CD40LG and COVID-19: Several COVID-19 patients displayed markedly high IgM signals to LNnO, a glycan containing 3 LacNAc units attached to a galactose residue (Galβ1–4GlcNAcβ1–3Galβ1–4GlcNAcβ1–3Galβ1–4GlcNAcβ1–3Gal).