Characteristics of anti-T-cell antibodies in systemic lupus erythematosus: evidence for selective reactivity with normal suppressor cells defined by monoclonal antibodies

Lymphocytotoxic antibodies in SLE: a review of the literature

In a great majority of patients with systemic lupus erythematosus (SLE) lymphocytotoxic antibodies (LCA) are detected. The reported prevalence depends on the methods of detection and definition of test-positivity. The pathogenetic role of LCA remains unclear. Different reports show that LCA can have an influence on mononuclear cell function, e.g., on production of interferon, or specifically on T-cell function. In several studies T-cell specificity of LCA cannot be shown. Sometimes an overlap between LCA and anti-B2M antibodies is found, suggesting that LCA have anti-B2M activity. Anti-B2M activity might have an impact on T-cell as well as on B cell function. Next to the anti-B2M activity, binding to nuclear material is claimed. Investigating the role of LCA in respect to lymphopenia, a direct relationship cannot be found; however, LCA might induce interferon production, resulting in lymphopenia. Several studies show or claim a relationship between the presence of LCA and neurological manifestations in SLE patients; the results, however, remain questionable due to the difference in detection methods as well as in definition of central nervous system (CNS) involvement. In other studies, an increased incidence of LCA is reported in relatives of SLE patients as well. In addition, LCA are reported in quite a lot of other diseases such as rheumatoid arthritis, ankylosing spondylitis, malignancies and viral illnesses. This latter association has led to the assumption that LCA might have a virus-related origin.

Changes in subset specificity of anti-T cell autoantibodies in systemic lupus erythematosus

Relative reactivity of anti-lymphocyte autoantibodies (ALA) from patients with systemic lupus erythematosus (SLE) against CD4+ and CD8+ T cells was studied using C-dependent microcytotoxicity assay. Of 46 SLE sera screened for anti-T cell autoantibodies, 27 sera (59%) showed significant cytotoxic reactivity. Of these, positive correlation between the titer of anti-T cell antibody and CD4/CD8 killing ratio (p < 0.01) was demonstrated. In time course study of individual patients, the CD4/CD8 killing ratio increased and decreased as the disease flared and subsided and was accompanied by parallel changes in the titer of anti-T cell antibody titer. Moreover, as sera were serially diluted, the CD4/CD8 killing ratio decreased in 5 out of 10 sera. These results suggest that discrepancy among reports concerning the subset specificity of anti-T cell antibodies may be due, in part, to differences in the titer of ALA in the sera studied and to the dilution of serum used.

Defective CD2 pathway T cell activation in systemic lupus erythematosus

CD2 (T11; sheep erythrocyte receptor) is the surface component of an alternative, antigen-independent pathway of human T cell activation. The response to certain anti-CD2 antibodies is relatively independent of accessory cell signals and therefore provides a direct measurement of T cell function. The CD2 pathway may be important in the differentiation of thymocytes, on which the expression of CD2 precedes the appearance of the CD3-T cell receptor complex. In view of the impaired T cell regulation of immune responses in patients with systemic lupus erythematosus (SLE), we examined the activation of peripheral blood lymphocytes by anti-CD2 antibodies in 57 SLE patients and 32 normal control subjects. The CD2 pathway response was lower in the SLE patients (P less than 0.0001); 18 of the 57 SLE patients had a lower response than any of the control subjects. The SLE low-responder patients did not differ from the normal-responder patients in terms of disease activity or use of antiinflammatory and immunosuppressive medications. Low responses to anti-CD2 were corrected to normal by the coaddition of a submitogenic amount of phorbol myristate acetate (1 ng/ml). In some low-responder patients, the responses were normalized by the removal of non-T cells. The data indicate that some SLE patients have impaired responses to CD2 pathway activation and that this may reflect intrinsic T cell defects and/or regulatory influences of non-T cells.

Isotype, distribution and target analysis of lymphocyte reactive antibodies in patients with human immunodeficiency virus infection

Anti-lymphocyte (ALA) antibodies were investigated by using both microcytotoxicity and immunofluorescence analyses in 87 subjects with different clinical features of human immunodeficiency virus (HIV) infection. A similar mean percentage of killing in microcytotoxicity assays using heterologous lymphocytes as cellular target was recorded in four groups of patients, including 36 HIV-seropositive asymptomatic subjects, 34 patients with HIV-induced lymphadenopathy syndrome (LAS), 13 with acquired immunodeficiency syndrome (AIDS)-related complex (ARC), and 4 patients with the full-blown AIDS. Conversely, an increasing percentage of ALA-positive subjects paralleled the evolution of the HIV infection. The majority of ALA were IgM isotype with a significant reactivity against T cells. This specificity was indifferently directed to CD3+, CD4+, and CD8+ lymphocytes. In additional experiments employing enzymatic digestion of lymphocyte membrane antigens, we demonstrated that CD4 and CD8 receptors were digested by the pronase, whereas CD3 molecules were highly resistant. Subsequent flow cytometry analyses using these pronase-digested T cells showed that reactivity of ALA for their target was unchanged. Our data suggest that antigenic specificities of ALA in HIV infection are resistant to pronase treatment and are not related to CD4 and CD8 molecules.

Cell surface antibodies in type 1 (insulin-dependent) diabetic patients. II. Presence of immunoglobulins M which bind to lymphocytes

A standardized cell surface antibody assay was used to measure binding of circulating human immunoglobulins to rat or piglet splenocytes. In 100-fold diluted serum fractions, lymphocyte surface antibodies were detected in 30% of Type 1 (insulin-dependent) diabetic patients under 20 years of age but in none of 33 control subjects. Binding occurred with T and B lymphocytes, appeared unrelated to Fc receptors or protein glycosylation and was not attributable to insulin or albumin antibodies. At clinical onset of the disease, the lymphocyte surface antibodies belonged primarily to the IgM-class. Their presence was positively correlated to that of IgM-pituitary cell surface antibodies and their absorption by anterior pituitary cells occurred as well as by splenocytes. Lymphocyte surface antibodies remained present during the first years of insulin treatment. They were also detected in first degree relatives of lymphocyte surface antibody-positive patients. It is unlikely that IgM-lymphocyte surface antibodies mark the destructive process in the pancreatic B cell population. They may, instead, express a state of immune reactivity which precedes the formation of IgG-autoantibodies and therefore be associated with an event in the development of diseases such as Type 1 (insulin-dependent) diabetes.

