CD40LG and COVID-19: In the COVID-19 patients with different severities, the levels of SARS-CoV-2-specific IgM, IgG, and IgA were significantly higher in patients with severe/critical and moderate disease than in those with mild disease (P = 0.004 and P < 0.001, P = 0.001 and P < 0.001, P = 0.009 and P = 0.017, respectively).