OCLN and rheumatoid arthritis: Both claudin-5 and occludin tissue protein levels were lower in the ipsilateral hemispheres of RA compared to WT-animals (claudin-5; WT: 0,79 ± 0,15, n = 8 vs. RA: 0,43 ± 0,07, n = 10; P = 0.0328; Fig. 3C,D/occludin; WT: 0,77 ± 0,06, n = 6 vs. RA: 0,52 ± 0,08, n = 8; P = 0.0284; Fig. 3E,F).