ADORA2A and rheumatoid arthritis: Increased expression of A2AR and A3R adenosine receptors has been measured in white cells of RA and in ankylosing spondylitis patients, an effect that decreased after anti TNF-alpha treatment, consistent with the known effect of TNF-alpha on the expression of adenosine A2AR via NF-kB activation (Varani et al., 2009; Varani et al., 2011; Ravani et al., 2017).