Depressed primary in vitro antibody response in untreated systemic lupus erythematosus. T helper cell defect and lack of defective suppressor cell function

Lymphocyte Subsets in a Large Cohort of Patients with Systemic Lupus Erythematosus

In search of markers of disease activity in patients with SLE we have investigated blood lymphocyte subsets from a large cohort of patient. Seventy-one patients were studied using a well-defined panel of fluorescent monoclonal antibodies which recognize the major T, B and NK lymphocyte subsets and activated cells. Flow cytometry was used with standard automated software.

Overall, SLE patients were lymphopenic. The proportion of activated T cells was increased and NK cells were decreased in both proportion and absolute numbers (P < 0.001). This decrease was more pronounced in the more active patients.

None of the T cell activation markers was shown to distinguish different degrees of disease activity. However, the percentage of NK cells was significantly reduced in active disease states (P< 0.01). Decreased numbers of NK cells could potentially reduce the resistance of SLE patients to infectious organisms.

Abnormalities of lymphocyte subsets in canine systemic lupus erythematosus

Canine systemic lupus erythematosus (SLE) is a disease clinically very similar to its human counterpart. But so far, no study has reported an accurate evaluation of the lymphocyte subsets in the canine disease. Here, we present a study in which lymphocyte subsets have been evaluated in the peripheral blood of 20 dogs suffering from spontaneous systemic lupus erythematosus (SLE) in active and inactive phases, before and during treatment with prednisone and levamisole. 22 healthy dogs have been used as a control population. We show that canine SLE in active phases is associated with a several lymphopenia (1050 +/- 520 10(6) cells/l versus 2130 +/- 1 020 10(6) cells/l in controls). A striking finding is the imbalance of the CD4 and CD8 subsets (respectively 56.7 +/- 10.7% and 10.9 +/- 3.8% of CD4+ and CD8+ lymphocytes versus 40.5 +/- 11.5% and 18 +/- 4.4% in controls) and a strong activation of T-cells in active phases (64.1 +/- 16.9% of 2B3+ cells versus 46.5 +/- 16.7%). Moreover, we observed a persistence of the T subset imbalance during spontaneous evolution. In contrast, the treatment induced in dogs showing a good response the correction of CD4/CD8 ratio and no clinical manifestations, whereas in low responders no such improvements were observed. Thus, this work suggests that the main immunological imbalance seen in SLE could be associated with defective suppressor cells and provides further evidence of similarity of human and dog SLE.

Lymphocyte subsets in a large cohort of patients with systemic lupus erythematosus

In search of markers of disease activity in patients with SLE we have investigated blood lymphocyte subsets from a large cohort of patient. Seventy-one patients were studied using a well-defined panel of fluorescent monoclonal antibodies which recognize the major T, B and NK lymphocyte subsets and activated cells. Flow cytometry was used with standard automated software. Overall, SLE patients were lymphopenic. The proportion of activated T cells was increased and NK cells were decreased in both proportion and absolute numbers (P < 0.001). This decrease was more pronounced in the more active patients. None of the T cell activation markers was shown to distinguish different degrees of disease activity. However, the percentage of NK cells was significantly reduced in active disease states (P < 0.01). Decreased numbers of NK cells could potentially reduce the resistance of SLE patients to infectious organisms.

In vitro induction of IgG anti-DNA antibody from high density B cells of systemic lupus erythematosus patients by an HLA DR-restricted T cell clone

An HLA-DR restricted T cell clone (26G11) which recognized a lymphoid cell-derived autoantigen associated with DR4 molecule was shown to induce not only autologous but also allogenic DR4+ B cells to produce large amounts of antibodies of the IgG and IgM classes. Using the helper activity of this clone, we investigated the mechanism of anti-DNA antibody production in DR-matched patients with systemic lupus erythematosus (SLE). When cultured with 26G11 cells, B cells from DR-matched normal control subjects produced large amounts of IgM anti-DNA antibody, but did not produce IgG anti-DNA antibody which is thought to have a pathological role in SLE. In contrast, B cells from DR-matched patients with active SLE spontaneously produced a fairly large amount of IgG anti-DNA antibody, and the production was augmented by the T cell clone. Little IgG anti-DNA antibody was produced by the B cells of patients with inactive SLE in either the presence or absence of T cell clone. We next fractionated B cells into low density B (LD-B) and high density B (HD-B) cells by centrifugation on discontinuous Percoll density gradients. IgG anti-DNA antibody was spontaneously produced by LD-B cells of active SLE patients but not by those either of inactive SLE patients or normal controls. On the other hand, although IgG anti-DNA antibody was not spontaneously produced by the HD-B cells of both active and inactive SLE patients, it could easily be induced by their culture with the T cell clone. Our results clearly show the existence of IgG anti-DNA antibody-producing B cells in the peripheral blood of SLE patients irrespective of their disease activity and suggest that autoreactive T cells may play a pathogenic role in SLE through the induction of autoantibody production.

Functional T cell subpopulations responsible for hyposecretion of IL-2 in patients with systemic lupus erythematosus

The ability of T cells to secrete IL-2 in patients with systemic lupus erythematosus (SLE) was investigated. In patients with SLE, impaired IL-2 production by peripheral blood lymphocytes stimulated with mitogens is well known. In this paper, we report that purified T cells stimulated with mitogens, in the presence of Epstein-Barr virus transformed B cells (B-LCL) as an accessory cell, however, could secrete a large quantity of IL-2 as much as normal T cells. In order to study this potential capacity of T cells to secrete IL-2 in patients with SLE, IL-2 secreting T cells were examined. To obtain these cells, T cells were divided into cluster forming cells and noncluster forming cells after short culture of T cells with accessory cells in the presence of Con A. Then the ability of IL-2 production in two kinds of separated T cells was examined. We found that 1) after short culture with B-LCL, the cluster forming T cells could secrete IL-2 when cultured again, but non-cluster forming T cells could not, even in the presence of B-LCL, 2) after short culture with macrophages, in normal donors and SLE patients, noncluster forming T cells were able to secrete a greater amount of IL-2 than cluster forming and undivided T cells when cultured with B-LCL.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-DNA antibody production by CD5+ and CD5- B cells of patients with systemic lupus erythematosus