Antilymphocyte antibodies against CD4+2H4+ cell populations in patients with systemic lupus erythematosus

In previous studies, we demonstrated that patients with active systemic lupus erythematosus (SLE) had significantly decreased percentages of circulating CD4+2H4+ suppressor/inducer cells. The decrease in this T cell subset was most frequent and most marked in patients with active SLE and renal disease. In the present study, we attempted to determine whether SLE patients had plasma antilymphocyte antibodies preferentially reactive with the CD4+2H4+ subset. We found that many SLE patients did have these specifically reactive antibodies. Furthermore, the presence of antilymphocyte antibodies reactive with CD4+2H4+ cells correlated with disease activity in these patients. Also, in vitro functional studies revealed that suppressor/inducer function was eliminated in the pokeweed mitogen-driven IgG synthesis system after the treatment of CD4 cells with patient plasma antilymphocyte antibodies and complement. These results suggest that antilymphocyte antibodies play a role in the elimination of CD4+2H4+ cells in patients with active SLE.

Lymphocytotoxic antibodies in systemic lupus erythematosus: studies of their temperature dependence, binding characteristics, and specificity in vitro

The lymphocytotoxicity of 33 lupus sera was tested against purified helper/inducer (OKT4) and cytotoxic/suppressor (OKT8) subsets of T lymphocytes at 15 degrees C and 37 degrees C in vitro. There was significantly less killing of both OKT4 and OKT8 cells at 37 degrees C (p less than 0.001 and p less than 0.01) and the ratio of OKT4/OKT8 cell killing at 15 degrees C (1.39 (0.73); mean (SD] was different from that observed at 37 degrees C (0.79 (0.42)) (p less than 0.001). OKT4 killing was greater than OKT8 killing in 21 out of 33 sera at 15 degrees C, while 22 of these sera showed predominantly OKT8 cytotoxicity at 37 degrees C. The relation between the OKT4/OKT8 cell ratio and OKT4/OKT8 serum killing was examined in 22 patients at both temperatures: a significant inverse correlation was observed at 37 degrees C (r = -0.53; p = 0.015) but not at 15 degrees C (p greater than 0.05). The addition of metabolic and cytoskeletal inhibitors increased cytotoxicity at 37 degrees C, but not IgM surface binding. A Scatchard binding analysis of the reaction at 15 degrees C showed that large numbers of antibody molecules were bound to both subsets, with a low average dissociation constant of less than or equal to 6 x 10(-8) mol/l, and electrophoretic blotting indicated that the target surface antigens varied in type and number among individual lymphocytotoxic sera. The demonstration of temperature dependent, tight binding between lymphocytotoxic antibody and variable antigens on the T cell surface emphasises the potential for this phenomenon to affect lymphocyte function in vivo in patients with systemic lupus erythematosus.

The role of Lyt-2+ T cells in the regulation of autoimmunity in murine lupus

Systemic lupus erythematosus (SLE) in humans and in mice is characterized by reduced suppressor T-cell activity. This observation suggests that selective loss or impaired function of suppressor T cells may contribute to the development of autoimmunity. To clarify the role of suppressor T cells in the pathogenesis of SLE, we used a rat MAb to selectively deplete Lyt-2+ ('suppressor/cytotoxic') T cells from lupus-prone NZB/NZW F1 (B/W) mice. Treatment consisted of weekly intraperitoneal injections of anti-Lyt-2 (2 mg/mouse) beginning at age 4 months, prior to the onset of overt clinical illness. Control mice received weekly injections of either non-immune rat IgG or saline. Despite sustained depletion of Lyt-2+ T cells, mice treated with anti-Lyt-2 were indistinguishable from control mice with respect to production of anti-DNA antibodies, development of renal disease, and mortality. These findings imply that Lyt-2+ T cells do not regulate autoimmunity in B/W mice. However, they do not exclude the possibility that Lyt-2+ T cells suppress autoimmunity in normal mice but are simply non-functional in B/W mice. Therefore, we also examined the consequences of depleting Lyt-2+ T cells from non-autoimmune C57BL/6 x NZW (B6/NZW) mice. Depletion of Lyt-2+ T cells from B6/NZW from age 4 to 10 months produced neither serologic nor clinical evidence of murine lupus. These observations suggest that suppressor T cell defects are not sufficient to cause murine lupus.

Isotype and cytotoxicity spectra of anti-lymphocyte antibodies in patients with systemic lupus erythematosus

IgG anti-lymphocyte antibodies (ALA) reactive with resting lymphocytes were demonstrated in sera of patients with systemic lupus erythematosus (SLE) by immunofluorescence and flow cytometry and were shown (i) to bind T cells by non-Fc receptor-related mechanisms, (ii) to potentiate antibody-dependent cellular cytotoxicity (ADCC) of lymphocytes in vitro which correlated with binding to T cells, and (iii) to occur at a similar frequency in 29 SLE sera (56%) as IgM ALA (59%). IgG ALA levels in sera negatively correlated with absolute numbers of circulating lymphocytes in patients (r = -0.48, P less than 0.05), as did IgM ALA levels (r = -0.54, P less than 0.05); however, a stronger correlation resulted when levels of both ALA isotypes were considered together (r = -0.61, P less than 0.01). Different groups of SLE patients were distinguished with respect to relative serum content of IgM and IgG ALA and corresponding serum capacity to predominantly mediate ADCC, complement-dependent cytotoxicity (CDC), or both. No correlation existed between serum ADCC and CDC activities in vitro (r = 0.22). However, SLE patient lymphocyte counts negatively correlated with ADCC (r = -0.59, P less than 0.01) and to a lesser but still significant extent with CDC (r = -0.47, P less than 0.05). The latter results suggested that ADCC, induced by serum IgG ALA, was a mechanism of cytoloysis which occurred independently of CDC and which, like CDC, was significantly associated with lymphopenia in vivo.

