Functional polymorphisms in the mannan-binding lectin 2 gene: Effect on MBL levels and otitis media

Evidence of an association between mannose binding lectin codon 54 polymorphism and adenoidectomy and/or tonsillectomy in children

Mannose binding lectin (MBL) is a calcium-dependent lectin that plays an important role innate immunity by activating the complement pathway. There have been a number of studies describing an association between the MBL genotype and disease susceptibility. MBL deficiency has been described as one of the factors leading to a number of infections in children with recurrent upper respiratory tractus infections (URTI). We hypothesized that MBL deficiency may be associated with recurrent URTI, which requires adenoidectomy and/or adenotonsillectomy. In this study to clarify this hypothesis we investigated whether there may be an association between two low producing MBL variants and adenoidectomy and/or tonsillectomy due to recurrent URTI in children. Blood samples were collected, adenoidectomy and/or tonsillectomy due to recurrent URTI and 50 controls (mean age 80.53 +/- 32.62 months). In all patients and controls codon 54 and codon 57 polymorphisms of the MBL gene were analyzed. None of the subjects from the patient group and control group carried codon 57 polymorphism of the MBL gene. The frequency of low-level MBL genotypes (AB and BB) for codon 54 polymorphism in the patient group was found to be significantly higher compared to the control subjects (55.7% versus 14%) (p<0.001). This study shows that the presence of low-level MBL alleles is associated with adenoidectomy and/or tonsillectomy caused by recurrent URTI in children.

Early acute otitis media: predictor for AOM and respiratory infections in schoolchildren?

OBJECTIVE

It has been reported that acute otitis media (AOM) and respiratory infectious morbidity still are common in schoolchildren. However, the significance of early initiation of AOM on later respiratory infections is not known. The aim of the study was to assess whether early initiation of AOM is a predictor for AOM and other respiratory infections in schoolchildren, and if environmental exposures and host factors in early life predict later AOM.

METHODS

A population-based, prospective study of 3754 children born in Oslo in 1992/93, of which 2549 children were followed from birth to 10 years. Main outcome measures were questionnaire-based information on AOM and other respiratory infections at ages 6 months, 1 year and 10 years.

RESULTS

Of the 190 (5.3%) children with one or more episodes of AOM before 6 months, 97 (51.1%) remained susceptible the next 6 months. The total number of children with one or more episodes of AOM from 6 to 12 months was 812 (25.1%). Of the 336 (13.2%) with AOM at 10, 95 (28.3%) also had AOM the first year of life. One or more episodes of tonsillopharyngitis or lower respiratory infections were experienced in 624 (24.4%) of the children at 10 years. There was a predominance of boys with AOM the first year of life, while girls were more prone to AOM at age 10. AOM the first year of life was not strongly associated with AOM at age 10 with crude and adjusted odds ratios 1.3 (95% CI 1.0-1.6) and 1.2 (95% CI 0.9-1.5), respectively. A corresponding tendency was found for other respiratory infections (tonsillopharyngitis or lower respiratory infections) at age 10. Tobacco smoke exposure at birth, early life atopic eczema and otitis media surgery increased the risk of AOM at age 10.

CONCLUSIONS

We found no strong association between early AOM and AOM and other respiratory infections in schoolchildren. Parental smoking at birth, early life atopic eczema and female gender were only weakly associated with AOM in 10-year olds while otitis media surgery was strongly associated with AOM in schoolchildren.

Association of CD14 promoter polymorphism with otitis media and pneumococcal vaccine responses

Innate immunity is of particular importance for protection against infection during early life, when adaptive immune responses are immature. CD14 plays key roles in innate immunity, including in defense against pathogens associated with otitis media, a major pediatric health care issue. The T allele of the CD14 C-159T polymorphism has been associated with increased serum CD14 levels. Our objective was to investigate the hypothesis that the CD14 C-159T allele is protective against recurrent acute otitis media in children. The association between the CD14 promoter genotype and the number of acute otitis media episodes was evaluated both retrospectively and prospectively in a cohort of 300 children. Serotype-specific immunoglobulin G (IgG) antibody responses after pneumococcal vaccinations were examined according to CD14 genotype to compare immune responsiveness across genotypes. An age-dependent association was found: compared with that for CC homozygotes aged between 12 to 24 months, TT homozygotes had fewer episodes of acute otitis media (79 versus 41%, respectively; P = 0.004); this relationship was absent in older children. Additionally, TT homozygotes showed higher serotype-specific anti-pneumococcal IgG antibody levels. Our data suggest that genetic variation in CD14, a molecule at the interface of innate and adaptive immune responses, plays a key role in the defense against middle ear disease in childhood and in pneumococcal vaccine responsiveness. These findings are likely to be important to these and other immune-mediated outcomes in early life.