CD40LG and COVID-19: Mean antibody levels for participants who did not exceed the 2570 RBD-IgG+IgMmL detection limit were 1300 RBD-IgG+IgM/mL (n = 14) and 1700 BAURBD-IgG+IgM/mL (n = 45) for the HD-COVID-19 negative and RD-COVID-19 negative subgroups, respectively