Human islet transplantation - Lessons from 13 autologous and 13 allogeneictransplantations

Background. A series of 13 islet autotransplantations and 13 islet allotran splantations performed between 1992 and 1999 at the University Hospital of Geneva are presented. Factors affecting the outcome are analyzed. Methods. Islet autotransplantation has been performed in seven patients wit h chronic pancreatitis and in six patients with benign tumors undergoing ex tensive pancreatectomy. Islet allografts were performed in C-peptide-negati ve patients simultaneously or after a kidney or lung transplantation. Each recipient received islets from one to four donors. Panel-reactive antibodie s were monitored by microlymphocytotoxicity test. Results, Eleven of 13 patients who underwent autotransplantation maintained insulin independence for 6 months to 5 years. Two years after autologous i slet transplantation, five of nine patients were insulin independent with a n glycosylated hemoglobin of 5.9%. Three late islet failures occurred in pa tients with chronic pancreatitis. Islet yield was significantly lower in pa tients with chronic pancreatitis than in patients with benign tumors (2044 equivalent islet number/gram resected pancreas versus 5184 equivalent islet number/gram; P=0.037). In islet allotransplantation, no early graft loss w as found. All 13 patients who underwent allotransplantation had basal C-pep tide levels above 0.3 nmol/L for 3 months to 5 years. Mean glycosylated hem oglobin decreased from 9.1% before transplantation to 5.5% at month 3. Insu lin independence was achieved in two type I diabetic patients. In four of s ix patients with graft failure, the graft had induced panel-reactive antibo dies. Conclusions. In islet autotransplantation, the reduced number of islets tha t can be isolated from fibrotic pancreata may be the major limiting factor. In islet allotransplantation, early graft function can now be consistently achieved. Islet allografts seem to be highly immunogenic, and chronic isle t failure cannot be prevented consistently by conventional immunosuppressio n.