IL6R and COVID-19: Due to COVID-19 patients having a higher number of these three important lymphocyte subsets of effector memory T4 cells, plasma blasts, and Tregs, the levels of IL-6 were also significantly higher; thus, use of anti-IL-6 receptor (IL-6R) monoclonal antibodies (mAbs), such as tocilizumab therapy, may be effective for COVID-19 treatment [32, 33].