Summary
Morbidities related to atherosclerosis, such as acute coronary syndromes (ACS) including
unstable angina and myocardial infarction, remain leading causes of mortality. Unstable
plaques are inflamed and infiltrated with macrophages and T lymphocytes. Activated
dendritic cells interact with T cells, yielding predominantly Th1 responses involving
interferon-gamma (IFN-γ) and tumour necrosis factor-alpha (TNF-α), while the role
of interleukin 17 (IL-17) is questionable. The expansion of CD28nullCD4 or CD8 T cells
as well as pattern recognition receptors activation (especially Toll-like receptors;
TLR2 and TLR4) is characteristic for unstable plaque. Inflammation modifies platelet
and fibrin clot characteristics, which are critical for ACS. Understanding of the
inflammatory mechanisms of atherothrombosis, bridging inflammation, oxidative stress
and immune regulation, will allow for the detection of subjects at risk, through the
use of novel biomarkers and imaging techniques including intravascular ultrasound,
molecular targeting, magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (18F-FDG)
positron emission tomography (PET). Moreover, understanding the specific inflammatory
pathways of plaque rupture and atherothrombosis may allow for immunomodulation of
ACS. Statins and anti-platelet drugs are anti-inflammatory, but importance of immune
events in ACS warrants the introduction of novel, specific treatments directed either
on cytokines, TLRs or inflammasomes. While the prime time for the introduction of
immunologically inspired diagnostic tests and treatments for atherosclerosis have
not come yet, we are closer than ever before to finally being able to benefit from
this vast body of experimental and clinical evidence. This paper provides a comprehensive
review of the role of the immune system and inflammation in ACS.
Note: The review process for this manuscript was fully handled by G. Y. H. Lip, Editor
in Chief.
Keywords
Acute myocardial infarction - atherothrombosis - inflammation - atherosclerosis -
immunity