Although the presence of anti-DNA antibody is a hallmark of systemic lupus erythematosus (SLE), neither the subsets of B cells that secrete anti-DNA antibody nor the stimuli responsible for the induction of anti-DNA secretion is known. In particular, the role of CD5+ B cells in human SLE, a distinct subpopulation of antibody-secreting cells shown previously to be a source of anti-DNA antibody in murine models of SLE, is unknown. To approach these questions, we developed a sensitive enzyme-linked immunospot (ELIspot) assay to measure spontaneous secretion of antibody to single-stranded (ss) DNA, double-stranded (ds) DNA, tetanus toxoid, and polyclonal immunoglobulin (Ig) by purified CD5+ and CD5- B cells of 15 SLE patients and 15 healthy control subjects. The B cells of only 1 of 15 healthy subjects secreted a significant level of anti-ssDNA antibody, and none secreted anti-dsDNA. By contrast, in the majority of SLE patients both CD5+ and CD5- B cells secreted IgG and/or IgM anti-ssDNA as well as anti-dsDNA antibody. Further analysis of the anti-ssDNA response revealed that the level of IgG and IgM anti-DNA antibody secretion by CD5- B cells correlated closely with the level of polyclonal Ig production by the same subpopulation (r = 0.81 and 0.70, respectively). In contrast, production of anti-DNA by CD5+ B cells occurred independently of polyclonal Ig production by both CD5+ and CD5- B cell subpopulations. These results suggest that in human SLE there exist two anti-DNA antibody-producing B cell subpopulations with distinct induction mechanisms: one (CD5+), which independently secretes anti-DNA, and another (CD5-), which produces anti-DNA as an apparent consequence of polyclonal B cell activation.

T lymphocyte activation in systemic lupus erythematosus analysed by proliferative response to nucleoplasmic proteins on nitrocellulose immunoblots

Polyclonal B cell activity in systemic lupus erythematosus (SLE) may be under T cell control. The use of nitrocellulose immunoblots for the analysis of recognition by peripheral blood lymphocytes of nucleoplasmic proteins in SLE patients led to the characterization of significant proliferative responses to 68K (U1 RNP); SS-B; B-B' and D (Sm) antigen in 15 of 20 patients. Variations of proliferative response were parallel to disease activity over a follow-up period of greater than or equal to 6 months, conferring some prognostic value to the assay of lymphocyte response to nucleoplasmic antigens. The pattern of reactivity differs from the corresponding serum antibody profile, and purified T cell suspensions (greater than 95% pure) were shown to proliferate in response to soluble nucleoplasmic antigens, indicating that T and B cell repertoires against nucleoplasmic proteins may differ. This suggests that activated helper T cells contribute to the fine modulation of B cell reactivity to subcellular particles to determine the particular antibody profile of the patients.

Heterogeneity of B cell responsiveness to interleukin 4, interleukin 6 and low molecular weight B cell growth factor in discrete stages of B cell activation in patients with systemic lupus erythematosus

To investigate the differential stages of B cell activation in patients with systemic lupus erythematosus (SLE), the effects of recombinant interleukin-4 (rIL-4) interleukin-6 (rIL-6), and low mol. wt BCGF (1-BCGF) on B cell proliferation and differentiation were evaluated. In a co-stimulatory assay with anti-IgM, proliferative response to rIL-4 and 1-BCGF showed no significant differences between SLE patients and healthy controls. In a restimulation assay, after pre-activation with anti-IgM for 3 days, proliferative response to rIL-4 and 1-BCGF was significantly decreased in SLE patients compared with normal healthy controls (P less than 0.01). With regard to rIL-6 induced B cell differentiation, SAC-pre-activated low density, large B cells from both SLE patients and healthy controls differentiated well, whereas high density B cells did not differentiate at all. Of particular interest, low density B cells from active patients directly differentiated into Ig secreting cells in response to rIL-6 without SAC activation. These data indicate that heterogeneity of B cell responsiveness to B cell-tropic interleukins resulted from the discrete stages of B cell activation in SLE.

Decreased expression of interleukin-2 binding molecules (p70/75) in T cells from patients with systemic lupus erythematosus

Using radiolabeled interleukin-2 (IL-2), affinity cross-linking and binding assays revealed that the expression of intermediate-affinity IL-2 binding molecules (p70/75) on freshly prepared T cells from patients with systemic lupus erythematosus (SLE) was significantly decreased in comparison with that in normal subjects. The proliferative response of T cells to high doses of IL-2 was also reduced in patients with SLE. The decreased expression of p70/75 reflects the hyporesponsiveness to IL-2 of T cells in patients with SLE.

Induction of excessive B cell proliferation and differentiation by an in vitro stimulus in culture in human systemic lupus erythematosus

B cell hyperactivity present in the body in patients with systemic lupus erythematosus (SLE) can be detectable via almost any measure of B cell function. Nonetheless, the basis for the B cell hyperactivity is difficult to study in vitro. In this study, we have obtained the resting B cells from patients with entirely inactive SLE by collecting them sedimenting in a high density fraction on a Percoll density gradient. These resting SLE B cells proliferated in vitro at a higher rate than normal B cells when exposed to Staphylococcus aureus Cowan I (SAC). In addition, significant proliferation was observed earlier in the course of culture in SLE patients than in normal controls. Moreover, the SLE resting B cells, once triggered by SAC produced abnormally high numbers of immunoglobulin-secreting cells in response to T cell-derived soluble factors. There was less frequency of circulating Leu 1+ B cells in the SLE patients than in normal controls. Moreover, not only Leu 1+ B cells but also Leu 1- B cells of SLE patients were more responsive to SAC than those of normal controls. The results indicate that the B cell hyperactivity in human SLE can be induced by in vitro stimuli, and may not be limited to the Leu 1+ B cell subset.

