Basophil expansion in IRF-2^-/- mice was independent of Stat6, CD8⁺ T cell, or IFN-α/β signals. The percentages of FcϵRIα⁺B220^- cells in the spleen in mice with the indicated genotypes are plotted. Each symbol represents the value of an individual animal and the horizontal bars, the means. In panel A, the values for IRF-2^-/-Stat6^-/- mice are significantly higher than those for IRF-2^+/-Stat6^+/- (P < .05) or for IRF-2^+/-Stat6^-/- (P < .01) mice but not significantly different compared to those for IRF-2^-/-Stat6^+/- mice (P > .5). In panels B and C, values for IRF-2^-/- and IRF-2^+/- mice are also significantly different (P < .005 and P < .05, respectively).