Suppression of adjuvant disease in the rat by heterologous antilymphocyte globulin.

The effect of antilymphocyte globulin (ALG) on adjuvant arthritis, an immunologically induced disease in the rat, was studied. ALG was prepared from the serum of rabbits immunized against rat lymphocytes. Adjuvant arthritis was induced in rats by a single intracutaneous injection of Freund's complete adjuvant; after 9 to 12 days, all control rats developed polyarthritis. Administration of antilymphocyte globulin about the time of adjuvant injection produced marked inhibition of clinical disease. Some suppression was apparent even when ALG was started after the onset of arthritis. Rats receiving ALG remained conspicuously healthy compared to controls. Urinary findings and renal histology showed no evidence of nephritis. The results of serum corticosterone determinations made it unlikely that adrenal stimulation contributed to the actions of ALG. Antilymphocyte preparations lowered peripheral lymphocyte counts and suppressed primary antibody responses to sheep erythrocytes, but had little effect on the skin reaction to PPD, even in rats protected from arthritis. All rats given ALG developed antibodies to rabbit globulin; there was no evidence that ALG inhibited the appearance of antibodies to itself, and prior hyperimmunization of rats with rabbit globulin did not interfere with the biological activity of ALG subsequently injected. Antisera produced separately against lymph node and thymus cells had identical properties with regard to agglutination of lymphocytes and thymus cells. Administered to rats, these preparations were equally potent in lowering lymphocyte counts and suppressing both adjuvant arthritis and the primary antibody response to sheep erythrocytes. It is concluded that ALG, as used in these experiments, is a potent immunosuppressive agent without obvious toxic effects.

Studies on the anti-inflammatory action of 6-mercaptopurine.

The mechanism of action of 6-mercaptopurine (6-MP) on an egg albumin-induced inflammatory lesion in the skin has been studied in rabbits treated with 6-MP in a daily dosage of 18 mg/kg. Relative to control animals, significant decreases in the numbers of large lymphocytes and monocytes in the blood were observed in the 6-MP-treated animals by the 9th day of treatment, without significant decrease in the numbers of polymorphonuclear leukocytes and small and medium lymphocytes. Concurrently, a significant decrease was also seen in the percentage of tissue mononuclear cells in the inflammatory skin lesion. There was a highly significant correlation between the numbers of monocytes in the blood and the per cent of mononuclear cells in the lesion. A mean of 52% of the mononuclear cells in the tissue lesion phagocytosed carbon offering further evidence that the major cell involved was the blood monocyte. In vitro incorporation of (3)H-Tdr by blood mononuclear cells was significantly reduced in the 6-MP-treated animals as determined by scintillation counting and radioautography. The large lymphocyte was the predominant cell type which was labeled in vitro. Small lymphocytes and monocytes were rarely labeled. The data obtained suggest that the anti-inflammatory effect of 6-MP, reflected in these experiments by a decrease in mononuclear cells in a tissue lesion, results from suppression of a bone marrow response to local inflammation, affecting principally proliferating precursors of blood monocytes and large lymphocytes. The possible importance of this action of 6-MP in the treatment of inflammatory and immunologically mediated disease is discussed.

Immunoelectron microscopic study of the distribution of T cell subsets in rheumatoid synovium.

