Rare phenotype and transplantability in cadaveric kidney transplant

The waiting list for kidney transplants in the Apulia region contains recipients (about 30%) who were never selected for transplant due to the rare HLA antigen phenotypes and homozygosis. Therefore, an algorithm was selected to equilibrate the chance for patients to be selected despite a rare phenotype. We calculated for each patient, the sum (%) of the A, B, DR antigen frequency (total phenotypic frequency; TPF). All the potential recipients were grouped into five classes in increasing order of TPF. The number transplanted depended on the phenotype frequency. The selection index was the quotient of the number selected and the total number of patients. The selection index was 0.28 to 0.43 to 0.79 to 1.34 to 2.38 from class 1 to 5. To equilibrate the transplantability of rare phenotype recipients on the waiting list, a bonus was introduced for the most disadvantageous frequency class. Adding the bonus modified the selection index as follows: 1.0 to 1.25 to 1.5 to 1.34 to 2.38, which appears more equilibrated except for the class 5. In conclusion, if a bonus is applied for rare phenotypes, the chance to be transplanted becomes similar between patients with other parameters the same.