Analysis of serial synovial biopsies in patients with rheumatoid arthritis: Description of a control group without clinical improvement after treatment with interleukin 10 or placebo

Objective. Analysis of serial synovial biopsy specimens is increasingly use d as an outcome measure for the evaluation of therapeutic interventions. Ho wever, observations in placebo treated groups are scarce. We describe the i mmunohistologic features of thr synovium in placebo treated patients with R A and in those who received interleukin 10 (IL-10). Methods. Ten patients with active RA received dosages of either placebo (n = 7) or 5 mu/kg (n = 1) or 10 mu g/kg (n = 2) of recombinant human IL-10 (r hIL-10; SCH 52000, Schering-Plough, Kenilworth, NJ, USA) daily for 28 conse cutive days. Synovial biopsy specimens from the knee joint were obtained by needle arthroscopy before and 4 weeks after initiation of treatment. Immun ohistochemistry was per formed using monoclonal antibodies specific for the following surface markers and cytokines: CD, CD4, CD8, CD38, CD68, CD55, I L-1 beta, IL-6, and tumor necrosis factor-alpha. Results. No patient exhibited clinical improvement after treatment with pla cebo or any rhIL-10 dosage. Microscopic analysis of synovial tissue reveale d no significant change in the scores for infiltration by inflammatory cell s or in the scores for the expression of cytokines after treatment. Conclusion, Studies of serial synovial biopsies from patients treated with placebo or IL-10 revealed no changes in immunohistologic scores. This sugge sts that the biopsy procedure itself has no effect on the features of the s ynovium.