TGFB1 and COVID-19: The hyperinflammatory state in COVID-19, with exacerbated production of cytokines promotes the class-switching of memory B cells to IgG via IFN-γ or IgA via TGF-β, resulting in a variety of antibodies with distinct kinetics (36) which may be an explanation for the production of different anti-SARS-CoV-2 isotypes.