Flt3L−/− mice have reduced numbers of leukocytes in the PB.

PB was obtained from flt3L+/+ and flt3L−/− mice by cardiac puncture. (A) WBC counts (n = 8). (B) Blood differentials (n = 8) (L = lymphocytes, n = neutrophils, M = monocytes). (C) Hematocrit (% packed cell volume) (n = 7). (D) Platelet counts (n = 8) were performed as described in “Materials and methods.” Data are presented as the mean ± SD. *P < .0004 for WBC,P = .0011 for percent lymphocytes, and P = .0026 for percent neutrophils.