ACTA1 and systemic lupus erythematosus: In addition, since the CD90+αSMA+ mesangial cells are an important source of proinflammatory cytokines like IL‐6 and TNF‐α in kidney,32, 33 the reduced mesangial cells in IL‐35p and Tregs‐treated lupus mice indicate an immunoregulatory functions of IL‐35 in vivo (Figures 6A, 6B and 6F).