Lymphocytotoxic antibodies in Israeli patients with rheumatoid arthritis

The presence, antigenic specificity, and clinical role of lymphocytotoxic antibodies (LCAs) were studied in 72 Israeli patients with rheumatoid arthritis (RA). Using the microlymphocytotoxicity assay on a cell panel of 47 donors, LCAs were found in 55% of the 72 RA sera, each displaying a distinct pattern of anti-lymphocytic reactivity, mostly against B lymphocytes. Human lymphocytic antigens (HLA) analysis of donors' lymphocytes suggested that activity of LCA-positive RA sera is HLA directed in 60% of cytotoxic sera. The anti-HLA antibodies found were not autoreactive and were not restricted to a particular class I or class II antigen. Relating the presence of LCAs to selective clinical features revealed that LCAs are inversely associated with the presence of an erosive disease (P < 0.01) and with the patients' HLA-DQw1 (P < 0.01). These findings suggest that LCAs in Israeli patients with RA are very common, multispecific and may have a protective role not mediated through interaction with self-HLA antigens.