AIDS and autoimmunity

While much evidence appears to support the hypothesis of AIDS being an autoimmune disease, equally impressive facts negate the theory. At most, one can presently speak only of the "autoimmune features" of this very complex syndrome. AIDS most strikingly presents with various autoantibodies including those directed against both red and white blood cells. These antibodies appear to be - at least in part - responsible for some of the autoimmune features of the disease. Several clinical and serological similarities exist between AIDS and the "classic" autoimmune disease SLE. In fact, following the isolation of HIV, researchers once again began searching for a viral etiology of SLE. It appears that while autoimmune mechanisms may explain some of the clinical and serologic manifestations of the disease, not enough evidence exists as yet to decidedly point either for or against its classification as an autoimmune disease.

Autoantibodies to intracellular proteins in human systemic lupus erythematosus are not due to random polyclonal B cell activation

Antibody binding to total protein extracted from a mammalian source (HeLa cells) and from a prokaryotic source (Escherichia coli) was compared in sera from patients with systemic lupus erythematosus (SLE) and sera from normal subjects. When the average numbers of peptides or proteins recognized by IgG antibodies were compared on immunoblots, SLE sera bound to a significantly greater number of proteins from the HeLa cell extract than did sera from normal individuals (P less than 0.001). In contrast, SLE sera actually bound to fewer E coli proteins than did the sera obtained from normal controls, although the difference was not statistically significant. There was no correlation between the number of E coli proteins and HeLa proteins recognized by individual SLE sera, and there was no trend toward reactivity with a larger number of antigens in sera containing higher levels of IgG. IgG from SLE sera did not bind to 6 purified eukaryotic protein standards (selected solely on the basis of differences in size and charge) either in their denatured state or in their native state. These findings indicate that the high levels of IgG antibodies against selected eukaryotic intracellular proteins in patients with SLE cannot be explained by a random polyclonal B cell activation.

Two distinct subsets of patients with systemic lupus erythematosus

This study was undertaken to examine the levels and function of peripheral blood immunoregulatory T cell subpopulations in systemic lupus erythematosus (SLE). T cell subpopulations can be distinguished by the T cell differentiation antigens CD4 (recognized by the monoclonal antibodies OKT4 or Leu3) and CD8 (recognized by the monoclonal antibodies OKT8 or Leu2). All SLE patients tested had normal percentages of CD8 cells in their peripheral blood. The SLE patients, however, fell into two groups based on their CD4 cell numbers. Fifty-five percent of the SLE patients had normal levels of CD4 cells (Group A) and therefore normal CD4/CD8 cell ratios, whereas 45% of the SLE patient population had markedly depressed CD4 cell levels (Group B) and significantly low CD4/CD8 cell ratios. T cells from normal donors and SLE patients were further examined for their ability to stimulate allogeneic normal B/M phi cells to secrete IgM in the presence of pokeweed mitogen (PWM). Utilizing this assay system two forms of immunosuppression were observed: (1) that mediated by high concentrations of purified CD4 cells and (2) that mediated by CD8 cells. High concentrations of purified CD4 cells, added to a constant number of allogeneic normal B/M phi cells, suppressed PWM-stimulated IgM synthesis. Group B SLE patients, with significantly low CD4 cell numbers, had defective CD4 cell-mediated suppression which was concentration dependent. This result was confirmed in a study using identical twins discordant for SLE. In this case CD4 cells from the SLE twin did not induce immunosuppression at a high concentration of CD4 cells whereas similar concentrations of CD4 cells from the normal twin resulted in suppression. SLE patients (Group A) with normal levels of CD4 cells had normally immunosuppressive CD4 cells. Suppression mediated by CD8 cells was demonstrated by the fact that removal of CD8 cells resulted in enhanced IgM synthesis induced by the remaining CD4 cells. Although all the SLE patients in this study had normal peripheral blood levels of CD8 cells, SLE Group A patients had defective CD8 cell suppression whereas CD8 function appeared to be normal in Group B patients. These results suggest that in SLE patients with depressed CD4 cell numbers (Group B) there is a corresponding defect in CD4 cell function. We demonstrate that in SLE Group B patients, defective suppression is due to a subset of T cells that bear the CD4 antigen. The SLE patient population (Group A) with normal CD4/CD8 ratios and normally functioning CD4 cells, however, appear to have normal CD4 cell-mediated suppression but defective CD8 suppressor cell function.

The decrease in peripheral blood CD4+ T cells following thermal injury in humans can be accounted for by a concomitant decrease in suppressor-inducer CD4+ T cells as assessed using anti-CD45R

Using single- and two-color fluorescence flow cytometry, 10 thermally injured human subjects were assessed over time for both percentages and absolute numbers of lymphocytes comprising peripheral blood lymphocyte subpopulations. The CD3+ lymphocyte percentage decreased significantly in the early postburn period, and this decrease could be accounted for entirely by a concomitant decrease in the CD4+ lymphocyte percentage. Further, the decline in CD4+ percentage was due to a specific decrease in the suppressor-inducer subset of CD4 as defined using anti-CD45R. No change in the helper-effector subset of CD4 was noted. The percentage of CD8+ lymphocytes did not change significantly at any time postburn nor did subsets of CD8 as defined using anti-CD11. Numerical changes in lymphocyte subsets were dominated by a general lymphopenia occurring on Day 4 following injury. However, suppressor-inducer (CD4+/CD45R+) T cells also decreased significantly on postburn Day 1. These results further elucidate phenotypic changes in immunoregulatory subsets following major injury and suggest a possible basis for depressed autologous mixed lymphocyte responsiveness of burn patient T cells, one of the functional immunologic defects associated with severe injury.

