part of part of has part has part characteristic of inheres in towards has modifier T cell naive T cell Abnormal T cell subset distribution Abnormal naive T cell proportion 2017-09-03T12:46:29Z Any abnormality in the proportion of naive T cells relative to the total number of T cells. Following the development of T cells in the thymus, they enter the blood stream and recirculate between the blood and peripheral lymphatic tissues. Mature recirculating T cells that have not yet encountered their specific antigen are known as naive T cells. Mature T cell not yet exposed to antigen with the phenotype CCR7-positive, CD45RA-positive, and CD127-positive. This cell type is also described as being CD25-negative, CD62L-high and CD44-low. Human mature CD4+ T cells are functionally heterogeneous and can be divided into naive and memory/effector populations based on the expression of cell surface markers. Although the most significant differences between these two populations are functional, the leukocyte common Ag (CD45) was promoted as a potential marker of memory T cells. CD45 Ag may be found in various isoforms depending on alternative splicing of three extracellularly expressed exons. The expression of the highest molecular weight isoform, referred to as CD45RA, defines the population of CD4+ unprimed lymphocytes. Activation of naive lymphocytes through TCR engagement is followed by loss of CD45RA Ag and transition to the expression of the smallest molecular weight isoform CD45RO. These primed cells express high levels of activation Ags, acquire effector functions, and need less costimuli requirements for further activation. Abnormal proportion of naive T cells Abnormal proportion of naive thymus-derived, alpha-beta T cells abnormal ratio blood