The sequential analysis of T lymphocyte subsets and interleukin-6 in polymyalgia rheumatica patients as predictors of disease remission and steroid withdrawal.

CD4 and CD8 T lymphocyte subsets, the late T cell activation marker, HLA-DR, and serum interleukin-6 (IL-6) levels of 57 polymyalgia rheumatica (PMR) patients were followed over 2 yr to investigate whether they could be used to predict the safe withdrawal of steroid therapy. Cell phenotypes were studied by flow cytometry and IL-6 levels by ELISA. %CD8 cells were reduced below the normal range in PMR patients prior to steroid therapy. In 56% of patients, the %CD8 T lymphocytes failed to return to normal levels when quiescent disease allowed cessation of steroid therapy. Activated CD8 T cells, as detected by HLA-DR positivity, were above the normal range at the initiation of therapy and showed a negative correlation with %CD8 T cells. The serum concentration of IL-6 fluctuated over 24 months, and the correlation between IL-6 and erythrocyte sedimentation rate (ESR) seen prior to treatment was not seen at later intervals. The %CD8 T cell and serum IL-6 levels are not a good indicator of disease activity in PMR and are, therefore, unable to predict the safe withdrawal of steroids.