ROLE OF HLA MATCHING IN LIVER TRANSPLANT

Abstract

A2 Aims: Whereas the role of HLA matching in renal transplantation is more or less established, its role in liver transplant is still very much a matter of debate. Methods: We conducted a search on various databases like PUBMED, EMBASE, and OVID using various combinations of key words like liver transplant, HLA, Major Histocompatibility Complex (MHC) etc. to locate all the studies on role of HLA matching in liver transplantation published in peer-reviewed journals in English language. The heterogeneity of the studies and lack of properly conducted randomized controlled trials did not lend the subject to a meta-analysis. The studies identified in this manner were hence subjected to a systematic review. Results: Opinions are split nearly in the middle on whether HLA matching is beneficial for liver transplant patients with nearly half the authors on either side. However most studies, including a number of those that concluded an adverse impact, have showed some immunological benefit for HLA matching. Amongst the beneficial outcome shown are decreased acute rejection, decreased incidence of steroid resistant rejection and chronic rejection, prolonged graft survival, prolonged patient survival, and higher chances of immunosuppression withdrawal. Whereas some found class I matching to be beneficial, others identified class II matching as useful. Matching could be harmful in two subgroups of patients with autoimmune diseases and viral infections. In these patients matching could worsen the outcome by some other not yet fully described HLA restricted mechanism. These patients could also account for the detrimental effect of matching observed in some studies. Most large studies on this topic, which have analysed these two groups of patients separate from the rest, have failed to show any substantial harm caused by matching in the remaining patients. Conclusions: Liver transplant can be performed with reasonable safety across major HLA incompatibilities and evidence is lacking to support any role for routine pretransplant matching. In patients with autoimmune disease and viral disease, matching may be harmful but whether an active effort should be made to avoid matching for these remains to be more fully elucidated.