Monoclonal murine anti-DNA antibody interacts with living mononuclear cells

A monoclonal mouse antibody, 4-B-5, that reacted with both single-stranded DNA (ssDNA) and double-stranded DNA showed direct reactivity and cell association with mouse thymocytes, as well as peripheral blood mononuclear cells. Absorption of 4-B-5 with peripheral blood mononuclear cells or with mouse thymocytes markedly reduced reactivity with both ssDNA and double-stranded DNA. However, treatment of mouse thymocytes or human T cells with DNase completely eliminated monoclonal anti-DNA reactivity with cells. The cellular reactivity was completely restored when monoclonal anti-DNA was incubated with DNase-treated cells in the presence of normal human serum. Normal human serum was found to contain 574 +/- 639 ng/ml of ssDNA. Coincubation or cell preincubation of mouse thymocytes with ssDNA produced a marked increase in 4-B-5 cell association. These findings indicate that mouse monoclonal anti-DNA can react with and can penetrate both mouse and human mononuclear cells, and that this reactivity may depend on the presence of cell membrane DNA on both types of target cells.

Subset specificity of antilymhocyte antibodies in systemic lupus erythematosus. II. Preferential reactivity with T4 + cells is associated with relative depletion of autologous T4 + cells

Using indirect immunofluorescence and flow cytometry, we determined the proportion and number of T3+, T4+, and T8+ cells in the peripheral blood of patients with systemic lupus erythematosus whose sera were positive for cold-reactive antilymphocyte antibodies versus values in patients whose sera were negative for these antibodies. There was a disproportionate reduction in T4+ peripheral lymphocytes when cold-reactive antilymphocyte antibodies preferentially cytotoxic for this subpopulation were present in autologous serum. The decrease in this subset was responsible for a reduction in the T4:T8 ratio; variation in the number and proportion of T8+ cells was insignificant. A similar, but autoantibody-independent, alteration in the T4+ subpopulation was found in patients who were receiving prednisone therapy. A relationship between T cell population abnormalities and systemic lupus erythematosus disease activity, per se, was not observed.

Decreased T-cell-mediated suppression of IgM--rheumatoid factor synthesis in rheumatoid arthritis

Circulating B-cell precursors specific for rheumatoid factor (RF) are present in normal subjects but spontaneous in vitro synthesis of RF occurs only in rheumatoid arthritis (RA). The regulatory role of RF-specific suppressor T cells in this process was studied in pokeweed mitogen-stimulated in vitro cultures of peripheral blood mononuclear cells. Addition of graded numbers of suppressor T8(+) cells from RA patients to normal B cells resulted in consistently less suppression of IgM and RF synthesis than that achieved by normal suppressor T cells. A preculture system was then used to probe for RF-specific suppressor precursor lymphocytes. RA T-cell populations failed to generate normal levels of RF-specific suppression during in vitro culture for 4 days. Incubation with human-aggregated IgG (HaIgG) resulted in an increase in RF-specific suppression to normal levels. The data indicate that induction and full expression of RF-specific suppressor T-cell function is blocked in vivo in RA but can be overcome in vitro by incubation with HaIgG.

Changes in anti-lymphocyte and anti-Ia antibodies during pregnancy in systemic lupus erythematosus

Anti-lymphocyte antibodies reactive with monocyte-depleted lymphocytes, T cells, or B cells were studied in 43 nonpregnant and 23 pregnant systemic lupus erythematosus (SLE) patients. Anti-Ia specificity was assayed in an enzyme-linked immunosorbent assay system. No difference in mean lymphocytotoxicity was noted between pregnant and nonpregnant SLE patients; however, anti-Ia lymphocyte antibody associated with disease activity was lower (P less than 0.01) in pregnant than in nonpregnant SLE patients. Lymphocytotoxic or anti-Ia antibody activity did not reliably predict the outcome of individual pregnancies.

An automated method for the detection of lymphocyte subset specific antibodies in multiple sclerosis sera

Cytotoxic antibodies specific for lymphocyte subsets have been described in patients with several autoimmune diseases and a role for these antibodies in the pathogenesis of these diseases has been suggested. We describe a quantitative and rapid technique for the detection of cytotoxic antibodies and for the delineation of their lymphocyte subset specificity. The technique is based on the automated technique for tissue typing and makes use of reference monoclonal antibodies which are mixed with the sera to be tested. Percentage lysis obtained with this technique correlated well with percentage staining by FACS analysis. The general applicability of the technique is illustrated by the demonstration of lymphocyte subset specific cytotoxic antibodies in sera from multiple sclerosis patients.

Direct demonstration of immunoregulatory T-cell defects in patients with systemic lupus erythematosus

The present study was undertaken to determine directly whether immunoregulatory T cells have a defective suppressor function in patients with systemic lupus erythematosus (SLE), and whether anti-T-cell antibodies are essential for immunoregulatory T-cell defects. Peripheral blood T cells and T-cell subsets were determined in 52 SLE patients. The ratio of T4 to T8 cells was distributed over a wider range in patients with SLE than in the controls. Patients with SLE were divided into three groups (low, normal and high) by the T4/T8 ratio. Lymphocytes from 12 SLE patients (7 with low and 5 with high T4/T8 ratios) were studied extensively. Their disease was inactive or in remission. Anti-T-cell antibodies were not detected, and yet the patients had immunological abnormalities characterized by the presence of antinuclear antibodies and hypergammaglobulinaemia. The SLE patients with high T4/T8 ratios had a decreased number of T8 cells, and defective suppressor-effector cells. In contrast, patients with low T4/T8 ratios had decreased T4 cells and/or increased T8 cells, and defective suppressor-inducer cells. Two patients with low T4/T8 ratios had both suppressor-effector and suppressor-inducer cell defects. These results indicate that immunoregulatory circuits in SLE patients are heterogeneous and that immunoregulatory defects exist even when the disease is inactive or in remission. Anti-T-cell antibodies were not essential for such immunoregulatory defects. Thus, immunoregulatory T-cell defects and the development of SLE may be independent conditions due to other unknown causes.

