[Neutrophil recovery by eltrombopag treatment in a patient with adult-onset autoimmune neutropenia and immune thrombocytopenia].

Adult-onset autoimmune neutropenia (AIN) is rarely self-limiting, unlike infant-onset AIN. Although several therapeutic agents have been reported, including corticosteroids, more effective treatment options may exist. Here, we describe neutrophil recovery by eltrombopag in a 52-year-old male AIN patient with immune thrombocytopenia (ITP) who was referred to our hospital with severe neutropenia. Within a year of referral, he developed moderate thrombocytopenia. He was diagnosed with AIN and concurrent ITP, based on the detection of antineutrophil antibodies and bone marrow aspiration, respectively. Further platelet count reduction and the appearance of purpura prompted an initial treatment of 0.5 mg/kg prednisolone. Thrombocytopenia remission was prompt but transient, with platelet counts rapidly declining before initiating prednisolone tapering. Similarly, absolute neutrophil counts (ANCs), after a shorter recovery period, returned to the baseline level below 2×10/l. Further platelet reduction was prevented by eltrombopag administration. Intriguingly, the ANCs recovered following platelet recovery and remained above 5×10/l for > three months despite prednisolone dosage tapering. To our knowledge, this is the first report describing the effectiveness of eltrombopag in AIN.