Safety And Efficacy Of Tofacitinib In Patients With Refractory Myasthenia Gravis: A Pilot Study

Inclusion Criteria: * fluctuating muscle weakness and fatigability classified as the Myasthenia Gravis Foundation of America (MGFA) clinical classification Type IIa-IVa; * more than 10% amplitude decrement in low frequency repetitive nerve stimulation, and less than 10% amplitude increment in high frequency repetitive nerve stimulation; * understanding and assigning the informed consent form, and having a good compliance with treatment. meet all of the criteria in above as well as at least one of the below: * refractory: insufficient response to full dose- and course- steroids treatment (0.75-1mg per kg per day for at least 3-6 months), failure to respond adequately to tacrolimus (no less than 3mg per day) for 3 months; * severe or intolerable adverse effects from conventional immunosuppressive therapy. Exclusion Criteria: * positive for muscle-specific kinase (MuSK) antibodies; * a tumor history except for thymoma; * a history of Type B and Type C hepatitis; * a history of tuberculosis or T-SPOT.TB tset positivity; * hepatic, renal and cardial insufficiency (baseline: ALT/AST\>50U/L;BNP\>200pg/ml）; * severe allergy or infection, or chronic or recurrent infection; * pregnancy; * hyperlipidemia; * participating other clinical trials