CD40LG and COVID-19: As shown in Figure 4B, in the 24 patients with a positive nucleic acid test, the combination of IgM and IgG detection of COVID-19 resulted in percentages of IgM(+)IgG(+), IgM(–)IgG(+), IgM(+)IgG(–), and IgM(–)IgG(–) of 62.50, 8.33, 16.67, and 12.50%, respectively.