conducted a single-center, four-blind, randomized trial on COVID-19 patients, and found that probiotic adjuvant therapy significantly increased the production of specific IgM and IgG responses to SARS-CoV-2, reduced the level of D- dimer, and reduced the risk of venous thromboembolism (such as pulmonary embolism), thus reducing the severity and mortality of COVID-19 patients (Gutiérrez-Castrellón et al., 2022). Here, CD40LG is linked to COVID-19.