CD40LG and COVID-19: Of six patients without a history of COVID-19 and with a positive Wondfo N total antibody test, all of them had negative nasal swab for SARS-CoV-2 by RT-PCR, and five of the patients had at least two positive confirmed serological tests (SARS-CoV-2 S IgG, S IgM, or N IgG).