ABO O blood group as a risk factor for platelet reactivity in heparin-induced thrombocytopenia

Jason H. Karnes, Jerome Rollin, Jason B. Giles, Kiana L. Martinez, Heidi E. Steiner, Christian M. Shaffer, Yukihide Momozawa, Chihiro Inai, Andrei Bombin, Mingjian Shi, Jonathan D. Mosley, Ian Stanaway, Kathleen Selleng, Thomas Thiele, Taisei Mushiroda, Claire Pouplard, Nancy M. Heddle, Michiaki Kubo, Elizabeth J. Phillips, Theodore E. WarkentinYves Gruel, Andreas Greinacher, Dan M. Roden

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Heparin-induced thrombocytopenia (HIT) is an unpredictable, potentially catastrophic adverse effect resulting from an immune response to platelet factor 4 (PF4)/heparin complexes. We performed a genome-wide association study (GWAS) with positive functional assay as the outcome in a large discovery cohort of patients divided into 3 groups: (1) functional assay-positive cases (n = 1269), (2) antibody-positive (functional assay-negative) controls (n = 1131), and (3) antibody-negative controls (n = 1766). Significant associations (α = 5 × 10−8) were investigated in a replication cohort (α = 0.05) of functional assay-confirmed HIT cases (n = 177), antibody-positive (function assay-negative) controls (n = 258), and antibody-negative controls (n = 351). We observed a strong association for positive functional assay with increasing PF4/heparin immunoglobulin-G (IgG) level (odds ratio [OR], 16.53; 95% confidence interval [CI], 13.83-19.74; P = 1.51 × 10−209) and female sex (OR, 1.15; 95% CI, 1.01-1.32; P =.034). The rs8176719 C insertion variant in ABO was significantly associated with positive functional assay status in the discovery cohort (frequency = 0.41; OR, 0.751; 95% CI, 0.682-0.828; P = 7.80 × 10−9) and in the replication cohort (OR, 0.467; 95% CI, 0.228-0.954; P =.0367). The rs8176719 C insertion, which encodes all non-O blood group alleles, had a protective effect, indicating that the rs8176719 C deletion and the O blood group were risk factors for HIT (O blood group OR, 1.42; 95% CI, 1.26-1.61; P = 3.09 × 10−8). Meta-analyses indicated that the ABO association was independent of PF4/heparin IgG levels and was stronger when functional assay-positive cases were compared with antibody-positive (functional assay-negative) controls than with antibody-negative controls. Sequencing and fine-mapping of ABO demonstrated that rs8176719 was the causal single nucleotide polymorphism (SNP). Our results clarify the biology underlying HIT pathogenesis with ramifications for prediction and may have important implications for related conditions, such as vaccine-induced thrombotic thrombocytopenia.

Original languageEnglish (US)
Pages (from-to)274-284
Number of pages11
Issue number3
StatePublished - Jul 21 2022

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

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