Increased γδ T cells in mice lacking Itk. (A) Flow cytometric analysis of γδ T cells in the thymus, spleen, and lymph node of WT and Itk^−/− mice. (B) The percentage and absolute number of γδ T cells were calculated from thymus and spleen. (C) Flow cytometric analysis of CD4 and CD8 populations of CD3⁺γδTCR⁺ cells in the thymus, spleen, and lymph nodes of WT and Itk^−/− mice. (D) The percentage of CD4⁺ γδ T cells, as well as the absolute number of CD4⁺ γδ T cells in the thymus and spleen of WT and Itk^−/− mice (n > 10 mice). *P < .01.