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