Mild COVID-19 infection despite chronic B cell depletion in a patient with aquaporin-4-positive neuromyelitis optica spectrum disorder

Coronavirus disease 2019 (COVID-19) is caused by the novel coronavirus SARS-CoV-2, which affects the lung and other organs. After an incubation period of 3-14 days, the infection presents with symptoms of variable severity, from mild flu-like disease to severe pneumonia and cytokine storm with increased mortality. Immunosuppressed patients may have higher risk of adverse outcomes; hence, there is an urgent need to evaluate the immune response and clinical outcomes of SARS-CoV-2 infection in these patients. Here, we report a 59-year-old woman with aquaporin-4-positive (AQPR4+) neuromyelitis Optica treated with rituximab who developed mild respiratory symptoms with COVID-19, despite B cell depletion at the time of infection.