We compared the temporal changes of immunoglobulin M (IgM), IgG, and IgA antibodies against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) nucleoprotein (N), spike 1 subunit (S1), and receptor‐binding domain (RBD), and neutralizing antibodies (NAbs) against SARS‐CoV‐2 in patients with coronavirus disease 2019 (COVID‐19) to understand the humoral immunity in COVID‐19 patients for developing drugs and vaccines for COVID‐19. Here, CD40LG is linked to COVID-19.