The perivascular mononuclear cell collections of the rheumatoid synovium were examined both at the light and electron microscopic level by an immunoperoxidase staining technique using monoclonal antibodies directed against T cell subsets. These accumulations were variable in composition and size, not only in specimens from different patients but in the same specimen. Some areas (lymphocyte-rich areas) contained mainly small lymphocytes in clusters and others (transitional areas) contained blast cells, macrophages, and plasma cells in addition to lymphocytes. The percentage of T4 staining cells correlated positively and the percentage of T8 staining cells correlated negatively with the percentage of lymphocytes in any given area. In contrast, the percentage of T4 cells correlated negatively and the percentage of T8 cells correlated positively with the percentage of macrophage-like cells in these areas. Approximately 80% of the total lymphocytes, both in the lymphocyte-rich areas and transitional areas, were T lymphocytes (OKT3 staining). In lymphocyte-rich areas, helper/inducer T lymphocytes (OKT4 staining) were predominent over suppressor/cytotoxic lymphocytes (OKT8 staining), and in such areas the mean T4:T8 ratio was 2.9. Macrophage-like cells were seen only in small numbers in this type of area. In the transitional areas, suppressor/cytotoxic lymphocytes (OKT8 staining) predominated over helper/inducer lymphocytes (OKT4 staining). In such areas the mean T4:T8 ratio was 0.8. The T8 cells in the transitional areas tended to be large in size and often had a blastic appearance, and the abundant macrophage-like cells infiltrating these areas were frequently in close contact with T8 lymphocytes. These findings indicate that the ratio of T4 to T8 lymphocytes in rheumatoid synovium varies with the type of area examined. In lymphocyte-rich collections, made up largely of quiescent small lymphocytes, T4 cells are predominant. In areas of apparent immunological reactivity, T8 cells are predominant. It is suggested that T8 cells proliferate in immunologically active areas of the synovium as a result of local stimulation of a T cell-mediated immune response.

Primary in vitro cell-mediated lympholysis reaction of NZB mice against unmodified targets syngeneic at the major histocompatibility complex.

T-cell cytotoxicity of NZV mice was tested after in vitro sensitization against a group of H-2 identical strains (BALB/c, B10.D2, DBA/2, HW19). A highly significant and unexpected unidirectional cell-mediated lympholysis (CML) reaction by the sensitized NZB effector cells on these targets was found. After sensitization in vitro with stimulator cells of one H-2d strain, NZB effector cells (H-2d) lysed all other H-2d targets and to a lesser degree, some non-H-2d targets (C57BL/10, DBA/1, B10.Q, CBA, B10.S, A.SW). NZB targets were not lysed. Differences in the major histocompatibility region between NZB and other H-2d strains could be excluded as a possible explanation for the observed reaction of NZB (H-2d) against other H-2d strains. These results consequently represent the first description of a primary in vitro CML directed against determinants not coded for in the major histocompatibility complex. The responsible effector cells are demonstrated to be T cells. The CML of NZB against H-2 identiical targets appears best explained by a reaction against minor histocompatibility antigens. This, and the observed cross-reactions, would indicate that the cytotoxic T-cell system in NZB mice is not subjected to restrictions found in all normal mouse strains tested until now under similar conditions. It is suggested that this hyperreactivity is related to the autoimmune responsiveness of the NZB strain.

Immunohistologic studies of synoviocytes and synovial exudate cells.

Inclusions were demonstrated in normal polymorphonuclear cells incubated with rheumatoid factor-positive synovial fluid. These stained positively for IgG, IgM, and the beta(1)C component of complement. When normal polymorphonuclear cells were incubated with factor-negative rheumatoid fluid, inclusions were not obtained. However, after addition of IgM rheumatoid factor to such fluids, discrete inclusions were observed with similar staining properties. In a minority of nonrheumatoid fluids, inclusions were also obtained after addition of IgM rheumatoid factor. The phagocytosis of inclusions from synovial fluids after addition of IgM rheumatoid factor suggests the presence of aggregated IgG in these fluids. Immunofluorescent staining of phagocytic synovial lining cells, isolated from synovial tissue by trypsin digestion, demonstrated a diffuse staining pattern for IgG and the beta(1)C component of complement in cells from both seropositive and seronegative patients. In seropositive patients, discrete inclusions were also observed which stained positively for IgG, IgM, and beta(1)C. These findings provide evidence of in vivo phagocytosis of immune complexes from the synovial fluid.

The pathogenesis of chronic inflammation in experimental antigen-induced arthritis. II. Preferential localization of antigen-antibody complexes to collagenous tissues.

