B-Lymphocyte Immunotherapy in Islet Transplantation for Initial Islet Graft Failure

Inclusion Criteria: * Enrolled in clinical trial DAIT CIT-05 (NCT00468442) * Islet graft failure: absent stimulated C-peptide (\<0.3ng/mL) in response to mixed meal tolerance test Exclusion Criteria: * Untreated proliferative diabetic retinopathy * Blood Pressure: systolic blood pressure\>160mmHg or diastolic blood pressure\>100mmHg * Measured glomerular filtration rate (GFR) using iohexol \< 80ml/min/1.73m\^2 Strict vegetarians with a calculated GFR \< 70ml/min/1.73m\^2 * Presence or history of macroalbuminuria \> 300mg/g of creatinine * Presence or history of panel-reactive anti-HLA antibodies above background by flow cytometry * For female participants: Positive Pregnancy Test, presently breast-feeding, or unwillingness to use effective contraceptive measures for the duration of the study and 3 months after discontinuation. For male participants: intent to procreate during the duration of the study or within 3 months after discontinuation or unwillingness to use effective measures of contraception. Oral contraceptives, Norplant, Depo-Provera and barrier devices with spermicide are acceptable contraceptive methods; condoms used alone are not acceptable. * Active infection including hepatitis B, hepatitis C, HIV, or TB as determined by a positive skin test or clinical presentation, or under treatment for suspected TB. Positive tests are acceptable only if associated with a history of previous vaccination in the absence of any sign of active infection. Positive tests are otherwise not acceptable, even in the absence of any active infection at the time of evaluation. * Negative screen for Epstein-Barr Virus (EBV) by IgG determination * Invasive aspergillus, histoplasmosis, or coccidiomycosis infection within one year prior to study enrollment * Any history of malignancy except for completely resected squamous or basal cell carcinoma of the skin * Known active alcohol or substance abuse * Anemia (Hgb \< 11 g/dL),neutropenia (\<1,500/µL), or thrombocytopenia (platelets \<100,000/µL) * A history of Factor V deficiency * Any coagulopathy or medical condition requiring long-term anticoagulant therapy (e.g., warfarin) after transplantation (low-dose aspirin treatment is allowed) or patients with an International Normalized Ratio (INR) \>1.5 * Severe co-existing cardiac disease, characterized by any one of these conditions: 1. recent myocardial infarction (within past 6 months) 2. evidence of ischemia on functional cardiac exam within the last year 3. left ventricular ejection fraction \<30% * Persistent elevation of liver function tests (LFTs) at the time of study entry (e.g., persistent SGOT (AST), SGPT (ALT), Alk Phos or total bilirubin, with values \>1.5 times normal upper limits * Symptomatic cholecystolithiasis * Acute or chronic pancreatitis * Symptomatic peptic ulcer disease * Severe unremitting diarrhea, vomiting or other gastrointestinal disorders potentially interfering with the ability to absorb oral medications * Hyperlipidemia despite medical therapy (fasting LDL cholesterol \> 130 mg/dL, treated or untreated; and/or fasting triglycerides \> 200 mg/dL) * Receiving treatment for a medical condition requiring chronic use of systemic steroids, except for the use of ≤ 5 mg prednisone daily, or an equivalent dose of hydrocortisone, for physiological replacement only * Use of any investigational agents within 4 weeks of enrollment * Administration of live attenuated vaccine(s) within 2 months of enrollment * Any medical condition that, in the opinion of the investigator, will interfere with the safe completion of the trial, such as chronic central neurologic disease * Treatment with any anti-diabetic medication other than insulin within 4 weeks of enrollment * A previous pancreas transplant, unless the graft failed within the first week due to thrombosis, followed by pancreatectomy and the transplant occurred more that 6 months prior to enrollment