HLA-B60 and HLA-B61 Discrimination by PCR using Sequence-specific Primers (PCR-SSP) Method

Woo, Hee Yeon; Yang, Yun Sun

Abstract

BACKGROUND
HLA-B40 is the most frequently identified HLA-B type in Koreans. Also HLA-B60 and B61 are the serologic split antigens of HLA-B40. But because of the lack of mono-specific alloantisera, cross reactivity of sera used as typing reagents, and poor antigenicity of some specific cells such as cord blood lymphocytes, discrimination between HLA-B60 and B61 has been often problematic in laboratories. In this study, authors evaluated whether the PCR-SSP method can be useful for accurate assignments of HLA-B60 and B61 or not.
METHODS
Twenty-nine lymphocytes samples which were suspected as heterozygotes or homozygotes of HLA-B60 or B61 and three samples typed as HLA-B40 are selected from stored cord blood and organ transplantation donors. HLA types of these samples were defined by serologic method using a commercial typing kit. PCR that amplified exons 2 and 3 of the HLA-B gene using sequence specific primer pairs exactly matched to HLA-B60 or B61 allele making up a serological specificity was done.
RESULTS
A clear discrimination between B60 and B61 was possible in all samples including 9 serologically ambiguous samples. Discrepancy between serologic typing and molecular typing was seen in three cases identified serologically as B40 positive but inable to define a split. Among three samples, two were identified as HLA-B61 and one was identified as HLA-B60.
CONCLUSIONS
Molecular typing was useful in discriminating between HLA-B60 and B61. The PCR-SSP method for HLA-B60 and B61 including other cross-reactive HLA types will be helpful as a supplemental method of the serologic typing.