DISTRIBUTION OF MICA ALLELES IN THE RUSSIAN POPULATION

Stress factors, infections, tumor transformation of the cells of organism induce the expression of MICA protein, which is a ligand for the NKG2D receptor of NK and T cells. The interaction of the NKG2D receptor on the surface of the cells of the immune system with MICA results in activation of lymphocytes and elimination of the ligand carrier. The MICA gene has a high level of polymorphism. To date, 87 alleles have been described; their products differ in ability to activate cytotoxic lymphocytes, that can affect the progression of a number of diseases, such as cancer, viral infections, autoimmune diseases. The distribution of MICA alleles in different ethnic groups varies considerably. The analysis of MICA polymorphism in a current ethnos is necessary for revealing the relationships between certain MICA alleles and different diseases. Goal. This work is aimed at studying of the distribution of MICA alleles in Russian population. Materials and methods. Polymorphism of MICA was analyzed according to the procedure proposed by Yizhou Zoe and Peter Stastny. The procedure included: 1) isolation of genomic DNA from whole blood; 2) PCR for amplification of a fragment of the MICA gene; 3) sequencing of the resulting PCR fragments. Analysis of the results of sequencing was carried out using the programs Vector NTI and Chromas Lite. Results. The genotype of the MICA alleles of 119 donors has been determined. Of the 87 MICA alleles described in the literature, 15 were found among the samples studied. The frequencies of MICA alleles were the following: *002 – 19.3%, *004 – 6.7%, *007 – 3.0%, *008 – 35.7%, *009 – 10.1%, *010 – 5.0%, *011 – 3.8%, *012 – 2.1%, *016 – 2.5%, *017 – 3.4% *018 – 5.5%, *019 – 0.4%, *027 – 1.3%, *053 – 0.8%, *068 – 0.4%. The distribution of MICA alleles in Russia was found to be similar to that of European countries. When comparing literary data for different countries of the world, it was found that the differences in the distribution of MICA alleles are expressed mainly between races, and not nations. Conclusions. In this paper, the distribution of MICA alleles in Russian population has been analyzed. It turned out to be very similar to those of other European countries and has a number of significant differences from the ethnoses of the Mongoloid race (Japan, China, Korea). The analysis of the distribution of MICA alleles in the Russian population may be useful for identifying the predisposition of individuals to certain diseases.

1. Chen D., Gyllensten U. MICA polymorphism: biology and importance in cancer. Carcinogenesis, 2014, Vol. 35, no. 12, pp. 2633-2642.

2. Ďurmanová V., Tirpakova J., Stuchlikova M., Shawkatova I., Kuba D., Sapak M., Buc M. Characterization of MICA gene polymorphism of HLA complex in the Slovak population. Ann. Hum. Biol., 2011, Vol. 38, no. 5, pp. 570-576.

3. Fürst D., Solgi G., Recker K., Mytilineos D., Schrezenmeier H., Mytilineos J. Sequence-based typing of major histocompatibility complex class I chain-related gene A alleles by use of exons 2-5 information. Tissue Antigens, 2011, Vol. 77, no. 3, pp. 201-205.

4. González S., Groh V., Spies T. Immunobiology of human NKG2D and its ligands. Curr. Top. Microbiol. Immunol., 2006, Vol. 298, pp. 121-138.

5. Guo S.W., Thompson E.A. Performing the exact test of Hardy-Weinberg proportion for multiple alleles. Biometrics, 1992, Vol. 48, no. 2, pp. 361-372.

6. Komatsu-Wakui M., Tokunaga K., Ishikawa Y., Kashiwase K., Moriyama S., Tsuchiya N., Ando H., Shiina T., Geraghty D.E., Inoko H., Juji T. MIC-A polymorphism in Japanese and a MIC-A-MIC-B null haplotype. Immunogenetics, 1999, Vol. 49, no. 7-8, pp. 620-628.

7. Molinero L.L., Marcos C.Y., Mirbaha F., Fainboim L., Stastny P., Zwirner N.W. Codominant expression of the polymorphic MICA alloantigens encoded by genes in the HLA region. Eur. J. Immunogenet. Off. J. Br. Soc. Histocompat. Immunogenet., 2002, Vol. 29, no. 4, pp. 315-319.

8. Pyo C.W., Hur S.S., Kim Y.K., Choi H.B., Kim T.Y., Kim T.G. Distribution of MICA alleles and haplotypes associated with HLA in the Korean population. Hum. Immunol., 2003, Vol. 64, no. 3, pp. 378-384.

9. Tian W., Cai J.H., Wang F., Li L.X. MICA polymorphism in a northern Chinese Han population: the identification of a new MICA allele, MICA*059. Hum Immunol., 2010, Vol. 71, no. 4, pp. 423-427.

10. Wenda S., Faé I., Sanchez-Mazas A., Nunes J.M., Mayr W.R., Fischer G.F. The distribution of MICA alleles in an Austrian population: Evidence for increasing polymorphism. Hum. Immunol., 2013, Vol. 74, no. 10, pp. 1295-1299.

11. Zou Y., Stastny P. High resolution MICA genotyping by sequence-based typing (SBT). Methods Mol. Biol., 2012, Vol. 882, pp. 183-195.