Quantitative analysis of in vivo-erythrophagocytosis in the liver from anemic FcγRIII wild-type and FcγRIII KO mice. Liver sections from FcγRIII wild-type (□) and FcγRIII KO (▪) mice on day 2 after injection induced by either 105-2H or 34-3C MRBCs were processed for Mac-1 immunostaining of macrophages counterstained with benzidin for the detection of erythrocytes. The amount of Mac-1⁺ liver macrophages containing ingested erythrocytes per mm² was assessed microscopically. Results are expressed as the mean values ± SEM obtained from three to five mice in each group. Significance is determined by Student’s t-test (*P < .05; **P < .001).