Inclusion Criteria:

          1. Adult patients, >=18 years of age;

          2. Patients with either histologically documented CD20-positive MZL or FL, WHO grade 1, 2
             or 3a

          3. Evidence of progression or lack of response following at least 1 prior treatment

          4. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2

          5. At least one bi-dimensionally measurable nodal or tumor lesion defined by CT scan as:
             greatest transverse diameter > 1.5 cm and a short axis ≥ 10mm

          6. Adequate hematologic function (unless abnormalities are related to NHL)

          7. Life expectancy >6 months

          8. Able and willing to provide written informed consent and to comply with the study
             protocol

        Exclusion Criteria:

          1. Evidence ongoing transformation into aggressive NHL

          2. Central nervous system lymphoma

          3. Patients with progressive multifocalleukoencephalopathy (PML)

          4. Prior use of any antibody therapy(except for Rituximab ) within 3 months of study
             start

          5. Prior use of any anti-cancer vaccine

          6. Prior administration of radiotherapy 42 days prior to study entry

          7. Prior administration of chemotherapy 28 days prior to study entry

          8. History of prior malignancy within the last 3 years, with the exception of curatively
             treated basal or squamous cell carcinoma of the skin and low-grade in situ carcinoma
             of the cervix

          9. History of severe allergic or anaphylactic reactions to monoclonal antibody therapy

         10. Known hypersensitivity to thalidomide or lenalidomide

         11. Regular treatment with corticosteroids prior to the start of cycle 1, unless
             administered for indications other than NHL at a dose equivalent to < 20 mg/day
             prednisone

         12. Any serious active disease or co-morbid medical condition (such as New York Heart
             Association Class II or IV cardiac disease, severe arrhythmia, myocardial infarction
             within the last 6 months, unstable arrhythmias, or unstable angina) or pulmonary
             disease (including obstructive pulmonary disease and history of bronchospasm or other
             according to investigator's decision)

         13. Infection with human immunodeficiency virus (HIV), hepatitis B or hepatitis
             C(including HBsAg,HBcAb positive with abnormal HBV DAN or HCV RNA )

         14. Pregnant or lactating females