Current trends in histocompatibility: clinical relevance versus laboratory phenomena

The role of conventionally analyzed data in tissue typing is decreasing in clinical transplantation. Improved immunosuppression seems increasingly capable of overcoming the immune response to known histocompatibility differences. The introduction of the concept of public specificities may improve the correlation between matching and graft outcome. The further understanding of the roles of cell-specific antigen systems, particularly those on the vascular endothelial cells, may also improve the clinical relevance of matching. The VEC antigens are becoming more important both in our understanding of histocompatibility and of sensitization. The sensitization of potential transplant candidates needs to be prevented by new protocols for transfusion. The amelioration of sensitization to histocompatibility antigens similar to that achieved in transplantation across the ABO barrier seems theoretically possible and should be an important research effort. Most importantly, sensitization needs to be more accurately defined. Sensitization to specific antigens (cell-specific as well as HLA) must be more carefully correlated with graft survival, and the quantitative aspects of sensitization must be better understood. Thus, there are new trends in the field of histocompatibility that hold promise for further improving the results of clinical transplantation and our understanding of the rejection process.