Efficacy and mechanism of intravenous immunoglobulin treatment for immune thrombocytopenia in adults

Abstract

Intravenous immunoglobulin (IVIg) has been used for almost 40 years as a biologic therapeutic for the treatment of immune thrombocytopenia (ITP). Originally found to ameliorate ITP in pediatric patients, IVIg is now used to treat adult patients with acute and chronic ITP and has become a first-line therapy for this autoimmune disease. Treatment in adult ITP usually consists of high-doses of IVIg, usually 1-2 g/kg given as one bolus dose or over 4 to 5 days. Success rates vary but in adults with acute ITP, response rates are around 60% but often the response is transient. In chronic ITP, IVIg is not as efficacious and is often used in combination with other therapeutics, such as glucocorticoids or rituximab or, rarely, these patients will undergo splenectomy. Despite its many years of use, the mechanism of action of IVIg in ITP remains controversial. Although IVIg has a good record of low toxicity in adult patients, most products contain anti-A and anti-B iso-agglutinins, which can cause hemolysis in non-blood group O patients, sometimes life-threatening, with blood group AB patients being at highest risk for a severe hemolytic episode. In addition, IVIg is expensive and is susceptible to world-wide shortages due to its human source material and expanding use to treat various autoimmune/inflammatory diseases. Despite these caveats, IVIg will likely continue to be a first-line therapy for adult ITP, particularly if bleeding.