TNF and COVID-19: Zinc supplementation that has also been proposed for COVID-19 treatment [105,106,107], is able to suppress allogeneic immune response (see [102]) and incubation of blood cells with welding fume particles resulted in a considerable increase not only of pro-inflammatory cytokines (including IL-1β, IL-6, IL-8, TNF-α) but also the tolerogenic cytokine IL-10 [104].