We describe a female diagnosed with non-allergic asthma. On March 24, 2016, examination of the skin-biopsy specimen revealed dense eosinophilic infiltration, and the Fip-1-like 1-platelet-derived growth factor receptor a fusion gene in peripheral blood mononuclear cells was negative. She was diagnosed with idiopathic hypereosinophilic syndrome. She was treated with intravenous methylprednisolone (MPSL), and subsequent oral MPSL. Then, she started to receive a monthly mepolizumab in June 2016, and successfully withdrew from daily use of oral MPSL. The patient has a mother diagnosed with non-allergic asthma. In February 2005, she was diagnosed with eosinophilic granulomatosis with polyangitis because of elevated antineutrophil myeloperoxidase antibodies, and the skin-biopsy specimen findings. She started to receive a monthly mepolizumab in June 2016. Corticosteroid therapy was successfully withdrawn. To our knowledge, this is the first case report suggesting mepolizumab may be a useful treatment for familial clustering of hypereosinophilic diseases.
anti-IL-5 antibody; eosinophilic asthma; eosinophilic granulomatosis with polyangitis; hypereosinophilic syndrome; mepolizumab