One-way donor-to-recipient human leukocyte antigen mismatch and graft-versus-host disease in liver transplantation: an observational study of a single-center experience in Korea.

Background: Graft-versus-host disease (GVHD) is a rare, but potentially fatal complication of liver transplantation. One-way human leukocyte antigens (HLA) mismatch has emerged as a risk factor for GVHD. However, the risk of mortality associated with HLA-one-way mismatch (OWMM) remains uncertain. We investigated the incidence and characteristics of GVHD. Methods: In total, 899 patients who underwent liver transplantation at a single center were retrospectively reviewed. The incidence of GVHD and 1- and 5-year survival rates were compared according to whether HLA-OWMM developed. Results: In the HLA-OWMM group, GVHD developed in two patients (14.3%). Notably, GVHD was only observed in living donor liver transplant (LDLT) recipients in the HLA-OWMM group. The HLA-OWMM group exhibited a lower 1-year patient survival rate than the control (i.e., non-HLA-OWMM) group (78.6% vs. 90.7%, P=0.120). However, the 5-year survival rate in the HLA-OWMM group was similar to that in the control group (78.6% vs. 78.2%, P=0.821). When the HLA-OWMM group was further stratified by the number of mismatched loci, the 5-year survival rate was 83.3% in patients with HLA-OWMM at one to two loci and 75.0% in those with HLA-OWMM at three loci. Conclusions: Despite the higher incidence of GVHD in LDLT recipients with HLA-OWMM, the 5-year patient survival rates were comparable to those in recipients without HLA-OWMM. The decision to perform LDLT in patients with HLA-OWMM depends on the patient's status and the organ supply of a specific region.