Given the key role of the pro-inflammatory cytokine IL-6 in COVID-19 pathogenesis [85], some studies proposed the use of tocilizumab, a monoclonal antibody (mAb) antagonist of IL-6 receptor (IL-6R), for COVID-19 treatment [77], but its efficacy should be carefully evaluated in the light of its known side effects, such as anemia and QT interval prolongation [86]. This evidence concerns the gene IL6R and COVID-19.