title: Smoking status interacts with the association between mannose-binding lectin serum levels and gene polymorphism and the carriage of oropharyngeal bacteria.
abstract: Mannose-binding lectin (MBL) role in the carriage of oropharyngeal bacteria is not known. We investigated the association of smoking, MBL2 polymorphisms, and MBL concentrations with oropharyngeal carriage of respiratory bacteria in young men. Oropharyngeal specimens, MBL concentrations, and MBL2 gene polymorphisms were measured in 124 asthmatic and 394 nonasthmatic Finnish military recruits. The carriage rates of S. pneumoniae (p = 0.002), N. meningitidis (p = 0.005), and beta-hemolytic streptococci (p < 0.001) throughout the military service were significantly higher among smokers than in nonsmokers. An MBL level below the median proved to be a significant risk factor for the carriage of N. meningitidis (odds ratio [OR] = 1.9; 95% confidence interval [CI] 1.0-3.6) and beta-hemolytic streptococci (OR = 2.0; 95% CI 1.2-3.2) in the nonsmokers and a borderline significant risk factor for the carriage of S. pneumoniae (OR = 1.5; 95% CI 0.9-2.6), whereas low MBL levels producing MBL2 haplotypes (LXA/LXA, LXA/O, HYA/O, LYA/O, O/O) seemed to be associated with the carriage of N. meningitidis (OR = 1.8; 95% CI 1.0-3.4) and S. pneumoniae (OR = 1.6; 95% CI 0.9-2.7). Thus, MBL deficiency may predispose nonsmokers to oropharyngeal carriage of these bacteria. We hypothesize that the major factor contributing to elevated bacterial carriage in smokers might be increased bacterial adherence to epithelial cells, which obscures the effect of MBL.
authors.affiliation: Department of Medical Microbiology, Institute of Diagnostics, University of Oulu, Oulu, Finland. ujounio@paju.oulu.fi
authors.forename: Ulla
authors.initials: U
authors.lastname: Jounio
authors.forename: Aino
authors.initials: A
authors.lastname: Rantala
authors.forename: Aini
authors.initials: A
authors.lastname: Bloigu
authors.forename: Raija
authors.initials: R
authors.lastname: Juvonen
authors.forename: Taina
authors.initials: T
authors.lastname: Lajunen
authors.forename: Sylvi
authors.initials: S
authors.lastname: Silvennoinen-Kassinen
authors.forename: Ari
authors.initials: A
authors.lastname: Peitso
authors.forename: Olli
authors.initials: O
authors.lastname: Vainio
authors.forename: Terttu
authors.initials: T
authors.lastname: Harju
authors.forename: Annika
authors.initials: A
authors.lastname: Saukkoriipi
authors.forename: Maija
authors.initials: M
authors.lastname: Leinonen
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000097:blood / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D015897:Comorbidity; D005387:Finland; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D037601:Mannose-Binding Lectin / Q000097:blood / Q000235:genetics*; D008589:Meningococcal Infections / Q000097:blood / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D009345:Neisseria meningitidis / Q000276:immunology* / Q000472:pathogenicity; D009960:Oropharynx / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D011008:Pneumococcal Infections / Q000097:blood / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012907:Smoking
chemical_list: C445619:MBL2 protein, human; D037601:Mannose-Binding Lectin