Impaired mobility of human T lymphocyte surface molecules during inactive systemic lupus erythematosus. Relationship to a defective cAMP pathway

The T lymphocytes of patients with active systemic lupus erythematosus (SLE) exhibit impaired capping of the surface molecules CD3, CD4, and CD8 and a defective cAMP-dependent pathway. Since the mobility of these molecules is regulated in part by cAMP, we sought to determine whether there is a specific defect(s) along the T cell cAMP pathway that contributes to the persistent capping disorder observed during inactive SLE. The data suggest that a defect may exist at the level of cAMP-dependent protein kinase activation or at a point distally. We propose that a disorder of cAMP-dependent protein kinase activity might account for the defect of capping observed in both the CD3, CD4 (helper/inducer) and CD3, CD8 (suppressor) subsets observed in SLE.

B cell hyperactivity and its relation to distinct clinical features and the degree of disease activity in patients with systemic lupus erythematosus

Peripheral blood B cells that were actively proliferating, those actively secreting immunoglobulin, and those expressing an early activation marker, Ba antigens, on the surfaces were quantitated in 25 patients with systemic lupus erythematosus (SLE). B cell hyperactivity was found in almost all of the SLE patients, as demonstrated by any one of these measures of B cell activity. Moreover, we observed a strong positive correlation between the degree of disease activity and the amount of spontaneous incorporation of 3H-thymidine by B cells; the magnitude of the increase in frequency of spontaneous Ig-secreting cells in peripheral blood correlated strikingly with certain clinical features in these patients. Our findings suggest that there is heterogeneity of B cell hyperactivity in individual patients with SLE and, thus, that clinical subsets of SLE can be identified on the basis of B cell hyperactivity.

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.

Defects of autologous mixed lymphocyte reaction-activated immunoregulatory T cells in patients with systemic lupus erythematosus

The present study was undertaken to determine the nature of the immunoregulatory T-cell defect after autologous mixed lymphocyte reaction (AMLR) activation in patients with systemic lupus erythematosus (SLE). Although AMLR was decreased in patients with SLE compared with normals, there was no difference in major proliferative cells (T4 cells and T4+JRA+ subset) in response to AMLR. Functional activity of AMLR-stimulated T4 subsets in patients with SLE and normals was examined in helper and suppressor/inducer assay, using pokeweed mitogen (PWM)-driven IgG synthesis. The T4+JRA- (helper) subset from SLE patients showed no greater activity than normals. However the T4+JRA+ (suppressor/inducer) subset from SLE patients showed decreased suppression induction compared with normals. This defect in the suppressor/inducer function was demonstrated even in patients with inactive SLR or in remission.

Interleukin-1-production by monocytes from patients with systemic lupus erythematosus

Production of interleukin-1 (IL-1) by glass-adherent monocytes from 18 patients with systemic lupus erythematosus (SLE) was measured. Patients were divided into three groups according to disease activity. A deficient production of IL-1 was found in monocytes of SLE patients both without stimulation and after stimulation with 5 micrograms of lipopolysaccharide. The decreased production correlated with the degree of disease. Addition of phorbol myristate acetate to monocytes caused only partial normalization of the decreased IL-1 production. The IL-1 deficiency in SLE is postulated to be a part of complex abnormalities of cell-mediated immunity in this disease.

Systemic autoimmune disease arises from polyclonal B cell activation

The number of B cells producing antibodies reactive with any of seven autoantigens or two conventional antigens was compared at the single-cell level to the total number of Ig-secreting B cells present in the spleens of NZB, MRL lpr/lpr, and BXSB autoimmune mice. The proportion of lymphocytes producing antibodies of each specificity, expressed as a percentage of the total B cell repertoire, was virtually identical among autoimmune and congenic nonautoimmune animals. Furthermore, B cells and serum antibodies reactive with conventional antigens increased commensurately with those reactive with autoantigens. These results indicate that systemic autoimmune diseases arise from polyclonal B cell activation.

Depressed antibody responses to exogenous antigens in mice with lupus-like graft-versus-host disease

Previous work has established that a disease resembling systemic lupus erythematosus (SLE) can be induced in certain nonirradiated F1 mice undergoing a suitable graft-versus-host reaction (GVHR), e.g., (C57BL/10 X DBA/2)F1 mice injected with DBA/2 T cells. Here, we studied the antibody responses of such autoimmune graft-versus-host F1 mice to exogenous antigens, i.e., sheep erythrocytes, trinitrophenyl keyhole limpet hemocyanin, and levan. We found that primary antibody responses, in particular of IgG isotype, to the T-dependent antigens, sheep erythrocytes, and trinitrophenyl keyhole limpet hemocyanin were strongly suppressed during the entire observation period. Secondary anti-sheep erythrocyte responses, however, were normal, although the peak response was delayed for about 3 days. In contrast to the long-lasting depression of responses to T-dependent antigens, primary antibody responses to the T-independent antigen levan were depressed only at an early stage (i.e., week 2) of the graft-versus-host reaction. In spite of their depressed antibody responses to exogenous antigens, the graft-versus-host F1 mice showed increased numbers of spleen cells spontaneously secreting IgG, and produced IgG autoantibodies characteristic of systemic lupus erythematosus. Mixing experiments performed in vitro with cultures involving graft-versus-host spleen cells revealed that the decreased antibody formation cannot be attributed to suppressor T cells nor to a defect in helper T-cell function. Instead, the mechanism of decreased immune reactivity in SLE-like GVHR seems to operate at the level of B cells. Parallels between the decreased immune reactivity observed in lupus-like GVH disease and that described in human SLE as well as in spontaneously arising murine SLE are discussed.

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.

