OBJECTIVE To assess long-term metabolic and immunological follow-up of microencapsulated human islet allografts into nonimmunosuppressed patients with type 1 diabetes (T1DM).
RESEARCH DESIGN AND METHODS Four nonimmunosuppressed patients, with longstanding T1DM, received intraperitoneal treatment (TX) of microencapsulated human islets. Anti-major histocompatibility complex (MHC) class I–II and GAD65 antibodies and islet cell antibodies were measured before and long term after TX.
RESULTS All patients turned positive for serum C-peptide response, both in basal and after stimulation, throughout 3 years of posttransplant follow-up. Daily mean blood glucose, as well as HbA1c levels, significantly improved after TX, with daily exogenous insulin consumption declining in all cases and being discontinued, just transiently, only in patient 4. Anti-MHC class I–II and GAD65 antibodies all tested negative at 3 years after TX.
CONCLUSIONS The grafts did not elicit any immune response, even in the cases where more than one preparation was transplanted, as a unique finding, compatible with encapsulation-driven “bioinvisibility” of the grafted islets. This result was never achieved with the recipient’s general immunosuppression.
- Received April 18, 2011.
- Accepted August 10, 2011.
- © 2011 by the American Diabetes Association.
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