Cell-mediated immunity in rheumatic disease

Rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis are the three most common systemic rheumatic diseases in which disordered immune function is thought to play a pathogenetic role. Each disease has different and characteristic abnormalities of the cellular immune system. In rheumatoid arthritis the identified abnormalities of immunoregulation are largely limited to specific antigens: Epstein-Barr virus and collagen. Systemic lupus erythematosus is characterized by exuberant B-cell activity with exaggerated humoral response, a diversity of autoantibodies, non-antigen-specific loss of suppressor cell function, and general suppression of cell-mediated immunity. In systemic sclerosis systemic defects of cellular and humoral immune function are mild, but the release of lymphokines and monokines at sites of inflammatory lesions is thought to be important in the pathogenesis of the disease. Similar immune cell-connetive tissue cell interactions are probably important in the propagation of rheumatoid synovitis. Thus, despite the many shared clinical and serologic features of these diseases as well as the presence of many patients who have clinically overlapping features of more than one of these entities, the immune defects and the immunopathogenesis of these disorders appear to be distinct.

Immunoglobulin from systemic lupus erythematosus serum induces interferon release by normal mononuclear cells

Ig fractions from patients with systemic lupus erythematosus (SLE) were tested with cultured normal peripheral blood mononuclear cells for induction of interferon release. Lymphocyte eluates, euglobulins containing IgG and IgM, and IgG or IgM from DEAE or sucrose gradients all induced interferon production. Lymphocytotoxic antibody in SLE sera showed a high correlation with capacity of isolated Ig fractions to induce interferon. Most interferon produced was of the gamma type. Monoclonal SLE IgM antilymphocyte antibody induced interferon synthesis.

Systemic lupus erythematosus and human development

The symptoms of systemic lupus erythematosus (SLE) suggest that the manifestations of the disorder are related to known or plausible control mechanisms in embryogenesis. It is suggested that homo sapiens has, in the course of evolution, developed novel processes controlling development.

Antibody-mediated killing of suppressor T lymphocytes as a possible cause of macroglobulinemia in the tropical splenomegaly syndrome

To investigate the pathogenesis of macroglobulinemia in the tropical splenomegaly syndrome (TSS), we assessed the functional activity of B lymphocytes and T cell subsets in a pokeweed mitogen-driven assay of immunoglobulin synthesis. Mononuclear cells from patients with TSS produced more IgM than cells from village or from distant controls. This appeared to result from a decrease in the number and/or activity of suppressor T cells of the T8+ phenotype. The lack of functional suppressor T lymphocytes was associated with the presence in sera from patients with TSS of IgM antibodies that specifically killed T8+, 9.3-, 60.1+ T cells from normal donors. These results support the hypothesis that macroglobulinemia in TSS results from defective immunoregulatory control of B cell function, and that this may be caused by lysis of suppressor T cells by specific lymphocytotoxic antibodies produced by patients with this syndrome.

Characterization of the spontaneous DNA-synthesizing and/or IgG-secreting cells in peripheral blood from patients with systemic lupus erythematosus

Characterization of the cells responsible for spontaneous DNA synthesis and/or IgG secretion in systemic lupus erythematosus (SLE) was undertaken by fractionation of the peripheral blood mononuclear cells (PBM). Each fraction was analyzed for its capacity to incorporate [3H]thymidine [( 3H]TdR) and secrete IgG without mitogen. The non-E rosette-forming cell (non-ERRC) fraction, which consisted of the surface immunoglobulin-positive [sIg(+)] cells and null cells, revealed a markedly increased spontaneous DNA synthesis (620.0 +/- 586.9 cpm) during the first hour of culture and an elevated spontaneous IgG secretion (8639 +/- 2630 ng/ml) during 9 days of culture. Of particular interest was the finding that both increased responses were conducted by the null cells; the null cell population had approximately a fourfold relative increase of [3H]TdR incorporation and a 60-fold relative increase of IgG secretion compared with the sIg(+) cell population. These results suggest that SLE patients have a small population of preactivated B-cell lineage cells, which lack sIg or have a very low density of sIg.

Subset specificity of antilymphocyte antibodies in systemic lupus erythematosus. Preferential reactivity with cells bearing the T4 and autologous erythrocyte receptor phenotypes

The relative specificity of systemic lupus erythematosus antilymphocyte antibodies for T cell subsets bearing the OKT4, OKT8, or autologous erythrocyte rosette (A-RFC) markers was examined in complement-dependent microcytotoxicity assays and by indirect immunofluorescence. Target cells included normal OKT4+ or OKT8+ T cell clones established from mitogen-activated blasts, resting or phytohemagglutinin-activated peripheral T cells highly enriched for OKT4+ cells or OKT8+ cells, and A-RFC+ and A-RFC- populations. In the majority of sera, cytotoxicity for T4+ cells was greater than that for T8+ cells regardless of cellular activation status. Overall cytotoxicity was considerably higher for activated cells, however, especially when warm assay temperatures were used. A-RFC+ targets were more reactive than nonrosetting T cells, and this was associated with strikingly higher relative fluorescence intensity of IgM staining. Despite these consistent differences in relative cytotoxicity or staining, antibody titers against all cell types were strongly correlated in individual sera. Absorption experiments failed to demonstrate distinct antibody specificities for T4+ and A-RFC+ cells. These data suggest that the major determinant of cytotoxic reactivity may be a single or limited number of surface antigens common to all T cells. Superimposed on this dominant system(s) is a special reactivity with certain distinct subsets and with activated T cells generally.

