The human thymus is required for establishment of a normal T cell repertoire in fetal development, as children born without a thymus (DiGeorge Syndrome) lack thymus-derived (T) and T cell immunity. While the function of the thymus in children for production of new T cells is clear, it has not been obvious that the adult thymus can produce significant numbers of new T cells. Until recently, no assays were available to directly evaluate postnatal thymic function. This paper reviews work on human thymic aging at Duke University School of Medicine and discusses the relevance of this work to devising new strategies for T cell immune reconstitution in man. VSports手机版.