We retrospectively analysed two selected patients, referred to our Haematology Department for refractory HTLV-1 associated myositis with circulating pathologic T-cell population with ATL phenotype. They respectively presented also HTLV-1 associated Crohn-like disease and myelopathy. Muscle biopsy of both patients was analysed to determine the pathologic infiltrate. Alemtuzumab was proposed as salvage therapy. Targeting CD52 with alemtuzumab showed good efficacy on myopathy of both patients for respectively 11 and 10months. Interestingly, this treatment showed also efficacy on circulating pathologic T-cell population and on concomitant digestive and neurological diseases. The double infected cells ablation and immunosuppressive propriety of alemtuzumab probably explains its interest in this infectious and dysimmunitary disorder. Even though alemtuzumab probably remains a suspensive treatment, its place should be assessed in controlled trial in this difficult to treat rare disease.