Analysis of the animals at 14 months of age. (A) Characteristics of the 4 genotypes at the age of killing. DM indicates Cdkn1b^+/−/MTCP1^TG; Tg, MTCP1 transgenics; Htz, Cdkn1^+/−; WT, wild type; WBC, white blood cell count; CD8m/CD8_T, ratio of CD8 memory cells (CD8⁺CD44^HI) to total CD8⁺ splenocytes determined by FACS; CD8m/T-cells, ratio of CD8 memory cells (CD8⁺CD44^HI) to total T-cell splenocytes (CD4⁺ and CD8⁺ lymphocytes) determined by FACS; CD4/CD8, ratio of CD8⁺ splenocytes to CD4⁺ splenocytes determined by FACS; §, 2 mice developed an erythroid metaplasia and were excluded from the study; *, significantly higher by Student t test in DM mice compared with the 3 other cohorts with P < .05; and **, significantly lower by Student t test in DM mice compared with the 3 other cohorts with P < .05; in parentheses is indicated the number of mice analyzed for WBC. (B) Histopathological analysis after HES staining of liver and spleen from characteristic mice for each genotype. Images were acquired with a DMRB microscope with 10×/0.30 and 20×/0.50 PL Fluotar objective lenses (Leica, Rueil-Malmaison, France) equipped with a KY-F50 Tri CCD camera (JVC, Clara Vision, Massy, France) and analyzed with Vega v2.0 software (Clara Vision) without further image processing. The lymphocytic nodules are indicated by arrows. Magnifications are indicated.