definition of adultonset rheumatoid arthritis from elderlyonset rheumatoid arthritis by studying tlymphocyte subpopulations their soluble receptors and soluble receptor of interleukin2 aims the study of the distribution of tlymphocyte subpopulations has revealed some immune characteristics of rheumatoid arthritis ra as well as polymyalgia rheumatica pmr there is much evidence that the subsets of tlymphocyte subpopulations are well correlated with the age of the patient and the precise diagnosis of ra and pmr the aims of the study were to evaluate the absolute number and percentage of tlymphocyte subpopulation subsets in peripheral blood and their soluble receptors and serum soluble receptors of interleukin2material and methods thirtysix patients with ra were divided into 21 adultonset ra aora and 15 elderlyonsets ra eora patients they were compared with 48 pmr patients 21 normal subjects under 45 years and 17 healthy elderly subjects over 65 years tlymphocyte subsets were studied by facscan with double stained specific monoclonal antibodies the el isa method was used to determine soluble receptors of cd4 and cd8 and il2results the aora patients had a significant alteration of tlymphocyte subpopulations as well as their specific soluble receptors compared to eora patients on the other hand distribution of tlymphocyte subpopulations in eora patients was quite similar to that in pmr patientsconclusions this method is probably not applicable for daily routine clinical practice but provides some interesting data for differential diagnosis between ra and pmr