Rituximab in Renal Allograft Recipients Who Develop Early De Novo Anti-HLA Alloantibodies

Stage 1 Inclusion Criteria for All Participants: * Willing to provide informed consent * Previously diagnosed end stage renal disease (ESRD) * Received kidney transplant within 3 and 36 months of study entry * Willing to comply with the study protocol * Willing to use acceptable forms of contraception during the study and for 12 months following rituximab/placebo therapy * Willing to refrain from breastfeeding during the study and for 12 months following rituximab therapy Stage 1 Inclusion Criteria for Pediatric Participants (\<\\=18 Years of Age): * Parent or guardian willing to provide informed consent * Have received all childhood vaccinations prior to study entry Stage 2 Inclusion Criteria for Pilot Treatment Study: * Three to 39 months post-transplant * Developed new antibodies detected at two time points within 1 month between 3 to 36 months post-transplant * Negative pregnancy test Stage 1 Exclusion Criteria for All Participants: * Recipient of a kidney from a donor older than 70 years of age * Multi-organ transplant * History of organ transplantation other than current kidney transplantation * Previous treatment with rituximab * History of severe allergic reactions to monoclonal antibodies * History of allergic reaction to iodine glomerular filtration rate (GFR) assay * Lack of intravenous (IV) access * Sensitized to greater than 5% Panel Reactive Antibody (PRA) within 12 weeks prior to transplant * History of recurrent bacterial or other significant infections…