[Islets of Langerhans or pancreas transplantation in the treatment of type 1 diabetes]. / La transplantation d'ilots de Langerhans ou de pancréas dans le traitement du diabète de type 1.

Type I diabetes is one of the big challenges in medicine of the 21st century, being a chronic disease with a high incidence and long term complications. Intensive insulin treatment can reduce these complications but harbors the risk of hypoglycemic events impacting on the quality of life of patients. Pancreas and islet of Langerhans transplantation are interesting alternatives to restore physiologic glucose metabolism. One could think that there might be some competition between these two treatments, but donor and recipient selection criteria are different and these two methods are therefore complementary. Here we discuss the adequate donor selection and the different settings of beta cell replacement therapy for type I diabetes, their risks and their benefit.

Absence of humoral and cellular alloreactivity in baboons sensitized to pig antigens.

AIM: to study whether sensitization to pig antigens results in humoral and/or cellular sensitization to alloantigens in baboons, and thus increases the risks of organ allotransplantation after xenotransplantation. Serum from baboons that were naive (n = 4), sensitized to Gal alpha 1,3Gal (Gal) antigens (n = 2), or sensitized to Gal + non-Gal pig antigens (n = 2) were tested by flow cytometry for the presence of immunoglobulin G (IgG) and IgM antibodies that bind to pig or baboon peripheral blood mononuclear cells (PBMC). Two allosensitized baboons were used as positive controls. The same 10 sera were tested in a complement-mediated cytotoxicity assay to detect cytotoxic antibodies against pig, allo and self-PBMC. The T-cell responses of the same baboons to allogeneic and pig PBMC stimulators in mixed lymphocyte reaction (MLR) were studied. All baboon sera contained cytotoxic antibodies that bound to pig PBMC. Binding and cytotoxicity were higher in xenosensitized baboons, particularly in those sensitized to Gal + non-Gal antigens (P < 0.001). None of the naive or xenosensitized baboon sera bound to baboon PBMC. Serum from allosensitized baboons showed anti-baboon IgG and IgM binding, but there was no increase in binding to pig PBMC or in cytotoxicity to pig cells. The MLR response to pig stimulators in baboons sensitized to non-Gal pig antigens was greater than that of naive or Gal-sensitized baboons (P < 0.001), but there was no increase in the response to baboon cells. In baboons, no in vitro evidence that a previous pig xenograft might endanger the outcome of a subsequent allograft was documented.