Using this simplified three-dilution ELISA, we analyzed a large panel of sera from COVID-19 convalescent donors (Conv) (presumptively seropositive) and archival pre-COVID sera (control [Ctrl]) (presumptively seronegative) (Table 1) for both IgG (Fig. 2a and b) and IgA (Fig. 3a and b). This evidence concerns the gene CD79A and COVID-19.