Recent findings have shown the DQ donor specific alloantibodies (DSA) are associated with transplant glomerulopathy and seem to appear more often than other loci DSA. We conducted an analysis of all patients transplant over a 6 year period to see the extent of the DQ-DSA problem in kidney transplantation.

Methods: 186 primary, HLA mismatched renal transplants were performed consecutively between 1999 and 2006 at East Carolina University and were not lost to follow-up. These patients were tested for antibodies by single antigen beads pre-transplant and sequentially post-transplant at 1, 3, 6, 9, 12 months and annually, thereafter. Tissue typing was performed using both serology and polymerase chain reaction-single-specific-primer (SSP) methods for HLA-A, -B, -DR, and –DQ antigens. All patients had 5 years of post-transplant follow-up or failed/died prior to the 5 year visit.

Results: All patients studied were mismatched for at least 1 HLA loci. Patients with a DQ mismatch were significantly more likely to develop any DSA. Compared to non-DQ mismatched patients with a 5 year cumulative DSA incidence was 25-30% for DQ mismatched patients versus 5% for those DQ matched (p=0.004, Fig A). Between HLA loci we found that the ratio of DQ-DSA to DQ mismatch was 2-4 times higher than DSA at any other mismatched loci patients (p<0.01, Fig B). Furthermore, 2 antigen DQ mismatched patients were twice as likely to develop DQ DSA when compared to 1 loci mismatched patients (p=0.03, Fig B). Of DQ-DSA, the most common (Fig C) and most detrimental specificity by itself was to DQ7 12 cases with 3 failures (Fig D).

Conclusion: This data suggest that DQ mismatching may pose the highest long-term risk to transplant patients because they lead to a disproportionate amount of alloantibodies.

Everly, M.: Employee, One Lambda. Terasaki, P.: Stockholder, One Lambda.

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