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High-dose therapy with autologous stem cell support after standard dose induction is a promising approach for therapy of primary central nervous system lymphoma (PCNSL). High-dose methotrexate (HD-MTX) is a standard drug for induction of PCNSL; however, data about the capacity of HD-MTX plus granulocyte–colony-stimulating factor (G-CSF) to mobilize hemopoietic progenitors are lacking.This investigation describes the data from stem cell mobilization and apheresis procedures after one or two cycles of HD-MTX for induction of PCNSL within the East German Study Group for Haematology and Oncology 053 trial. Eligible patients proceeded to high-dose busulfan/thiotepa after induction therapy and mobilization.Data were available from nine patients with a median age of 58 years. The maximal CD34+ cell count per μL of blood after the first course of HD-MTX was 13.89 (median). Determination was repeated in six patients after the second course with a significantly higher median CD34+ cell count of 33.69 per μL. Five patients required two apheresis procedures and in four patients a single procedure was sufficient. The total yield of CD34+ cells per kg of body weight harvested by one or two leukapheresis procedures was 6.60 × 106 (median; range, 2.68 × 106-15.80 × 106). The yield of CD34+ cells exceeded the commonly accepted lower threshold of 3 × 106 cells per kg of body weight in eight of nine cases. Even in the ninth, hemopoietic recovery after stem cell reinfusion was rapid and safe.HD-MTX plus G-CSF is a powerful combination for stem cell mobilization in patients with PCNSL and permits safe conduction of time-condensed and dose-intense protocols with high-dose therapy followed by stem cell reinfusion after HD-MTX induction.