IL6R and arthritic joint disease: However, one of the first indications that IL-7 was likely to play a critical role in experimental inflammatory arthritis also stemmed from the earlier studies by Sawa et al. [56] who showed that mice homozygous for the F759 mutation in the gp130/IL-6R subunit showed elevated Stat3 activation and a rheumatoid-like arthritic joint disease.