The presence of iBALT post-SARS-CoV infection and the local production of BAFF and APRIL during infection may play an essential role in regulating and activating a local immune response, increasing the production of specific antibodies, including IgG and IgA in the airways, and inducing long-lasting resident B and T memory cells that can offer subsequent protection. This evidence concerns the gene TNFSF13 and severe acute respiratory syndrome.