First Report of Severe Autoimmune Hemolytic Anemia During Eltrombopag Therapy in Waldenström Macroglobulinemia-Associated Thrombocytopenia.

Autoimmune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA) can be observed in Waldenström macroglobulinemia (WM). The autoimmune disorders are primarily mediated by autoimmune monoclonal gammopathy, but drug-induced hemolysis should also be considered. Herein, we presented the case of a 63-year-old female WM patient complicated with ITP, who was admitted to our department with a complaint of abdominal pain. After first half of bortezomib/dexamethasone/rituximab (BRD) chemotherapy, her platelet level recovered, but subsequently decreased to extremely low level (around 1-2×109/L), and the patient suffered from platelet transfusion refractoriness. During the management of refractory thrombocytopenia, the patient developed severe hemolytic anemia, and further tests confirmed warm AIHA. FcγRIIα polymorphism test showed that the patient had FcγRIIα-131RH, which implied that the AIHA may not be WM-related. Given the effects of ibrutinib in controlling WM, secondary AITP and AIHA, ibrutinib single treatment was started, which quickly corrected the thrombocytopenia within five days, but not hemolysis. With a relatively safe platelet level, eltrombopag was stopped, and the hemolysis relieved three days after eltrombopag withdrawal. This is the first report on eltrombopag-induced AIHA in the management of WM-associated ITP.