New IDEaS for HIT treatment, anyone?

Abstract

In this issue of Blood, Kizlik-Masson et al1 show that a bacterial protease, immunoglobulin G (IgG)-degrading enzyme of Streptococcus pyogenes (IdeS), by cleaving heparin-induced thrombocytopenia (HIT) antibodies, can potentially serve as an effective treatment of HIT. HIT is a serious prothrombotic disorder characterized by antibodies to platelet factor 4 (PF4)-polyanion complexes. Despite the recognition of HIT decades ago, outcomes remain concerning. A recent large population-based study of ∼100 000 HIT patients showed that HIT still inflicts significant morbidity and mortality.2 Roughly one-third of HIT patients develop thrombosis, and 1 in 10 patients die during the HIT hospitalization. An additional, somewhat less recognized issue is that of bleeding associated with the use of non-heparin alternative anticoagulants2-4 so much so that the American Society of Hematology 2018 guidelines for management of heparin-induced thrombocytopenia calls for research on “…development of novel therapeutics that target pathways in the pathogenesis of HIT proximal to coagulation that could be effective in reducing thrombosis without increasing the risk of hemorrhage.”5.