Patient description: A 17 year old boy complains of vomiting, non-bloody diarrhea, abdominal pain, fever, chills and loss of appetite for the past 3 days. He ate a salad at a restaurant prior to his diarrhea onset. Physical exam was remarkable for pallor, jaundice, and diffuse abdominal tenderness. Lab results were as follows: Hemoglobin: 9.7 g/dL Platelet: 110,000 /cu.mm Creatinine: 3.6 mg/dL blood urea nitrogen (BUN): 73 mg/dL direct bilirubin: 2.4 mg/dL lactate dehydrogenase (LDH): 881 IU/L (normal: 110-265 IU/L) Peripheral blood smear showed a moderate number of schistocytes and helmet cells. Shiga-like toxin-producing E. coli (STEC) stx1/stx2 were found in stools. He has no other underlying disease and he is not on any medications.

Clinical trial eligibility criteria: eligible ages (years): 60.0-80.0,  Lymphoma Diffuse Large B-cell Lymphoma Ages Eligible for Study: Between 60 and 80 years old Genders Eligible for Study: Both Accepts Healthy Volunteers: No For patients registered at the time of initial diagnosis Patient with histologically proven CD20+ diffuse large B cel (DLBCL) 5WHO classification 2008) including clinical subtypes (primitive mediastinal, intravascular, etc.). Patients with De Novo Transformed DLBCL from low grade lymphoma (Follicular, other..) may also be included. Patients with DLBCL associated with some small cell infiltration in bone marrow may also be included Or CD20+ B-cell lymphoma with intermediate features between DLBCL and Burkitt or with intermediate features between DLBCL and classical Hodgkin lymphoma Or CD20+ Follicular lymphoma grade 3B Or CD20+ Aggressive B-cell lymphoma unclassifiable previous untreated with chemo or radiotherapy For patients registered after response evaluation to first line treatment with R-CHOP Patient with histologically proven CD20+ diffuse large B cell (DLBCL) 5WHO classification 2008) including clinical subtypes (primitive mediastinal, intravascular, etc.). Patients with De Novo Transformed DLBCL from low grade lymphoma (Follicular, other..) may also be included. Patients with DLBCL associated with some small cell infiltration in bone marrow may also be included Or CD20+ B-cell lymphoma with intermediate features between DLBCL and Burkitt or with intermediate features between DLBCL and classical Hodgkin lymphoma Or CD20+ Follicular lymphoma grade 3B Or CD20+ Aggressive B-cell lymphoma unclassifiable Have reached a CR or PR after first line treatment with at least 6 cycles of R-CHOP 14 regimens and up to 8 cycles of R-CHOP21 Previously untreated with Radiotherapy For all patients aged from 60 to 80 years at time of registration Ann Arbor stages II-IV at time of initial diagnosis aaIPI> 1 at time of initial diagnosis  Any other histological type of Lymphoma, Burkitt included Any history of treated or non treated small B-cell lymphoma Central nervous system or meningeal involvement by lymphoma Contraindication to any drug contained in the chemotherapy regimen Myocardial infarction during last 3 months or unstable coronary disease or uncontrolled chronic symptomatic congestive heart insufficiency NYHA III-IV Uncontrolled hypertension Uncontrolled diabetes mellitus as defined by the investigator Active systemic infection requiring treatment previously known HIV positive serology Active hepatitis B or C Prior history of malignancies other than lymphoma within 3 years