title: Prevalence of systemic immunoreactivity to Aggregatibacter actinomycetemcomitans leukotoxin in relation to the incidence of myocardial infarction.
abstract: BACKGROUND
  Chronic infections and associated inflammatory markers are suggested risk factors for cardiovascular disease (CVD). The proinflammatory cytokine, interleukin (IL)-1β, is suggested to play a role in the regulation of local inflammatory responses in both CVD and periodontitis. The leukotoxin from the periodontal pathogen Aggregatibacter actinomycetemcomitans has recently been shown to cause abundant secretion of IL-1β from macrophages. The aim of the present study was to compare the prevalence of systemic immunoreactivity to A. actinomycetemcomitans leukotoxin in myocardial infarction (MI) cases (n = 532) and matched controls (n = 1,000) in a population-based case and referents study in northern Sweden.
  
  
  METHODS
  Capacity to neutralize A. actinomycetemcomitans leukotoxin was analyzed in a bioassay with leukocytes, purified leukotoxin, and plasma. Plasma samples that inhibited lactate-dehydrogenase release from leukotoxin-lysed cells by ≥ 50% were classified as positive.
  
  
  RESULTS
  Neutralizing capacity against A. actinomycetemcomitans leukotoxin was detected in 53.3% of the plasma samples. The ability to neutralize leukotoxin was correlated to increasing age in men (n = 1,082) but not in women (n = 450). There was no correlation between presence of systemic leukotoxin-neutralization capacity and the incidence of MI, except for women (n = 146). Women with a low neutralizing capacity had a significantly higher incidence of MI than those who had a high neutralizing capacity.
  
  
  CONCLUSIONS
  Systemic immunoreactivity against A. actinomycetemcomitans leukotoxin was found at a high prevalence in the analyzed population of adults from northern Sweden. The results from the present study do not support the hypothesis that systemic leukotoxin-neutralizing capacity can decrease the risk for MI.
authors.affiliation: Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden. anders.johansson@odont.umu.se
authors.forename: Anders
authors.initials: A
authors.lastname: Johansson
authors.forename: Marie
authors.initials: M
authors.lastname: Eriksson
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Ahrén
authors.forename: Kurt
authors.initials: K
authors.lastname: Boman
authors.forename: Jan-Håkan
authors.initials: JH
authors.lastname: Jansson
authors.forename: Göran
authors.initials: G
authors.lastname: Hallmans
authors.forename: Ingegerd
authors.initials: I
authors.lastname: Johansson
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D057134:Antibodies, Neutralizing / Q000097:blood; D016022:Case-Control Studies; D015897:Comorbidity; D005098:Exotoxins / Q000276:immunology* / Q000633:toxicity; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology*; D009500:Neutralization Tests; D015661:Pasteurellaceae / Q000276:immunology* / Q000472:pathogenicity; D016871:Pasteurellaceae Infections / Q000453:epidemiology*; D016036:Seroepidemiologic Studies; D013548:Sweden / Q000453:epidemiology
chemical_list: D000907:Antibodies, Bacterial; D057134:Antibodies, Neutralizing; D005098:Exotoxins; C018579:leukotoxin