Hepatitis C-associated granulomas after liver transplantation: morphologic spectrum and clinical implications

Liver granulomas have been described in biopsy specimens from people with de novo chronic hepatitis C virus (HCV) infection and in allograft biopsy specimens from recipients of transplants for HCV-related liver disease. The latter have not been well studied, and there are no data regarding the prevalence, morphologic spectrum, and clinical significance of HCV-associated granulomas after liver transplantation. We observed granulomas in allograft liver biopsy specimens of 4 (8%) of 53 recipients of transplants for HCV-related end-stage liver disease during a 3-year period. Initial appearance of granulomas ranged from 4 to 41 weeks after transplantation. Lobular and portal nonnecrotizing, epithelioid granulomas and lobular microgranulomas were observed, with the latter predominating. Serum transaminase and alkaline phosphatase levels were significantly higher in patients with granulomas than in age- and sex-matched control subjects, but histologic disease activity, cellular rejection scores, HCV genotypes, viral titers, and retransplantation rate owing to recurrent disease were not significantly different. Our study suggests that a granulomatous response to HCV infection occurs in a subset of patients after transplantation; however, this histologic finding does not portend a worse clinical outcome.