Tocilizumab used against Rheumatoid arthritis is a monoclonal antibody against :
Monoclonal antibody against IL-6 : Tocilizumab               
Monoclonal antibody against IL-6 receptor : Sarilumab
Both are approved for Rheumatoid arthritis.
Interleukin-6
Interleukin-6 receptor
Interleukin-5
Interleukin-5 receptor