LYMPHOCYTE SUBPOPULATIONS IN PATIENTS WITH PRIMARY FIBROMYALGIA

Objective. Fibromyalgia(FM) is a clinical entity of unknown etiology f requently diagnosed in rheumatology. The potential involvement of the immune system in its pathogenesis has been suggested. Studies of abnor mal T cell subpopulations often have been inconclusive. We attempted t o clear this point by comparing lymphocyte subpopulations, including s ome of the newer activation markers, in patients with FM and healthy c ontrols. Methods. Sixty-five patients with FM and 56 healthy controls were studied. Flow cytometry was used as a quantification technique to measure lymphocyte subpopulations, CD3 (T cells), CD19 (B cells), CD1 6 (natural killer cells), CD4 (T helper/inducer cells), CD8 (T cytotox ic/suppressor cell), CD25 (interleukin 2 receptor), CD69 (activation i nducer molecule marker), CD71 (transferrin receptor) and CD54 (ICAM-1) ; CD4/CD8 ratios were also estimated. Results. The number of T cells e xpressing activation markers CD69 and CD25 was decreased in patients w ith FM; the other subpopulations were similar in patients and controls . Conclusion. Our results suggest a defect in T cell activation in pat ients with FM.