Christian Späth, Thomas Neumann, William H. Krüger

• T-Cell Prolymphocytic Leukaemia (T-PLL) is an aggressive disease with a poor prognosis and only curable by allogeneic stem cell transplantation. We describe the case of a male suffering from T-PLL. Therapy was alemtuzumab followed by an allograft from an unrelated donor. T-PLL relapsed after allogeneic stem cell transplantation. Discontinuation of immunosuppression had no effected and three increasing doses of donor lymphocytes were given within one month. The patient developed acute GvHD of the lover (grade III). GvHD was successfully treated by steroids and ruxolitinib and graft-versus-leukaemia effects induced a complete remission of T-PLL. 18,5 months after transplantation the patient is well and alive without GvHD under immunosuppression with ruxolitinib. Flow cytometry of peripheral blood was negative for residual leukemic cells.