Comparison of Intravenous Immune Globulin and High Dose Anti-D Immune Globulin as Initial Therapy for Childhood Immune Thrombocytopenic Purpura.

Background: Intravenous immune globulin (IVIG) and anti-D immune globulin are common first line therapies for pediatric immune thrombocytopenic purpura (ITP). Recently, a prospective randomized study in childhood ITP showed that high dose anti-D immune globulin (75 mcg/kg) was superior to the standard dose (50 mcg/kg) and as effective as IVIG (Tarantino et al Journal of Pediatrics, 2006). Since then, high dose anti-D immune globulin is being increasingly used in children with ITP. However, anti-D immune globulin can be associated with hemolysis and other side effects, especially at higher doses. We review our experience with IVIG and high dose anti-D immune globulin as initial treatment of childhood ITP.

Methods: We retrospectively reviewed the electronic medical records of children diagnosed with ITP between January 2003 and May 2008. We collected demographic data, complete blood counts, treatment details, adverse drug reactions (ADRs), and long-term outcome of these patients. Patients received either intravenous immune globulin (1 g/kg) or anti-D immune globulin (75 mcg/kg). All patients included received premedication with acetaminophen and diphenhydramine prior to either treatment. Response was defined by rise in platelet count after one dose or within 7 days of treatment; treatment failure = platelets<30,000/cmm, partial response= 30,000/cmm<platelets<50,000 response=”platelets” full=”” and=”” cmm,=””>50,000/cmm.

Results: A total of 53 patients were included for analysis (Table 1). Both groups had similar treatment response and there was no statistical difference in their initial presentation (presence of wet purpura, baseline platelet count, and hemoglobin), length of hospital stay, need for additional treatments, or development of chronic ITP. However, patients who received anti-D immune globulin experienced a higher rate of ADRs, particularly chills and rigors. In addition, 2 patients in the anti-D immune globulin group developed severe anemia requiring medical intervention. One of these 2 patients had hemoglobinuria consistent with intravascular hemolysis. Also, patients with wet purpura had higher rates of treatment failure (32%) compared to those without wet purpura (6%), regardless of the treatment modality.

Conclusions: Our study confirms that both IVIG and high dose anti-D immune globulin are effective first line therapies in childhood ITP. However, we observed increased ADRs in the high dose anti-D group in contrast to previously published reports. Further studies are needed to evaluate the safety of high dose anti-D immune globulin and determine the utility of using wet purpura to predict treatment failure.

Table 1: Clinical and laboratory characteristics of study patients