In an experimental arthritis induced by injection of bovine serum albumin or egg albumin into the joints of previously immunized animals, it has been demonstrated that the major portion of the radioactively labeled antigens injected was localized to avascular collagenous tissues in the joint, i.e., articular cartilage, menisci, and intra-articular ligaments. The antigens were partially eluted from the tissues with 5 M guanidine solution, but not with acid buffers or by 3 M magnesium chloride. The radioactive material eluted with guanidine was at least 80% precipitable by specific antisera. The radioactively labeled-inducing antigen was identified on the surface of articular collagenous tissues from arthritic joints by radioautography and immunofluorescence. Rabbit immunoglobulin and C3 were demonstrated in the same sites by immunofluorescence. The presence of specific antibody in collagenous tissues was demonstrated by the selective in vitro binding of (125)I-labeled-inducing antigen to menisci from arthritic joints of immunized animals. The evidence obtained indicates that in this model of chronic arthritis, the inducing antigen persists for long periods of time in the form of immune complexes in the surface layers of the intra-articular collagenous tissue. The antigen retained in this form may be responsible for the chronicity of the synovitis by serving as a direct stimulus for the maintenance of prolonged antibody synthesis in the synovium and by providing a source of complement-fixing antigen-antibody complexes for the mediation of joint inflammation.

Defective B cell tolerance in adult (NZB X MZW)F1 mice.

Hapten-specific tolerance was induced in vitro by trinitrophenyl-human gamma globulin (TNP32HGG) to a comparable degree in B cells from adult autoimmune (NZB X NZW)F1 (B/W) mice and normal BDF1, CBA/J, and DBA/1J mice. When a lower epitope density tolerogen (TNP7HGG) was used, B/W mice were significantly less sensitive than normal mice to the induction of B cell tolerance. This finding of defective B cell tolerance in adult B/W mice is consistent with previous reports that document other B cell abnormalities that may relate to the expression of autoimmune disease.

Inhibition of human endothelial cell proliferation by gold compounds.

Neovascularization has a role in the propagation of rheumatoid synovitis because the spread of mononuclear cell infiltration and the growth of pannus are dependent on the growth of new blood vessels. Growth of such vessels requires local endothelial cell (EC) proliferation. Inhibition of synovial EC proliferation, therefore, would have the potential to diminish rheumatoid inflammation. We have, therefore, studied the effects of gold sodium thiomalate (GST), auranofin, and gold chloride on the proliferation of human umbilical vein EC. GST suppressed both basal and EC growth factor-induced tritiated thymidine incorporation into EC in a dose-dependent fashion. Inhibition was observed with concentrations as low as 1 microgram/ml GST, 5 micrograms/ml gold chloride, and 0.1 microgram/ml auranofin, levels attainable in blood and synovium of patients. These results suggest that gold compounds have an antiangiogenic effect. The low concentrations inhibiting EC proliferation suggest that gold compounds may suppress rheumatoid synovitis by reducing the number of small blood vessels available for mononuclear cell infiltration and synovial tissue proliferation.

Electron microscopic study of rheumatoid synovial vasculature. Intimate relationship between tall endothelium and lymphoid aggregation.

The relationship between (a) "tallness" and (b) cross-sectional area of the endothelial cells (EC) of postcapillary venules (PCV) and capillaries and the cellular composition of adjacent perivascular mononuclear cell infiltrates in rheumatoid (RA) synovial membrane has been examined by electron microscopy. "Tallness" of the EC was measured as the ratio of the height of the EC to its base (H/B). H/B showed a strong positive correlation with the number and percent of perivascular lymphocytes, i.e., the denser the lymphoid aggregation, the taller the EC. In contrast, H/B showed negative correlations with percent perivascular plasma cells, macrophages, and fibroblast(cyte)s. No such correlations were observed with pericapillary infiltrates. A computer-based morphometric technique yielded similar relationships between the cross-sectional area of the EC and the composition of the perivascular infiltrates. These results indicate that the EC of PCV in lymphocyte-rich areas of synovium tend to be tall and to occupy an increased fraction of the cross-sectional area of the vessel. In contrast, in areas rich in macrophages and plasma cells, EC tend to be flat and to occupy a smaller fraction of the cross-sectional area. PCV in uninfiltrated interstitial areas and in normal synovium had flat EC, and capillaries had flat EC regardless of the character of the surrounding infiltrate. Finally, PCV in lymphocyte-rich areas closely resembled those of tonsil in appearance. Our findings indicate that the PCV of the RA synovial membrane from which lymphocytes emigrate to form perivascular lymphoid aggregates resemble those of lymphoid tissue. They suggest that chronic inflammatory tissue and normal lymphoid tissue share mechanisms of lymphocyte emigration.

