IL6 and COVID-19: Moreover, viral pneumonia in mild-moderate COVID-19 might be substantially mediated by cytokines and cellular pathways pathogenically upstream of IL-6, such as IL-33, IL-9 or IFNγ, which can be released by virus-damaged respiratory epithelial cells, type-2 innate lymphoid cells and γ/δ T cells (7); indeed, at this stage, IL-6 may negatively modulate T-cell release of IFNγ and granzymes (18, 42).