CD8 LYMPHOCYTE SUBSETS IN ACTIVE POLYMYALGIA-RHEUMATICA - COMPARISON WITH ELDERLY-ONSET AND ADULT RHEUMATOID-ARTHRITIS AND INFLUENCE OF PREDNISONE THERAPY

The aim of this study was to evaluate CD8 lymphocyte subsets in active polymyalgia rheumatica (PMR), to determine whether low percentages of CD8+ cells could be used to differentiate PMR from elderly-onset (EOR A) and adult rheumatoid arthritis (RA), and to investigate the effects of prednisone on CD8 lymphocyte subsets. A significant reduction of p ercentages and absolute numbers of CD8bright+ cells was observed in pa tients with active PMR. Both CD8bright+, CD57- and CD8bright+, CD57+ s ubsets were significantly reduced. Reduced percentages of CD8+ cells w ere observed in 55% of patients with active PMR/giant cell arteritis ( GCA), in 23% with EORA and in 44% with adult RA. Prednisone therapy in PMR patients, after only 1 week, increased the lymphocyte count and t he absolute numbers of lymphocyte subsets significantly. However, the percentages of CD8bright+ cells remained persistently low for the 2 yr study period in 80% of the patients with low pre-treatment levels. Ou r results demonstrate that CD8 cell percentage is a poor epidemiologic al discriminator for PMR diagnosis. Notwithstanding the rise in absolu te numbers of CD8 cell subsets induced by prednisone, the persistently low percentages of CD8+ cells in a group of PMR patients indicate an abnormality connected with the disease.