Intragraft localization of activated nuclear factor kappaB in recurrent hepatitis C virus disease following liver transplantation.

Nuclear factor kappaB (NF-kappaB) is activated during viral infection and is central to the regulation of host immune responses. The NF-kappaB activation status and its morphological sources were assessed by immunohistochemistry in allograft biopsy specimens of orthotopic liver transplantation patients with recurrent hepatitis C virus (HCV). Hepatocellular NF-kappaB immunostaining was detected in HCV cases compared with controls (nontransplant: P <.001; transplant: P =.006), which correlated with the number of NF-kappaB positive hepatocytes (P =.007) and contrasted to the absent to weak staining of controls (nontransplant: P =.001; transplant: P =.009). Enhanced NF-kappaB staining of cytokeratin 19-positive bile ducts and proliferating ductules in the HCV group was in contrast to controls. Intense NF-kappaB immunoreactivity was detected in CD68-positive Kupffer cells and macrophages of all HCV specimens compared with a few controls (nontransplant: P <.001; transplant: P =.001) and contrasted to the weak staining of controls (nontransplant: P <.001; transplant: P =.001). NF-kappaB-positive immunoreactivity correlated with the number of T cell receptor (TCR) alpha/beta-positive lymphocytes (P <.001), which was not observed in controls. In those HCV cases showing evidence of necroinflammatory activity (grade) and individual features of portal inflammation, periportal inflammation/piecemeal necrosis, lobular inflammation, and fibrosis (stage), higher NF-kappaB staining intensity scores within bile ducts, proliferating ductules, hepatocytes (piecemeal necrosis: P =.016; stage: P =.030), and lymphocytes (stage: P =.044) and increased number of NF-kappaB-positive cells within bile ducts, proliferating ductules (grade, lobular inflammation, piecemeal necrosis, stage: P =.022), hepatocytes, and lymphocytes were observed. Increased staining intensity and frequency of NF-kappaB-positive cells were similarly observed in HCV-positive allografts obtained from patients under tacrolimus- compared with cyclosporine-based immunosuppression. These data implicate an immunoregulatory role of intragraft NF-kappaB activation in the pathogenesis and progression of posttransplantation HCV disease recurrence.