Rheumatoid pericarditis: new immunopathological aspects.

Rheumatoid pericarditis (RP) is a well known extraarticular manifestation of rheumatoid arthritis (RA). It is not frequently diagnosed despite its high reported prevalence in post-mortem studies. There have been no immunohistological studies of its presence in pericardial membranes. Here we report a complete immunohistological study of two RA patients with RP complications, using a panel of monoclonal antibodies (mAbs) for the recognition of B, T, and NK cells. Both cases showed strong and almost exclusive pericardial membrane infiltration of CD8+ T-cells which was correlated with a higher than expected similar increase in the subset of peripheral blood lymphocytes (PBL). These findings suggest an important role for CD8+ T-cells in chronic RA, especially in this extraarticular manifestation of the disease.

Growth factor activity of IL-6 in the synovial fluid of patients with rheumatoid arthritis.

OBJECTIVE: We set out to determine whether the ability of synovial fluids (SF) in patients with rheumatoid arthritis (RA) to facilitate the proliferation of synovial tissue-derived fibroblastic cell lines was related to the presence of growth factors and/or cytokines. METHODS: The growth factor activity of 20 RA SF was measured by their ability to induce anchorage-independent growth of the rat NRK-49F (49F) fibroblastic strain. The presence of transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF) was also assessed using neutralising anti-TGF-beta or anti-PDGF-AB mAbs. Cytokines were measured by functional assays or ELISA: RESULTS: We observed a correlation between growth factor activity and the IL-6 levels in SF. Both were correlated to the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in SF and serum. IL-6 (at concentrations above 10(4) U/ml), synergized with growth factors in the induction of the anchorage independent (AI) growth of 49F cells. Pretreatment of SF with a neutralising anti-IL-6 mAb substantially reduced the capacity of these SF to induce AI growth of 49F cells, confirming the growth factor activity of IL-6 in this test. In contrast, IL-6 alone or in association with PDGF, epidermal growth factor (EGF) or TGF-beta had no effect on the anchored growth of synovial tissue-derived fibroblasts, and treatment of SF with a neutralising anti-IL-6 mAb did not affect their ability to increase the growth rate of synovial tissue-derived fibroblasts. CONCLUSIONS: These results strongly suggest that IL-6 is responsible for the observed correlation between the growth factor activity of SF and inflammatory indexes such as ESR and CRP. However, neither IL-6 nor PDGF were responsible for the observed positive effect of SF on synovial fibroblastic cell lines.

CD57+ T lymphocytes are derived from CD57- precursors by differentiation occurring in late immune responses.

CD3+ T cells expressing the 110-kDa CD57 antigen are found in survivors of renal, cardiac and bone marrow transplants, in patients with acquired immune deficiency syndrome and in patients with rheumatoid arthritis. They are also present in normal individuals and expand upon ageing. They do not grow in culture and their role in the immune response is poorly understood. The expression of the various isoforms of the leukocyte common antigen (CD45) identifies a spectrum of differentiation in CD4+ and CD8+ T cells ranging from naive (CD45RA+CD45RBbrightCD45RO-) through early primed cells (CD45RA-RBbrightROdull) to highly differentiated memory cells which are CD45RA-RBdullRObright. CD45 isoforms expressed by CD57+ T cells showed distinct differences between CD4+ and CD8+ populations, but in each case indicated an advanced state of differentiation. The expression of T cell receptor V beta families was highly variable between individuals, but both CD57+ and CD57- cells show a full range of the specificities tested. V beta expression was more closely related within either the CD4+ or the CD8+ subsets, irrespective of CD57 expression, than between these subsets, suggesting a relationship between CD57+ and CD57- cells within the same T cell pool. This possibility was supported by experiments showing that CD3+CD57+ lymphocytes were similar to CD3+CD57- T cells in terms of the production of basic T cell cytokines [interleukin (IL)-2, IL-4, and interferon-gamma]. Furthermore, in vitro stimulation of CD3+CD57- T cells in secondary mixed leukocyte reaction or by co-culture with IL-2 and IL-4 induced the appearance of CD3+CD57+ cells with phenotypic and functional similarities to in vivo CD3+CD57+ cells. These data strongly suggest that the expression of CD57 is a differentiation event which occurs on CD57- T cells late in the immune response.

Human mucosyl lymphocyte marker expression in synovial fluid lymphocytes of patient with rheumatoid arthritis.