In vitro production of autoantibodies to U1 ribonucleoproteins by peripheral blood mononuclear cells from patients with connective tissue diseases

Antibodies to U1 ribonucleoproteins produced by peripheral blood mononuclear cells from patients with connective tissue diseases were measured by a sensitive enzyme-linked immunosorbent assay and by immunoblotting. Mononuclear cells from patients with high-titer serum antibodies spontaneously started secreting IgG anti-U1 RNP antibodies on the second day after culture. The amount of anti-U1 RNP in the culture supernatants reached maximum level on day 8. The most effective production of anti-U1 RNP by B cells was observed when they were cultured in the presence of T cells and adherent cells. Mononuclear cells from patients without anti-U1 RNP antibodies or from normal subjects did not produce a measurable amount of anti-U1 RNP. Treatment of mononuclear cells by cycloheximide resulted in complete inhibition of anti-U1 RNP secretion, which indicates that antibody in the culture supernatants reflects the active biologic phenomenon in vitro. The methods described should be useful in the study of the cellular mechanisms involved in antinuclear antibody production of connective tissue diseases.

B cell hyperactivity in systemic lupus erythematosus: selectively enhanced responsiveness to a high molecular weight B cell growth factor

To characterize B cell hyperactivity in systemic lupus erythematosus (SLE) patients we studied the early events of B cell activation in 14 patients and controls. We measured B cell proliferation induced by three interleukin (IL) preparations (20-kDa B cell growth factor, BCGF, recombinant IL2 and 50-kDa BCGF) in the absence and in the presence of an anti-mu antibody (Ab). SLE B cells exhibited a markedly enhanced proliferative response to the 50-kDa BCGF in the absence of an anti-mu Ab, while responding normally in the presence of a first signal. This pattern of hyperactivity was observed in 11 out of 14 patients tested, and was absent in control patients. In contrast, SLE B cells behaved like normal B cells for the response to the other two IL tested, and to the anti-mu Ab alone. It should be pointed out that SLE B cells responded normally to recombinant IL2 whereas T cells from the same patients exhibited a decreased response to this IL. The selectively enhanced responsiveness of SLE B cells to the 50-kDa BCGF suggests that the events leading to B cell hyperactivity in this disease affect the early stages of B cell activation.

Stimulating and differentiation factors for human B lymphocytes in systemic lupus erythematosus

T cells from 18 untreated SLE patients produced significantly more B cell growth factor (BCGF) than did those from normal subjects. Those from SLE patients with active disease produced significantly more than did those from patients with inactive disease. The response to BCGF of SAC-stimulated B lymphocytes from SLE patients was higher than that of B lymphocytes from normal individuals. Similarly preactivated B cells from five of seven SLE patients also proliferated upon the addition of interleukin 1 (IL-1) whereas those of normal subjects did not. Simultaneous addition of IL-1 and BCGF had a synergistic proliferative effect on B cells from two of seven SLE patients but not on any of the controls. Interleukin 2 (IL-2) had no proliferative effect in either SLE or normal B cells. Supernatant fractions from T cells of seven of 10 patients with active SLE and three of 10 with inactive SLE induced more IgG production by CESS cells than did those of normal subjects indicating a higher production of B cell differentiation factor by SLE T cells than by those of controls. Our findings may explain the reported preactivation and predifferentiation of peripheral blood B cells from SLE patients and give insight into the mechanisms leading to the production of autoantibodies in this disease.

Impaired T-cell-independent B-cell maturation in systemic lupus erythematosus: coculture experiments in monozygotic twins concordant for Klinefelter's syndrome but discordant for systemic lupus erythematosus

In a case of monozygotic twins discordant for systemic lupus erythematosus (SLE), coculture experiments with isologous (i.e., genetically identical) lymphocytes were performed. Adequate T-helper-cell function in the SLE twin was demonstrated. Lack of B-cell responsiveness to T-cell-dependent and T-cell-independent polyclonal activators points to a T-cell-independent B-cell maturation defect in the SLE twin.

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.

Induction of alpha/beta interferon and gamma interferon in mice infected with Listeria monocytogenes during pregnancy

Alpha/beta interferon (IFN-alpha/beta) was induced in the bloodstream of mice 48 h after intravenous infection with Listeria monocytogenes, whereas IFN-gamma was induced in the bloodstream 6 h after stimulation with specific antigen on day 5 of infection in virgin mice. In contrast, no IFN-alpha/beta or IFN-gamma was produced in the bloodstream of pregnant mice after L. monocytogenes infection. However, unusual acid-labile IFN-alpha/beta instead of IFN-gamma was produced in some of the pregnant mice in response to specific antigen. The bacterial growth in the organs of pregnant mice in the early stage of infection was normal, but resulted in the delay of T-cell-dependent elimination of bacteria from the organs of pregnant animals in the late stage, and numerous bacteria were detected in both the placenta and the fetus. The significance of the IFN system induced by L. monocytogenes infection in pregnant mice is discussed.

Spontaneous immunoglobulin A secretion and lack of mitogen-responsive B cells in systemic lupus erythematosus

In an analysis of lymphocyte functions of systemic lupus erythematosus (SLE) patients, B cell abnormalities such as a lack of mitogen-responsive B cells and a predominance of spontaneous IgA-secreting cells (SC) were found. Lymphocyte functions of 20 SLE patients were studied. Impaired proliferative response to B cell mitogen, Staphylococcus aureus strain Cowan I (Cowan I), was observed, whereas the response to T cell mitogen phytohemagglutinin was normal. High levels of spontaneous IgA-SC were observed in SLE patients (greater than 10(2) cells/10(4) peripheral blood mononuclear cells [PBMC]), whereas spontaneous IgM-, IgG-, or IgE-SC were not proportionately increased. The number of spontaneous IgA-SC decreased with time in culture and became undetectable by day 5 of culture. In contrast, spontaneous immunoglobulin- (IgM, IgG, and IgA) SC were not observed in healthy volunteers (less than 10 cells/10(4) PBMC). Moreover, in SLE patients failure of induction of immunoglobulin-secreting cells (ISC) was observed when B cells were stimulated by Cowan I and B cell differentiation factor at any day tested, whereas ISC were induced in healthy volunteers on day 6 of culture. Depletion of T cells or macrophages did not affect the results obtained. These results suggest that the abnormalities observed in SLE B cells are not due to the in vitro direct effects of suppressor macrophages or suppressor T cells, and that the condition of the predominance of spontaneous IgA-SC and the unresponsiveness to exogenous stimulation may be emblematic of hyperactive B cells in SLE.

