In addition, KCNK5 expression has previously been reported to be strongly correlated with RA disease severity [41] and up-regulation of KCNK5 expression was found to be predictive of treatment failure in RA patients receiving the anti-IL-6 therapy tocilizumab [41], which inhibits RA inflammation through a different biological pathway to that targeted by anti-TNF therapies. This evidence concerns the gene KCNK5 and rheumatoid arthritis.