Inclusion Criteria:  Diagnosis of COVID-19 infection Positive SARS CoV2 PCR Enrolled in the Mayo Clinic COVID-19 registry History of treatment with anti-CD20 drugs within past 3 years  Exclusion Criteria:  Patients who declined to have their chart reviewed for research purpose. Patients who have received convalescent plasma within the previous 3 months of COVID-19 diagnosis Patients who have received monoclonal antibodies that target SARS-CoV-2 in the past three months