In terms of their bipolar, spindle shape and prominent secretory machinery (31) as evidenced by punctate IL‐22 staining, these cells are reminiscent of the IL‐22–producing fibroblast‐like synoviocytes recently reported to be protective against RA (32); hence, our results support the notion that ES‐62 mediates protection against joint pathology via an IL‐22–dependent mechanism. Here, IL22 is linked to rheumatoid arthritis.