[Use of anti-D (Rh) IgG or intramuscular polyvalent human immunoglobulin in the treatment of chronic autoimmune thrombocytopenic purpura]

Abstract

The present study compares the effect of the intramuscular injection of low doses of IgG anti-D or human polyvalent immunoglobulin (Ig) on the platelet count of patients with CATP. Forty patients (14 children, 26 adults), 11 who had undergone splenectomy, were divided in the following groups of treatment: 20 patients received a single injection of 300 micrograms of IgG anti-D, 6 patients received the same dose as above plus 0.5 mg/kg daily of prednisone v.o and 14 patients received 640 mg of polyvalent Ig. Each patient was sequentially studied by measuring peripheral blood parameters, reticulocyte index, direct Coombs' test and C3-C4 determinations. Their blood group and Rh factor had been previously determined. The platelet response was evaluated as refractory (no response) and favorable (platelet increment over 50,000/microliters compared with initial platelet count). Patients with a favorable response over a month were considered as a prolonged remission. The results showed a favorable platelet response in 74% of the patients that received a single injection of IgG anti-D alone (one of the patients was Rh negative) or associated to prednisone, and 42.8% of the cases when polyvalent Ig was used. The patients who had not undergone splenectomy obtained better results than the group with splenectomy (62% vs 45%) and children showed a better response than adults (78.5% vs 46.1%). Forty five percent of prolonged remissions (including the Rh negative patient) were obtained with both schemes of IgG anti-D administration and only 28.5% when polyvalent Ig was used. The remissions were significantly longer with IgG anti-D (p < 0.01). The hematological and serological parameters did not show any significant modifications in all the cases and there was no adverse effects with the treatment. In conclusion, the intramuscular injection of immunoglobulins, especially IgG anti-D, produce an increase in the platelet count in some patients with CATP, several of them can obtain prolonged remissions, particularly children and patients that had not received immunoglobulins previously. This treatment is safe, ambulatory, easy to administer, and relatively inexpensive.