Systemic lupus erythematosus: delineation of subpopulations by clinical, serologic, and T cell subset analysis

Patients with systemic lupus erythematosus (SLE) (n = 194) were analyzed for correlation of clinical features. In addition, the proportions of the two major T cell subsets were determined in 87 subjects. Two patient subgroups were discerned: one in which severe renal disease, leukopenia, and thrombocytopenia predominated, and a second in which sicca syndrome and involvement of the central nervous system, lungs and muscle occurred. The ratio of T helper/inducer to T suppressor/cytotoxic cells was reduced in the first group and increased in the second. We conclude that SLE does not comprise a single disease entity, but rather represents a number of syndromes with overlapping clinical features. The correlation of clinical symptoms with the proportions of circulating T cell subsets suggests that several immunologic mechanisms may underlie the various types of SLE.

Correction of interleukin-2 production in patients with systemic lupus erythematosus by removal of spontaneously activated suppressor cells

Interleukin-2 (IL-2) production in vitro is depressed in systemic lupus erythematosus (SLE) patients. It is not known whether this abnormality is caused by a defect in the producer lymphocytes or by excessive suppression. We report that removal of OKT8 (Leu 2a)+ cells increased the IL-2 production by in vitro-stimulated lymphocytes to normal or above normal levels in 19 of 21 SLE patients. This increase was more apparent in those patients with clinically inactive disease and/or receiving less than 7.5 mg of prednisone. Removal of OKT8+ cells from normals did not significantly increase IL-2 activity. SLE, but not normal, OKT8+ cells decreased IL-2 production when added back to autologous OKT8-depleted cells. In some experiments, OKT8+ cells from normal donors also suppressed IL-2 production in SLE. This result suggests that the defect in IL-2 production is complex and may involve multiple cell interactions. Three lines of evidence suggest that the SLE OKT8+ cells actively inhibit the production of IL-2 rather than passively absorb this lymphokine: (a) only 3.2% of SLE lymphocytes expressed IL-2 receptors as detected with anti-Tac; (b) freshly prepared SLE lymphocytes did not absorb IL-2; and (c) cell-free supernatants from SLE OKT8+ cells inhibited IL-2 production, but not IL-2 activity. Double-labeling studies by flow cytometry revealed that 19.3% of SLE OKT8+ cells were also Ia-positive, and approximately 33% co-expressed the natural killer cell marker, HNK-1 (Leu 7). Removal of Leu 7+ cells also significantly elevated IL-2 production in SLE. These studies suggest that one or more circulating mononuclear cell subsets in SLE patients can suppress IL-2 production and that one subset may possibly belong to a non-T, non-B "third mononuclear population."

Modulation of the sodium periodate (NaIO4) response in systemic lupus erythematosus (SLE): effect of interleukin-1 (IL-1), interleukin-2 (IL-2), phorbol myristate acetate (PMA), and indomethacin

The proliferative activity of peripheral blood mononuclear cells (PBMN) from patients with systemic lupus erythematosus (SLE) activated by sodium periodate (NaIO4) is greatly diminished. The effect of the cytokines Interleukin-1 (IL-1) and Interleukin-2 (IL-2) on the NaIO4 reaction was investigated. Addition of IL-1 resulted in partial restoration of the reaction of SLE PBMN to NaIO4, and a similar effect was demonstrated in the presence of phorbol myristate acetate (PMA). Addition of IL-2 to NaIO4 activated SLE PBMN, however, caused a marked improvement in their proliferative activity. The presence of indomethacin resulted in only a slight increase in [3H]thymidine incorporation by the NaIO4-treated SLE cells. The results suggest that the defect in the response of SLE PBMN cells to NaIO4 is due to inadequate availability of IL-1 and IL-2. Excessive production of prostaglandin in SLE might also contribute to the defective response to NaIO4 but does not appear to play a major role.

The in vitro production of anti-nuclear antibodies by human peripheral blood mononuclear cells. Demonstration of T cell requirement and soluble inducing factor(s) for anti-nuclear antibodies triggering in patients with systemic lupus erythematosus

Peripheral blood mononuclear cells (PBMC) of 29 patients with systemic lupus erythematosus (SLE) and 14 normal individuals were investigated for the in vitro production of anti-nuclear antibodies (ANA). Twenty-eight of 29 SLE patients but only one control spontaneously produced ANA in unstimulated PBMC. Pokeweed mitogen induced ANA synthesis in six controls. No detectable ANA was observed in B cell enriched fraction except in two cases of SLE. Recombination of B + T cell enriched fractions and PBMC supernatants from SLE patients could induce B cells to synthesize ANA. These results indicate that: (1) SLE patients spontaneously produced ANA in vitro whereas controls rarely did; (2) autoreactive clones exist in normal individuals but are kept under control and (3) T cell help is required for ANA triggering.

The in vitro production and regulation of anti-double stranded DNA antibodies by peripheral blood mononuclear cells from normals and patients with systemic lupus erythematosus

The in vitro production of anti-double stranded DNA antibodies (anti-DNA) by peripheral blood mononuclear cells (PBMC) was investigated in 19 patients with systemic lupus erythematosus (SLE) and in 12 normal individuals, using a micro solid phase enzyme immunoassay. PBMC from SLE patients spontaneously produced anti-DNA with a higher frequency (16 of 19) than did PBMC of controls (three of 12). In addition SLE patients produced predominantly IgG antibodies. PWM and DNA enhanced anti-DNA synthesis is spontaneously low and non-producers, but acted as inhibitors in spontaneously high producers. The partial removal of T cells decreased or abolished anti-DNA synthesis in four of nine SLE patients. In contrast the B cell enriched fractions of five of nine SLE and five of seven normal patients produced the same or higher anti-DNA levels than did the corresponding unseparated PBMC. These results suggest evidence for autoreactive B cells in SLE as well as in normals, and therefore the combination of these autoreactive B cells with helper and/or suppressor T cell disorders could lead to the over production of anti-DNA seen in different patients with SLE.

