Novel 6p21.3 Risk Haplotype Predisposes to Acute Coronary Syndrome

Circ Cardiovasc Genet. 2016 Feb;9(1):55-63. doi: 10.1161/CIRCGENETICS.115.001226. Epub 2015 Dec 17.


Background: The HLA-DRB1*01 allele of the human leukocyte antigen has been associated with acute coronary syndrome. Genome-wide association studies have revealed associations with human leukocyte antigen and non-human leukocyte antigen genes of 3 major histocompatibility complex gene classes but not at allelic level.

Methods and results: We conducted a large-scale genetic analysis on a case-control cohort comprising 5376 acute coronary syndrome cases and 4852 unrelated controls from 4 populations of 2 European countries. We analyzed the risk candidate allele of HLA-DRB1*01 by genomic real-time polymerase chain reaction together with high-density single nucleotide polymorphisms of the major histocompatibility complex to precisely identify risk loci for acute coronary syndrome with effective clinical implications. We found a risk haplotype for the disease containing single nucleotide polymorphisms from BTNL2 and HLA-DRA genes and the HLA-DRB1*01 allele. The association of the haplotype appeared in 3 of the 4 populations, and the direction of the effect was consistent in the fourth. Coronary samples from subjects homozygous for the disease-associated haplotype showed higher BTNL2 mRNA levels (r=0.760; P<0.00001).We localized, with immunofluorescence staining, BTNL2 in CD68-positive macrophages of the coronary artery plaques. In homozygous cases, BTNL2 blocking, in T-cell stimulation assays, enhanced CD4(+)FOXP3(+) regulatory T cell proliferation significantly (blocking versus nonblocking; P<0.05).

Conclusions: In cases with the risk haplotype for acute coronary syndrome, these results suggest involvement of enhanced immune reactions. BTNL2 may have an inhibitory effect on FOXP3(+) T cell proliferation, especially in patients homozygous for the risk alleles.

Clinical trial registration:; Unique Identifier: NCT00417534.

Keywords: BTNL2; MHC; acute coronary syndrome; association studies; expression experiments; genetics; haplotype; human leukocyte antigen; regulatory T cell; single nucleotide polymorphism.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Coronary Syndrome* / genetics
  • Acute Coronary Syndrome* / metabolism
  • Acute Coronary Syndrome* / pathology
  • Aged
  • Aged, 80 and over
  • Butyrophilins
  • Cohort Studies*
  • Coronary Vessels / metabolism
  • Coronary Vessels / pathology
  • Female
  • HLA-DRB1 Chains / genetics
  • HLA-DRB1 Chains / metabolism
  • Haplotypes
  • Humans
  • Macrophages / metabolism
  • Macrophages / pathology
  • Male
  • Membrane Glycoproteins* / genetics
  • Membrane Glycoproteins* / metabolism
  • Middle Aged
  • Plaque, Atherosclerotic* / genetics
  • Plaque, Atherosclerotic* / metabolism
  • Plaque, Atherosclerotic* / pathology
  • Polymorphism, Single Nucleotide*
  • Risk Factors
  • Th2 Cells / metabolism
  • Th2 Cells / pathology


  • BTNL2 protein, human
  • Butyrophilins
  • HLA-DRB1 Chains
  • Membrane Glycoproteins

Associated data