CIRCULATING T-CELL SUBTYPES IN POLYMYALGIA-RHEUMATICA AND GIANT-CELL ARTERITIS - VARIATION IN THE PERCENTAGE OF CD8+ CELLS WITH PREDNISOLONE TREATMENT

Objectives-Some reports have described a decreased percentage of circu lating CD8+ cells in patients with polymyalgia rheumatica and giant ce ll arteritis (PMR/GCA) before treatment and persisting for some months during treatment with corticosteroids. Other studies have found no su ch changes. There are overt methodological variations between these st udies and there may also be hidden differences, such as the timing of blood samples. The purpose of this study was to investigate T cell sub types in patients with PMR/GCA while controlling for variables known t o affect T cells. Methods-Circulating T cell subsets were measured in 36 patients with PMR/GCA before and during treatment with prednisolone . Blood samples during treatment were taken before the daily dose of p rednisolone. The whole blood lysis method was used followed by flow cy tometry. Results-Compared with controls, CD8+ cells were not reduced b efore treatment in patients with PMR/GCA (0.44 x 10(9)/1; 28% of lymph ocytes). CD4+ cells were also normal (0.78 x 10(9)/1; 48% of lymphocyt es). During treatment with prednisolone total T cells increased from 1 .18 to 1.59 x 10(9)/1 and CD4+ cells increased from 0.78 to 1.05 x 10( 9)/1. The percentage of CD8+ cells decreased on treatment from 28 to 2 5%. Conclusion-This study does not confirm the finding of some groups that the percentage of circulating CD8+ cells is reduced in patients w ith PMR/GCA before treatment. It does show that the percentage of CD8 cells decreases during treatment with corticosteroids. This needs to be considered when designing studies of lymphocyte subsets in diseases treated with corticosteroids.