Background: Inflammation and possibly chronic infections are associated with acute coronary syndromes; however, the mechanisms responsible for this association are not yet fully elucidated. The aim of this study was to assess whether the hyperreactivity of the inflammatory system, that we have shown in unstable patients with persistently elevated C-reactive protein and with recurrence of symptoms, was associated with chronic infection.
Methods: In 20 unstable angina patients seropositivity and antibody levels vs Cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae were measured and correlated with the interleukin-6 production in vivo in 1 ml of whole blood stimulated with 0.1 microgram lipopolysaccharide for 4 hours.
Results: No positive correlation was found between antibody titer and interleukin-6 levels. No correlation was also found between seropositivity to Cytomegalovirus, Helicobacter pylori or Chlamydia pneumoniae and interleukin-6 levels.
Conclusions: Our study suggests that seropositivity for infective agents, including Chlamydia pneumoniae, does not affect the monocyte response to lipopolysaccharide and thus cannot account for the enhanced interleukin-6 production observed in unstable angina patients with raised levels of C-reactive protein and worse prognosis, and suggests the predominant role of the individual response to different stimuli.