Dendritic cell-lymphocyte clusters that form spontaneously in rheumatoid arthritis synovial effusions differ from clusters formed in human mixed leukocyte reactions.
Lymphocytes cluster about dendritic cells (DC) spontaneously in 48 h cultures of rheumatoid arthritis synovial fluid (RA SF) mononuclear cells and in peripheral blood autologous or allogeneic mixed leukocyte reactions. In the latter case, the clusters are predominantly CD4+ T cells (T4/T8 greater than 5) and with time progress in blastic cells that express IL-2 (Tac) and/or transferrin (T9) receptors. In contrast, the clusters in RA SF cultures have a T4/T8 ratio of less than 1 and a majority of the T8 cells coexpress the Leu 7 marker. T cells in these clusters remain inert and with time the clusters disintegrate. Addition of IL-1, IL-2, or IFN-gamma alone or in combination had no effect on RA SF clusters but T cells became blastic when exposed to 10% RA SF. Mixing experiments using RA SF DC with normal T cells and RA T cells with normal DC show that both RA SF DC and T cells are immunofunctional. In addition, clusters of RA SF from a patient with active tuberculosis proliferated vigorously to PPD. Therefore, the unique RA SF cluster profile may reflect the memory nature of the RA SF T cells resulting in a paucity of T cells that are responsive to autologous stimulation. However, an immunosuppressive role for the double-labeled (CD8 and Leu 7) cells has not been excluded.
Tsai
V
V
Department of Medicine, University of California, San Diego 92103.
Zvaifler
N J
NJ
D000943:Antigens, Differentiation / Q000032:analysis; D001172:Arthritis, Rheumatoid / Q000473:pathology*; D003712:Dendrites / Q000473:pathology*; D005122:Exudates and Transudates / Q000473:pathology*; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000473:pathology*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008858:Microscopy, Phase-Contrast; D010641:Phenotype; D013582:Synovial Fluid / Q000032:analysis*; D013585:Synovitis / Q000473:pathology
D000943:Antigens, Differentiation