Experimentally induced stress in rheumatoid arthritis of recent onset: Effects on peripheral blood lymphocytes

Objective: To examine the effects of experimentally-induced stress on the mobilization of peripheral blood lymphocytes (PBL) in patients with rheumatoid arthritis (RA) of recent onset. Methods: Twenty-two (16 F, 6 M) patients (mean age 57.6 yrs.) and 23 (15 F, 8 M) healthy subjects (mean age 54. 7 yrs.) were subjected to experimental stressors. The numbers of T- cells, B-cells, and NK-cells were determined before and after the completion of tasks inducing physical and mental effort. Results: The change in PBL in response to stress was about equal for patients and healthy subjects (p > 0.75 in all PBL subsets). In patients as well as in healthy subjects, the correlations between PBL and cortisol changes in response to stress tended to be positive, while the correlations between PBL and cardiovascular changes were positive in healthy subjects, but zero or negative in patients. Moderate to high (0.32 ≤ r ≤ 0.55) correlations between PBL changes and pain were observed. Conclusion: Experimentally-induced changes in PBL (as well as cortisol) are normal in patients with early RA who are receiving long term medication, but correlations between these changes and autonomic nervous system responses are zero or negative. This apparent shift in the control of the change in PBL in response to stress is observed in particular in patients with more pain. The pathophysiological significance of these findings should be clarified in longitudinal studies.