Decreased 19S antibody response to bacterial antigens in systemic lupus erythematosus.

The antibody response to immunization with Brucella and the levels of natural antibody to Escherichia coli and Shigella were compared in patients with systemic lupus erythematosus and control groups. After Brucella immunization, SLE patients showed a significantly lower antibody response in whole serum and in the macroglobulin antibody fraction separated by sucrose density gradient centrifugation. Sucrose gradient fractionation of natural antibodies to E. coli and a polyvalent Shigella antigen showed a significant decrease in macroglobulin antibody against four of the five E. coli antigens tested and the Shigella polyvalent antigen in SLE patients when compared with a group of normal individuals and a matched control group with pulmonary tuberculosis. Whole serum natural antibody titers against 5 of 13 Shigella antigens were significantly lower in the SLE patients when compared with the normal group, and against 7 of 13 when compared with the matched tuberculosis controls. Whole serum titers against 8 of 13 E. coli antigens were significantly lower in the SLE patients when compared with normal subjects. The observed decreased antibody response to bacterial antigens in SLE patients, occurring mainly in the macroglobulin fraction, is discussed in relation to the increased incidence of infection commonly observed in these patients.

In vitro synthesis of immunoglobulin by rheumatoid synovial membrane.

A technique for the in vitro culture of rheumatoid synovial tissue with (14)C-amino acids and isolation and quantitation of the newly synthesized immunoglobulins has been developed. This technique has been used to compare immunoglobulin synthesis of 12 rheumatoid synovia with that of synovia from nonarthritic patients and with that of normal human lymph nodes and spleen. In addition, the spleen of a patient with Felty's syndrome has also been examined. Immunoglobulin synthesis in rheumatoid synovia has been shown to be quantitatively and qualitatively similar to that of normal human spleen and lymph nodes although somewhat less active than the Felty's syndrome spleen examined. 79% of the immunoglobulin produced in rheumatoid synovia was of the IgG type, whereas IgM comprised 10% and IgA, 11% of the total. Less than 10% of the IgM synthesized was found to be rheumatoid factor. A fraction containing approximately 90% of its radioactivity in the form of IgG has been obtained for further studies.

Inhibition of antigen- and mitogen-induced human lymphocyte proliferation by gold compounds.

Gold sodium thiomalate (GST) inhibited in vitro antigen- and mitogen-triggered human lymphocyte DNA synthesis. Inhibition of responsiveness was observed with concentrations of GST equivalent to gold levels found in serum or tissues of patients receiving chrysotherapy, Inhibition was dependent upon the gold ion itself since GST and gold chloride were both inhibitory whereas thiomalic acid was not. Inhibition could not be explained by nonspecific killing of cells or by an alteration in the kinetics of the responses. GST inhibited mitogen-induced proliferation most effectively when present from the initiation of culture and could not inhibit the responsiveness of cells which previously had been activated by concanvalin A. These findings indicated that GST blocked a critical early step in lymphocyte activation. The degree of GST-induced inhibition of proliferation was increased in cultures of cells partially depleted of monocytes. Moreover, inhibition was reversed by supplementation of these cultures with purified monocytes. These observations suggested that GST blocked thymus-derived (T)-lymphocyte activation by interfering with a requisite function of the monocyte population in initiating such responses. Prolonged incubation of peripheral blood mononuclear cells with GST resulted in diminished mitogen responsiveness upon subsequent culture in the absence of gold. The addition of fresh monocytes restored responsiveness to these populations. Furthermore, preincubation of purified monocytes with GST rendered them deficient in their ability to support mitogen-induced T-lymphocyte proliferation on subsequent culture. These observations indicate that the major effect of GST results from interference with the functional capability of the monocyte population.

