Distribution of MICA diversity in the Chinese Han population by polymerase chain reaction sequence-based typing for exons 2-6.

Major histocompatibility complex class I chain-related gene A (MICA) is located 46 kb centromeric to HLA-B locus and encodes a stress-inducible protein. MICA allelic variation is thought to be associated with disease susceptibility and immune response to transplants. In this study, polymerase chain reaction sequence-based typing (PCR-SBT) method for MICA alleles has been established. Genomic DNAs from 100 healthy Chinese Han individuals were typed for MICA alleles by this method. The microsatellite polymorphism in the exon 5 of MICA gene, MICA*Del allele, and human leukocyte antigen-B alleles was also detected by the polymerase chain reaction-GeneScan, polymerase chain reaction sequence-specific primer, and PCR-SBT methods, respectively. Fourteen MICA alleles were found in the population, with MICA*00801/04 having the highest frequency of 27.0%. MICA*A4, *A5, *A5.1, *A6, and *A9 microsatellites were identified. Two samples with HLA-B*4801 were MICA*Del positive, with the frequency of 1.0%. The data showed that the new PCR-SBT method for MICA alleles was reliable and Chinese Han population was distinct in distribution of MICA alleles.