TNFRSF13C and infection: Taken together, although prior CS exposure does not alter the expression of the three BAFF receptors on B cells during infection, given the important role of BAFF in inducing Aicda expression and TI IgA class switching in lung B cells in the early stage of infection, these results suggest that CS may hinder early mucosal S-IgA responses through BAFF inhibition in the lung during influenza virus infection.