Extramedullary erythropoiesis in spleens of HNF1A^−/−mice. (A) Relative spleen weight (left), total spleen weight (middle), and body weight (right) of 80-day-old and 140-day-old HNF1A^+/+ and HNF1A^−/− mice (n = 9 vs 12, and n = 5 vs 6, respectively). **P < .01 and ***P < .001 for 80-day-old or 140-day-old HNF1A^+/+ vs HNF1A^−/−; §P < .05 and §§§P < .001 for 80-day-old vs 140-day-old HNF1A^+/+ or for 80-day-old vs 140-day-old HNF1A^−/− (1-way ANOVA followed by Tukey post hoc analysis). (B-C) Splenic cell populations from HNF1A^+/+ (n = 5) and HNF1A^−/− (n = 6) mice with a mean age of 140 days as analyzed by flow cytometry. (B) The percentage (left) and total cell numbers (right) corresponding to LSK and MEP cell populations as indicated. (C) Representative images and gating strategy of HNF1A^+/+ and HNF1A^−/− erythroid populations in spleen (i). The percentage (ii-iii) and total cell numbers (iv-v) in spleen corresponding to proerythroblasts (Pro), basophilic erythroblasts (Baso), polychromatic erythroblasts (Poly), orthochromatic erythroblasts (Ortho), reticulocytes (Retic), and mature RBCs as indicated. *P < .05, **P < .01, and ***P < .001 for HNF1A^+/+ vs HNF1A^−/− (Student t test).