O048 Vote counting and sign testing methodology to assess the effect of tissue typing in liver transplantation

Abstract Introduction Liver grafts are currently matched by blood group and size. Due to immune privilege of transplanted livers, tissue typing (HLA matching) is not routinely undertaken. Emerging evidence suggests typing may be beneficial for specific patient groups. This systematic review aimed to determine patient and graft outcomes in HLA matched liver transplant patients. Methods Criteria included primary articles exploring effects of typing for liver transplantation, identified from PubMed/MEDLINE and Web of Science databases until January 2022, excluding articles published pre-2000. The Newcastle-Ottawa scale assessed risk of bias. Cochrane protocols for synthesis without meta-analysis (vote counting and sign testing) determined proportions of studies favouring typing. Results All 28 included articles were cohort studies with low-medium bias risk. Graft survival syntheses favoured typing across all patients in studies of both living (LDLT) and deceased donor liver transplantation (DDLT), where 1 study showed a beneficial effect, and 1 showed no effect. In LDLT-only studies, 2 showed benefit, 4 showed no effect, and 1 showed harm. Additionally, typing was favoured in adult-only DDLT recipients. Rejection syntheses favoured typing across all patients for studies of LDLT, DDLT, and both, and for subgroups including adult-only, paediatric-only, tacrolimus-treated, and negative lymphocyte crossmatch. Patient survival syntheses favoured typing across all patients, and for adult-only, PBC, and hepatitis/viral/cirrhosis diseases subgroups, in DDLT studies. Graft failure syntheses favoured typing across all patients in LDLT-only studies, and both LDLT & DDLT. Conclusion Findings evidenced disparate subgroup benefits of typing, and numerous studies reported no effect, or harmful effects.