TNF and COVID-19: The gating strategy and a representative flow cytometry pseudocolor plot showing the baseline, SARS-CoV-2 antigens and PMA/I stimulated Th1/Th17 cytokines are shown in Figure 2A. As shown in Figure 2B, late convalescent COVID-19 individuals exhibited significantly elevated frequencies of mono-functional Th1 (TNFα expressing) or dual-functional Th1/Th17 (IFNγ/IL-2 or IFNγ/TNFα or IFNγ/IL-17A or IL-2/TNFα or TNFα/IL-17A co-expressing) or multi-functional (IFNγ/IL-2/TNFα) cells at baseline.