Increased concanavalin A induced suppression in treated and untreated coeliac disease

The generation of suppression by concanavalin A in peripheral blood mononuclear cells in treated and untreated coeliac subjects using an in vitro assay was found to be significantly increased when compared with controls. The response of peripheral blood mononuclear cells to the plant mitogen concanavalin A (con A) was also significantly depressed in both groups of coeliac patients. It is proposed that the depressed cell mediated immunity found in this and other studies in coeliac patients is because of increased suppression. The possible connection between these findings and the increased incidence of malignancy also found in coeliac disease is discussed.

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.

Further characterization of mitogen-induced autorosette-forming cells: correlation with T-cell subsets and with lymphocyte proliferative responses to mitogens

Spontaneous autologous rosette-forming cells (ARFC), which form rosettes with autologous erythrocytes, have been of interest as a subset of thymus-derived lymphocytes (T cells). An association of these cells with concanavalin A (Con A)-induced ARFC has been suggested. Furthermore, the Con A-induced ARFC have been shown to be a suppressor T-cell subset in the Con A-generated suppressor system. We have previously reported the induction of ARFC from T cells by several T-cell mitogens such as phytohemagglutinin-P (PHA) and allogeneic non-T cells other than Con A. In the present report, we further characterized the mitogen-induced ARFC and have extended the study to patients with systemic lupus erythematosus (SLE). We have found that ARFC are also inducible from peripheral blood T cells by pokeweed mitogen (PWM). Studies of T-cell surface markers on the ARFC using OKT monoclonal antibodies confirmed the induction of ARFC from both OKT4- and OKT8-reactive T cells by either Con A, PHA, or PWM stimulation. However, OKT4-reactive T cells were the major cellular source of the ARFC induced by all of the mitogens. In studies of SLE patients, proportions of both Con A- and PWM-induced ARFC were found to be significantly low in PBL of SLE patients treated with moderate or large doses of prednisone, with or without concomitant immunosuppressants, but not in SLE patients without such treatment. Proportional analysis of the T cells and their subsets suggested association of these alterations in the mitogen-induced ARFC with the OKT4-reactive T cells, since a significant decrease in the OKT4-reactive T-cell subset was demonstrated in the PBL of these patients. Proportions of PHA-induced ARFC, however, were not significantly different between SLE patients and healthy adults. Moreover, positive correlations of the mitogen-induced ARFC with lymphocyte proliferative responses to each mitogen were established in both SLE patients and healthy adults. These results further support our previous observation that suggest the receptors for autologous erythrocytes are enhanced or reexpressed on those T cells which are highly activated by mitogens.

Phenotypes of T lymphocytes in systemic lupus erythematosus: decreased cytotoxic/suppressor subpopulation is associated with deficient allogeneic cytotoxic responses rather than with concanavalin A-induced suppressor cells

Patients with systemic lupus erythematosus (SLE) have decreased precursors of cytotoxic/suppressor T lymphocytes in their peripheral blood, as determined by monoclonal antibodies. To determine whether decrease of the cytotoxic or the suppressor parts (or both) of this subpopulation of T lymphocytes is being reflected by this peripheral mononuclear cell (MNC) abnormality, a series of experiments was conducted in which both the suppressive function (concanavalin A induced and spontaneous) and the generation of cytotoxic responses against alloantigens were tested. Cytotoxic responses were consistently diminished while suppressor capacity of MNC from patients with SLE (measured on several assays of normal T- and B-lymphocyte functions) was comparable to that of MNC from normal individuals. The defect in cytotoxic responses to alloantigens by MNC from SLE patients persisted following secondary stimulation in mixed-leukocyte cultures; the cytotoxic responses were not amplified and remained well below the responses of normal MNC. These experiments indicate that the decreased peripheral population of cytotoxic/suppressor lymphocytes in SLE patients represents low or absent precursors of cytotoxic cells rather than of precursors of suppressor cells.

In vitro immune response of SLE lymphocytes. The mechanism involved in B-cell activation

Peripheral blood lymphocytes from 26 patients with systemic lupus erythematosus (SLE) and six normal individuals were tested for IgG synthesis in the presence or absence of PWM. Lymphocytes from patients with active SLE synthesized increased amounts of IgG in the absence of PWM and reduced amounts of IgG in the presence of PWM. Serum from patients with active SLE had an enhancing effect on the in vitro IgG synthesis of normal lymphocytes. The IgG or F(ab')2 fractions of SLE serum retained the enhancing effect on in vitro IgG synthesis, and the enhancing activity was absorbed by human spleen cells. As little as 4 h of incubation with SLE serum was needed for the enhancing activity of normal lymphocytes. Treatment of B lymphocytes appeared to be of main importance for an increase in the in vitro IgG synthesis of SLE serum-treated lymphocytes. These results suggest that anti-B-lymphocyte antibodies from patients with active SLE are responsible in part for the hyperactive response of SLE B lymphocytes.

T lymphocyte subpopulations defined by two sets of monoclonal antibodies in chronic active hepatitis and systemic lupus erythematosus

Lymphocyte subpopulations were enumerated in human peripheral blood using murine monoclonal antibodies with specificity for all peripheral blood T lymphocytes (OKT3, alpha-Leu 1) and for the helper subset (OKT4, alpha Leu 3a) and suppressor/cytotoxic subset (OKT8, alpha Leu 2a). Patients with chronic active hepatitis (CAH) (23) or systemic lupus erythematosus (SLE) (10), compared with healthy subjects (20), had a lower mean T lymphocyte count. Patients with CAH had normal numbers of suppressor/cytotoxic (TSC) cells, but fewer helper (TH) cells than healthy subjects (0 . 96 +/- 0 . 11 X 10(9)/1 versus 1 . 45 +/- 0 . 15 X 10(9)/1), and those with SLE also had fewer TH cells (0 . 93 +/- 0 . 11 X 10(9)/1). Patients with CAH receiving azathioprine (n = 8) had significantly fewer TSC cells, and a higher TH/TSC ratio (2 . 69 +/- 0 . 35) than those (n = 15) not on this therapy (1 . 85 +/- 0 . 15). When patients taking azathioprine were excluded, no correlation was found between disease activity and the TH/TSC ratio for either disease.

