We did not detect IL-17 in the plasma of our healthy subjects or in the methotrexate-treated RA subjects (Figure 6B) but did detect IL-17 in the SF of three out of six patients (4.40 ± 28.8 pg/mL, range of 0.41 to 28.7 pg/mL; n = 3). Here, IL17A is linked to rheumatoid arthritis.