HLA-specific antibody distribution in renal transplant waiting list patients: utility of antigen frequency data in the definition of HLA-reactive epitopes.

The use of single antigen bead (SAB) technology has allowed for previously unheralded levels of antibody detection, both in terms of sensitivity and specificity. Human leukocyte antigen (HLA) specific antibody profiles can now be defined in clinically relevant timescales. However, a degree of expertise is still required in order to interpret SAB data and accurately assign antibodies to the epitope level. This study describes how the use of antigen frequency data can be used to support the identification of HLA-reactive epitopes. It also highlights how sharing of epitopes can explain SAB reactivity against HLA antigens found at extremely low frequency in the population.