Inhibition of human helper T cell function in vitro by D-penicillamine and CuSO4.

The effect of d-penicillamine (Pen) and mixtures of Pen and copper sulfate on the capacity of normal human peripheral blood mononuclear cells (PBM) to generate immunoglobulin-secreting cells (ISC) in response to the T-cell-dependent polyclonal B-cell activators pokeweed mitogen (PWM) and staphylococcal protein A (SPA) was examined. PBM obtained from normal individuals were incubated for 1-2 h at 37 degrees C with medium alone, Pen, CuSO(4), or a mixture of Pen and CuSO(4). After washing, the cells were incubated for 6-7 d with PWM or SPA and then, with a reverse hemolytic plaque assay, assayed for the number of ISC generated. Preincubation of PBM with either Pen (100 mug/ml) or CuSO(4) (2 mug/ml) did not alter the subsequent capacity of the cells to generate ISC in response to PWM or SPA. In contrast, responsiveness to both mitogens was nearly abolished when PBM were similarly preincubated with a mixture of Pen and CuSO(4). Inhibition of responsiveness could not be ascribed to cell death, carry-over of the inhibitors, or an alteration in the concentration of PWM or the length of incubation yielding maximum responses. Co-culture experiments demonstrated that Pen and CuSO(4) preincubation had not caused augmented suppressor cell function. Experiments in which PBM were separated into adherent and nonadherent populations indicated that Pen and CuSO(4) preincubation inhibited the responsiveness of the nonadherent cells but did not alter the accessory cell function of monocytes. To determine whether Pen and CuSO(4) preincubation effected T- or B-cell function, PBM were separated into B- and T-cell-enriched populations, individually preincubated with Pen and CuSO(4), and then co-cultured with PWM. The results indicated that Pen and CuSO(4) markedly inhibited helper T-cell function and had little effect on the capacity of B cells to generate ISC. The observation that in the presence of CuSO(4) Pen inhibits helper T-cell activity may, in part, explain the therapeutic efficacy of Pen in rheumatoid arthritis and especially the capacity of Pen therapy to decrease antiglobulin titers in treated patients.

Lymphokine stimulation of collagen accumulation.

Lymphokine-rich supernates from normal human peripheral blood mononuclear cells, stimulated by the mitogen phytohemagglutinin, have been shown to cause enhanced collagen accumulation by human embryonic lung fibroblasts (WI-38), as measured by hydroxyproline content of fibroblast monolayers, [14C] proline incorporation into soluble collagen and collagenase release of radioactivity in supernates and monolayers of cultures incubated with [14C] proline. This fibroblast-stimulating activity, demonstrable by suitable dilutions of the supernates, coexisted with a number of other lymphokine activities such as lymphotoxin, proliferation inhibitory factor, and cloning inhibitory factor, which tend to reduce the numbers of function of fibroblasts. The increased content of collagen appeared to be the product of selected surviving and responding fibroblasts. The factor causing this increased collagen accumulation was nondialyzable and stable at -70 degrees C. It represents the first described lymphoid cell-derived activity capable of enhancing collagen accumulation. Fibroblast-stimulating activity may be implicated in the abnormal fibrosis seen in association with chronic inflammation in a variety of disease states. It may have special relevance to progressive systemic sclerosis.

Inhibition of human endothelial cell proliferation in vitro and neovascularization in vivo by D-penicillamine.

