Genetic polymorphisms and serum levels of mannose-binding lectin in Chinese pediatric patients with common infectious diseases.

Mannose-binding lectin (MBL) is a collagen-like serum protein that plays an important role in first-line host defense, especially in infants and young children. The objective of this study was to explore the genetic polymorphisms and serum protein levels of MBL in Chinese pediatric patients with common infectious diseases, including recurrent respiratory infection (RRI), acute respiratory infection (ARI), active cytomegalovirus (CMV) infection, localized abscess, and otitis media.,MBL genetic polymorphisms of 151 pediatric patients with infectious diseases and 105 healthy controls were detected by PCR and sequencing. Serum MBL levels of all the patients and controls were measured using a Human MBL ELISA Kit. Differences in MBL genetic polymorphisms and serum levels between patients and controls were analyzed by statistical methods.,The frequencies of allele H/L at position -550 of the promoter and three haplotypes - HYPA, HYPB, and LYPB - were statistically different between patients and controls (p<0.05). The frequencies of genotypes 'YA' and 'XB', relevant to serum protein levels, were also significantly different between patients and controls (p<0.05). Serum MBL levels of patients with active CMV infection were significantly lower than those of controls (p<0.05). Conversely, serum MBL levels of patients with ARI and localized abscess were significantly higher than those of controls (p<0.05).,Genetic polymorphisms attributable to mutations in the promoter and exon 1 of the MBL2 gene appear to be relatively common in pediatric patients with infectious diseases. Low serum MBL levels may play a role in the high sensitivity of pediatric CMV infections.