 78:6476-6480. Ortaldo, J. R., et al. 1981. Determination of surface antigens of highly purified human NK cells by flow cytometry with monoclonal antibodies. J. Immunol. 127:2400-2409.
12. Pandolfi, F., et al. 1982. Immunologic evaluation of T chronic lymphocyte leukemia ceils: correlations among phenotype, functional activities and morphology. Blood 4:688-695. 13. Pandolfi, F., et al. 1982. Abnormalities of regulatory T-cell subpopulations in patients with primary immunoglobulin deficiencies. Clin. Immunol. Immunopathol. 22:323-330. 14. Pandolfi, F., et al. 1982. A population of sheep rosetting cells lacking T- and monocytie-specific antigens, as detected by monoclonal antibodies. Clin. Immunol. Immunopathol. 22:331-339. 15. Uchiyama, T., et al. 1977. Adult T-cell leukemia: clinical and hematologic features of 16 cases. Blood 50:481-492.
Editors' Corner
It is anticipated that every issue of the Clinical Immunology Newsletter for 1983 will consist of articles revolving around a central theme. Among areas of interest which will be covered in future issues are diabetes, legionellosis, acquired immunodeficiency syndrome as well as interferons, transplantation, cancer, inflammation, immunomodulation, and many others. Each of these areas will deal with theoretical as well as practical aspects of clinical immunology including, if at all possible, recent reports of international meetings and workshops and pertinent clinical case studies. The basic concept that threads the three major articles appearing in this issue of the Newsletter is that of using specific reagents for the identification of mononuclear leukocyte subpopulations. Although the present vogue of recombinant DNA technology has somewhat overshadowed hybridoma technology, the latter represents a development of equal promise. The recent commercial availability of monoclonal antibodies brings them to
(~) 1983 by ElsevierScience PublishlngCo., Inc.
the reach of clinical immunologists for research, diagnostic, and therapeutic purposes. Doctors Si and Whiteside describe the merits of the avidin-biotinperoxidase technique as applied to the immunophenotyping of lymphoid cells in situ. They emphasize, without exaggeration, the need for establishing a correlation between the numbers of mononuclear cell subpopulations depicted in tissues and those observed in the peripheral circulation as well as the value of interpreting pertinent findings to confirm a histopathologic diagnosis. Doctors Aiuti and Pandolfi discuss the use of monoclonal antibodies in the characterization of human T and large granular lymphocytes. They go one step further and provide us with a word of caution when assuming that the expression of a given antigen on the surface of a certain lymphoid cell subpopulation is strictly related to its regulatory function. In contrast, Dr. Kleinman has contributed greatly in reviving an old observation on bacterial adherence.
Thanks to the present knowledge which has emerged as a result of giant strides in the field of hybridoma technology it is now possible, as demonstrated by Dr. Kleinman, to assess the value of bacteria as tools for the identification of human lymphocytes and in probing host natural resistance. We hope that subsequent developments along these lines will not only contribute to a basic understanding of normal immune functions and immunopathologic mechanisms, but will also be of practical importance to the clinical laboratory immunologist. M.R.E.
35