Immunocytological studies of Epstein-Barr viral antigen and antibody in rheumatoid synovial fluids.

Evidence for intra-articular immunity to Epstein-Barr virus (EBV) was sought in synovial fluids (SF) and SF phagocytes derived from patients with and without rheumatoid arthritis (RA). Antibody titres to EBV were not significantly different in SF of 32 RA and 25 non-RA patients. Whereas the majority of RA patients (69%) showed Ig-containing complexes (IC) in SF phagocytes, fluorescent antibody staining of these by anti-EBV serum was negative except with 6 RA patients. Extended analysis of the SF phagocytes of the latter, however, showed no EBV specificity in their IC, suggesting that these represented non-specific "pseudo-IC'. These studies do not support a role for EBV-containing IC in the propagation of rheumatoid synovitis and demonstrate that not all immunofluorescent inclusions in RA phagocytes (ragocytes) represent immune complexes.