Background: We previously reported that in patients possessing human leukocyte antigen (HLA)-DQ-directed antibodies, the target molecule may include the patient's own DQβ chain if it is paired with non-self-DQα chain, thus forming a different DQ target. Herein, we sought to assess the breadth of this phenomenon.
Methods: Serum samples from 104 patients awaiting kidney transplantation, known to have DQ antibodies, were studied. Antibody identification was performed using luminex-based HLA class II single-antigen bead assays from two vendors; DQA1/DQB1 typing was performed using luminex polymerase chain reaction - sequence specific oligo prob hybridization (PCR-SSO) technology.
Results: A total of 71% of the 104 serum samples studied contained antibodies reactive against test beads coated with the patient's own DQα- or β-chain components. Of those, 35 patients (34%) exhibited antibodies to their own DQβ chain when in combination with non-self-DQα chains; and 64 patients (62%) had antibodies to their own DQα chain when in combination with non-self-DQβ chains. This is a striking observation.
Conclusions: To the best of our knowledge, this is the first systematic, high-resolution evaluation of DQ antibody repertoire. With the expansion of virtual crossmatching, particularly in the context of a national registry, the need for more detailed DQ antibody or antigen evaluation is critical to improve operational efficiency and patient outcomes.