CD40LG and COVID-19: Our results demonstrated the serological diversity of serum IgG, IgA, and IgM antibodies against SARS‐CoV‐2 N, S1, and RBD and NAbs against SARS‐CoV‐2 in patients with COVID‐19 and the necessity of combinational measurements of the antibody isotype levels against each structural protein of SARS‐CoV‐2 and NAb levels to further elucidate the immune mechanism of COVID‐19.