Association between mannose-binding lectin gene polymorphism and pediatric cytomegalovirus infection

Mannose-binding lectin (MBL) is an important constituent of the human innate immune system, and can bind to a wide range of pathogens, including viruses such as influenza A, HIV, herpes simplex 2, and SARS-CoV. MBL deficiency results from single nucleotide polymorphisms (SNPs) in exon 1, and the promoter region of the human MBL2 gene has been found to be associated with susceptibility to a number of infections. However, studies on the interactions between MBL and CMV infection are limited. In this study, we investigated 104 children suffering from HCMV infection, in an effort to find any association between MBL and HCMV infection of children in China. We analyzed the genotypes of 104 HCMV patients and 105 healthy controls, and investigated the distributions of polymorphisms at -550(H/L), -221(Y/X), and +4(P/Q), together with their structural variants. Although there was no significant difference in the distribution of B alleles between HCMV patients and healthy controls, the frequencies of the high-MBL-level related genotype of YA type in HCMV patients were significantly lower than those seen in healthy controls, while low-level related genotypes of XB type were more common in HCMV patients. In addition, CMV-DNA quantification revealed higher viral loads of the XB type in HCMV patients. Thus we can speculate that as an acute response protein and a pattern-recognition molecule of the innate immune system, MBL may play a role in protecting against HCMV infection in children, and MBL gene mutations may be a significant risk factor for the development of infantile HCMV infection.