SummaryIntroduction:aging is associated with several immunologic changes. Regulatory (Treg) and effector T cells are involved in the pathogenesis of infectious, neoplastic, and autoimmune diseases. Little is known about the effects of aging on the frequency and function of these T cell subpopulations.Methods:peripheral blood mononuclear cells (PBMC) were obtained from 26 young (under 44 years old) and 18 elderl...