CD40LG and COVID-19: The detection of specific IgM and IgG for SARS-CoV-2 has been performed by most studies, but few have detected specific IgA for SARS-CoV-2 [44].Therefore, Ma H et al. evaluated a total of 87 confirmed COVID-19 patients and used a set of chemical luminescence kits to detect the presence of receptor-binding domain (RBD) specific IgA, IgM, and IgG.