The purpose of this study is to improve the overall survival of Mantle-Cell-Lymphoma (MCL) by a new concept of treatment with primary curative intention consisting of six courses of immunochemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation (SCT) and HLA-identical allogenic SCT after a dose-reduced conditioning regimen of total body irradiation (TBI) with 2 Gy and Fludarabine in younger patients with primary Mantle-Cell-Lymphoma