Serum markers of T-cell activation in relapses of Wegener's granulomatosis.

Levels of soluble IL-2 receptor (sIL-2R), soluble CD4 (sCD4) and CD8 (sCD8) were measured by sandwich ELISA as markers for T-cell activation in serial serum samples drawn monthly from 16 patients showing 18 histologically proven relapses of Wegener's granulomatosis (WG). Levels of sIL-2R increased from 1162 U/ml (median, 95% CI 843 to 1814 U/ml) at three months before the relapse to 1684 U/ml (95% CI 1254 to 2202 U/ml) at the time of relapse for the whole group (P = 0.10). The 8 major relapses showed a profound rise in sIL-2R levels (P < 0.01). The level of sIL-2R at the moment of relapse correlated with the level of C-reactive protein (r = 0.547, P < 0.05) and with the disease activity score (r = 0.814, P < 0.001). There were no significant changes in levels of sCD4 or sCD8.