Treatment with the adenosine deaminase blocker DAA significantly reduced IL-6 release in OA synovial cells, while in RA cells, only the highest DAA concentration, 10−7 M, caused a significant IL-6 reduction (OA: 10−9 M p = 0.022, 10−8 M p = 0.004, 10−7 M p < 0.001; RA: 10−7 M p = 0.003, 10−9 M compared to 10−7 M p = 0.003) (Figure 4B). Here, ADA is linked to rheumatoid arthritis.