Effect of high-dose intravenous immunoglobulin therapy on blood rheology

Stroke has been reported after high-dose intravenous immunoglobulin (IVIG) therapy, so a study was conducted to find out what effect IVIG has on factors influencing blood flow. The influence of IVIG on plasma viscosity, blood viscosity, and erythrocyte aggregation was examined in vitro and in vivo. For the in-vitro experiments different amounts of IVIG were added to whole blood or plasma from healthy subjects. The in-vivo effects were assessed during five courses of treatment with IVIG (24-54 g/day) in 4 patients with chronic immune thrombocytopenia (ITP). Concentration of IgG infused correlated strongly with viscosity of plasma and whole blood, both in vitro and in vivo, and plasma viscosity increased to beyond the normal range after IVIG treatment. The changes in viscosity that occur after IVIG therapy can impair blood flow, and in patients at risk of cardiovascular and thromboembolic events they might be sufficient to produce myocardial infarction or stroke.