(13), found that patients with asymptomatic COVID-19 and LTBI had higher levels of serum cytokines including IFN-γ, TNF-α, IL-1α, IL-1β, IL-2, IL-6, IL-12, IL-15, IL-17, IFN-α, IFN-β, IL-3, GM-CSF, IL-10, IL-25 and IL-33, chemokines CCL3 and CXCL10, and growth factors VEGF and TGF-α, compared to patients with only COVID-19 However, for cytokines IL-4, IL-5, IL-13 and IL-1Rα, chemokines CCL2, CCL4, CCL5, CCL11, CCL19, CCL20, CXCL1, CXCL2, CXCL8 and CX3CL1, and growth factors EGF, FGF-2, PDGF-AA, PDGF-BB, Flt-3L, GZB, PDL-1, TRAIL and CD40L there were no significant differences. Here, IL6 is linked to COVID-19.