The balance of the immune system between HLA-G and NK cells in unexplained recurrent spontaneous abortion and polymorphisms analysis

Human leukocyte antigen (HLA)-G is involved in immunoregulatory processes and particularly in pathogenesis of inflammatory disorders such as recurrent spontaneous abortions (RSA). The purpose of the current study was to examine whether two single nucleotide polymorphisms (SNPs) of HLA-G gene (rs1736936 and HLA-G*0105N) influence susceptibility to recurrent spontaneous abortion. Genomic DNA from 117 RSA patients and 117 normal fertile control individuals was isolated using the salted out method. The two single nucleotide polymorphisms in HLA-G gene were analyzed using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). Differences between the two groups were analyzed by SPSS19 software using Chi-square test. The results revealed a significant increase in HLA-G*0105N allele in the proportion of whole group of RSA women compared with fertile controls (P value = 0.015), OR (95 % CI) = 2.054 (1.798–2.347), as well as an absence of homozygosity for HLA-G*0105N in the study population. No significant difference was observed between the RSA and the fertile groups in terms of alleles and genotypes frequency of rs1736936 (P value = 0.323), OR (95 CI %) = 1.056 (0.844–1.319). The presented data suggest that the investigated HLA-G*0105N allele is potentially associated with RSA through linkage disequilibrium with other genetic elements. Meanwhile, the rs1736936 SNP do not predispose to RSA in the study population.