Synovial fluid lymphocytes in different subtypes of juvenile rheumatoid arthritis

Abstract

We studied the subsets of synovial fluid (SF) lymphocytes and their activation states in 4 subtypes of juvenile rheumatoid arthritis. The expression of lymphocyte differentiation antigens and activation markers (Ia and Tac) appeared to be similar in these subgroups. Tac+ DNA‐synthesizing T blasts represented, at most, 5% of all SF mononuclear cells. This finding was in clear contrast to the high proportion of Ia‐positive SF mononuclear cells. There were no differences in Ia and Tac expression or DNA synthesis among the different juvenile rheumatoid arthritis subgroups. This finding suggests that the cell‐mediated immune response may represent secondary features of the disease that are involved as a final common pathogenetic pathway.