Abstract

Background: Cardiovascular diseases, including chronic heart failure with reduced ejection fraction (HFrEF), pose a substantial global health burden, emphasizing the need for better understanding of their genetic and immune-related mechanisms. While the immune system, particularly human leukocyte antigens (HLAs), has garnered attention in cardiovascular research, their specific role in HFrEF remains unclear. This study aims to explore the association between HLA alleles and cardiovascular risk in HFrEF, focusing on disease progression, prognosis, and underlying mechanisms. Methods and Results: Ninety-six chronic HFrEF patients underwent four-digit HLA typing analysis in a case-control study. Analysis of HLA alleles revealed the HLA-DR2 family (mostly HLA-DRB5*0101) carried by 14 patients (15.1%). HLA-DR2 showed the highest significant association with mortality. Additional cohort analysis confirmed elevated cardiac injury markers, including Troponin T, in HLA-DR2 carriers, independent of renal function. Multivariate analysis revealed a higher incidence of myocardial infarction in DRB5 carriers, while non-carriers had higher associations with stroke, CKD, and hyperuricemia. Analysis of 3000 plasma proteins from 30,000 UK participants also showed increased inflammatory (TIMD4,CD80) and CV risk associated (IGFBP7) markers were strongly elevated in HLA-DR2 subjects. Mechanistic insights were obtained through CITE-seq analysis of immune cells from HLA-DR2 carriers and non-carriers, revealing enhanced antigen presentation and pro-inflammatory gene expression in carriers. Functional experiments confirmed that silencing HLA-DRB5 in macrophages reduced antigen presentation and T cell activation. HLA-DR2 carriers also exhibited greater T cell activation and polarization, with HLA-DR2 (specifically HLA-DRB5*0101 allele) silencing in dendritic cells diminishing T cell invasion potential into cardiac organoids. Conclusions: This study associates HLA-DR2 alleles, specifically HLA-DRB5*0101, with prognosis in chronic heart failure and myocardial injury, indicating an increased risk for cardiovascular pathology in carriers. These findings underscore the potential of HLA typing for enhancing risk stratification and informing targeted therapies in HFrEF. Further research is warranted to explore targeted treatments for HLA-DRB5 carriers, offering potential avenues for precision medicine in managing heart failure.