Prevalence of systemic immunoreactivity to Aggregatibacter actinomycetemcomitans leukotoxin in relation to the incidence of myocardial infarction

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.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.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.Chronic inflammations, such as periodontitis, are suggested to be risk factors for the development of cardiovascular diseases [1]. It has been suggested that the total pathogenic burden from the oral cavity, and possibly also from the gut, correlates with disease markers of atherosclerosis [2]. Periodontitis is a bacteria-induced inflammatory condition that causes degradation of the tooth-supporting tissues, bone and connective tissue [3,4]. Bioactive molecules released from pathogenic microorganisms located in the subgingival biofilm cause imbalance in the inflammatory response, which results in loss of the tooth-supporting tissues [5]. For the host to maintain homeostasis within the periodontal tissues, the immune response system contributes to controlling the microbial colonization and invasion [6]. This immune response includes local and systemic production of antibodies induced by antigens from the microorganisms that ar