One possible reason for this failure could be that our patient’s TGFβ, which is a potent inducer of IL-9 [33], failed to stimulate IL-9 production, probably because of the inflammatory context with a high IL-6/IL-4 balance and instead stimulated IL-17, which may have contributed to disease severity in COVID-19 patients. The gene discussed is TGFB1; the disease is COVID-19.