Soluble P-selectin, but not circulating cell-free DNA, is a potential diagnostic biomarker in heparin-induced thrombocytopenia

Abstract

Background: Heparin-induced thrombocytopenia (HIT) is characterized by the presence of anti-platelet factor 4 (PF4) antibodies, which bind to platelets via Fcγ receptor IIA (FcγRIIA), potentially leading to thrombosis.

Objectives: To identify novel immunothrombosis markers and assess their diagnostic utility in HIT.

Methods: A single-center cross-sectional retrospective study was performed including 144 patients from a cohort that included 69 confirmed HIT patients (PF4+/serotonin release assay [SRA] +), 39 patients in whom HIT was excluded (PF4+/SRA-), and 11 patients negative by both screening and confirmatory tests (PF4-/SRA-). Additionally, 26 healthy volunteers were included as controls. We utilized multiplex arrays and ELISA to evaluate 41 biomarkers of immunothrombosis and digital PCR to quantify circulating cell-free DNA (ccf-DNA).

Results: Compared with healthy controls, HIT patients showed increased levels of D-dimer and soluble thrombomodulin, but reduced ADAMTS-13, consistent with a procoagulant status. Soluble adhesion molecules (soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1), cytokines (interleukin [IL]-6, IL-8), and markers of platelet (sP-selectin, thromboxane 2 [TXB2], sFcγRIIA) and endothelium activation (angiopoietin-2), along with mitochondrial and genomic ccf-DNA, were elevated, implying a prothrombotic phenotype. Notably, sP-selectin was the only marker that differentiated PF4+/SRA+ patients from PF4+/SRA- and PF4-/SRA- patients and controls (P < .001). TXB2 also distinguished PF4+/SRA+ from PF4+/SRA- but not from the other 2 groups. Receiver operating characteristic analysis yielded an area under curve (AUC) of 0.83 for P-selectin and 0.80 for PF4 ELISA. Combining P-selectin and PF4 ELISA improved AUC to 0.88 (82.6% sensitivity, 87.2% specificity). Multivariate analysis revealed that soluble P-selectin is independently associated with HIT.

Conclusion: HIT results in significant immunothrombotic responses, with sP-selectin as potential biomarker for the diagnosis of this condition.

Keywords: GPVI; KKO; heparin-induced thrombocytopenia; immunothrombosis; platelet factor 4.