Continuous Intravenous Immunoglobulin and Platelet Infusion in Allogeneic Stem Cell Transplant Patients with Allo-Immune Thrombocytopenia

Introduction: Patients undergoing stem cell transplant (SCT) for treatment of hematologic malignancies have often been exposed to many blood products and may be allo-immunized. This makes platelet transfusions less effective, which is problematic in patients who are expected to be profoundly thrombocytopenic for 3-4 weeks. A second-line intervention in patients with refractory immune thrombocytopenia is continuous intravenous immune globulin (IVIG) at doses of 1 g/kg/day for 2 days and continuous platelet transfusion (1 pack of platelets/hour for 72 hours). This intervention has not been studied in allo-immunized SCT patients.

Methods: A retrospective chart review was performed at the University of Wisconsin Hospital to assess outcomes of the continuous IVIG and platelet regimen in allo-immunized SCT patients from 1/1/2009 to 12/31/2012. All patients also received concurrent aminocaproic acid. Data points collected include primary hematologic diagnosis, indication for treatment, platelet response, clinical bleeding events, requirement for further therapy, other complications during hospital stay, and in-hospital mortality.

Results: All of the patients had an increase in platelet count and there were no new bleeding events during the treatment period. The regimen does not appear to provide any long-standing improvement in platelet response.

	SCT Type	PRA (percentage)	Indication for Treatment
Patient 1	Double umbilical cord	13	Refractory thrombocytopenia without bleed
Patient 2	8/8 HLA matched peripheral	84	Refractory thrombocytopenia with oropharyngeal bleeding
Patient 3	Double umbilical cord	100	a. Refractory thrombocytopenia with fever b. Refractory thrombocytopenia with GI bleed

Discussion: Continuous IVIG and platelet transfusion does not appear to decrease allo-reactivity as had been hoped for. However, it does appear to be safe and does provide a temporary platelet increase. Other means of minimizing risk for bleeding remain important and  include use of aminocaproic acid and HLA matched platelets, prevention of hypertension while thrombocytopenic, pre-transplant testing for platelet reactive antibodies so HLA matched platelets may be obtained sooner, and choice of transplant conditioning regimen.