Treatment of childhood idiopathic thrombocytopenic purpura with Rhesus antibodies (anti-D)

We have recently reported that a rise of platelet numbers in ITP can be induced by blockade of the RES with antibody-coated red blood cells. We now present a collaborative study in which 15 Rhesus-positive children with ITP (nine boys and six girls aged 1–15 years) were treated with low-dose anti-D. Ten patients had chronic ITP (duration 6–47 months), five had acute ITP. Doses of 28–50 g anti-D/kg bodyweight per course were given intravenously. In all patients clinical signs of bleeding ceased and platelet counts were elevated. An excellent, good or fair response with platelet increments of >100, 50–100, or 20–50×10⁹/l, respectively, was observed in 19, 7, and 12 out of 45 courses in chronic ITP, and in 4, 1, and 2 out of 8 courses in acute ITP. The platelet increase (>40×10⁹/l) persisted for 10 to over 360 days in chronic ITP. There were no untoward side reactions. Haemoglobin values remained stable in all patients but laboratory signs of mild, compensated haemolysis ensued. The direct antiglobulin test became positive in all cases due to anti-D IgG. Previous therapy of patients with chronic ITP included high-dose immunoglobulins and prednisone. These regimens were both effective but remissions were short. We conclude that anti-D therapy is an effective and safe form of treatment in childhood ITP.Abbreviations ITP idiopathic thrombocytopenic purpura - IgG immunoglobulin G - RES reticuloendothelial system - RBC red blood cells - Rh Rhesus - DAT direct antiglobulin test