DEVELOPMENT OF AUTOIMMUNE THROMBOCYTOPENIA AFTER HIGH-DOSE CHEMOTHERAPY AND AUTOLOGOUS PERIPHERAL BLOOD STEM CELL SUPPORT FOR METASTATIC BREAST CANCER

Abstract

Autoimmune thrombocytopenia (AT) occurs after not only allogeneic but also autologous SCT following high-dose myeloablative chemotherapy against malignant tumors. A 50-year-old woman was diagnosed with metastatic breast cancer (MBC) and received myeloablative chemotherapy followed by autologous peripheral blood stem cell transplantation. Purpura developed on day +40 after transplantation, and a diagnosis of AT was made based on her bone marrow picture and elevation of serum PA-IgG level. Her thrombocytopenia was refractory to treatment with high-dose intravenous immune globulin (IVIG) and steroids. Although her platelet count recovered to within the normal range after splenectomy, 14 months after receiving SCT she died of disseminated intravascular coagulation syndrome caused by progression of cancer metastasis. There have been 10 reported cases of AT developing after high-dose myeloablative chemotherapy against malignant tumors followed by autologous SCT. We suggest that the thrombocytopenia after engraftment was caused by activation of dormant auto-immunity, which our patient potentially had, in conjunction with an insufficient quantity and quality of suppressor T-cells before complete reconstruction of the immune system after myeloablative conditioning. The clinical course of our patient was specific and different from previously reported cases since a splenectomy was necessary due to her thrombocytopenia being refractory to both steroid and IVIG therapy.