BACKGROUND: Acute liver graft rejection is still a common complication after liver transplantations. The diagnostics of this process is based on histological findings, resembling the presentation of HCV infection. Correct differentiation between acute rejection and recurrent HCV hepatitis is very important because of differences in treatment. From the practical point of view, C4d could be used in liver transplantology for differential diagnostics of acute graft rejection and recurrence of HCV infection.

MATERIAL AND METHODS: The study was performed in liver graft biopsies obtained from 57 patients with acute rejection and from 26 patients with hepatitis C recurrence. The sections were probed immunohistochemically using antibody specific to C4d. The following parameters were analyzed statistically: the percentage of immunoreactive biopsies, the localization of C4d deposits, and the relationships between C4d-positive biopsies with acute rejection and hepatitis C recurrence.

RESULTS: Within liver graft biopsies with acute rejection and hepatitis C recurrence, the immunoreactivities of C4d were present almost exclusively along venous, arterial, and arteriolar endothelium in the portal spaces. C4d deposits were found in 33 patients with acute rejection (57.9%) and in 17 patients with hepatitis C recurrence (65.38%). The study demonstrated no statistically significant difference in C4d expression in liver biopsies from acute graft rejection patients as compared with HCV infection recurrence (chi-squared =1.5566774 df=1 p=0.45560). Both groups demonstrated positive reactions within biopsies.

CONCLUSIONS: Our results suggest that C4d deposits are insufficient in differentiation between both examined liver pathologies, but could be a useful marker in the diagnostics of acute liver rejection with humoral component.

Keywords: hepatitis C recurrence, C4d complement fragment, acute liver rejection, Hepatitis C, Liver Transplantation