LYMPHOCYTES FROM THE SITE OF DISEASE ARE FUNCTIONALLY DIFFERENT FROM PERIPHERAL-BLOOD LYMPHOCYTES AND MAY DEMONSTRATE ETIOLOGICALLY RELATEDANTIGEN, SPECIFICITY

Over a 12-year period, in vitro synovial lymphocyte responses to micro biological antigen stimulation were measured by the [H-3]thymidine upt ake method in referred patients with all types of non-crystal, non-sep tic, inflammatory arthritis. From this large study group comparisons o f synovial with peripheral blood lymphocyte (PBL) responses were avail able in 9 patients with enteric reactive arthritis (ERA), 12 patients with sexually acquired reactive arthritis (SARA) and 18 patients with recurrent or persistent oligoarthritis or with polyarticular 'rheumato id' arthritis. Employing 2-tailed t tests, analysis of variance (ANOVA ) or meta-analysis, as appropriate to the obtained data, significant d ifferences were found between synovial and peripheral blood responses. In only 2 of 9 patients with bacteriologically defined ERA, in only 4 of 12 patients with SARA and in only 2 of 18 patients with oligoarthr itis or 'rheumatoid' arthritis did the PBLs show statistically signifi cant responses to the antigen that elicited a significant response fro m synovial lymphocytes. It is concluded that lymphocytes from the site of disease are often functionally different from PBLs and may demonst rate etiologically related antigen specificity; thus they may be a pre ferred source of lymphocytes for the investigation of immunologically mediated disease, the etiology of which is not understood. This viewpo int is supported by a recent paper on the specificity of hepatic lymph ocytes for a protein of hepatitis C in patients with chronic hepatitis C, and also by the use of tumour-infiltrating lymphocytes for anti-me lanoma therapy.