IL1B and rheumatoid arthritis: More notable differences were observed with regard to Treg cell suppression of IL‐1β, IL‐1 receptor antagonist (IL‐1Ra), IL‐7, macrophage inflammatory protein 1α (MIP‐1α)/CCL3, and MIP‐1β/CCL4, which were suppressed by CD45RO+ Treg cells from healthy controls, whereas this was not consistently observed in cultures with Treg cells from RA patients (Figure 4 and Supplementary Table 2, available on the Arthritis & Rheumatology web site at http://onlinelibrary.wiley.com/doi/10.1002/art.39408/abstract).