CD40LG and COVID-19: In the seventh edition, if “the specific IgM antibody and IgG antibody of 2019-nCoV are reported in serum as positive,” or “the 2019-nCoV specific IgG antibody in serum changes from negative to positive, or rises ≥ 4 times in the recovery phase above that in the acute phase,” this is also diagnosed as COVID-19.