CD40LG and pneumonitis: According to the China guideline of Diagnosis and Treatment of Pneumonitis Caused by SARS-CoV-2 (Corman et al., 2020), available and widely accepted clinical diagnostic tools for COVID-19 include molecular methods of full genome sequencing and real-time quantitative polymerase chain reaction (RT-qPCR)), lung CT scan, serological evaluation of anti-viral immunoglobulin M (IgM), G (IgG) antibodies, and viral culture (Ettaboina et al., 2021).