Inclusion Criteria:

1. Relapsed CD20-positive B-cell diffuse large cell lymphoma (demonstrated in lymph nodes or bone marrow), chemosensitive (at least PR).
2. Age: up to 18-70 years of age.
3. Prestudy performance status of 0, 1, or 2 according to the WHO.
4. No anti-cancer therapy started within three weeks, prior to study initiation, and fully recovered from all toxicities associated with prior surgery, radiation treatments, chemotherapy, or immunotherapy. No prior rituximab within three weeks of starting therapy.
5. If patients had prior radiation, this should have not involved more than 25% of the bone marrow.
6. Acceptable hematologic status within two weeks prior to patient registration, including: Absolute neutrophil count ({segmented neutrophils + bands} x total WBC) > 1,500/mm³ and platelet counts > 80,000/mm³
7. IRB -approved signed informed consent.
8. Patients determined to have <10% bone marrow involvement with lymphoma within 60 days before study entry as defined by bone marrow aspirates and biopsies.
9. Female patients included must not be pregnant or lactating.
10. Patients should have at least 4-6 x 10^6 CD34+/kg peripheral stem cells collected. Around 1-2 million cells will beheld as back up.
11. Voluntary signed, written IRB-approved informed consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care.
12. Men and women of reproductive potential must agree to follow accepted birth control methods for the duration of the study. Female subject is either post-menopausal or surgically sterilized or willing to use an acceptable method of birth control (i.e., a hormonal contraceptive, intra-uterine device, diaphragm with spermicide, condom with spermicide, or abstinence) for the duration of the study. Male subject agrees to use an acceptable method for

Exclusion Criteria:

1. Failed stem cell collection of >/= 4x10^6CD34+/kg.
2. Prior radioimmunotherapy.
3. Presence of active CNS lymphoma.
4. Patients with abnormal liver function: total bilirubin > 1.5 mg/dl.
5. Patients with abnormal renal function: serum creatinine > 1.6 mg/dl.
6. Serious nonmalignant disease or infection which, in the opinion of the investigator and/or the sponsor, would compromise other protocol objectives.
7. Corrected DLCO < 50% and FEV subscript 1 or FVC < 50% predicted.
8. Cardiac EF < 50% by 2-D Echogram.
9. Prior radiation to lungs.
10. Abnormal cytogenetics predictive of secondary cancers, such as -5,-7.
11. Pregnant (Positive Beta HCG test in a woman with child bearing potential defined as not post-menopausal for 12 months or no previous surgical sterilization) or currently breast-feeding. Pregnancy testing is not required for post-menopausal or surgically sterilized women.
12. Patients with other malignancies diagnosed within 2 years prior to Study entry (except skin squamous or basal cell carcinoma).
13. Active uncontrolled bacterial, viral fungal infections.
14. Major surgical procedure or significant traumatic injury within 4 weeks prior to Study entry.
15. Serious, non-healing wound, ulcer, or bone fracture.
16. History of abdominal fistula, gastrointestinal perforation or intra-abdominal abscess within 3 months prior to Study entry.
17. History of Stroke within 6 months.
18. Myocardial infarction within the past 6 months prior to Study Day 1, or has New York Heart Association (NYHA) Class III or IV heart failure or arrythmias, unstable angina, uncontrolled congestive heart failure or arrythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities. Prior to study entry, any ECG abnormality at screening must be documented by investigator as not medically relevant.
19. Uncontrolled chronic diarrhea.
20. Serious medical or psychiatric illness likely to interfere with participation in this clinical study.