Inclusion Criteria:

- All patients must have biopsy proven diagnosis of low- and intermediate-grade
non-Hodgkin lymphoma (NHL) working formulation B, C,D, E, F, and G; including mantle
cell lymphoma; patients with transformed lymphoma are also eligible

- Demonstrated monoclonal CD20 positive b-cell population in lymph nodes and/or bone
marrow

- Patients must have relapsed after achieving a complete or partial response to prior
therapy, have never responded to prior therapy or have poor risk disease

- Patients with prior bone marrow involvement must have bone marrow aspiration and
biopsy within 60 days prior to stem cell collection which shows =< 10% lymphomatous
involvement of total cellularity; alternatively, patients with prior bone marrow
involvement should have a normal bone marrow study which shows =< 10% lymphomatous
involvement within 28 days before salvage chemotherapy

- Normal renal function test with serum creatinine of < upper limit of normal (ULN),
and a creatinine clearance of >= 60 ml/min (measured or calculated)

- Adequate pulmonary function as measured by forced expiratory volume in 1 second
(FEV1) > 60% of predicted measured, or a diffusion capacity of carbon monoxide (DLCO)
>= 50% of predicted measured

- Cardiac ejection fraction of > 50% by echocardiogram or multi gated acquisition
(MUGA) scan; the left ventricular ejection fraction (LVEF) from the prestudy
echocardiogram (ECHO) or MUGA may be used for eligibility purposes, even if the
prestudy stress test indicated a lower LVEF

- Adequate liver function tests with a bilirubin of =< 1.5 x ULN and serum glutamic
oxaloacetic transaminase (SGOT) or serum glutamic pyruvic transaminase (SGPT) =< 2 x
ULN

- Negative human immunodeficiency virus antibody

- Eastern Cooperative Oncology Group (ECOG) performance status = 0 or 1; karnofsky
performance status (KPS) >= 80

- No active central nervous system (CNS) disease or prior history of CNS disease

- Patients must have recovered from last therapy and should be at least four weeks from
prior radiation or systemic chemotherapy on the day of administration of Y2B8

- After the last systemic therapeutic chemotherapy (Cytoxan, administered only for stem
cell mobilization is not considered therapeutic) and prior to initiation of high dose
treatment, the patient should have a baseline computed tomography (CT) scan and
positron emission tomography (PET) scan done; an fluorodeoxyglucose-computed
tomography (FDG/CT) scan is sufficient, however, is clinically indicated, an
additional diagnostic CT may be ordered; exception: if scans were done and were
negative for disease just prior to priming chemotherapy (therapeutic or
nontherapeutic) and subsequent stem cell harvest, they do not need to be repeated
prior to initiation of high dose treatment

Exclusion Criteria:

- Presence of human anti-Zevalin antibody (HAZA)

- Prior radioimmunotherapy

- Failure to collect adequate number of CD34+ cells >= 3 x 10^6/kg

- Abnormal cytogenetic study not related to the underlying lymphoma on the bone marrow
aspirate sample prior to stem cell collection; if cytogenetics were not performed on
the marrow aspirate prior to stem cell collection, cytogenetics on the peripheral
blood may be performed

- Prior bone marrow transplantation

- Prior malignancy except for:

- Adequately treated basal cell or squamous cell skin cancer

- Adequately treated noninvasive carcinoma

- Other cancer from which the patient has been disease-free for at least five
years

- Active evidence of Hepatitis B or C infection; Hepatitis B surface antigen positive

- Patients who have had prior radiation to the lung will be excluded from the study,
although mediastinal irradiation will be permitted if minimal lung is in the
treatment volume

- Patients who have received > 500cGy radiation to the kidneys will be excluded from
the study

- Patients who are pregnant or lactating