Objective. To examine synchronous changes in soluble interleukin-2 receptor (sIL-2R) levels, daily indicators of emotional stress, joint inflammation, and reported pain in patients with rheumatoid arthritis (RA).

Methods. Fourteen patients were studied on each of 6 occasions, 2 weeks apart. Measures included daily ratings of mood disturbance, undesirable events, and joint pain; clinical examination of joint swelling; and serum assays of sIL-2R. Pooled within-person correlations among these variables were calculated.

Results. Consistent with the results of previous research, joint inflammation covaried directly with sIL-2R levels. Changes in mood disturbance were unrelated to changes in joint inflammation, but increases in mood disturbance were linked with decreases in sIL-2R levels and increases in reported joint pain.

Conclusion. These findings provide preliminary evidence that psychoimmune processes may be implicated in short-term changes in RA disease activity.