Genotyping technology may help increase the number of kidney transplants and reduce waiting times

ABO blood type compatibility between organ donors and recipients is critical for safe transplants. Across different ABO blood groups, patients with ABO blood type often experience longer waiting times, resulting in fewer donors. Type B blood type is more prevalent among blacks and Asians. African Americans are more likely to request kidney transplants than other groups, making the limited number of type B kidney donors a contributor to the health inequality. Fortunately, research has shown that individuals with type B blood can safely receive kidney transplants from a subset of type A (type A) individuals.2 subgroup) who have lower levels of A antigen than other type A individuals. While current routine testing is not able to identify all A2 Individuals and investigators at Brigham and Women’s Hospital, a founding member of General Brigham’s Health Care System, and other collaborators report that genetic analysis can be used to identify up to 65 percent more A2 donors, thus increasing the potential number of kidney transplants for B blood group recipient candidates each year. Results are published in American Journal of Transplantation.

ABO blood type incompatibility between patient and organ donor continues to be the third largest contributor to minority inequality. By introducing genotyping technology, we can better serve type B individuals in the transplant system and reduce waiting times.”

William Lane, MD, PhD, correspondent author, Department of Pathology

Currently, subclassification is largely done by the lectin assay, which is a test that uses a plant-derived protein to determine how much antigen an individual produces. Researchers from Brigham and Women’s Hospital and Southwest Immunodiagnostics analyzed more than 750 samples from type A kidney donors at the two centers, subclassified with both lectin tests and genetic tests. In collaboration with researchers from the New York Blood Center, an additional 124 samples with inconclusive lectin testing were combined into the study to further examine discrepancies between lectin testing and genotyping. The samples were also reviewed by the co-authors at Lund University Hospital to confirm and refine the subclassification.

Overall, findings from this multicenter study indicate that current lecture writing may underestimate the actual number of A.2 Individuals among type A kidney donors. In particular, the researchers found that deceased donors were not identified as A2 Individuals often like living donors because some of these individuals have received type A blood transfusions1 (other than a2) individually. Because a2 The subtype is determined by a single genetic change in 98 percent of cases, and genotyping can be a more accurate way to identify A2 Individuals with variance in A. antigen levels.

Work is currently underway to demonstrate that type B recipients can safely and effectively receive kidney transplants from A2Genetically classified individuals. Although genotyping is not yet widely available, the authors believe that genotyping can complement existing tests whenever a donor is transferred or lectin testing is inconclusive, and demonstrated efficacy may eventually be approved as a registry test for subclassification.

“Genotyping is a more specific test that overcomes limitations with current tests,” Lin said. “Transplants are always a balancing act of resources, but with this technology, we may be able to divert more donors toward an underserved area of ​​candidates awaiting transplants.”

Source:

Brigham and Women’s Hospital

Journal reference:

Joseph, A.; et al. (2023) ABO genotyping finds more chances of A2 to B renal transplantation than lectin-based subtyping. American Journal of Transplantation. doi.org/10.1016/j.ajt.2022.12.017.

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