Increased cellularity and skewed B1/B2 and B1b/B1a ratios in peritoneal exudate from Itchy mice. (A) Peritoneal exudate cells from WT, Itch^+/−, and Itch^−/− mice were stained for B2 (IgD^hiIgM^lo) and B1 (IgM^hiIgD^lo) cells after gating on lymphocytes using side and forward scatter profiles. The percentage of each population is indicated. (B) B1 cells were further gated for B1a (Mac1⁺CD5⁺) and B1b (Mac1⁺CD5⁻). The percentages of each subpopulation are indicated next to each gate. Results of representative mice (n = 12) are shown. (C) Total numbers of individual peritoneal B-cell subpopulations (± SD) are shown for WT (□; n = 12), Itch^+/− (; n = 12), and Itch^−/− (■; n = 22) mice.