Donor Stem Cell Transplant in Treating Patients With Mantle Cell Lymphoma

OBJECTIVES: Primary * Determine progression-free survival in patients with mantle cell lymphoma undergoing low-intensity allogeneic stem cell transplantation. Secondary * Determine overall survival of these patients. * Determine the toxicity by way of adverse event profile of this regimen in these patients. OUTLINE: This is a multicenter study. * Reduced intensity conditioning: Patients receive carmustine IV over 2 hours on day -6, etoposide IV over 1 hour and cytarabine IV over 15 minutes on days -5 to -2, alemtuzumab IV over 2 hours on days -5 to -1, and melphalan IV on day -1. * Donor stem cell transplant: Patients undergo stem cell transplantation on day 0 with filgrastim (G-CSF)-mobilized peripheral blood stem cells or bone marrow stem cells. * Graft-versus-host disease (GVHD) prophylaxis: Patients receive cyclosporine IV or orally on day -1 to 30 and taper to day 100. * Donor lymphocyte infusion (DLI) therapy: Patients with evidence of disease progression, mixed chimerism, or low level residual disease undergo DLI every 3 months for up to 15 months in the absence of GVHD. After completion of study, patients are followed every 3 months for 2 years.