Histological examination of spleen pathology. Spleen sections from control (A through D) and FL-overexpressing (E through H) animals at 2 weeks posttransplantation (A, C, E, and G) or 6 weeks posttransplantation (B, D, F, and H) are shown. H&E-stained sections are shown in (A), (B), (E), and (F) and Masson's trichrome-stained sections are shown in (C), (D), (G), and (H). In control mice, normal splenic architecture is regained over the 6-week period posttransplantation, with no evidence of fibrosis (blue staining) demonstrated by Masson's trichrome staining. In contrast, FL-overexpressing mice develop enlarged splenic white pulp (E; arrowheads) by 2 weeks posttransplantation. No appreciable focal collagen deposition occurred by 2 weeks posttransplantation (G). By 6 weeks posttransplantation, massive splenic necrosis was evident (F; star), with evidence of fibrosis in the splenic parenchyma (H; asterisk) and adjacent to the capsule (H; broad arrow). All photomicrographs were captured with a 6× objective.