Abstract 1024: Auto-Antibody Serum Profile as Novel Biomarker for Acute Myocardial Infarction
Rationale The immune system is thought to play an important role in the initiation and progression of atherosclerosis. Monocytes and T-lymphocytes that adhere to damaged endothelium can activate residing macrophages, endothelial cells and vascular smooth muscle cells, which all actively participate in the cellular immune response. Fatty streak formation, the earliest form of atherosclerosis, results from lipid ingestion by macrophages, leading to foam cell formation. In time, these lesions can ultimately lead to plaque rupture and subsequently acute myocardial infarction (AMI). There is a constant search for biomarkers for vulnerable plaque formation and rupture to prevent an impeding AMI. Although different biomarkers have been advocated, the majority is associated with concurrent myonecrosis. Here, we propose a new concept in cardiovascular biomarker analysis by screening for an IgG/IgM auto-antibody serum profile analysis by a chip based platform.
Methods & Results An antigen microarray was used (I-chip, ImmunArray, Tel Aviv, Israel), bearing over 740 proteins related to immune regulation, inflammation, angiogenesis and apoptosis. Serum samples from 50 patients with an AMI one to four months before, vs. 42 matched controls were tested by investigators blinded to the individual patient. A single antibody titer raised against F55 predicted a recent AMI with a specificity of 67% and a sensitivity of 86%. A combined serotype profile of 14 specific IgG/IgM auto-antibodies was able to predict a previous event by 85% specificity and 87 % sensitivity.
Conclusion The antigen microarray was able to identify patients with previous AMI with high sensitivity and specificity at a time point when conventional biomarkers have been normalized, illustrating the intrinsic memory of the immune system. All results were obtained with a generic microarray and resulted in a discrimination power of the classifier of 87%. This unique biomarker approach allows differentiation between IgG and IgM patterns and may permit analysis of the IgG auto-antibody profile at the acute moment of an AMI, as it is generated in the days prior to the acute ischemic event. Additional studies will focus on the ability of the antigen chip to prospectively predict cardiovascular coronary events.