SUMMARY

The phenotypic characteristics of peripheral blood lymphocytes were investigated in 22 patients suffering from active polymyalgia rheumatica/giant cell arteritis (PMR/GCA) prior to steroid treatment. We observed a significant reduction in the absolute number and the relative percentage of CD4-, CD8+ and CD3+, CD16+ and/or CD56+ cells compared to con-trols. Fifteen patients were investigated prospectively over a 6-month period of prednisone therapy. At the end of the study CD4-CD8+ cells had increased significantly compared to baselines, CD3+CD16+ and/or CD56+ cells remained sig-nificantly lower when compared to controls. We did not observe any abnormalities in the absolute number and percentage of HLA-DR+ T lymphocytes, CD5+ B cells and NK cell phenotypes before or during steroid treatment. Our study con-firms that there was significant increase in the absolute number of CD8+T cells during steroid treatment in the PMR/GCA patients, but indicates the persistence of an immunological alteration despite the control of disease manifestations. KEY WORDS: Polymyalgia rheumatica, Giant cell arteritis, Lymphocyte subpopulations, Steroid therapy. ALTHOUGH the etiology and pathogenesis of polymyal-gia rheumatica (PMR) and giant cell arteritis (GCA) remain unknown, there is data indicating dysregulation and activation of the immune system [1-5]. A reduced percentage of CD8+ T cells in peripheral blood ha