In line with our study, IL-21 was widely reported to mediate pathologic effects in several inflammatory diseases, such as inflammatory bowel disease, rheumatoid arthritis, psoriasis, systemic lupus Erythematosus, pneumonia virus of mice infection, experimental autoimmune encephalomyelitis (EAE), and type 1 diabetes [17, 18, 39]. Here, IL21 is linked to infection.