To investigate the effects of D-penicillamine (D-Pen) on angiogenesis, we have studied the effects of this drug on in vitro proliferation of human endothelial cells (EC) and in vivo corneal neovascularization. D-Pen, in the presence of copper sulfate, suppressed tritiated thymidine ([3H]TdR) incorporation into EC in a dose-dependent manner. Significant inhibition was observed with D-Pen concentrations attainable in the serum and tissues of treated patients. Neither D-Pen nor copper ion alone significantly affected [3H]TdR incorporation into EC. The inhibition by D-Pen and copper was blocked by catalase (CAT) or horseradish peroxidase but not by boiled CAT or SOD. When rabbits were daily injected intravenously with D-Pen at the per kilogram dosage administered to rheumatoid patients, neovascularization as quantitated by the proliferation of corneal new blood vessels was significantly inhibited. These results suggest that hydrogen peroxide generated by D-Pen and copper exerts a pronounced antiangiogenic effect through inhibition of EC proliferation. It is, therefore, considered that D-Pen may suppress rheumatoid synovitis by reducing the number of small blood vessels available for the emigration of chronic inflammatory cells, and the proliferation of the synovial tissue.

Serum heat-labile opsonins in systemic lupus erythematosus.

To study possible mechanisms responsible for the increased susceptibility to infection of patients with active systemic lupus erythematosus (SLE), a study of the serum heat-labile opsonic capacity (HLOC) in such patients was undertaken. With leukocytes from normal donors, the sera of 12 of 30 patients with active SLE demonstrated decreased HLOC for E. coli 075. The phagocytic activity was partially restored by normal serum, suggesting that decreased HLOC was responsible for the defective phagocytosis. While 8 of 10 patients with active SLE and concomitant infections showed deficient opsonic capacity to E. coli 075, only 4 of 20 such patients without infections showed the defect (P = 0.01). None of 12 patients with inactive disease had deficient opsonic capacity. Similar results were obtained with S. aureus 502A as the test bacterium. In the patients surviving infection, recovery of normal serum opsonic capacity was rapid and usually coincided with an increase of serum complement to normal levels. In three patients with active SLE and infection, the causative microorganisms were isolated and opsonic capacity for these organisms tested with the individual patients' sera. In each case, sera obtained at the onset of the infectious episode had low opsonic capacity when compared with normal sera. Serum C3 proactivator levels were low in 9 of 11 sera with deficient opsonic capacity. However, similar low values were found in other SLE sera with normal HLOC, suggesting that other factors of the opsonic system were also depleted. Addition of the classical complement components C1, C4, C2, C3, and C5 to sera with deficient HLOC failed to restore activity. Addition of pure C3 proactivator also failed to restore activity. However, addition of C3 proactivator together with 50 degrees C-heated normal serum restored activity, indicating that factors active at the early steps of opsonic activation via the alternative pathway of complement were necessary to restore opsonic activity. These findings indicate that in active SLE, a decrease of components of the alternate pathway of complement activation results in an acquired defect of serum HLOC and perhaps other related complement-mediated functions. This defect may be an important factor in the increased susceptibility to infections of patients with active systemic lupus erythematosus.

Immunoglobulin classes of DNA binding activity in serum and skin in systemic lupus erythematosus.

36 systemic lupus erythematosus patients with native DNA binding activity (nDNA-BA) in the serum and subepidermal immunoglobulin deposits were studied to determine the relationship of the immunoglobulin (Ig) class distribution of serum nDNA-BA to the clinical characteristics of their disease and to the Ig class present at the dermal-epidermal junction (DEJ). The patients with predominantly (86-98%) IgM nDNA-BA in the serum had less active disease, mild or no renal involvement, and longer survival than those with predominantly (51-95%) IgG nDNA-BA in the serum. Renal biopsies in eight patients with predominantly IgM nDNA-BA in the serum showed relatively benign histologic changes in the kidney. In contrast, renal tissue from 23 patients with predominantly IgG nDNA-BA showed more severe histologic changes. All patients had multiple skin biopsies. Patients with predominantly IgM nDNA-BA consistently had only IgM at the DEJ. Patients with predominantly IgG nDNA-BA had IgG, usually in association with IgM, at the DEJ. The findings demonstrate that a minority of systemic lupus erythematosus patients may exhibit a limited anti-nDNA response characterized by the presence of chiefly IgM nDNA-BA in the serum and that this is reflected by the presence of mild disease and IgM alone at the DEJ. The development of IgG nDNA-BA is associated with more severe and active disease.

Lymphotoxin formation by lymphocytes and muscle in polymyositis.

