Leflunomide ameliorates experimental autoimmune myasthenia gravis by regulating humoral and cellular immune responses

•Leflunomide could be a therapeutic candidate for MG treatment.•The germinal center response in EAMG rats was reduced by leflunomide.•Leflunomide rebuilds the balance of CD4+ Th cells by suppressing Th1 cells and promoting Treg cells.•Leflunomide inhibits Tfh cells through the IL-21/STAT3 pathway.