T cell Activation
Utility: Functional evaluation of T cell activation.
Specimen: 8 - 15 mL peripheral blood in sodium heparin (green top).
CPT codes: 86359, 86360, 86355, 86357, 88184, 88185 x 6, 81887.
Clinical indication/general description
When T cells are activated through the T cell receptor, a number of signal transduction events occur leading to the expression of the surface marker CD69 at early time points (4 hours) and CD25 at late time points (4 days). This assay can be used to evaluate infants with defective T cell function.
A functional flow cytometric-based assay evaluates activation of T helper cells (CD3+CD4+) and T cytotoxic cells (CD3+CD8+) using CD25 and CD69 surface expression. Quiescent lymphocytes express low levels of the CD25 and CD69 antigens and upon activation the expression of CD25 and CD69 is markedly increased.