[Two patients with progressive multifocal leukoencephalopathy with immune response against JC virus showing good long-term outcome by combination therapy of mefloquine, mirtazapine, and risperidone].

Patient 1 was a 59-year-old woman receiving prednisolone for idiopathic hypereosinophilia. Brain MRI of patient 1 disclosed slight gadolinium enhancement at lesions, indicating inflammation. Patient 2 was a 32-year-old woman with systemic lupus erythematosus under immunosuppressive therapy. Brain biopsy of patient 2 showed balanced infiltration of CD8+ and CD4+ T lymphocytes at the sites of lesions. Both subjects were diagnosed as having progressive multifocal leukoencephalopathy (PML) shortly after the onset of neurological symptoms and were treated with a combination of mefloquine, mirtazapine, and risperidone. Both patients remain alive with improved neurological symptoms even after long-term follow-up (24 months in patient 1 and 45 months in patient 2). Although the prognosis of PML is very poor, our findings suggest that pharmacotherapy may be effective for patients with well-controlled immune reactions against the JC virus.