Inverse association of ApoB and HSP60 antibodies with coronary artery disease in Indian population.

Objective: Atherosclerosis is an autoimmune condition and the underlying cause of coronary artery disease (CAD). Circulating antibodies to self-antigens can have a pathogenic or protective function in atherosclerosis. The objective of the study was to understand the association of autoantibody levels with CAD and its correlation with circulating immune cells.

Methods: We assessed antigen concentration and antibodies to apolipoprotein B (ApoB) and heat shock protein (HSP)60 by ELISA in 252 acute coronary syndromes (ACS), 112 patients with stable angina (SA) and 203 healthy controls from Indian population. T cells in peripheral blood mononuclear cells (PBMC) were enumerated by flow cytometry. Cytokine concentrations were measured by multiplex assay.

Results: IgG and IgM antibodies to ApoB and HSP60 proteins were significantly lower in patients with ACS while only IgG levels to ApoB were lower in patients with SA, compared with control. Subjects in the highest tertile of antibodies showed significantly lower OR for ACS (IgG 0.52, 95% CI 0.31 to 0.88, p=0.02 and IgM 0.58, 95% CI 0.34 to 0.98, p=0.04), ApoB100 (IgG 0.52, 95% CI 0.31 to 0.88, p=0.02 and IgM 0.58, 95% CI 0.34 to 0.99, p=0.04) and HSP60, respectively. Interestingly, T helper 17 (TH17) cells showed an inverse relationship with ApoB and HSP60 IgG antibodies (r2 =-0.17, p<0.001 and r2 =-0.20, p<0.001, respectively), while interleukin 17 concentrations were negatively correlated with IgM antibodies to the proteins.

Conclusion: This study shows that higher antibodies to ApoB and HSP60 proteins are less often associated with ACS and that these antibodies are inversely associated with inflammatory Th17 cells.