title: Increased DNA and/or RNA content of synovial fluid cells in rheumatoid arthritis: a flow-cytometry study.
abstract: Flow-cytometry studies of DNA and RNA content were carried out in acridine orange-stained synovial fluid lymphocytes from 11 patients presenting with classical or definite rheumatoid arthritis. Monoclonal antibodies were used to detect specific T cell surface antigens (OKT3, OKT4, OKT8) and antigens associated with lymphocyte activation (OKIa 1, OKT10). T3 positive cell percentages were comparable to those of normal blood, although T4/T8 ratios were decreased in 4 out of 5 cases, and HLA-DR positive cells increased. Six out of 11 patients showed percentages of dividing cells varying from 2.2 to 7.2% as compared with less than 1% in the other patients and in normal blood. Nondividing cells were characterised by an increase in their RNA content compared with normal blood. A greater increase of RNA content was observed in patients with lower percentages of dividing cells, suggesting a G1/S block. Changes in cellular DNA and/or RNA contents provide a valuable parameter of lymphocyte activation, not necessarily linked to the expression of differentiation antigens by activated cells.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002455:Cell Division; D004247:DNA / Q000032:analysis*; D005260:Female; D005434:Flow Cytometry; D006681:HLA-D Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000032:analysis* / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012313:RNA / Q000032:analysis*; D013582:Synovial Fluid / Q000032:analysis* / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000145:classification
chemical_list: D006681:HLA-D Antigens; D000949:Histocompatibility Antigens Class II; D012313:RNA; D004247:DNA