We used this 11 antigens protein array to measure the total antibody response (IgG, IgM and IgA) and the subclass responses (IgG1, IgG3, IgA1 and IgA2) in 70 ICU and 63 non-ICU COVID-19 patients, along with 22 pre-pandemic serum samples. Here, IGHG3 is linked to COVID-19.