Host genetics and susceptibility to congenital and childhood cytomegalovirus infection: a systematic review

AIM To summarize available evidence on the role of host genetics in the susceptibility to congenital and childhood cytomegalovirus (CMV) infections by conducting a systematic review of published studies. METHODS We searched online databases (PubMed, Web of Science, Scopus and HuGe Navigator) for relevant studies with well-defined inclusion and exclusion criteria and assessed the risk of bias using novel Confounding-Selection-Information bias score (CSI). RESULTS 5105 studies were initially identified, but only 5 met all the inclusion criteria and were analyzed in detail. Polymorphisms of the toll-like receptors (TLRs) and mannose-binding lectin (MBL) genes were shown to have an impact on the CMV infection in infants. Polymorphisms of the TLR2 (rs3804100, rs1898830), TLR4 (rs4986791), and TLR9 (rs352140) were shown to have a role in congenital CMV infection. Low MBL levels were associated with CMV infection in Chinese individuals, a finding that was not replicated in Caucasians. The overall credibility of evidence was weak. CONCLUSIONS Based on currently available very limited amount of evidence, it is uncertain whether congenital and childhood CMV infections are under host genetic control. Additional primary studies are needed with more specific research hypotheses that will enable gradual understanding of specific mechanisms of the CMV pathogenesis. More genetic studies in the future will facilitate better understanding of host susceptibility and likely enable novel preventative and curative measures.