Since its inception, the Diabetes Research Institute (DRI) has made significant contributions to the field of diabetes, pioneering many of the techniques used in diabetes centers around the world. Through several clinical trials, DRI has demonstrated that diabetes can be successfully reversed as a result of islet cell transplant. Over the years the following protocols in islet cell transplantation have been initiated: 2000/0329; 2000/0196; 2004/0205; 2000/024; 2006/0200; 2006/0508; 2006/0210. All of the studies listed above will be source of study subjects for this study. Approximately 30 subjects are expected to be enrolled and followed in this trial. After islet-cell transplantation in the parent studies, each subject receives maintenance immunosuppressive medications. The purpose of this protocol is to collect additional follow-up for safety and efficacy from subjects with graft function after their completion in their parent study. It is expected that most subjects will retain measurable islet function and, in the islet-alone studies, continue to receive immunosuppressive medications at the time of completing their parent study.