OBJECTIVE: Human mucosyl lymphocyte marker (HML-1) antigen is an activation antigen and adhesion molecule of the beta 7 integrin family, which is generally restricted to T cells found in the intestinal epithelium. Expression of the membrane antigen as defined by the monoclonal antibody HML-1 was studied on peripheral blood (PB) lymphocytes and synovial fluid (SF) lymphocytes in 10 patients with rheumatoid arthritis (RA) and in a control group of patients with osteoarthritis (OA). METHODS: Double fluorescence activated flow cytometry was used to assess HML-1 expression with T cell subtype antigens (CD3, CD4, CD8) or activation markers interleukin 2 receptor (IL-2R) (CD25), HLA-DR, and lymphocyte function associated antigen (LFA-1) (CD11a) were assessed by flow cytometry. RESULTS: HML-1 antigen expression in PB lymphocytes of patients with RA (7.3%) was found to be comparable to the control group (6.4%). In contrast, 25.4% (range 14-43%) of SF lymphocytes expressed HML-1 antigen, compared to 13.6% of SF lymphocytes in patients with OA (p < 0.001). In RA, 62% of HML-1 positive cells from SF lymphocytes were the CD8 subtype, compared to 10.6% of PB lymphocytes (p < 0.003), and 18% of control SF lymphocytes (p < 0.05). Furthermore, HML-1 antigen and HLA-DR antigen were coexpressed in 75% of RA SF lymphocytes compared to 29.6% of control SF lymphocytes (p < 0.01). In contrast, coexpression of LFA-1 and the Il-2R did not differ from that of control. CONCLUSION: We describe overexpression of the adhesion molecule HML-1 in SF lymphocytes of patients with RA, preferentially in the CD8 subset. These results suggest a similarity between the expression of activation antigens in SF lymphocytes of patients with RA and T lymphocytes present in the intestinal epithelium.

Increased percentage of CD3+, CD57+ lymphocytes in patients with rheumatoid arthritis. Correlation with duration of disease.

OBJECTIVE: To determine whether a small CD3+ lymphocyte population expressing 110-kd CD57 antigens (HNK1) is expanded in patients with rheumatoid arthritis (RA), as it is in patients who have undergone bone marrow transplantation and patients with the acquired immunodeficiency syndrome, and to investigate whether it is involved in the pathogenesis of RA. METHODS: The phenotype of CD3+, CD57+ lymphocytes was analyzed by flow cytometry, and correlations between the percentage of these cells in the blood and various clinical and biologic parameters were investigated. RESULTS: The percentage of CD3+, CD57+ lymphocytes was increased in RA patients compared with controls. These lymphocytes expressed T cell receptor alpha/beta. Eighty percent expressed the CD8 accessory molecule, and 20% expressed the CD4 accessory molecule. The leukocyte common antigen CD45RA isoform was expressed by these CD3+, CD57+ lymphocytes in blood. The HLA-DR antigen was expressed in synovial fluid but not in blood. Finally, the percentage of these lymphocytes in the blood correlated with the duration of RA. CONCLUSION: The expansion of the CD3+, CD57+ lymphocyte population and their activation in the synovial fluid of RA patients suggest that these cells are involved in the inflammatory process.

T cell receptor distribution in rheumatoid synovial follicles.

OBJECTIVE: In rheumatoid arthritis (RA) joint erosion is accompanied by T cell infiltration of the synovial tissue. The resulting T cell receptor (TCR) repertoire is a combination of antigen driven shaping, nonspecific selection by endothelial cell-T cell interactions, and cytokine mediated chemoattraction. Considering the conflicting results of molecular biology studies of the TCR repertoire in RA, we attempted to obtain new data to clarify the situation through microscopic distribution analysis of TCR beta chain diversity in synovium follicular CD4/CD8 subsets. METHODS: We used dual color fluorescence confocal microscopy with CD4/CD8 monoclonal antibodies (Mab) and a panel of new anti-V beta Mab. The analysis focussed on lymphocyte rich, follicle-like areas of synovial tissue from 4 patients with RA. RESULTS: The expression of individual TCR beta families varied between areas within the T cell follicles, and between patients. Normal absolute levels of some beta chains can be completely skewed towards one subset, indicating that overall TCR evaluation is insufficient. CONCLUSION: Confocal microscopy analysis of localized TCR diversity in RA synovium offers novel insight into overall V beta gene usage, which appears to be the accumulation of several localized microexpansions.