IL6 and rheumatoid arthritis: Considering that before COVID-19 pandemic, tocilizumab was used in the treatment of rheumatoid arthritis, it was observed that in those patients the risk of bacterial and fungal infection is high because tocilizumab, by blocking IL-6, produces an impaired B cell proliferation, T-cell differentiation, and cytotoxicity [59], and also decreases the host’s immune response [78].