EPITOPE SPECIFICITY OF HLA DQA1 AND DQB1 ANTIBODIES DETECTED IN SERA FROM RENAL TRANSPLANT RECIPIENTS.

The precise characterization of HLA antibodies is important for the management of sensitized renal transplant candidates. Sensitization to HLA molecules is due to recognition of mismatched HLA epitopes of the sensitizing event which led to the production of antibodies specific for "private" or "public" epitopes of the immunizing HLA molecule. The recent development of assays using Single Antigen beads coated with DQ heterodimers (DQAI and DQBI) permits to distinguish DQAI from DQBI alloantibodies.Besides, analyzing the beads' reaction patterns in relation to amino acid sequences of antibody-reactive alleles it is possible to identify DQAI and DQBI sensitizing epitopes. This study, carried out on a large number of HLA-DQAI/DQBI sensitized patients, confirms the great immunogenicity of mismatched DQ molecules especially of a previous kidney transplant. Since we have ascertained the different clinical impact of anti-DQBI and anti-DQAI donor specific antibodies on graft outcome, the accurate characterization of anti-DQ antibodies may be helpful in transplanting high sensitized transplant candidates.