Clinical research of incomplete immune tolerance to donor specific blood group antigen in pediatric ABO incompatible living donor liver transplantation recipients / 中华器官移植杂志

ABSTRACT

Objective:To explore the potential immune mechanism of pediatric ABOi-LDLT presenting low humoral immune response to donor specific blood group antigen.Methods:From June 2013 to December 2020, clinical data were retrospectively reviewed for 29 patients of long-term surviving pediatric ABOi-LDLT.There were A to O ABOi-LDLT( n=10)and B to O ABOi-LDLT( n=19). Graft types included left lateral lobe( n=26)and left hemi-liver( n=3). The median age of liver transplantation was 10 months, the median weight 8.0 kg and the median follow-up time 41.9 months.The titers of donor specific blood group antibodies and non-donor specific blood group antibodies(IgG, IgM)were continuously monitored before transplantation and at 1, 3, 6, 12, 24, 36 months post-transplantation.Protocol or event-based liver biopsy was performed to determine whether or not there was antibody-mediated rejection. Results:The titer of donor specific blood group antibody in recipients was significantly lower than that of non-donor specific blood group antibody( P<0.001). Among 18 protocol liver pathological biopsies, two cases were C4d positive for vascular endothelium.Five abnormal event-based liver biopsies were completed and one was C4d positive in bile duct endothelium.No pathological sign of typical blood group antibody mediated antigen-antibody complex mediated cascade immune reaction was detected in liver pathological biopsy.Typical pathological signs of blood group antibody mediated rejection were absent in protocol liver biopsy. Conclusions:Donor specific blood group antibody is expressed at a low level in pediatric ABOi-LDLT recipients.It presents as incomplete immune tolerance to donor specific blood group antigen.