Analysis of secondary hematopoietic organs and mature blood cells. (A) Images of a representative spleen and thymus from 12-week-old Msi2^+/+ and Msi2^Gt/Gt mice. (B) Number (±SEM) of nucleated cells in spleen and thymus (n = 11). (C) Hematologic analysis of peripheral blood from young (n = 16) and old (n = 28) Msi2^+/+ and Msi2^Gt/Gt mice, showing the number of leukocytes, RBCs, and platelets. The black bars represent the mean value for each group. Error bars indicate SEM. *P < .05; **P < .005; ***P < .0005.