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.

Successful treatment of vaccine‐induced prothrombotic immune thrombocytopenia (VIPIT): COMMENT from Roberge, et al.

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bination of APTT reagent and analyzer, 1,3,10 but also by the anti-Xa reagent used for calculation. 1 In conclusion, taken together, our results 1,5 and the data reported by Kovacs et al 2 clearly highlight the urgent need for a better standardization of the anti-Xa assay and particularly the development of better standardized calibration materials.

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“…However, some aHIT cases required a higher cumulative IVIG dose following lower-than-expected or transient results. [5][6][7] Possible variable inhibitory effect of different IVIG products, polymorphisms in the FcɣIIa receptors, and use of ideal body weight for dose calculation could be explanations for variable effects. 5 Caution is advised regarding a possible variable response after the recommended IVIG regimen in treatment for aHIT and thus, possibly for VITT.…”

“…[5][6][7] Possible variable inhibitory effect of different IVIG products, polymorphisms in the FcɣIIa receptors, and use of ideal body weight for dose calculation could be explanations for variable effects. 5 Caution is advised regarding a possible variable response after the recommended IVIG regimen in treatment for aHIT and thus, possibly for VITT. Repeating another IVIG dose should be considered if thrombocytopenia or clinical response are insufficient.…”

Diffuse prothrombotic syndrome after ChAdOx1 nCoV-19 vaccine administration: a case report

“…According to the Italian Society for the Study of Haemostasis and Thrombosis (SISET) position statement [ 7 ] and the evolving international recommendations [ 1 ], the severity of the thrombocytopenia at presentation (< 50 × 10 9 /L) imposed the immediate initiation of IVIG [ 8 ] and dexamethasone, as a means of interrupting VITT antibody-induced platelet activation. Conversely, the absence of worsening intracranial hemorrhage allowed us not to consider platelet transfusion.…”

Autoimmune heparin-induced thrombocytopenia: a rare manifestation of COVID-19

“…Previous studies have shown that intact IgG fragments inhibit platelet activation by antibodies. 13 It is important to note that IVIG exhibits prothrombotic effects and may exacerbate symptoms and increase morbidity in a patient presenting with existing blood clots. The patient was also initially started on dexamethasone since TTP was a differential diagnosis.…”