Recovery from COVID-19 in a B-cell-depleted multiple sclerosis patient

Approximately 200,000 multiple sclerosis (MS) patients worldwide receive B-cell-depleting immunotherapy with rituximab (anti-CD20), which eliminates the ability to generate an antibody response to new infections. As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies might help viral clearance, these patients could be at risk of severe complications if infected. Here, we report on an MS patient who had received rituximab for similar to 3 years. The patient was examined 5 days before the onset of coronavirus disease 2019 (COVID-19) symptoms and was admitted to the hospital 2 days after. She recovered 14 days after symptom onset despite having a 0% B lymphocyte count and not developing SARS-CoV-2 immunoglobulin G (IgG) antibodies.