Genotyping technique may help increase kidney transplant numbers and reduce wait times

ABO blood group compatibility between organ donors and recipients is critical for safe transplantation. Among the different ABO blood types, patients with blood type B generally have a longer waiting time for kidney transplantation because type B blood is a less common ABO blood type, resulting in fewer donors. Type B blood type is more common in blacks and Asians. African-Americans are more likely than other groups to require a kidney transplant, making the limited number of Type B kidney donors a factor in health inequalities. Fortunately, research shows that people with type B blood can safely get blood from a subgroup of type A blood (A2 Subgroup with reduced A antigen levels compared to other A individuals). Although current routine testing does not identify all A2 Individuals at Brigham and Women’s Hospital, investigators, founding members of the Mass General Brigham Health Care System and other collaborators report that genetic analysis can be used to identify up to 65 percent of A2 donors, thereby increasing the potential number of kidney transplants per year for B recipient candidates.The results were published in American Journal of Transplantation.

ABO incompatibility between patients and organ donors remains the third largest contributor to minority transplant inequities. By introducing genotyping technology, we can better serve Type B individuals in the transplant system and reduce waiting times. “

William Lane, MD, PhD, Corresponding Author, Department of Pathology

Currently, the A subtype is primarily determined by the lectin assay, a test that uses plant-derived proteins to determine how much of the A antigen an individual produces. Researchers from Brigham and Women’s Hospital and Southwestern Immunodiagnostics analyzed more than 750 samples from Type A kidney donors at both centers, sorted by lectin testing and genetic testing. In collaboration with researchers at the New York Blood Center, an additional 124 samples with indeterminate lectin test results were included in the study to further examine differences between lectin testing and genotyping. Co-authors at Lund University Hospital also reviewed the sample for further confirmation and refinement of the subtypes.

Overall, the results of this multicenter study suggest that current lectin typing may underestimate the actual amount of A2 Individuals among type A kidney donors. In particular, the researchers found that deceased donors were not identified as A2 Individuals as often as living donors because some of them receive transfusions with type A blood1 (non-A2)personal.Because A2 In 98% of cases, the subtype is determined by a single gene change, and genotyping may be a more precise way to identify A2 A Individual with variability in antigen levels.

Ongoing work indicates that type B recipients can safely and effectively receive kidney transplants from type A2– genotype individual. Although genotyping is not yet widely used, the authors suggest that genotyping can complement existing tests, and the proven validity may eventually be approved as subtyping, as long as the donor has been transfused or lectin testing is inconclusive. Record the test.

“Genotyping is a more specific test that can overcome the limitations of current tests,” Lane said. “Transplantation is always a balancing act of resources, but by using this technology, we may be able to transfer more donors to areas that are underserved by waiting candidates for transplant.”


Brigham and Women’s Hospital

Journal reference:

Joseph, A., Wait. (2023) ABO genotyping uncovers more A2 to B kidney transplant opportunities than lectin-based typing. American Journal of Transplantation.

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