Suppressor-cell functions in bullous pemphigoid

T Cells from 14 patients in the active stage of bullous pemphigoid and 10 patients in the inactive stage of the disease were studied with Leu-1, Leu-2, and Leu-3 monoclonal antibodies. The proportions of total T cells and T cells expressing either helper or suppressor phenotype in the peripheral blood of patients were not significantly different to those observed in normal subjects. In 15 patients with active disease, immunoregulatory mechanisms were functionally studied using an assay measuring the amount of total IgG synthesized in vitro. Peripheral-blood leukocytes were separated into T- and B-cell fractions, and cultured in various combinations. In ten experiments, prior to culturing with B cells, the T cells were irradiated to remove their suppressor function. No statistically significant differences were observed in the amount of total IgG synthesized by B cells obtained from patients and normal subjects when they were cultured with untreated T cells or irradiated T cells obtained from patients or normal controls. These results indicate that, in patients with bullous pemphigoid, there is no loss of suppressor-cell function or increased helper-cell function as assessed by measuring the total IgG synthesized. Therefore, the immunoregulatory defect, if present, is a highly specific one and can only be studied using antigen-specific assays.

Antinuclear antibody determination: the present state of diagnostic and clinical relevance

Determination of antinuclear antibodies (ANA) will gain in diagnostic significance if a specific type of ANA can be related to a defined clinical disorder. The past decade has brought us quite a lot of papers dedicated to this subject. Yet, with exception of the DNA/anti-DNA system, observed correlations have remained scarce or contradictory. Also, still little is known about the pathogenic role of ANA. Perhaps more recent approaches using biochemical technologies will provide us with highly purified nuclear antigens necessary to study possible correlations at a more sophisticated level.

Subset specificity of lupus antilymphocyte antibodies studied by two-colour microfluorimetry

Subset specific lymphocytotoxic activity of lupus sera was studied by a combination of selective immunofluorescence labelling and complement-mediated lysis. Most frequently death of B cells was detected. Many of the sera caused lysis of T lymphocytes; selective cytotoxicity against suppressor T cells could be observed less frequently. All the anti-T4, anti-T8 and anti-B lymphocyte antibodies proved to be cold reactive.

Primary Sjogren syndrome: clinical and immunopathologic features

Primary Sjogren syndrome is an autoimmune condition in which dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) result from lymphocytic infiltration of lacrimal and salivary glands. Clinical and laboratory features of 60 primary Sjogren syndrome patients seen at our clinic during the past three years are presented. These patients illustrate the wide spectrum of extraglandular features that may occur as a result of lymphoid infiltration of lung, kidney, skin, stomach, liver, and muscle. They further emphasize the difficulty in classifying a patient as primary or secondary Sjogren syndrome (ie, sicca symptoms associated with systemic lupus erythematosus, rheumatoid arthritis, or scleroderma), particularly early in the disease course. As an initial step in understanding the pathogenesis, the lymphocytes that infiltrate the salivary glands and lymph nodes were characterized by using monoclonal antibodies that recognize distinct lymphocyte subsets and by using in vitro functional assays. These studies have demonstrated that affected tissues have infiltrates of T cells with helper/inducer activity and with a high frequency of "activation antigens." The immunohistologic techniques are useful in differentiating "benign" and "pseudolymphoma" lesions (both due predominantly to T cells) from non-Hodgkin lymphoma (usually due to B-cell infiltrates). Although there is no "cure" for primary Sjogren syndrome patient's symptoms may be significantly improved by measures aimed at prevention of ocular and dental complications and by the recognition of extraglandular features that may be amenable to specific treatment.

Cellular mechanism of DNA-specific antibody synthesis by lymphocytes from systemic lupus erythematosus patients

The cellular mechanism of anti-DNA antibody synthesis in patients with systemic lupus erythematosus (SLE) was studied by DNA-specific solid-phase radioimmunoassay. Anti-DNA antibody synthesis in response to DNA was T-dependent, and the experiments with reconstituted lymphocytes from identical twins discordant for SLE showed that B cells and T cells from SLE patients must cooperate to synthesize anti-DNA antibody. Anti-DNA antibody synthesis by lymphocytes from patients with inactive SLE was enhanced by T4 cells and suppressed by T8 cells in response to DNA. Although T4 cells from patients with active SLE could enhance anti-DNA antibody synthesis by autologous B cells, their T8 cells could not suppress anti-DNA antibody synthesis by autologous B cells. These results indicate that elevated anti-DNA antibody synthesis in response to DNA in patients with active SLE is due to abnormalities of both SLE B cells and SLE T cells. They further indicate that dysfunction of T8 cells from patients with active SLE may, in part, be responsible for deficient regulation of anti-DNA antibody synthesis.

Monoclonal antibody investigation in rheumatoid arthritis: presence of a T cell subpopulation bearing a double marker

Using a double marking technique of peripheral blood lymphocyte (PBL) from 23 patients suffering from rheumatoid arthritis (RA) and 12 normal healthy subjects (NHS), the authors were able to demonstrate that there was no alteration in the OKT8 + ve population of RA patients, when compared with NHS. On the contrary, an increased percentage of the subpopulation of lymphocytes OKT4 + ve was detected. Finally, the presence of a subpopulation of T cells carrying both the receptors for monoclonal antibodies OKT4 and OKT8 has been detected.

