Flow cytometry and cytoadherence studies of sera from children with juvenile rheumatoid arthritis and normal controls

Immunoregulatory aberrations in patients with polyarticular juvenile rheumatoid arthritis

The presence of hypergammaglobulinemia and various circulating autoantibodies in children with polyarticular juvenile rheumatoid arthritis (JRA) implies an immunoregulatory disorder. We report here experiments planned to elucidate the underlying cellular aberrations in this disease. Twelve children with polyarticular JRA were studied. Percentages of Leu-1, Leu-2, and Leu 3 T cells were comparable to those of normal individuals. Immunofluorescent double staining studies demonstrated elevated numbers of activated (DR+) T cells of both Leu-2 and Leu-3 phenotype. B cells characterized both phenotypically (Leu-12) and functionally (as spontaneous plaque-forming cells, PFC) were elevated. In vitro PFC responses to pokeweed mitogen (PWM) and Epstein-Barr virus (EBV) were diminished. The levels of concanavalin A-induced suppressor cells of the PWM-stimulated PFC responses were comparable to control values. In contrast, the EBV-associated suppressor T cells were significantly impaired in both EBV-seropositive and EBV-seronegative patients. These studies indicate that peripheral blood B-cell activity is abnormal in polyarticular JRA. Defective T-cell responses in vitro suggest that this may be due to disruption of normal regulatory circuits between B and T cells and may contribute to the pathogenesis of this disease.

Immunological abnormalities in juvenile chronic arthritis

The immunological alterations that have been reported in juvenile chronic arthritis are reviewed. Their role in patient management and classification as well as their possible etiopathogenetic relevance are discussed.

Salmonella typhimurium mitogen induces proliferation of human B lymphocytes

The maturation of human B lymphocytes can be described as a sequence of activation, proliferation, and differentiation into immunoglobulin-secreting cells. A variety of mitogens which are T cell dependent or independent have been employed to study this process. These moieties generally induce B-cell activation and proliferation followed by differentiation, making the study of initial events difficult. This study characterizes the mitogenic activity of Salmonella typhimurium mitogen (STM), a protein fraction of S. typhimurium. Glass-nonadherent peripheral blood lymphocytes were rosetted with affinity-purified rabbit anti-human F(ab')2-coupled ox erythrocytes and separated on a Ficoll-Hypaque gradient. This population of B lymphocytes, when cultured in dilutions of STM showed dose-dependent proliferation by [3H]thymidine incorporation. Maximal proliferation occurred on Day 7 using STM at 100 micrograms/ml (control, 5692 +/- 1704 cpm; STM, 58,541 +/- 5655 cpm). On Day 7 the percentage of blast cells by Giemsa stain was 14 +/- 4% in control cultures and 52.5 +/- 8.7% with STM. ELISA quantitation of IgG and IgM in culture supernatants revealed no secretion above unstimulated controls. When B lymphocytes were enriched by a negative selection technique, significant proliferation was not observed. STM is a novel B lymphocyte mitogen which induces proliferation but not activation or differentiation of human B lymphocytes into immunoglobulin-secreting cells.

Cytotoxic anti-T cell antibodies in children with juvenile rheumatoid arthritis

The object of this investigation was to determine the prevalence of anti-T cell antibodies in 66 children with various connective tissue diseases. Anti-T cell antibodies were found in 43/44 juvenile rheumatoid arthritis (JRA) patients (mean cytotoxicity 15.0%) and in 10/10 children with systemic lupus erythematosus (mean cytotoxicity 20.0%), but in only 1/15 normal controls and in none of 12 children with other arthritides. There was no significant difference in mean percent cytotoxicity among the JRA subclasses. In the JRA patients, the percent cytotoxicity was positively correlated with the erythrocyte sedimentation rate (P = 0.01), but not with the presence or absence of rheumatoid factor, antinuclear antibodies, or immune complexes. The sera of 3 JRA patients repeatedly inhibited the stimulation of normal lymphocytes by mitogens and antigens by 47-99% (measured by the incorporation of 3H-thymidine into DNA) when added to the culture system in the first 24 hours; normal sera did not. Sera from patients with JRA have increased reactivity with mitogen-activated lymphocytes and T cells compared with unstimulated cells as determined by flow cytometry. The expression of the "JRA antigen" requires protein synthesis but not DNA synthesis or cell division. We conclude that the majority of patients with active JRA have cytotoxic anti-T cell antibodies and that in selected patients, these antibodies may play a role in regulation of the immune response.

T gamma subset specificity of lymphocyte reactive factors in juvenile rheumatoid arthritis and systemic lupus erythematosus sera

Sera from 34 patients with juvenile rheumatoid arthritis (JRA), 31 patients with systemic lupus erythematosus (SLE), and 22 normal controls were studied for microcytotoxicity before and after clearing in the ultracentrifuge. Normal T cells as well as T gamma and non-T gamma subpopulations were used. Before ultracentrifugation all test sera showed apparent T gamma cell specificity in the microcytotoxicity assay where rabbit complement was added. JRA and SLE sera produced much higher proportions of cell killing than normal controls. Ultracentrifugal clearing resulted in marked diminution in microcytotoxicity of JRA and some SLE sera. However, a considerable proportion of lupus sera continued to show T cell subset cytotoxicity after ultracentrifugal clearing. No evidence for significant alteration of T gamma rosetting capacity was recorded when ultracentrifuge-cleared test sera were preincubated with T cells prior to T gamma EA rosette formation. Apparent T gamma cytotoxic specificity in some uncleared JRA and SLE sera may relate to high molecular weight materials (IgM and immune complexes) present in such samples, whereas in others it relates to lymphocyte reactive antibody with subset reactivity.