Successful anti-D immunoglobulin therapy in refractory chronic idiopathic thrombocytopenic purpura showing reduction in thrombocytes even after splenectomy

An 8 year old female child was treated with steroid hormones, anabolic steroid hormones and high dose γ-globulin therapy for 2 years since being diagnosed with idiopathic thrombocytopenic purpura at the age of 6 years. Treatment produced only transient efficacy, and thrombocytopenia persisted. A scintigram taken 2 years after the onset of the disease using [^l25 I]-labelled heated auto red cells revealed accumulation of radioactivities in the spleen, and therefore splenectomy was performed. However, thrombocytopenia (10 times 10⁹/L) developed again 3 weeks after the operation, for which she was treated again with high dose γ-globulin with only transient recovery. Then, anti-D immunoglobulin was injected intramuscularly at 250 μg per dose for a total of four doses and the platelet count was restored to the normal range. Since then her platelet count has been maintained higher than 200 times 10⁹/L for these 11 months. The scintigram taken after splenectomy showed an accumulation of radioactivities in the liver. After administration of anti-D immunoglobulin, transient subclinical hemolysis appeared. The mechanism whereby anti-D immunoglobulin exerts the efficacy described here may be considered to be by blockage of Fc receptors of macrophages, as is the case for high dose γ-globulin therapy. However, since the recovery in the platelet count persisted, it appears that changes in the immune system other than the above described mechanism have contributed to the recovery.