The distribution of the major peripheral blood T, B and NK cell subsets does not predict the clinical outcome of Graves' disease patients after methimazole therapy

Biological markers capable of predicting the clinical outcome of antithyroi d drug therapy could be clinically useful in selecting the modality of trea tment for Graves' disease, but at present they are unavailable. In the pres ent study we prospectively explore the Value of 22 different peripheral blo od T, B and NK lymphocyte subsets to predict remission and relapse in a gro up of 42 Graves' disease patients. Eighteen patients were studied at diagno sis, before treatment, and 24 during antithyroid drug therapy. All cases we re followed-up for at least one year after finishing an 18 month cycle of m ethimazole therapy. The combination of flow cytometry and 3- color immunofl uorescence did not reveal significant differences in the distribution of th e major peripheral blood T, B and NK cell subsets between the relapsed pati ents and those in remission, both in the groups studied at diagnosis and in those analyzed during the cycle of antithyroid drug therapy. In our search for a prognostic marker for relapse prediction we found that some lymphoid subpopulations such as total B cells, total NK and NK CD8+ ce lls showed high sensitivity (88-100%). In turn, other subsets such as TCD8, total T and B cells expressing the CD25 antigen displayed high specificit y (77-88%).