BTK and systemic lupus erythematosus: STAT1 serine-727 phosphorylation has been found to play a critical role in B cells via promoting autoimmune Ab-forming cell and germinal center responses, thus sequentially stimulating autoantibody production in SLE (10), while the use of kinase inhibitors, such as Bruton tyrosine kinase inhibitors and p38α MAPK kinase inhibitors, showed efficacy in SLE treatment (11, 12).