CD8+ lymphocyte subset in polymyalgia rheumatica and arteritis temporalis. Inverse relationship between the acute hepatic phase reactants and the CD8+ T-cell subset.
Laboratory hallmarks of giant cell arteritis (GCA) are mainly an elevated ESR and a decreased level of the CD8+ T-lymphocyte subset. Because a normal or minimally raised ESR is found in 10-20% of patients with an active GCA, we assessed the role of the CD8+ T-cell subset in patients with high and low acute hepatic phase response. Fifty-five patients with active, untreated disease were studied. The median ESR was 85 mm/h and the median CRP was 57 mg/l (normal controls less than 10 mg/l). The median CD8+T-cell reading was 0.197 X 10(9)/l and the median CD8% was 10.0 (3.8 - 23), which was significantly different from normal controls (CD8+ T-cells 0.511 X 10(9)/l, CD8+% 22 (12 - 32] (p less than 0.05). A low acute phase response (median ESR 41 mm/h, range 12-47) was identified in 11 patients or 20%. In these patients the median CD8+ T-cell reading was 0.176 x 10(9)/l and the median CD8+% 8.5 (4.3 - 15). These CD8+ values were significantly lower than values for the CD8+ T-cells (0.209 x 10(9)/l) and CD8+% (10.0), found in patients with a high acute phase response (median ESR 90 mm/h, range 50 - 145) (p less than 0.01). Our study confirms the presence of a subgroup of patients with PMR/AT who, despite active disease, exhibit a low acute phase response, and further indicates that this subgroup is characterized by a marked depletion of CD8+ T-cells in peripheral blood.