Cellular immunity in patients with systemic juvenile rheumatoid arthritis.

We studied the cellular immune responses in 10 patients with systemic form of juvenile rheumatoid arthritis. The numbers of peripheral T lymphocytes and their helper/inducer and cytotoxic/suppressor subpopulation were within normal levels. Activated T lymphocytes (DR+) were slightly increased but not at statistically significant levels. In contrast to the T cells, B lymphocytes were increased; both the percentage of B cells (B1+) and the number of cells spontaneously secreting IgG, IgA, and IgM were increased. Stimulation of peripheral mononuclear cells in vitro with pokeweed mitogen induced poor plaque-forming cell responses, which were partially improved upon removal of monocytes. The presence of concanavalin A in the cultures led to complete suppression. We conclude that patients with systemic JRA are characterized primarily by B-cell rather than T-cell abnormalities.