Decreased total lymphocytes and increased fraction of NK cells in spleens from BCAP^−/− mice. Each point represents an individual wild-type (WT, ▴) or BCAP^−/− (●) mouse 7 to 24 weeks of age, and mean values are represented by horizontal lines. (A) The total number of splenocytes harvested was counted manually, and dead cells were excluded by trypan blue staining. P value was calculated using a 2-tailed Student t test. (B) Percentages of cells in spleens that are CD3⁻NK1.1⁺ (NK), CD3⁺NK1.1⁻ (T), CD3⁺NK1.1⁺ (NKT), or CD3⁻NK1.1⁻ (Other). “Other” cells are almost exclusively B cells (data not shown). P values are as follows: NK < .001, T = .61, NKT = .51, and Other = .07. (C) Lymphocyte populations in the bone marrow of WT and BCAP^−/− mice. No statistically significant difference was found in the percentages of bone marrow lymphocyte subpopulations.