title: Low ficolin-2 levels in common variable immunodeficiency patients with bronchiectasis.
abstract: Common variable immunodeficiency (CVID) encompasses a heterogeneous group of antibody deficiencies characterized by susceptibility to recurrent infections and sequelae, including bronchiectasis. We investigated the relevance of the lectin complement pathway in CVID patients by analysing ficolin-2 and ficolin-3 serum levels and genotyping single nucleotide polymorphisms (SNPs) in the FCN2 and FCN3 genes. Our results show that ficolin-2 levels in CVID patients are significantly lower (P < 0.0001) than in controls. The lowest ficolin-2 levels are found in CVID patients with bronchiectasis (P = 0.0004) and autoimmunity (P = 0.04). Although serum levels of ficolin-3 were similar in CVID patients and controls, CVID patients with bronchiectasis again showed lower levels when compared to controls (P = 0.0001). Analysis of single nucleotide polymorphisms in the FCN2 gene confirmed known influences on ficolin-2 serum levels, but did not support a genetic basis for the observed ficolin-2 deficiency in CVID. We found that CVID patients with bronchiectasis have very low levels of ficolin-2. The reason for the deficiency of ficolin-2 in CVID and any possible causal relationship is currently unknown. However, as bronchiectasis is a very important factor for morbidity and mortality in CVID, ficolin-2 could also serve as biomarker for monitoring disease complications such as bronchiectasis.
authors.affiliation: Centre for Chronic Immunodeficiency (CCI), University Medical Centre Freiburg, University of Freiburg, Freiburg, Germany.
authors.forename: M-L
authors.initials: ML
authors.lastname: Metzger
authors.forename: I
authors.initials: I
authors.lastname: Michelfelder
authors.forename: S
authors.initials: S
authors.lastname: Goldacker
authors.forename: K
authors.initials: K
authors.lastname: Melkaoui
authors.forename: J
authors.initials: J
authors.lastname: Litzman
authors.forename: D
authors.initials: D
authors.lastname: Guzman
authors.forename: B
authors.initials: B
authors.lastname: Grimbacher
authors.forename: U
authors.initials: U
authors.lastname: Salzer
mesh_terms: D015415:Biomarkers / Q000097:blood; D001987:Bronchiectasis / Q000097:blood / Q000150:complications / Q000235:genetics / Q000401:mortality; D015331:Cohort Studies; D017074:Common Variable Immunodeficiency / Q000097:blood / Q000150:complications / Q000235:genetics / Q000401:mortality; D005260:Female; D006023:Glycoproteins / Q000097:blood / Q000235:genetics; D006801:Humans; D037102:Lectins / Q000097:blood / Q000235:genetics; D008297:Male; D020641:Polymorphism, Single Nucleotide; D000097604:Ficolins
chemical_list: D015415:Biomarkers; D006023:Glycoproteins; D037102:Lectins; D000097604:Ficolins; C109662:FCN3 protein, human
keywords: CVID; complement; ficolin-2; ficolin-3; lectin pathway