Evidence for a role of IFNα and IFNβ in the induction of IFN response activity in RA was provided by Mavragani and colleagues [33] who demonstrated the concomitant presence of IFN bioactivity, which could be inhibited by neutralizing antibodies against IFNα and IFNβ, in the serum of RA patients. This evidence concerns the gene IFNA1 and rheumatoid arthritis.