Relationship between systemic lupus erythematosus T cell subsets, anti-T cell antibodies, and T cell functions

Previous studies have shown that patients with systemic lupus erythematosus (SLE) had differing T cell T4+/T8+ ratios and that the ratio correlated with clinical features of the disease. In the present study, we wished to determine whether the peripheral blood T cell subsets in these patients were related to the specificity of anti-T cell antibodies found in their plasma. Plasma from 24 SLE patients that reacted with greater than 20% of normal T cells were analyzed for their effect on in vitro pokeweed mitogen-stimulated immunoglobulin synthesis and for their reactivity with human T4+ and T8+ cells. Anti-T cell antibodies found in SLE patients have a spectrum of reactivities. We concentrated upon antibodies that interfere with suppressor function. One group of SLE anti-T cell antibodies reacts preferentially with the T8+ suppressor effector cell whereas another is reactive with T4+ suppressor inducer subsets. SLE patients with high T4+/T8+ ratios had anti-T cell antibodies predominantly reactive with the T8+ suppressor effector cells. Patients with low T4+/T8+ ratios, on the other hand, had anti-T cell antibodies reactive with either the T4+ suppressor inducer or with both the T4+ suppressor inducer and T8+ suppressor effector cells. In addition, a fourth group was defined whose anti-T cell antibodies were neither reactive with a functional T4+ suppressor inducer nor a functional T8+ suppressor effector cells. There was a significant correlation between the circulating T4+/T8+ ratio of peripheral T cells in these patients and the relative ability of their anti-T cell antibodies to kill T8+ cells vs. T4+ cells (gamma = 0.666, P less than 0.001). These results support the notion that in SLE different cellular defects in the immunoregulatory circuit underlie the development of autoimmune reactions and that the anti-T cell antibodies may cause numerical and functional deficiencies in T cell subsets.

Lymphocyte-reactive antibodies in acquired immune deficiency syndrome

Antilymphocyte antibodies were studied using the Terasaki microcytotoxicity technique in 21 gay patients including 7 with Kaposi's sarcoma, 5 with opportunistic infection, and 9 with lymphadenopathy syndrome. A significant increase in lymphocyte-reactive antibody was noted in 61% of this group. Similar studies using serum from 25 apparently healthy gay males showed lymphocytotoxic antibody in only one instance. When isolated T-cell subsets (OKT4+ or OKT8+) were utilized, a few sera from acquired immune deficiency syndrome (AIDS) patients apparently showed preferential killing for helper-inducer or suppressor-cytotoxic T-cell subsets, however, this showed no correlation with T-cell phenotypic profiles of OKT4 or OKT8+ cells in concurrent peripheral blood studies. When isolated normal OKT4 or OKT8 T-cell subsets were treated with complement and AIDS serum showing apparent T-cell subset specificity and treated T cells added to B cells, macrophages, and OKT4 or OKT8 cells cultured with pokeweed mitogen, no discernible effect on either help or suppression of IgG or IgM synthesis was recorded.

Functional differences of anti-T-cell antibody in patients with systemic lupus erythematosus and ulcerative colitis

The loss of suppressor T-cell function results in an abundant production of autoantibodies in systemic lupus erythematosus (SLE). As a cause of this suppressor T-cell defect, anti-T-cell antibody seems to be of prime importance. On the other hand, anti-T-cell antibodies can be detected in various other autoimmune diseases, but their functional characteristics have not been determined. In the present study, the functional characteristics of anti-T-cell antibody from a selected subgroup of patients with ulcerative colitis (UC) were compared with those from patients with SLE. Anti-T-cell antibody from the patients with SLE reacted with a T8 subset, resulting in a suppressor defect, whereas anti-T-cell antibody from the UC patients reacted primarily with a T4 subset. Functionally, SLE- T cells failed to proliferate in response to concanavalin A, whereas UC- T cells from UC patients failed to proliferate in response to phytohaemagglutinin. In the Ig synthesis system, both SLE- and UC- T cells increased Ig production of B cells. Since UC+ T cells did not contribute to the generation of Con-A-inducible suppressor activity, we believe that serum from the selected subgroup of patients with UC reacted with the inducer T-cell subset.

Functional heterogeneities among concanavalin A-activated OKT4+ and OKT8+ cells by using autologous erythrocyte rosette technique

Normal human peripheral blood T lymphocytes activated by concanavalin A (Con A) were fractionated into OKT4+ and OKT8+ populations by complement-dependent cell lysis using OKT8 and OKT4 antibodies, respectively. By using the preferential ability of some, but not all, Con A-activated T cells to form rosettes with autologous erythrocytes, each population was further divided into autorosetting cells and nonautorosetting cells, and thus Con A-activated OKT4+ autorosetting, OKT4+ nonautorosetting, OKT8+ autorosetting, and OKT8+ nonautorosetting cells were obtained. The immune regulatory function of these populations was then investigated using a pokeweed mitogen-driven B cell plaque-forming cell system. These studies demonstrated that (a) autorosetting cells can exert potent suppressor activity regardless of their phenotypes of OKT4+ and OKT8+ antigens, and fail to help B cell differentiation; suppressor function mediated by these cells is radiosensitive; moreover, receptors for autologous erythrocytes may constitute either the interleukin 2 (IL2) receptors themselves or a component of an IL2 receptor-effector complex involved in modulating the growth signal that IL2 transmits to T cells; (b) OKT4+ nonrosetting cells serve adequately as radioresistant helper cells, but are devoid of suppressor cells; and (c) OKT8+ nonrosetting cells are found to lack either suppressor or helper activity, suggesting that they may belong to a T lymphocyte subset distinct from the subsets related to immune regulation. The results lead us, therefore, to the conclusion that there may exist functional heterogeneities among both the OKT4+ and OKT8+ populations; these heterogeneities can be dissected by virtue of the autologous erythrocyte rosette technique.

Immunoregulatory cell subsets in Goodpasture's syndrome: evidence for selective T suppressor-cell depletion during active autoimmune disease

In a patient with documented untreated Goodpasture's syndrome, serial determination of T-cell subsets using monoclonal antibodies and flow cytometry revealed a persistent but variable deficiency of T-suppressor cells during the period of active disease. As the percentage of OKT8+ cells (suppressor/cytotoxic T cells) returned to normal levels, anti-basement membrane autoantibody production decreased and finally disappeared. Possible pathogenetic implications of immunoregulatory cell imbalance specifically in reference to Goodpasture's syndrome are discussed.

