Serum concentrations of soluble interleukin 2 receptor in patients with rheumatoid arthritis: effect of second line drugs.

Serum soluble interleukin 2 receptor (sIL-2R) concentrations reflect lymphocyte activation in vivo. An investigation was carried out to determine if sIL-2R concentrations correlate with existing disease activity parameters in patients with rheumatoid arthritis (RA) and whether these concentrations are modulated by treatment with second line drugs. Seventy nine patients with rheumatoid arthritis with active disease were prospectively treated with sodium aurothiomalate, auranofin, or sulphasalazine. Sequential concentrations of sIL-2R were measured by enzyme linked immunosorbent assay (ELISA). No correlations were observed between sIL-2R concentrations and clinical parameters and there were only moderate associations with concentrations of C reactive protein and the erythrocyte sedimentation rate. Concentrations of sIL-2R did not significantly change with treatment. It is concluded that sIL-2R probably measures an aspect of rheumatoid synovitis distinct from acute phase reactants and is not influenced by treatment with second line drugs.