IL6 and COVID-19: A prototype example is interleukin (IL)-6, which is described as pro-inflammatory in reports of its role in COVID-19 (see below) despite reports showing IL-6 inhibits induction of the prototype pro-inflammatory cytokine tumor necrosis factor alpha (TNF) (Aderka et al., 1989; Schindler et al., 1990; Dinarello, 1991a).