Patient description: A 34 year old man comes to the clinic complaining of dizziness and severe diarrhea since yesterday. He has returned from an international trip few days ago and was living in a camp in Sudan for a month. He developed abdominal pain followed by bloating and nausea as well as loose bowel movements. Soon he was having profuse watery diarrhea without odor. The stool is watery and white but the patient has no fever. Blood pressure is 95/62 lying down and drops to 75/40 standing. The skin turgor has reduced. HR is 110 and he looks ill with dry mucosa. V. cholerae was seen in dark-field microscopy of a fresh stool specimen. The lab study is as bellow: Sodium 137 meq/L Potassium 2 meq/L Chloride 94meq/L CO2 15 meq/L Fecal leukocytes None seen Fecal occult blood Negative

Clinical trial eligibility criteria: eligible ages (years): 1.0-31.0,  B Acute Lymphoblastic Leukemia B Lymphoblastic Lymphoma Down Syndrome All B-ALL patients must be enrolled on APEC14B1 and consented to Screening (Part A) prior to treatment and enrollment on AALL1731. APEC 14B1 is not a requirement for B-LLy patients. B-LLy patients may directly enroll on AALL1731 Age at diagnosis Patients must be >= 365 days and < 10 years of age (B-ALL patients without DS) Patients must be >= 365 days and =< 31 years of age (B-ALL patients with DS) Patients must be >= 365 days and =< 31 years of age (B-LLy patients with or without DS) B-ALL patients without DS must have an initial white blood cell count < 50,000/uL (performed within 7 days prior to enrollment) B-ALL patients with DS are eligible regardless of the presenting white blood cell count (WBC) (performed within 7 days prior to enrollment) Patient has newly diagnosed B-cell ALL, with or without Down syndrome: > 25% blasts on a bone marrow (BM) aspirate OR if a BM aspirate is not obtained or is not diagnostic of B-ALL, the diagnosis can be established by a pathologic diagnosis of B-ALL on a BM biopsy OR a complete blood count (CBC) documenting the presence of at least 1,000/uL circulating leukemic cells  Patient must not have secondary ALL that developed after treatment of a prior malignancy with cytotoxic chemotherapy. Note: patients with Down syndrome with a prior history of transient myeloproliferative disease (TMD) are not considered to have had a prior malignancy. They would therefore be eligible whether or not the TMD was treated with cytarabine With the exception of steroid pretreatment or the administration of intrathecal cytarabine, patients must not have received any prior cytotoxic chemotherapy for either the current diagnosis of B ALL or B LLy or for any cancer diagnosed prior to initiation of protocol therapy on AALL1731 For patients receiving steroid pretreatment, the following additional apply Non-DS B-ALL patients must not have received steroids for more than 24 hours in the 2 weeks prior to diagnosis without a CBC obtained within 3 days prior to initiation of the steroids DS and non-DS B-LLy patients must not have received > 48 hours of oral or IV steroids within 4 weeks of diagnosis Patients who have received > 72 hours of hydroxyurea B-ALL patients who do not have sufficient diagnostic bone marrow submitted for APEC14B1 diagnostic testing and who do not have a peripheral blood sample submitted containing > 1,000/uL circulating leukemia cells Patient must not have acute undifferentiated leukemia (AUL) Non-DS B-ALL patients with central nervous system [CNS]3 leukemia (CNS status must be known prior to enrollment) Note: DS patients with CNS3 disease are eligible but will be assigned to the DS-High B-ALL arm. CNS status must be determined based on a sample obtained prior to administration of any systemic or intrathecal chemotherapy, except for steroid pretreatment