Prevention of de Novo Allosensitization in Islet Transplant Recipients Following Complete Graft Loss

This study is testing whether a medication called belatacept, which calms the immune system, can prevent a transplanted islet patient's immune system from developing antibodies against new donors, which could make future transplants harder to perform. **You may be eligible if...** - You have type 1 diabetes and have already received an islet cell transplant (a procedure where insulin-producing cells from a donor pancreas are placed into your liver) - You are being considered for a second or additional islet transplant - You do not currently have antibodies against donor tissues - You are in otherwise stable health **You may NOT be eligible if...** - You already have high levels of antibodies against donor tissues - You have active infections (especially those that could worsen with immune suppression, like tuberculosis or certain viral infections) - You have significant kidney, liver, or blood problems - You are pregnant or planning pregnancy - You have had certain cancers or lymphomas Talk to your doctor to see if this trial is right for you.