CD40LG and COVID-19: At T0, the screening with Maglumi assay (able to capture response to previous SARS-CoV-2 infection) gave results below the cut-off of 1.0 AU/mL for IgM for all subjects enrolled in the study; IgG above 1.1 AU/mL were detectable only in the COVID-19 convalescent, with a median of 7.10 AU/mL (IQR 10.92).