This study reports the time kinetics of IgM and IgG antibodies in COVID-19 and assesses the serologic profiles of patients with COVID-19 using two commercially available serologic assays based on fluorescent immunoassay (FIA) and enzyme-linked immunosorbent assay (ELISA) from a single medical institution in Seoul, Republic of Korea. The gene discussed is CD40LG; the disease is COVID-19.