Background: To determine the relationship between markers of innate immunity and clinical outcomes in patients with heart failure (HF) after acute myocardial infarction (AMI). Atherogenesis and HF is associated with the altered control of inflammation by innate immune defenses that include pattern-recognition molecules such as Toll-like receptors (TLRs) and mannose-binding lectin (MBL).
Methods and results: We assessed circulating levels, and relationships with adverse outcomes of MBL and sTLR2 levels in 234 patients with AMI complicated with HF. Blood was sampled at baseline (median 3 days after AMI), 1 month, 1 year, and 2 years. For comparison, we also measured MBL and sTLR2 levels in 20 age- and sex-matched healthy controls. Patients with post-MI HF had markedly decreased serum levels of sTLR2 at baseline that increased during follow-up, but did not reach the concentrations present in healthy controls. In contrast, serum MBL levels were initially normal in patients with post-MI HF, but decreased during follow-up, and MBL levels measured 1 month after the index infarct were inversely associated with a higher incidence of reinfarction.
Conclusion: These findings suggest that circulating levels of MBL and sTLR2 may reflect different aspects of the innate immune response and further suggest the involvement of innate immunity responses in the pathogenesis of post-MI HF.