Effect of Medication on Synovial Fluid Leukocyte Differentials in Patients With Rheumatoid Arthritis

We compared leukocyte populations in synovial fluid samples from 45 rheumatoid arthritis patients, grouped according to medications taken. Seventeen of the 22 patients receiving only nonsteroidal antiinflammatory drugs had lymphocytes as the single predominant cell. None of the 23 patients receiving second‐line agents had lymphocyte predominance. These findings may have important implications for drug mechanisms and must be considered in future studies of synovial fluid.