Phase 2 Trial of Prophylactic Rituximab Therapy for Prevention of CGVHD

Recipient Inclusion Criteria: Between 18 and 76 years of age Chronic lymphocytic leukemia (CLL): Unmutated IgG VH gene status Mutated IgG VH genes (> 2% nucleotide change compared to somatic sequence) Complete remission benefit most from allogeneic hematopoietic stem cell transplant (HSCT). (Physicians will be encouraged to provide aggressive chemotherapy prior to nonmyeloablative transplantation.) Mantle cell lymphoma (MCL): Transplant physicians believe subject would benefit from allogeneic HSCT. Adequate renal (Cr < 2.4 mg/dL) and hepatic (Bilirubin < 3.0 mg/dL, Aspartate aminotransferase (AST) < 100 IU) function. Men and women of reproductive potential must agree to use an acceptable method of birth control during treatment and for six months after completion of treatment. All subjects must provide written informed consent Donor Inclusion Criteria: Genotypically or phenotypically human leukocyte antigen (HLA)-identical. Age < 76 unless cleared by institutional PI Capable of giving written, informed consent. Must consent to peripheral blood stem cell (PBSC) mobilization with G-CSF and apheresis Recipient Exclusion Criteria: Recipient has a 9 of 10 or 10 of 10 HLA identical donor (high resolution molecular genotyping at HLA A, B, C and DrB1, and DQ) Pregnancy Lactating Serious uncontrolled infection HIV seropositivity Hepatitis B or C seropositivity Cardiac function: ejection fraction < 40% or uncontrolled cardiac failure Pulmonary: Diffusing capacity - carbon monoxide (DLCO) < 50% predicted Liver function abnormalities: elevation of bilirubin to ≥ 3 mg/dL and/or AST > 100 Renal: creatinine > 2.4 Karnofsky performance score ≤ 60% Patients with poorly controlled hypertension (systolic blood pressure > 150 or diastolic blood pressure > 90 repeatedly). Known life-threatening hypersensitivity to rituximab or other anti-B cell antibodies. Inability to comply with the allogeneic transplant treatment. Uncontrolled central nervous system (CNS) involvement with disease Donor Exclusion Criteria: Identical twin to subject Contra-indication to subcutaneous G-CSF at a dose of 16 mg/kg/d for 5 consecutive days Serious medical or psychological illness Prior malignancy within the preceding five years, with the exception of non-melanoma skin cancers. HIV seropositivity