CD19 and B-cell chronic lymphocytic leukemia: <h4>Background</h4>There is an urgent need for highly efficacious antiviral therapies in immunosuppressed hosts who develop coronavirus disease (COVID-19), with special concern for those affected by hematological malignancies.<h4>Case presentation</h4>Here, we report the case of a 75-year-old male with chronic lymphocytic leukemia who was deficient in CD19<sup>+</sup>CD20<sup>+</sup> B-lymphocyte populations due to previous treatment with anti-CD20 monoclonal antibodies.