Peripheral blood leukocyte counts. (A) Total leukocyte counts. Blood was collected from the tail vein of 6 male mice of each genotype. The total leukocytes were counted on a hemocytometer. (B) Leukocyte subset counts. Flow cytometry was used to determine the fraction of each subset. Neutrophils were determined as Gr-1^highF4/80^low cells, eosinophils as Gr-1^intermediateF4/80^high cells (these cells are also very high in SSC), and monocytes as Gr-1^highF4/80^high and Gr-1^-F4/80^high cells. Values are means plus or minus SEM; *P < .05; **P < .01; ***P < .001.