Therapeutic Effect And Safety Of FK506 In Myasthenia Gravis And Preliminary Study Of Its Therapeutic Mechanism

Part one The Preliminary Clinical Study of Low-dose Tacrolimus in the Treatment of Refractory Generalized Myasthenia GravisObjectives To study the efficacy and safety of low-dose tacrolimus in the treatment of refractory generalized myasthenia gravis.Methods 16 cases of definitely diagnosed refractory generalized MG(Osserman orⅡb orⅢorⅣ) were treated with FK-506(3 mg/d) for 16 weeks.Clinical and safety assessments were evaluated at baseline and 4 weeks,8 weeks,12 weeks,16 weeks after initial FK-506 administration.The FK-506 serum concentration was tested at 8-12 weeks after initial treatment.Results 15 patients finished the 16 weeks treatment.Two patients had transiently slight elevation of ALT and AST.However,no further side effect was found in these patients.At the end of treatment,all patients were found to have clinical improvement.MGFA,ADL and MMT were improved significantly(p＜0.05).And the dosage of combined medications was also decreased.Conclusions As a preliminary clinical study,low-dose tacrolimus was found effective and safety in the treatment of intractable generalized MG.Part two Preliminary study of the therapeutic mechanism of FK506 on myasthenia gravis(in vitro) Objectives To investigate the therapeutic mechanisms of FK506 on patients with myasthenia gravis(MG),focusing on soluble cytokines.Methods 28 peripheral blood samples were recruited from 22 general type MG patients who were diagnosed from clinical symptoms,laboratory tests and EMG by two or more neurological doctors.And there were 20 peripheral blood samples from 20 healthy controls.Then peripheral blood mononuclear cells(MNC) were isolated by density gradient centrifugation on Lymphoprep,and divided into 4 parts.Each part was cultured with Tacrolimus of different concentrations(0,2 ng/ml,10 ng/ml and 50 ng/ml respectively) at 37℃for 48 hours.Finally,The supernatants were collected,and soluble cytokines(IL-2,IL-12,IFN-γ,IL-4,IL-10,IL-13 and TNF-α)and adhesion molecule(sICAM-1) were measured by ELISA.Results FK506 significantly elevated the production of Th1 cytokines(IL-2) and Th2 cytokines(IL-10) in healthy controls(p＜0.05),and didn't inhibite the production of TNF-αsignificantly (p＞0.05).However,FK506 increased the production of Th1 cytokines(IL-2 and IFN-γ) and Th2 cytokines(IL-4 and IL-10) in patients(p＜0.05),as well as the production of sICAM-1(p＜0.05),while it significantly decreased the production of TNF-α.Conclusions FK506 is not as simple as an immunosuppressive drug.It inhibits the secretion of inflammatory cytokine,but induces production of Th1/Th2 cytokines and sICAM-1.Conclusions:1.As a preliminary clinical study in China,we found that low-dose tacrolimus was obviously effective and safe in the treatment of intractable generalized MG.2.FK506 is not so simple as an immunosuppressive drug.It induces production of Th1-stimulating cytokines,Th1 and Th2 cytokines,and it also upregulates the production of adhesion molecules sICAM-1,and inhibits the secretion of inflammatory cytokine.