Intravenous Immune Globulin (IVIG) for Treatment of Autoimmune Heparin-Induced Thrombocytopenia: A Systematic Review

Abstract

Objective: To evaluate intravenous immune globulin (IVIG) for autoimmune heparin-induced thrombocytopenia (aHIT), including platelet recovery, IVIG dose, dosing weight, IVIG product used, and complications reported. Data Sources: PubMed and EMBASE were searched from inception through June 21, 2020. Search terms included heparin-induced thrombocytopenia, HIT, intravenous immune globulin, IVIG, autoimmune HIT, aHIT, and immune globulin. Study Selection and Data Extraction: Patients administered IVIG for HIT and diagnosed by immunoassay (optical density ≥2) or positive activation assay were included. Data Synthesis: Twenty-four cases were reviewed; 92% had persistent aHIT. Time to IVIG administration post–nonheparin anticoagulant initiation was 9 days (median). Most common IVIG cumulative dose was 2 g/kg (dosed as 1 g/kg/d for 2 consecutive days); 75% had a favorable platelet increase (≥50 × 109/L) within 5 days of initial IVIG dosing. Relevance to Patient Care and Clinical Practice: aHIT is characterized by critically low platelets, thrombosis, and a persistent delay in platelet recovery despite treatment with a nonheparin anticoagulant. An immunoassay and subsequent confirmatory activation assay (at low, high, and 0 IU/mL unfractionated heparin levels) is recommended to confirm diagnosis. Patients nonresponsive to nonheparin anticoagulants within 5 days of initiation should be evaluated for IVIG treatment (2 g/kg cumulative dose). More data are needed to clarify appropriate IVIG dosing weight, although based on current published literature, it is recommended to use actual body weight. Conclusions: Data reported support use of IVIG as adjunctive therapy for patients with aHIT. Judicious IVIG use based on key clinical and laboratory findings is critical.