IL6R and rheumatoid arthritis: In addition to the previously reported method of tocilizumab targeting the IL-6 receptor, there are other clinical methods to target the IL-6/IL-6 receptor (IL-6R) pathway, such as siltuximab (targeting IL-6, approved in Castleman disease) and sarilumab (targeting IL-6R, approved in rheumatoid arthritis), which may also act as potential drugs for the treatment of COVID-19 (2, 7, 12).