CD4 and lupus nephritis: While, transfer of enriched Breg cells from CD19cre/Hspa13fl/fl mice displayed the impaired capacity in increasing the CD4+Foxp3+ Tregs frequency, reducing serum anti‐dsDNA autoantibody levels, and ameliorating lupus nephritis especially with less severe glomerular pathology and inflammatory cell infiltration in renal arterioles and perivascular interstitium when compared with Breg cells from Hspa13fl/fl mice (Figure7a–c).