Favorable outcome of granulocyte colony-stimulating factor use in neuromyelitis optica patients presenting with agranulocytosis in the setting of rituximab.

Neuromyelitis optica is a severe autoimmune condition affecting the central nervous system characterized by a relapsing disease course. Rituximab is a chimeric monoclonal antibody against the protein CD20, and is one of the most utilized medications for management of this disease. A known complication of rituximab use is neutropenia. We report on two patients who developed symptomatic early-onset rituximab-induced agranulocytosis who safely received granulocyte colony-stimulating factor. Neutrophil counts recovered quickly and both patients continue to receive rituximab without further incident.