Bortezomib and Fludarabine With or Without Rituximab in Treating Patients With Relapsed or Refractory Indolent Non-Hodgkin's Lymphoma or Chronic Lymphocytic Leukemia

Inclusion Criteria: * Diagnosis of chronic lymphocytic leukemia (CLL) OR indolent non-Hodgkin's lymphoma (NHL) of any of the following subtypes: * Follicular lymphoma: * Grade I follicular small cleaved cell; * Grade II follicular mixed cell; * Grade II follicular large cell; * Diffuse small cleaved cell; * Small lymphocytic lymphoma; * Lymphoplasmacytic lymphoma (Waldenstrom's macroglobulinemia) * AND * Extranodal marginal zone B-cell lymphoma (mucosa-associated lymphoid tissue \[MALT\] lymphoma); * Nodal marginal zone B-cell lymphoma (monocytoid B-cell lymphoma); * Splenic marginal zone lymphoma (splenic lymphoma with villous lymphocytes); * Mantle cell lymphoma: * No blastic phase mantle cell lymphoma * Relapsed or refractory, progressive disease: * First, second, or third relapse * Measurable disease, meeting 1 of the following criteria: * At least 1 unidimensionally measurable lesion at least 20 mm by conventional techniques OR at least 10 mm by spiral CT scan (for NHL patients); * OR: * Lymphocytosis \> 50,000/mm3 OR evidence of progressive bone marrow infiltration failure (e.g., hemoglobin 10 g/dL) OR thrombocytopenia (i.e., platelet count \< 100,000/mm3) with \> 30% infiltration of bone marrow by leukemia (for CLL patients) * No measurable lymphadenopathy (for CLL and Waldenstrom's macroglobulinemia patients) * No evidence of CNS lymphoma * Performance status: * ECOG 0-2 * Life expectancy: * More than 12 weeks * No history of uncontrolled orthostatic hypotension * No symptomatic congestive heart failure * No unstable angina pectoris * No cardiac arrhythmia * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * HIV negative * No uncontrolled concurrent illness * No grade 2 or greater neuropathy * No history of allergy or anaphylaxis to mannitol, bortezomib, fludarabine, or boron * No ongoing or active infection * No psychiatric illness or social situation that would preclude study compliance * At least 4 weeks since prior monoclonal antibody (MoAB) therapy: * Patients who have received MoAB therapy within the past 3 months must have documented disease progression since receiving this therapy * No prior allogeneic stem cell transplantation * More than 4 weeks since prior chemotherapy * Prior fludarabine allowed * At least 1 week since prior steroids * At least 3 months since prior radio-immunotherapy * More than 4 weeks since prior radiotherapy * No prior bortezomib * Absolute neutrophil count at least 1,500/mm3 * Platelet count at least 75,000/mm3 (greater than 50,000/mm3 if lymphomatous bone marrow involvement is present) * Bilirubin no greater than 2.0 mg/dL * AST/ALT no greater than 4 times normal * Creatinine clearance greater than 40 mL/min * No other concurrent investigational agents or treatments for the malignancy * No brain metastases * OR: Quantitation of IgM paraprotein (for Waldenstrom's macroglobulinemia patients)