B cell-deficient patients gain protective T cell immunity following SARS-CoV-2 vaccination and infection, study finds

B cell deficiency is a common condition that can result either from immunosuppressant drugs used to treat autoimmune disease or certain cancers—such as rituximab (RTX)—or from natural immune deficiency. These patients suffer from a weakened immune system that is less effective at combating both viral and bacterial diseases. As B cells are a key type of immune cell that produces antibodies, a deficiency results in a significant decrease in antibody count that can lead to severe disease or death upon infection with SARS-CoV-2.