The reactivity of the 231 reference human sera and 32 goat antisera expected to be negative for antibodies to SARS-CoV-2 proteins (Table 1) and the 84 sera from COVID-19 patients were tested in COVID-19 IgG and IgM IBs and their reactivity with different combinations of antigens in the two IBs analyzed. The gene discussed is CD40LG; the disease is COVID-19.