Inclusion Criteria:

- Aged from 18 to 65 years.

- Patient with pathologically proven, high grade B-cell Lymphoma CD 20 positive (WHO
classification) :

- Diffuse large B cell lymphoma.

- Adverse prognostic factors IPI>1

- In Complete Remission, or partial response to first line treatment.

- Previously treated with chemotherapy regimen containing rituximab: R CHOP or R ACVBP

- Chemo-sensitive disease

- PET Scan prior transplant

- Eligible for autologous stem cell transplantation

- With a minimum life expectancy of 3 months.

- Negative HIV, HBV and HCV serologies (in the last 4 weeks except after vaccination).

- Having previously signed a written informed consent.

Exclusion Criteria:

- Histological transformation in diffuse large B cell lymphoma, any type of low grade
lymphoma

- More than one line of treatment. Prior transplantation. Prior exposure to Zevalin

- Central nervous system or meningeal involvement by lymphoma.

- Contraindication to any drug contained in the chemotherapy regimen.

- Any serious active disease or co-morbid medical condition (according to the
investigator's decision and information provided in the IDB).

- Poor renal function (creatinin level up to 2.5 maximum normal level) unless these
abnormalities are related to the lymphoma.

- Poor hepatic function (total bilirubin level up to 30 micro mol/l, transaminases up
to 2.5 maximum normal level) unless these abnormalities are related to the lymphoma.

- Poor bone marrow reserve as defined by neutrophils less than 1.5 G/l or platelets
less than 100 G/l

- Large bone marrow irradiation more than 40percent.

- Bone marrow infiltration

- Lack of sufficient autologous hematopoietic stem cells for transplantation.

- Prior treatment with murine antibodies

- Known hypersensibility to murine antibodies or proteins

- Any history of cancer during the last 5 years, with the exception of non-melanoma
skin tumors or stage 0 (in situ) cervical carcinoma.

- Treatment with any investigational drug within 30 days before planned first cycle of
chemotherapy and during the study.

- Adult patient unable to give informed consent because of intellectual impairment.

- Pregnant or lactating women.