title: Plasma levels of mannan-binding lectin in relation to periodontitis and smoking.
abstract: BACKGROUND
  Mannan-binding lectin (MBL) is an important molecule of innate immunity; it acts as an opsonin and stimulates the classical complement pathway. Moreover, it has been suggested that MBL acts as a weak acute phase protein. We investigated whether MBL levels are increased in periodontitis, and we tested whether individuals deficient for MBL are more susceptible to periodontitis.
  
  
  METHODS
  A total of 219 subjects participated in the study. Plasma samples from 115 periodontitis patients and 104 healthy controls were taken, and the MBL levels were measured by enzyme-linked immunosorbent assay (ELISA). MBL levels were analyzed in relation to periodontitis, taking into consideration age, gender, ethnic and educational background, and smoking status. In some analyses, subjects with MBL plasma levels <0.8 microg/ml were considered MBL deficient.
  
  
  RESULTS
  MBL plasma concentrations were not significantly different in moderate and severe periodontitis compared to controls (1.6, 1.4, and 1.6 microg/ml, respectively). Also, the prevalence of MBL deficiency was not found to be different between controls and moderate and severe periodontitis (45%, 37%, and 36%). However, among all subjects and among the non-deficient subjects, MBL levels were markedly increased in heavy smokers (>10 cigarettes per day), irrespective of periodontal disease status, in comparison to non-smokers and light smokers. MBL plasma levels did not show a correlation with plasma C-reactive protein (CRP) and were also not related to the prevalence of specific periodontal pathogens.
  
  
  CONCLUSIONS
  MBL levels were not elevated in periodontitis, and MBL deficiency was not related to susceptibility for periodontitis. The fact that MBL levels were higher among heavy smokers is the subject of further investigation.
authors.affiliation: Department of Periodontology, Academic Center for Dentistry Amsterdam, University of Amsterdam and Vrije University, Amsterdam, The Netherlands.
authors.forename: Gaia
authors.initials: G
authors.lastname: Maffei
authors.forename: Nannette
authors.initials: N
authors.lastname: Brouwer
authors.forename: Koert M
authors.initials: KM
authors.lastname: Dolman
authors.forename: Ubele
authors.initials: U
authors.lastname: van der Velden
authors.forename: Dirk
authors.initials: D
authors.lastname: Roos
authors.forename: Bruno G
authors.initials: BG
authors.lastname: Loos
mesh_terms: D000328:Adult; D000367:Age Factors; D016976:Aggregatibacter actinomycetemcomitans / Q000302:isolation & purification; D016301:Alveolar Bone Loss / Q000145:classification; D002097:C-Reactive Protein / Q000032:analysis; D004198:Disease Susceptibility; D004522:Educational Status; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D037601:Mannose-Binding Lectin / Q000097:blood* / Q000172:deficiency; D010514:Periodontal Pocket / Q000145:classification; D010518:Periodontitis / Q000097:blood* / Q000145:classification / Q000382:microbiology; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D012737:Sex Factors; D012907:Smoking / Q000097:blood*
chemical_list: D037601:Mannose-Binding Lectin; D002097:C-Reactive Protein