MICB polymorphisms and haplotypes with MICA and HLA alleles in Koreans

Major histocompatibility complex (MHC) class I chain-related gene B (MICB) is located within the human MHC class I region. The location of MICB in the MHC region may imply the presence of linkage disequilibrium with polymorphic MICA and human leukocyte antigen (HLA) loci. MICB is also polymorphic; however, MICB polymorphisms have not been investigated in Koreans. Using sequence-based typing (SBT), we estimated the allelic frequencies of MICB and haplotypes with MICA, HLA-B, and HLA-DRB1 at high resolution in a population of 139 unrelated Korean individuals. Eight MICB alleles were identified. The most frequent allele was MICB*005:02/*010 (57.2%), followed by *002 (11.5%), *004 (8.3%), *005:03 (8.3%), and *008 (6.8%). The most common two-locus haplotypes were MICB*005:02/*010-MICA*010 (19.4%), MICB*005:02/*010-DRB1*15:01 (6.5%), and MICB*005:02/*010-B*15:01 (10.4%); the most common three-locus haplotypes were B*15:01-MICA*010-MICB*005:02/*010 (5.8%) and MICA*010-MICB*005:02/*010-DRB1*04:06 (10.4%); and the most common four-locus haplotype was B*15:01-MICA*010-MICB*005:02/*010-DRB1*04:06 (5.8%). This is the first study to provide information about MICB allele frequencies and haplotypes with HLA in Koreans. These study results should help understand mechanisms of disease association between the MICB locus and neighboring loci in Koreans.