Deletion of Eδ partially rescues lymphocytopenia in ATM-deficient mice. (A) Representative flow cytometric analyses of premalignant thymocytes from wild-type (WT), ATM^−/−, Eδ^−/−, and ATM^−/−Eδ^−/− mice (4-6 weeks). (B) Total thymic γδ cell number counts (×10⁶). (C) Total number of thymocytes and DP cells (×10⁶). (D) SP cell number counts (×10⁶). Data represent the average ± standard deviation from at least 5 independent mice of each genotype (see supplemental Figure 1A for details). The P values between 2 genotypes were calculated based on the 2-tailed Student t test assuming unequal variance. Supplemental Figure 1B summarizes the P value from pairwise comparison for total, DP, and SP thymocytes between different genotypes.