Decreased production of and response to interleukin-2 by cultured lymphocytes from patients with systemic lupus erythematosus

We studied the production of and response to interleukin-2 (IL-2) by peripheral blood T lymphocytes from 19 systemic lupus erythematosus (SLE) patients who received no treatment at the time they were studied. Eight had active disease and the rest were in remission. Results were compared with those obtained in 12 healthy subjects of similar age. T cells from SLE patients, whether activated with phytohemagglutinin or in autologous mixed lymphocyte reactions, were found to yield little IL-2, to have a low response to IL-2 from its own, or other sources, and to absorb IL-2 poorly, IL-2 produced by SLE cells, albeit scant, was absorbed normally by activated T cells from normal subjects. Our findings may contribute to the understanding of the immunoregulatory defect in SLE.

Defective B cell function in systemic lupus erythematosus

The in vitro synthesis of specific anti-influenza virus antibody was measured in cultures of peripheral blood lymphocytes from 25 patients with systemic lupus erythematosus (SLE) and 23 control subjects. Whilst all cultures derived from normal individuals synthesized specific antibody, cultures from patients with SLE were consistently unable to produce anti-influenza antibody. This defect could not be corrected by manipulating the culture conditions or by in vivo immunization. Co-cultivation of separated SLE-B or control B cells, with SLE-T or control T cells showed that the immunodeficiency exhibited by the SLE peripheral blood lymphocytes resides in the B cells.

Heterogeneity of immunoregulatory T-cell subsets in systemic lupus erythematosus. Correlation with clinical features

Immunoregulatory T-cell subsets as defined by differentiation antigens were studied in 32 patients with systemic lupus erythematosus (SLE) and 16 healthy persons using the monoclonal antibodies OKT 3 or anti-Leu 4 (T cells), anti-Leu 2a (suppressor/cytotoxic cells) and anti-Leu 3a (helper/inducer cells). Compared with the 95 percent confidence limits in control subjects, decreases or increases of Leu 3a+ cells were observed in 23 patients, whereas abnormal percentages of Leu 2a+ cells were observed in only 10 patients (p less than 0.002). The ratio of Leu 3a+ to Leu 2a+ cells varied over a much broader range (0.31 to 4.14) in patients with SLE than in control subjects (95 percent confidence limit 1.04 to 2.20). Furthermore, the helper:suppressor ratio correlated significantly (p less than 0.001) with a numerical clinical characterization of the patients. A low helper: suppressor ratio was observed in patients with severe renal disease, thrombocytopenia and onset of SLE by 20 years of age. Patients with a high helper:suppressor ratio had multisystem disease including lymphadenopathy, but only rarely SLE renal disease. Patients with a normal helper:suppressor ratio had the most widespread multisystem disease, often involving the kidneys and the central nervous system. The ratio was not correlated with duration of illness, disease activity or corticosteroid dosage in the patients examined. The study suggests that SLE is not one disease entity, but rather a symptom complex with different immunoregulatory abnormalities and associated manifestations.

Impaired primary in-vitro antibody response in progressive systemic sclerosis patients: rôle of suppressor monocytes

The primary in-vitro antibody response developed by peripheral blood mononuclear cells (PBM) towards trinitrophenyl coupled to polyacrylamide beads (TNP-PAA) was evaluated in 17 untreated patients with progressive systemic sclerosis (PSS). This response was markedly depressed as compared with that of 19 control patients and 28 normal subjects. In eight PSS patients and eight normal controls the anti-TNP response was measured before, and after, a PBM filtration on nylon wool columns. This procedure dramatically reduced the proportion of monocytes identified as mononuclear cells staining positively for peroxidases, and restored the response of PSS PBM to the level observed in normal PBM. In four experiments, plastic-adherent cells from either normal subjects of PSS patients were added to autologous nylon-passed PBM. This did not modify the response from normal PBM but inhibited the response of PSS PBM. The inhibitory effect of PSS plastic-adherent cells was insensitive to a 2,000 R X-ray irradiation. These results strongly suggest that the impaired in-vitro antibody response observed in PSS can be attributed to a suppressor monocyte. The concanavalin-A-induced suppressor cells of the antibody response were assayed in PSS. They exerted a suppressive effect to the same extent as in controls.

Abnormalities of T-cell subsets in glomerulonephritis and systemic lupus erythematosus

In this study, three kinds of monoclonal antibodies directed at human T lymphocytes, produced by mouse hybridomas and termed OKT3, OKT4, and OKT8, were used in an indirect immunofluorescence assay, to analyze the distribution of peripheral T lymphocyte subsets in 41 patients with glomerulonephritis (GN) and 11 patients with systemic lupus erythematosus (SLE). As assessed by functional studies, OKT4 and OKT8 defined the helper and cytotoxic/suppressor T lymphocytes subsets, respectively, whereas OKT3 recognized all peripheral T-cells. Among GN patients, the ones presenting membranous GN (MGN), IgA disease, and lipoid nephrosis associated with segmental and focal hyalinosis (FGS) showed significant decrease of their peripheral cytotoxic/suppressive T cells. On the contrary, no significant alteration was found in the peripheral T cell distribution of patients with membranoproliferative GN (MPGN) and lipoid nephrosis associated with minimal-change GN (MCGN). Unexpectedly, there was a tendency for peripheral cytotoxic/suppressive T lymphocytes to be high in the majority of SLE patients, and only two of these subjects exhibited a relative decrease in peripheral OKT8 marked cells. The steroid therapy received by our patients might account for this discrepancy with previous reports of altered suppressor function in active SLE.