52-P

Abstract

To test a new approach for decreasing the risk of crossing HLA antibodies barrier in highly sensitized cardiac transplant candidates. Our approach utilizes the epitope analysis ClustlW2 multiple sequence alignment program for proteins (EMBL-EBI) and the C1q assay to analyze the antibodies pattern and cytotoxic properties in cardiac transplant candidates. The presence of high level HLA antibodies can impact the access of highly sensitized heart transplant candidate to transplantation. In patients with high PRA and in imminent need for an allograft, the transplantation across positive donor specific antibodies might be the only option. Some transplant programs choose the unacceptable antigens that they will transplant across based on the antibodies levels detected semi-quantitively by Luminex platform expressed in MFI. However, it is well know that the majority of HLA antibodies are directed against shared epitopes and consequently, the MFI values might not accurately reflect the DSA levels. Another potential factor is that the normal Luminex platform cannot differentiate between the complement fixing and the non-complement fixing HLA antibodies. The new C1q testing addition is recently utilized to detect complement fixing antibodies. Epiotope analysis that can provide an actual estimate of the HLA antibodies strength in combination with C1q can be used to decrease the risk for transplanting highly sensitized heart candidates.