Refractory Megaloblastic Anemia with Myeloperoxidase-Deficient Neutrophils

Abstract

The enzyme myeloperoxidase contributes to the ability of human leukocytes to kill fungi and bacteria. We studied a 61-year-old man with megaloblastic anemia and two populations of neutrophils: 99.2% lacked myeloperoxidase activity; 0.8% had it. In vitro, these neutrophils had a greatly impaired ability to kill Staphylococcus aureus 502A, Candida albicans, and C. tropicalis. The patient developed fungal pneumonia (Aspergillus fumigatus and C. albicans) and, despite therapy with amphotericin B, died of systemic aspergillosis.