Muscle pieces from 11 patients with dermatomyositis or polymyositis were incubated with autologous peripheral blood lymphocytes and the supernates examined for the production of lymphotoxin, a mediator of delayed hypersensitivity, using human fetal muscle monolayers as the target cell. In the case of all 10 active patients, production of lymphotoxin was demonstrated. This mediator was also demonstrated when muscle alone was incubated from two patients with extensive cellular infiltration. Lymphotoxic activity was not found in supernates obtained by incubation of muscle from nine control subjects with their autologous peripheral blood lymphocytes. Addition of methyl prednisolone to active cultures inhibited the action of lymphotoxin on the muscle monolayers. Lymphotoxin was not demonstrated when breast tumor tissue from a patient with dermatomyositis was incubated with autologous lymphocytes. The lymphotoxic agent in the active supernates had similar chromatographic properties to those of a sample of purified lymphotoxin. These findings suggest that muscle injury in polymyositis is a result of a cellular immune response to an antigen present in involved muscle tissue.

Immunomodulatory effect of procainamide in man. Inhibition of human suppressor T-cell activity in vitro.

Procainamide (PA) induces the production of a number of autoantibodies in a high proportion of treated individuals and in some a syndrome closely resembling systemic lupus erythematosus. The mechanism underlying this action of PA is unclear. To examine the possibility that PA might induce autoantibody formation by altering normal immunoregulatory mechanisms, the action of this drug on an in vitro model of antibody formation in man was examined. PA was found to augment the generation of immunoglobulin-secreting cells (ISC) from human peripheral blood mononuclear cells (PBM) in response to pokeweed mitogen but had no effect on pokeweed mitogen-induced tritiated thymidine incorporation. When purified populations of B and T cells were used, PA enhanced the generation of ISC in B-cell cultures supported by untreated T cells but not by T cells treated with mitomycin C. These results indicate that PA augmented B-cell responses by inhibiting suppressor T-cell activity and not by augmenting helper T-cell or B-cell function. N-Acetyl-procainamide had no effect on the generation of ISC in this system. The effect of PA on concanavalin A (Con A)-induced suppressor cell activity was also examined to determine whether PA altered the generation or expression of suppressor T-cell function. PBM were cultured with 30 microgram/ml of Con A for 48 h to generate suppressor cells. When these were co-cultured with fresh PBM, the number of ISC generated was decreased by 58.1 +/- 3.4% (mean +/- SEM, n = 6). Cells that had been similarly incubated without Con A were not inhibitory. The addition of PA to the Con A-stimulated cultures inhibited the generation of suppressor cells as indicated by the fact that the response of fresh cells co-cultured with the Con A-stimulated cells was diminished by only 27.2 +/- 4.3%. In this system too, N-acetyl-procaimamide had no effect. By contrast, adding PA only to the co-culture of Con A-stimulated cells with fresh PBM had a less marked effect on suppressor cell function. These results indicate that the major action of PA is to inhibit the generation of suppressor T-cell activity. Such an effect may explain the capacity of this agent to induce autoantibody formation in treated individuals.

Immunoglobulin in clinically uninvolved skin in systemic lupus erythematosus: association with renal disease.

23 of 42, or 55%, of patients with systemic lupus erythematous had immunoglobulin deposits along the epidermal basement membrane of uninvolved skin (positive lupus band test [LBT]). In patients with low serum complement levels, 91% had a positive LBT), as compared with 15% in those with normal complement levels. The LBT was positive in 70% of patients with clinical and laboratory evidence of renal disease, but in only 31% of patients without renal disease. 81% of patients with the more severe histologic forms of lupus nephritis, i.e., proliferative glomerulonephritis and membranous glomerulonephritis, and positive tests, whereas only 23% with mesangial glomerulitis or normal histologic findings were positive. Immunoglobulins of the same class found in the skin were detected in the glomeruli of patients examined by renal biopsy. These results suggest that there is a relationship between the occurrence of immunoglobulin in the epidermal basement membrane and the presence of the more severe forms of lupus nephritis.