Association of toll-like receptors polymorphism and intrauterine transmission of cytomegalovirus

BACKGROUND Congenital Cytomegalovirus (CMV) is a very common intrauterine infection which can cause severe developmental disabilities. Transmission of the virus to the fetus occurs in only 40% of primarily infected women. The probability of intrauterine transmission is higher when infection occurs during the second trimester of pregnancy than in the first trimester. The Toll-like receptors (TLRs) protein family plays a key role in both innate immune response to CMV infections and in normal pregnancy. Specific single nucleotide polymorphisms (SNPs) in TLRs can affect CMV infections and maternal-fetal interface expression. Therefore, TLR SNPs could be involved in intrauterine transmission determination. STUDY AIM To establish a correlation between TLR2 (rs4696480, rs3804100, rs1898830), TLR3 (rs3775291) and TLR7(rs179008) SNPs with CMV intrauterine transmission during the first and second trimester. METHODS SNPs of 83 pregnant women with primary CMV were analyzed by Real-Time PCR and PCR-RFLP assay and compared to intrauterine transmission state. RESULTS Women bearing the GG genotype in the rs1898830 TLR2 SNP who were infected with CMV during the second trimester did not transmit the virus to the fetus. Likewise, in the co-dominant or recessive models of this SNP, a significant association was found between the genotypes and CMV intrauterine transmission. In all cohort women or in women infected during the first trimester, no such associations were found between the tested SNPs and intrauterine transmission of the virus. CONCLUSION Women bearing the GG genotype in the rs1898830 SNP, who are infected with CMV during the second trimester of pregnancy, have a low likelihood of transmitting the virus to the fetus.