(a) Light-micrographic analysis of liver tissues. Histopathological examination was performed using hematoxylin and eosin–stained liver tissues obtained from GVHD-induced mice treated with control IgG (left) or anti-CCR5 antibody (right) at the second week after cell transfer. ×200. (b) Characterization of liver inflammatory foci during GVHD. GVHD-induced mouse livers were harvested and tissue sections prepared at the second week after induction. All micrographs show immunohistochemically stained frozen sections of areas encompassing a portal vein. Top row: left, CD8 staining, ×100; center, CD8 staining, ×400; right, CD4 staining, ×100. Center row: CCR5 staining, ×100. Bottom row: left, MIP-1a staining, ×100; right, MIP-1a staining, ×600. CD8 and CD4 are stained with red precipitates; CCR5 and MIP-1a are stained with brown precipitates.