Allelic diversity of MICA gene and MICA/HLA-B haplotypic variation in a population of the Murcia region in southeastern Spain.
Major histocompatibility complex class I-related chain A (MICA) is located at 46 kb centromeric of HLA-B. It is highly polymorphic and interacts with NKG2D, its receptor on the surface of NK, Tgammadelta and T CD8 lymphocytes. Data on MICA polymorphism in different populations are still limited. Our aim was to establish allelic diversity of MICA gene and linkage disequilibrium with HLA-B in our population. DNA was obtained from 154 unrelated healthy individuals from the Murcia region in southeastern Spain. HLA-B genotyping was performed using polymerase chain reaction (PCR)-sequence-specific oligonucleotide probes and allele-specific PCR-sequence-specific primers, and MICA genotyping by using PCR-sequence-specific oligonucleotide probes. A total of 19 MICA alleles were detected on this study. MICA*008 was the most frequent allele (25.3%), followed by MICA*002 (16.1%), MICA*004 (14.9%), MICA*001 (7.8%), MICA*009 and MICA*016 (7.1%), and MICA*010 (4.6%). Eleven alleles had frequencies of <1%. In the haplotype analysis, MICA*008-B*0702 was found to be the most common, followed by MICA*004-B*4403 and MICA*001-B*1801, MICA*002-B*3501, MICA*008-B*4402, MICA*004-B*4901, MICA*008-B*0801, and MICA*002-B*3801. The frequency of MICA*010-B*1501, MICA*008-B*1302, MICA*015-B*4501, and MICA*008-B*4001 was remarkable inasmuch as these two last haplotypes have not been reported in Spanish population. Indeed, MICA*016 linked to B*1402 has also not been reported in the literature. In conclusion, the allelic diversity in our population is similar to other Caucasian populations; however we found a series of less frequent alleles, in addition to as-yet-undescribed haplotypic associations in other populations of Caucasian origin.
Lucas
Daniel
D
Immunology Service, University Hospital Virgen de la Arrixaca, Murcia, Spain.
Campillo
José Antonio
JA
López-Hernández
Ruth
R
Martínez-García
Pedro
P
López-Sánchez
Manuela
M
Botella
Carmen
C
Salgado
Gema
G
Minguela
Alfredo
A
Alvarez-López
María Rocío
MR
Muro
Manuel
M
D000483:Alleles; D005260:Female; D005787:Gene Frequency; D014644:Genetic Variation; D005828:Genetics, Population; D015235:HLA-B Antigens / Q000235:genetics*; D006239:Haplotypes; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D013030:Spain
D015235:HLA-B Antigens; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A