Accommodation: does it apply to human leukocyte antigens?

The term "accommodation" was invoked to describe endothelial cell resistance to antibody-mediated rejection after ABO-incompatible kidney or experimental xenograft transplantation. Currently, there is much interest in how to achieve successful human leukocyte antigen (HLA)-incompatible allograft transplantation in HLA-sensitized patients and how to treat antibody-mediated rejection after ABO-compatible HLA-incompatible allotransplantation. The term "accommodation" is often used interchangeably to describe patients who have donor-specific ABO or HLA alloantibodies in the absence of damage to their allograft. Here, we suggest that there are important differences between the immune responses to protein versus carbohydrate antigens and that graft HLA molecules may respond differently to antibodies (and antibody isotypes) than ABO antigens. Neither the mechanisms nor a phenotype of accommodation have been defined fully. Further research is needed to define mechanisms of both resistance and susceptibility to antibody-mediated injury and to predict under which circumstances allograft accommodation may occur.