Value of Rituximab in Humoral Chronic Rejection After Renal Transplantation

Inclusion Criteria: * Renal allograft recipients at least 1 year after transplantation with GFR \> 25 ml/min x 1,73m2 (MDRD) * Single organ recipients of renal allograft * Patients who have provided informed consent * Patients who are \>= 18 years of age * Patients who have biopsy proven CAN with C4d+ deposits and/or plasma-cells and/or B-lymphocytes within the last 4 weeks before inclusion * Patients who are treated with ACE/AT1 Blocker more than 1 week before inclusion Exclusion Criteria: * Patients who suffer from HIV infection * Patients with a history of Hepatitis B * Patients with Hepatitis C (active/chronic) * Patients who have a contraindication for the use of rituximab, such as leukopenia or experienced infusion-related adverse events to former antibody treatment * Patients who showed signs of acute cellular rejection in the biopsy * Patient has a malignancy or history of malignancy within the last 5 years, except non-metastatic basal or squamous cell carcinoma of the skin that has been treated successfully. * Patient has a systemic infection requiring treatment. * Female patients who are pregnant or lactating * Patients who have any form of substance abuse, psychological illness or any other condition, which, in the opinion of the investigator, may interfere with the patient's ability to understand the requirements of the study. * Patients who have a proteinuria \>4g/24h * Patient is unlikely to comply with the visits scheduled in the protocol. * Patient is simultaneously participating in another investigational drug study or has participated in such study within 28 days before entry in this study.