THE VALUE OF PERCENTAGE OF CD8-LYMPHOCYTE LEVELS IN DISTINGUISHING POLYMYALGIA-RHEUMATICA FROM EARLY RHEUMATOID-ARTHRITIS( T)

Objective. To determine whether the low absolute numbers and percentag es of CD8 positive T cells in the circulation of patients with polymya lgia rheumatica (PMR) could be used as a new diagnostic criterion for the disease. Methods. The % CD4 and CD8 positive T lymphocyte sub-popu lations were measured in 37 patients with PMR before treatment and dur ing steroid treatment over the subsequent 2 years, in 21 patients with rheumatoid arthritis (RA), and in 27 normal (N) control subjects. Res ults. During the study, 10 patients, who were initially diagnosed as P MR, were reclassified as having had a myalgic onset of RA (PMR-RA), ac cording to the American College of Rheumatology criteria for the diagn osis of RA. No decreased %CD8+ T lymphocyte subset had been observed i n these patients at presentation, before steroid therapy, or during tr eatment with steroids when compared with the RA and N groups. Conclusi on. The measurement of %CD8+ T cell subset may provide a simple method for determining whether patients presenting with myalgia are ''true'' PMR or are destined to develop RA.