Expression of the microglial proliferation regulatory proteins in variant Creutzfeldt–Jakob disease and Alzheimer disease. A–C, Immunohistochemical analysis of the expression of IL34 (A), PU.1 (B), and C/EBPa (C) in the white and gray matter of the temporal cortex of vCJD and AD brains compared with age-matched controls (CTL; representative images). Quantification data expressed as mean ± SEM of the number of IL34+ (D), PU.1+ (E), or C/EBPa+ (F) cells per square millimeters. G, H, Immunohistochemical analysis of the expression of Ki67 (marker of proliferation, G) in microglial cells (Iba1+, G) and IL34 (H) in astrocytes (GFAP+, H) in the temporal cortex of vCJD brains. A–C, Nuclei are stained with H/E (blue). G, H, Fluorescent sections evaluated with confocal microscopy. *p < 0.05, **p < 0.01, ****p < 0.0001, expressed versus the correspondent age-matched control. Data were analyzed with a two-way ANOVA and a post hoc Tukey test (n = 9–10). Scale bars: A–C, G, H (in A, G, H), 100 μm.