Background: The performance of a new intermediate-resolution method using a PCR-Luminex platform and LABType® SSO A, B DRB1 kits as an HLA typing method for the cord blood (CB) registry of the Korean population was investigated.
Methods: A total of 1,413 cord blood units (CBUs) were enrolled - 1,382 from Koreans and 31 from non-Koreans or mixed-ancestry individuals. HLA-A, -B, and -DRB1 typing was performed using the LABType® SSO typing kits. HLA typing with the DNA method and 2-digit results are mandatory for the public CB bank in Korea according to the “CB Act."
Results: The proportions of ambiguous results in the 2-digit assignment were 14.6% (206/1,413) and 14.8% (205/ 1,382) among the total subjects and the Korean donors, respectively. In the 2-digit resolution, 3 different HLA-A types (69 CBUs), 31 HLA-B types (124 CBUs), and 3 HLA-DRB1 types (13 CBUs) showed ambiguous results. The ‘most probable type’ to the ambiguous results based on the reported Korean HLA allele frequencies were able to be assigned. The most probable results were 100% consistent with the confirmed types as determined by the HD kits (DRB1) and additional PCR-SBT or PCR-SSP tests (A and B). Luminex technology is more automated and less labor intensive than the conventional SSO typing method, and the results are less affected by differences between inspectors.
Conclusions: Although it is not satisfactory as a sole confirmation test and cannot be used as a replacement for the PCR-SBT test, the combination of Luminex technology with LABType® SSO kits and population frequency data provides a proper typing platform that can be used as a qualifying test for CB registries.