[CD8+ T-lymphocytes. Evaluation of the diagnostic value in patients with giant cell arteritis]

In patients with temporal arteritis and polymyalgia rheumatica, a marked depletion of percentage and number of circulating CD8+ T-lymphocytes are found in most cases. We assessed the diagnostic value of CD8+ levels in a larger group of patients with temporal arteritis and polymyalgia rheumatica before and after treatment with prednisolone and in relation to patients with other medical and rheumatic diseases. Median percentage and number of CD8+ cells in patients with polymyalgia rheumatica were significantly decreased (CD8+% 12.0, CD8+ cells 0.192 x 10(9)/l) compared with 1) controls (CD8+% 23.0, CD8+ cells 0.51 x 10(9)/l), 2) patients with other rheumatic diseases (CD8+% 20.8, CD8+ cells 0.39 x 10(9)/l), 3) patients with other medical diseases (CD8+% 20.6, CD8+ cells 0.46 x 10(9)/l). After 600 days of prednisolone treatment CD8+ values increased significantly (CD8+% 14.5, CD8+ cells 0.324 x 10(9)/l). In a cohort of patients with a low a priori probability of giant cell arteritis (39%), the positive predictive value of a significantly low CD8+ concentration was 51% while the likelihood of no disease with a normal CD8+ value was 71%.