Increased Risk of Asthma in Chlamydia pneumoniae Infected Children with Variant Alleles in Mannose-Binding Lectin

Children with a variant allele of mannose-binding lectin (MBL) who have been infected with Chlamydia pneumonia are more susceptible to asthma, according to a recent Hungarian study.

Children with a variant allele of mannose-binding lectin (MBL) who have been infected with Chlamydia pneumonia are more susceptible to asthma, according to a recent Hungarian study.A number of studies have described a link between C. pneumoniae infection and asthma, wherein infected adults have exacerbated symptoms of asthma. Studies in children, however, have given mixed results, suggesting unidentified variables in the role of C pneumoniae in the initiation and early development of asthma. Adrienne Nagy, MD, at the Budai Children’s Hospital, Budapest, Hungary, and colleagues evaluated the relationship between C. pneumoniae infection and asthma in children, with respect to the genotype of the MBL locus.The study included 139 children with asthma and 174 healthy control children. C. pneumoniae infection was detected by enzyme-linked immunosorbent assay (ELISA) using C. pneumoniae specific-antibodies. In addition, variant alleles of MBL were identified by PCR-Restriction Fragment Length Polymorphism (RFLP) for subgroup analysis.Results found no significant difference between the incidence of C. pneumoniae infection in children with asthma and the incidence in healthy children. More specifically, similar percentages of children in each group gave positive results for C pneumoniae-specific antibodies.However, when only children with variant MBL alleles were analysed, results indicated that significantly more asthmatic children were positive for C. pneumoniae antibodies than healthy controls (63.7% vs. 40.7%, respectively). Asthmatic children with a variant MBL allele were 2.21 times more likely to be C. pneumoniae positive than healthy children with a variant MBL allele, when data were adjusted for age and gender. Furthermore, children infected with C. pneumoniae had a higher risk of asthma if they had a variant MBL allele. This risk was even greater in children with chronic or recurrent infection (adjusted odds ratio 5.38).Dr. Nagy concludes that “this study indicates the important role of variant MBL alleles in the susceptibility to asthma in children infected with C. pneumoniae.”(Source: J Allergy Clin Immunol 2003 Oct;112:4:729-34. “The development of asthma in children infected with Chlamydia pneumoniae is dependent on the modifying effect of mannose-binding lectin”: By Deanna M Green, PhD: Docotor’s Guide News: November 2003)