title: Mannan-binding lectin insufficiency in children with recurrent infections of the respiratory system.
abstract: Blood samples were collected over a 4-year period from 335 children (aged 1-16 years) suffering from recurrent respiratory infections and 78 controls. The patients were subdivided into four groups: I, children with no immune system defects detected (n = 101); II, children with allergies (n = 94); III, children with humoral response defects (n = 93); and IV, children with disturbances of cellular immunity (n = 66). Nineteen patients had both humoral and cellular abnormalities. All patients and controls were investigated to determine the exon 1 and promoter region variants of the mbl-2 gene. MBL serum concentrations were also determined in samples from 291 patients and 75 controls. The proportion of O (B, D or C) alleles was significantly higher in the patient group compared to controls, and this association was strongest for subgroup III. The promoter LX variant frequency was also commoner in the patients as a whole, and significantly so in subgroups II and IV. Genotypes markedly influenced MBL concentrations in all groups, and correlated with ability to activate the lectin pathway of complement activation. The strongest and most significant inverse correlations between serum MBL and respiratory disease were found in patient group III and in 17 patients with multiple humoral and/or cellular abnormalities. Among nine patients with unexpectedly low LP activity in view of their MBL concentrations, one person was found to be MASP-2 deficient. Our results indicate that mannan-binding lectin insufficiency, with or without a coexisting immune defect, is associated with the occurrence of recurrent respiratory infections in childhood, and this relationship is particularly strong and statistically significant in children with concomitant impairments of humoral immunity.
authors.affiliation: Laboratory of Immunobiology of Infections, Centre of Medical Biology and Microbiology, Polish Academy of Sciences, Lodz, Poland. mcedzynski@cbmim.pan.pl
authors.forename: M
authors.initials: M
authors.lastname: Cedzynski
authors.forename: J
authors.initials: J
authors.lastname: Szemraj
authors.forename: A S
authors.initials: AS
authors.lastname: Swierzko
authors.forename: L
authors.initials: L
authors.lastname: Bak-Romaniszyn
authors.forename: M
authors.initials: M
authors.lastname: Banasik
authors.forename: K
authors.initials: K
authors.lastname: Zeman
authors.forename: D C
authors.initials: DC
authors.lastname: Kilpatrick
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015935:Complement C4b / Q000032:analysis; D005091:Exons; D005838:Genotype; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000276:immunology*; D037601:Mannose-Binding Lectin / Q000031:analogs & derivatives* / Q000097:blood / Q000172:deficiency* / Q000235:genetics*; D050606:Mannose-Binding Protein-Associated Serine Proteases; D009154:Mutation; D011401:Promoter Regions, Genetic; D012008:Recurrence; D012141:Respiratory Tract Infections / Q000276:immunology*; D012697:Serine Endopeptidases / Q000235:genetics; D018709:Statistics, Nonparametric; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: C445619:MBL2 protein, human; D037601:Mannose-Binding Lectin; D015935:Complement C4b; C105296:MASP2 protein, human; D050606:Mannose-Binding Protein-Associated Serine Proteases; D012697:Serine Endopeptidases