74-P

• Published in: Human immunology Vol. 74; p. 104
• Main Authors: Zhang, Aiwen, Reville, Patrick, Nowacki, Amy, Thomas, Dawn, Kawczak, Paul, McMichael, John, Sobecks, Ronald, Askar, Medhat
• Format: Journal Article
• Language: English
• Published: 01.11.2013
• Subjects: Allergy and Immunology
• ISSN: 0198-8859
• DOI: 10.1016/j.humimm.2013.08.149

Aim In this study, we investigate the distribution of MICA 129 genotypes and characterized MICA-HLA-B haplotype in two major North American populations. Methods We retrospective reviewed our laboratory electronic database for individuals with high resolution HLA-B and MICA typing and known ethnicity. Total 724 individuals [692 Caucasians (C) and 32 African Americans (AA)] were identified. Typing was performed by PCR-Sequence Specific Oligonucleotide Probes and/or Sequence Based Typing. MICA 129-MM, MV, and VV genotype distribution was investigated. Two-locus haplotype frequencies (HF) and LD between MICA and HLA-B alleles were estimated using the ELB algorithm on haplotypes that reached HF ⩾ 0.5% and p -value < 0.05 threshold. The relative strength and significance of LD was determined by calculating the LD coefficient r2 and p -values generated using a chi-square test with 1 d.f, all carried out in Arlequin v.3.5. Results Compared to C, AA had higher incidence of MM (30% AA vs. 12% C), similar percentage of MV (43% AA vs. 40% C), and lower incidence of VV (27% AA vs. 48% C), p − value <0.0001. Fifty-three of MICA and HLA-B haplotypes were analyzed (28 in CC and 25 in AA). The most frequent haplotype in C was B∗07:02-MICA∗008 and in AA was B∗08:01-MICA∗008. Among the most frequent haplotypes (top 10), only B∗08:01-MICA∗008 and B∗57:01-MICA∗017 were shared by both groups. In C, the highest ranking MICA-B haplotypes contained B alleles that were among the highest allele frequency. Among 10 haplotype shared in both C and AA populations, 70% (7/10) haplotype contained MICA 129-M allele. Conclusions There is a significant difference of MICA129 genotype distribution between C and AA. MICA 129-M allele more frequently distributed among the MICA and HLA-B haplotype shared in both C and AA populations.