IL21 and COVID-19: However, we find it interesting that TLR7, as well as IL-6, IFNα, IFNγ, TNFα, and other DN related cytokines or chemokines are involved in the pathway.59 Of note, TLR7 hyper-responsiveness is considered as crucial in the promotion of pathology mediated by IL-21,13 IL6 and IFNα.62 Also, the elevated soluble mediators in severe COVID-19, such as IL-6, CXCL10 and TNFα, may suppress GC reactions, and thus promote extrafollicular pathways.63,64,65