Immunological factors and liver fibrosis in pediatric liver transplant recipients.

BACKGROUND: The aim of our study was to retrospectively assess any correlation between graft fibrosis and selected immunological factors in pediatric liver transplant recipients. MATERIAL AND METHODS: The study was performed on 33 patients after living related donor transplantation, divided into 2 groups depending on history of acute rejection episodes after transplantation. We assessed liver biopsies for presence of fibrosis, signs of antibody-mediated rejection, inflammatory infiltrations, and changes in bile ducts. We correlated these findings with assessment of anti-HLA antibodies. RESULTS: Among 14 patients with ACR, a history fibrosis was found in 8 patients (57%). In 19 patients without a history of ACR, fibrosis was found in 9 patients (47%). Anti-HLA antibodies were found in 47% of patients with fibrosis and in only 18.75% of patients without fibrosis. Among 3 patients with signs of antibody-mediated rejection, all had fibrosis in the graft 2 years after transplantation. We did not find any patient with chronic rejection or ductopenia. CONCLUSIONS: We suggest that there is a correlation between ACR and development of graft fibrosis present in liver grafts from recipients with normal liver biochemistry. Anti-HLA antibodies class II seems to be most important in development of fibrosis.

Antibody-mediated rejection in pediatric liver transplant recipients.

BACKGROUND: Antibody-mediated rejection (AMR), associated with the presence of C4d deposits, is well-defined in kidney transplantation but much less documented in liver transplantation (LTx). The aim of our study was to retrospectively analyze a group of pediatric liver transplant recipients who experienced episodes of acute rejection in the past, for the signs of AMR and its impact on liver histology. MATERIAL/METHODS: Our study population consisted of 18 patients after living related donor liver transplantation with a history of acute cellular rejection (1-5/patient). In all of them, actual liver function was good at almost 2-year median follow-up after transplantation. We reassessed all liver biopsies taken from these children between 5 days to 5.7 years after transplantation for signs of acute cellular rejection and antibody-mediated rejection. In all patients, anti-HLA antibodies were also assessed at least 2 years after transplantation (2.18-12.27 years, median 6.795 years). RESULTS: There were 27 episodes of acute rejection proved by liver biopsy. Signs of AMR were found in 6 of 18 patients (33.3%). In 5 of these patients, donor-specific (DSA) and non-specific anti-HLA antibodies were also identified. In the group of 12 patients with acute rejection without histochemical signs of AMR, anti-HLA antibodies were found in sera of only 5 of 12 patients after transplantation. CONCLUSIONS: Our study shows some correlation between C4d-positive reaction in liver biopsies with acute cellular rejection and presence of anti-HLA antibodies, particularly against HLA class II. We did not find any difference in the late graft function, which could be correlated with the presence of AMR. Further studies on larger groups of patients are necessary.