Pegfilgrastim and Rituximab in Treating Patients With Untreated, Relapsed, or Refractory Follicular Lymphoma, Small Lymphocytic Lymphoma, or Marginal Zone Lymphoma

Inclusion Criteria:

* Untreated or relapsed/refractory follicular, SLL or MZL (i.e. no limit to number of prior treatments as long as patients meet other study criteria)
* Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
* Measurable tumor size (at least one node measuring 4 cm\^2 in bidimensional measurement)
* Expected survival of \> 6 months
* Prior rituximab or other monoclonal immunotherapy permitted and eligible for rituximab monotherapy
* Full recovery from any significant toxicity associated with prior surgery, radiation therapy, chemotherapy, or immunotherapy
* Absolute neutrophil count \> 1.0 x 10\^9/L
* Platelets \> 50 x 10\^9/L
* Patients may receive erythropoietin growth factors to maintain adequate hemoglobin levels (\>= 8.0 mg/dl)
* Creatinine \< 1.5 x upper normal levels (UNL)
* Total bilirubin \< 1.5 mg/dL (\> 25.65 umol/L)
* Aspartate aminotransferase \< 5 x UNL
* Alkaline phosphatase \< 5 x UNL
* Informed consent approved in institutional review board (lRB)
* CD20+ B-cell lymphoma

Exclusion Criteria:

* Prior history of human immunodeficiency virus (HIV)-positivity (routine HIV testing is required pretreatment)
* Serious non-malignant disease (e.g. active uncontrolled bacterial, viral, or fungal infections) or other conditions which, in the opinion of the principal investigator would compromise other protocol objectives
* Presence of central nervous system (CNS) lymphoma
* Chemotherapy within 4 weeks of the first scheduled study treatment
* Another primary malignancy (other than squamous or basal cell carcinoma of the skin or in-situ carcinoma of the cervix) for which the patient has not been disease-free for at least five years
* Major surgery, other than diagnostic surgery, within four weeks
* Patients with non-Hodgkin lymphoma (NHL) other than relapsed/refractory follicular, MZL or SLL
* Patients must not have a history of cardiac disease, defined as New York Heart Association Class II or greater or clinical evidence of congestive heart failure
* Concurrent use of other investigational agents
* Pregnant or breast feeding
* Subjects of reproductive potential who are not using adequate contraceptive precautions, in the judgment of the investigator
* Known hypersensitivity to any recombinant E coli-derived product, murine proteins, or any components of the study medications
* Concerns for the subject's compliance with the protocol
* Any premalignant myeloid condition or any malignancy with myeloid characteristics (e.g. myelodysplastic syndromes, acute or chronic myelogenous leukemia)
* Patient is currently enrolled in, or has not yet completed at least 30 days since ending another investigational device or drug trial