Effects of beta c genotype on leukocyte counts in Mx1-Cre, Nf1^flox/flox mice. (A) Data from 6 Mx1-Cre, Nf1^flox/flox, beta c^−/−(○) and 6 Mx1-Cre, Nf1^flox/flox, beta βc^+/+ mice (▵) show a modest elevation in total leukocyte counts relative to 5 beta c^−/−(•) or 7 wild-type (▴) animals. Leukocyte counts are significantly higher in the Mx1-Cre, Nf1^flox/flox, beta c^+/+ group by 6 months of age. (B) Lymphoid (□) and myeloid (▪) cell counts are shown at 3 months of age for mice of each genotype: 12 Mx1-Cre, Nf1^flox/flox, beta c^+/+; 12 Mx1-Cre, Nf1^flox/flox, beta c^+/−; 8 Mx1-Cre, Nf1^flox/flox, beta c^−/−; 8 beta c^+/+; 12 beta c^+/−; 9 beta c^−/−. Error bars indicate SD from the mean.