IL17A and rheumatoid arthritis: However, the addition of LPS to the above cultures did not reveal an increased propensity of Treg cells from RA patients to express the proinflammatory cytokines IL‐17, IFNγ, or TNF as compared to Treg cells from healthy controls (see Supplementary Figure 3B, available on the Arthritis & Rheumatology web site at http://onlinelibrary.wiley.com/doi/10.1002/art.39408/abstract).