[Treatments with immunoglobulin and thrombotic adverse events]

Treatments with intravenous or subcutaneous immunoglobulin (Ig) are used in a broad variety of disorders. Tolerance of Ig is usually good but adverse events, including some serious ones, have been reported and may differ among different Ig preparations. Thrombotic complications occur in 0.6 to 13% of cases and can involve arterial or venous circulation, rarely both. Deep venous thrombosis with or without pulmonary embolism, stroke or myocardial infarction remained the most frequent thrombotic complications. Some risk factors have been identified, mainly old age, multiple cardiovascular risk factors, and past history of thrombo-embolic manifestations. Several mechanisms are suggested to explain this increased risk of thrombotic complications. Indeed, Ig treatments increase the plasma viscosity, increase and activate platelets, can trigger the coagulation cascade through the presence of activated factor XI in some Ig preparations, and release vasoactive molecules responsible for vasospasm. Patients have to be carefully monitored and risk factors to be identified as soon as possible. The role of antiplatelets or anticoagulation is not well determined but should probably be proposed to patients with high risk.