Hspa13 deficiency in MZ B cells contributed to lupus pathology by reducing IL‐10 production and the proportion of Tregs. Thus, our results illustrated the vital role of Hspa13 in promoting IL‐10‐producing Breg induction and its regulatory function, and partially elucidated the reason for the impaired regulatory function of MZ B cells in lupus‐prone mice. Here, IL10 is linked to systemic lupus erythematosus.