Increased responsiveness of rheumatoid B lymphocytes to stimulation by Epstein-Barr virus.

Blood lymphocytes from rheumatoid patients and normal subjects were examined for responsiveness in culture to Epstein-Barr virus (EBV) infection by outgrowth assay and 3HTdR uptake. With both unseparated and B-cell-enriched lymphocytes the frequency and rate of outgrowth to form permanent cell lines were significantly higher for rheumatoid than for normal cells. In B-enriched rheumatoid preparations the proportion of responsive cells was also greater, and DNA synthesis was induced by a lower infecting dose of EBV in rheumatoid than in normal cells. The percentage of autologous T cells needed to ensure regression of B-cell proliferation in EBV-infected cultures was considerably higher with rheumatoid than with normal cells. These findings suggest that in rheumatoid arthritis the abnormal lymphocyte responsiveness to EBV has two components, a T-cell immunoregulatory defect, and a separate increased responsiveness of B cells to EBV.