ELECTRON-MICROSCOPY AND IMMUNOLABELING OF YERSINIA ANTIGENS IN HUMAN SYNOVIAL-FLUID CELLS

Recent findings have emphasized the involvement of bacterial antigens in synovitis in reactive arthritis. It is still unclear, however, in w hat form the microbial material exists in the joint. Both antigen-cont aining cells and intact bacteria have been proposed as candidates on t he basis of immunohistochemical studies of the synovial membrane. This study addresses that question by electron microscopy and peroxidase i mmunolabeling of synovial fluid cells from three patients with reactiv e arthritis triggered by Yersinia enterocolitica O:3. For all three pa tients a diffuse reaction in the cytoplasm of phagocytes was interpret ed as bacterial material in a degraded form. These results are consist ent with our proposal that intact bacteria rarely, if ever, enter the joints of Yersinia-triggered reactive arthritis patients.