Class II major histocompatibility antigens and the etiology of systemic lupus erythematosus

It is hypothesized that the underlying immunoregulatory dysfunction in systemic lupus erythematosus (SLE) is altered recognition by T cells of self class II major histocompatibility antigens (Ia). The resultant cellular autoreactivity would directly cause certain of the immunopathological manifestations of SLE. The perception by T cells of self non-MHC antigens in the context of altered Ia on antigen presenting cells would also stimulate specific help for autoantibody production. Autoimmunity induced by the graft-versus-host reaction is an experimental model that illustrates this potential mechanism (A. G. Rolink, S. T. Pals, and E. Gleichmann, J. Exp. Med. 157, 755, 1983; R. A. Eisenberg, S. Y. Craven, and P. L. Cohen, Arth. Rheum. 26, S19, 1983).

Binding of immunoglobulin-G from patients with thyroid autoimmune disease to normal T lymphocytes

Sera from patients with Graves' disease and Hashimoto's thyroiditis were reacted with normal T lymphocyte preparations in an attempt to detect binding of immunoglobulin G (IgG) to T cells. Sera from normal subjects and patients with toxic adenomas served as controls. Each serum was reacted with at least three different preparations of normal T cells. Bound IgG was identified using a fluoresceinated second antibody, antihuman IgG. Positive cells were enumerated by means of epifluorescent microscopy. IgG from 57.8% of toxic Graves' patients, 30.7% of Graves' patients who were euthyroid after treatment, and 41.6% of Hashimoto's patients bound to normal T cells more than did IgG from normal controls. Reactivity of toxic adenoma sera was similar to that of normal sera. When the positive sera were reacted with helper or suppressor/cytotoxic T cell preparations (separated by negative selection technique), the binding was shown to be directed against suppressor/cytotoxic T cells but not against helper cells. These data indicate that a significant proportion of patients with autoimmune thyroid disease have IgG in their serum which react with a subset of normal T suppressor/cytotoxic cells. This phenomenon could be the expression of anti-lymphocyte antibodies, which may relate to previously recognized reductions in number and function of suppressor T cells in autoimmune thyroid disease.

Immunoregulatory T-cells and lymphocytotoxic antibodies in active multiple sclerosis: weekly analysis over a six-month period

Immunoregulatory T-cell subsets were measured at weekly intervals over a 4 to 6 month period using monoclonal antibodies (anti-T4 = inducer cell; anti-T8 = suppressor/cytotoxic cell) in a group of 6 patients with multiple sclerosis (MS) and in 4 age- and sex-matched controls. Decreases in the T8 subset and increases in the T4:T8 ratio were present in 4 of the patients with MS but not in controls. Two patients who were neurologically stable during the study period had no changes in the T4:T8 ratio; 2 patients with intermediate disease activity of the relapsing-remitting type had elevated ratios on 3 and 4 occasions respectively; the patient with the most clinically active MS had an abnormal ratio 12 of 27 times. One patient with chronic-progressive MS had an elevated ratio on each occasion tested. No abnormalities in T-cell subsets were present in any of the controls. On three occasions an elevated T4:T8 ratio appeared to precede an acute relapse by 1.5 to 7 days. Lymphocytotoxic antibodies (LCA) against whole lymphocytes or against isolated T-cell subsets were measured in these patients and in a larger group of MS patients, and were not found to correlate with changes in T-cell subsets. This report extends previous findings linking changes in T-cell subsets to disease activity in patients with MS.

Enumeration of human lymphocyte subpopulations by immunofluorescence: a comparative study using automated flow microfluorometry and fluorescence microscopy

These studies reveal that the enumeration of peripheral blood mononuclear cells by fluorescence microscopy and automated flow microfluorometry show a high degree of correlation whether the cells came from normals, individuals with common variable immunodeficiency, chronic lymphocytic leukemia of B cell origin or chronic lymphocytic leukemia of T cell origin. There was excellent agreement between these two methods when counting positive cells stained by the pan-T monoclonal antibodies OKT3 and Leu-1, the helper T reagents OKT4 and Leu-3a, and the suppressor T antibodies OKT8 and Leu-2a. The values obtained for B cells using a pan-B (HB-2) cell antibody analyzed by fluorescence microscopy and automated flow microfluorometry gave a correlation coefficient of 0.86. The percentage of cells identified by antibodies with reactivities toward peripheral blood monocytes (MMA or Leu-M1), the HLA-DR determinant, and HNK-1 (Leu-7) positive cells gave correlation coefficients of 0.90, 0.90, and 0.80 respectively when compared by the 2 methods mentioned above. These data suggest that comparable values for lymphocyte subpopulations in human blood samples can be obtained using the most convenient and available technology.

T-cell macrophage subset interactions and decreased autologous mixed lymphocyte reaction in Sjögren's syndrome

T-cell macrophage subset interactions were studied in relation to the decreased autologous mixed lymphocyte reaction (AMLR) in 15 patients with Sjögren's syndrome (SS). Monoclonal antibodies against a macrophage (M theta) subset (Mac-120) stimulatory in the AMLR and against nonpolymorphic determinants of Ia antigen were used to identify adherent M theta. Four patients with decreased AMLR had a reduced percentage of Mac-120+ cells, suggesting that a defect in stimulatory M theta may account for their decreased AMLR. No correlation was found between the magnitude of the AMLR and the percentage of Ia+ M theta. Another six patients with diminished AMLR had a normal to high percentage of Mac-120+ M theta. However, this group of SS patients showed a decreased response to Concanavalin A, suggesting that they may have a defect in the responding T cells. Patients with normal AMLR had normal percentages of Mac-120+ M theta and showed normal responses to T-cell mitogens and alloantigens. These results suggest that a defective AMLR may have multiple causes. SS patients are heterogeneous in this regard and can be sorted into three groups using the AMLR and monoclonal antibodies.

