CD40LG and infection: In addition, also due to shortcomings of RT-PCR approach to detect SARS-CoV-2, the serum immunoglobulin (Ig) anti-SARS-CoV-2 type M (IgM)/IgG antibody detection against the SARS-CoV-2 internal nucleoprotein (NP) and surface spike protein receptor-binding domain (RBD) may be used in diagnosis of COVID-19 and to monitor the disease stages and identify past infection and immunity [83,86].