IMPAIRED INTERLEUKIN-8-DEPENDENT CHEMOTAXIS BY SYNOVIAL-FLUID POLYMORPHONUCLEAR LEUKOCYTES IN RHEUMATOID-ARTHRITIS

The accumulation of polymorphonuclear leukocytes (PMN) in synovial flu id is a common feature of rheumatoid arthritis (RA). We studied the ch emotactic response of PMN obtained from the synovial fluid and from th e peripheral blood of patients with RA using a modified Boyden's metho d, in which interleukin-8 (IL-8) or N-formylmethionyl-leucyl-phenylala nine (FMLP) was used as a chemotactic agent. The IL-8-induced response of peripheral blood PMN from 15 patients with RA did not differ from that of 15 healthy controls. A decreased chemotactic response to IL-8 was, however, observed in PMN from the synovial fluid of 12 patients w ith RA compared with peripheral blood cells of the same individual. Th is defective chemotactic ability of PMN was inversely correlated with the number of infiltrating cells in the synovial fluid. We also obtain ed similar results with FMLP. These results indicate that the chemotac tic ability of PMN may be reduced after migrating to the synovial flui d.