The effect of plasmapheresis and drug immunosuppression on T-cell subsets as defined by monoclonal antibodies

The number of total T-cells and the number of helper/inducer T-cells decreased in 27 of 31 patients with immunologic disorders treated with plasmapheresis and drug immunosuppression. The number of suppressor/cytotoxic T-cells increased in the majority of patients. The helper/inducer to suppressor/cytotoxic cell ratio, which was initially elevated in 26 of 31 patients, decreased significantly in all but 2 patients after therapy. Ten patients were already on drug immunosuppression at the time plasmapheresis was started, and all 10 showed increased helper/inducer to suppressor/cytotoxic cell ratio despite their drug therapy. The helper/inducer to suppressor/cytotoxic cell ratio decreased in all ten patients after plasma exchange. The number and the percentage of total T-cells and helper/inducer cells decreased from prepheresis levels while the number and the percentage of suppressor/cytotoxic cells increased. Plasmapheresis, in combination with drug immunosuppression, was effective in decreasing the elevated helper/inducer to suppressor/cytotoxic cell ratio in disorders of the immune system. In contrast, patients on immunosuppressive drug therapy alone had persistently high immunoregulatory ratio.

Response of lupus nephritis to plasmapheresis without demonstration of circulating immune complexes

A case of post-partum SLE in a 25-year-old Mexican-American woman is presented. The disease was associated with systemic vasculitis and diffuse proliferative glomerulonephritis. Abundant evidence for the deposition of complement activating immune complexes was found in skin and kidney biopsies, but no circulating immune complexes could be measured. Therapeutic modalities including corticosteroids administered both orally and intravenously, azathioprine, antihypertensives, and hemodialysis failed to effectuate lasting benefit. Large volume plasmapheresis led to immediate improvement and a dramatic return of renal function. A mechanism of action for the resulting effect is considered.

Lymphocyte subsets in patients with systemic lupus erythematosus

The role of abnormal numbers and function of lymphocyte subsets in SLE remains, to date, unclear. Evidence exists for both functional T lymphocyte and B lymphocyte defects although the data for T lymphocyte defects appear more compelling. The role of autoantibodies on these cellular defects is also unclear. They may take on an important pathophysiologic role in depletion of certain lymphocyte subsets with subsequent alteration of function or they may, in fact, be interesting epiphenomena since an inverse relationship of depressed T lymphocyte numbers and function to increased levels of LCTA are frequent. Many other factors clearly influence lymphocyte function and disease expression including genetics and endocrine factors. As methodologies improve, a clearer understanding of the pathogenesis of SLE will emerge.

Neuroimmunology I: Immunoregulation in neurological disease

Aberrations in immune function that ultimately result in disease states may involve three aspects of immune regulation: (1) regulatory T cells, which both suppress and induce immune responses; (2) idiotype-antiidiotype networks, which serve as internal regulatory networks during generation of an immune response; and (3) immune response genes, which determine genetic differences in an individual's immune response. Three major diseases of the nervous system, multiple sclerosis, myasthenia gravis, and acute inflammatory polyneuropathy (Guillain-Barré syndrome), are classified as "autoimmune" in nature and may be due to underlying disorders of immunoregulation. In multiple sclerosis there is a loss of suppressor T cells in the peripheral blood during attacks, in myasthenia gravis there are thymic abnormalities and antibodies against the acetylcholine receptor, and in acute inflammatory polyneuropathy, macrophage-mediated destruction of peripheral nerve myelin occurs in the context of sensitized T cells and is usually associated with a preceding viral illness. In each of these diseases the following central questions must be answered: (1) against what antigen (or antigens) of the nervous system is the autoimmune response directed? (2) what is the mechanism of immune damage? and (3) what initiates, or triggers, the autoimmune response?

Modulation of T-lymphocyte differentiation antigens: potential relevance for multiple sclerosis

Effects of the anti-T-cell monoclonal antibodies OKT3, OKT5, and OKT8 on T-cell surface properties and cell functions were evaluated. Incubation of mononuclear cells isolated from peripheral blood for 48 hr with each monoclonal antibody in the absence of complement resulted in modulation of their respective surface antigens; i.e., the number of cells detected by immunofluorescence as positive for the T3, T5, and T8 surface antigens was reduced. T3, T5, and T8 antigens modulated independently. A radiolabeled second antibody technique confirmed modulation by OKT3 and OKT8 and indicated that T-cell differentiation antigens can regenerate in culture. Incubation of mononuclear cells with OKT3 increased the number of sheep erythrocyte-binding lymphocytes (E+-rosetting cells) and markedly increased the number of avidly E+-rosetting cells. Incubation with OKT8 reduced the number of E+- and of avidly E+-rosetting cells. OKT3 induced both mitogenic reactivity and suppressor cell activity; cells modulated by OKT8 exhibited reduced mitogenic reactivity and reduced suppressor cell function. The decreases in total T cells, in avid T cells, in suppressor cell number, and in suppressor cell function that follow modulation by OKT8 mimic changes observed in multiple sclerosis patients.

Autologous and allogeneic mixed lymphocyte reactions in progressive systemic sclerosis

The autologous and allogeneic mixed lymphocyte reactions (MLR), observed when peripheral blood mononuclear cells from 20 patients with progressive systemic sclerosis were used, were compared with those of age-, sex-, and race-matched normal controls. Such cells were separated by gradient centrifugation of sheep red blood cell (E) rosettes into stimulator (E- or non-T cell) and responder (E + or T cell) populations. The autologous MLR of both the progressive systemic sclerosis and normal peripheral blood mononuclear cells varied widely but there was no statistical difference between the means of each group. In the allogeneic MLR, proliferation between progressive systemic sclerosis non-T cells and normal T cells was significantly less than that of normal non-T cells and progressive systemic sclerosis T cells (P = 0.001). A decreased autologous MLR, while noted with other autoimmune diseases, was lacking in progressive systemic sclerosis. This suggests a different defect. The differences in the allogeneic MLR also suggest that either progressive systemic sclerosis non-T cells were poor stimulators or T cells associated with this disease were better responders when compared with similarly prepared cell populations from normal individuals. The MLR differences could have also resulted from compositional subset alterations or the sharing of a common antigen. HLA-DR5 was found in 9 of the 17 white patients with progressive systemic sclerosis. Although these individuals were evenly distributed as low, medium, and high responders, this finding showed that some progressive systemic sclerosis non-T cells shared a common antigen.