title: Low mannose-binding lectin levels and MBL2 gene polymorphisms associate with Chlamydia pneumoniae antibodies.
abstract: OBJECTIVE
  Mannose-binding lectin (MBL) has been shown to inhibit infection of host cells by Chlamydia pneumoniae in vitro. We studied if MBL levels and MBL2 polymorphisms associate with the presence of C. pneumoniae antibodies in vivo.
  
  
  METHODS
  Single nucleotide polymorphisms (SNPs) of the MBL2 gene (promoter alleles H/L, X/Y and P/Q; and exon 1 variant alleles B, C and D and wild-type allele A) were genotyped and serum MBL concentrations and C. pneumoniae IgG, IgA and IgM antibodies were analysed in 889 Finnish military recruits.
  
  
  RESULTS
  An MBL level below the median concentration and the MBL2 P/P genotype were significant risk factors of IgG or IgA seroconversions or the presence of IgM antibodies during military service (adjusted odds ratio (OR) 1.5; 95% confidence interval (CI) 1.1-2.1 and OR 1.5; 95% CI 1.0-2.2, respectively). In addition, the promoter Y/Y (OR 1.6; 95% CI 1.1-2.3) and exon 1 variant allele genotypes (OR 1.4; 95% CI 1.0-2.0) were possibly associated with elevated antibodies.
  
  
  CONCLUSIONS
  These results suggest, for the first time, that low serum MBL levels and MBL2 polymorphisms may associate with elevated C. pneumoniae antibodies and seroconversions and thus support the previous findings in vitro.
authors.affiliation: Child and Adolescent Health and Wellbeing Unit, National Institute for Health and Welfare, Oulu, Finland. aino.rantala@thl.fi
authors.forename: Aino
authors.initials: A
authors.lastname: Rantala
authors.forename: Taina
authors.initials: T
authors.lastname: Lajunen
authors.forename: Raija
authors.initials: R
authors.lastname: Juvonen
authors.forename: Aini
authors.initials: A
authors.lastname: Bloigu
authors.forename: Mika
authors.initials: M
authors.lastname: Paldanius
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: Maija
authors.initials: M
authors.lastname: Leinonen
authors.forename: Pekka
authors.initials: P
authors.lastname: Saikku
mesh_terms: D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood / Q000276:immunology*; D023521:Chlamydophila Infections / Q000235:genetics* / Q000276:immunology*; D016993:Chlamydophila pneumoniae / Q000276:immunology*; D005387:Finland; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D008297:Male; D037601:Mannose-Binding Lectin / Q000097:blood* / Q000235:genetics*; D008889:Military Personnel; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000906:Antibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C445619:MBL2 protein, human; D037601:Mannose-Binding Lectin