Transplantation

About: Transplantation is a research topic. Over the lifetime, 276584 publications have been published within this topic receiving 7961661 citations.

Oral tolerance originates in the intestinal immune system and relies on antigen carriage by dendritic cells.

Abstract: Oral tolerance induction is a key feature of intestinal immunity, generating systemic nonresponsiveness to ingested antigens. In this study, we report that orally applied soluble antigens are exclusively recognized in the intestinal immune system, particularly in the mesenteric lymph nodes. Consequently, the initiation of oral tolerance is impeded by mesenteric lymphadenectomy. Small bowel transplantation reveals that mesenteric lymph nodes require afferent lymph to accomplish the recognition of orally applied antigens. Finally, oral tolerance cannot be induced in CCR7-deficient mice that display impaired migration of dendritic cells from the intestine to the mesenteric lymph nodes, suggesting that immunologically relevant antigen is transported in a cell-bound fashion. These results demonstrate that antigen transport via afferent lymphatics into the draining mesenteric lymph nodes is obligatory for oral tolerance induction, inspiring new therapeutic strategies to exploit oral tolerance induction for the prevention and treatment of autoimmune diseases.

Bone marrow mesenchymal progenitor cells inhibit lymphocyte proliferation by activation of the programmed death 1 pathway.

Abstract: Bone marrow mesenchymal progenitor cells (BMSC) are used for regenerating tissues of mesodermal origin, as well as tissues of different embryological derivation. Experimental evidence shows that BMSC are able to suppress the activation of the immune response by mechanisms that are still not completely understood. Thus far, in vitro studies carried using human or mouse cells indicate that autologous or allogeneic BMSC strongly suppress proliferation of T lymphocytes, triggered by cellular stimuli, nonspecific mitogenic stimuli, or antigenic peptides. Using cell proliferation and blocking assays, we demonstrated that BMSC inhibited the activation of murine splenocytes, T, and B lymphocytes. Direct contact of BMSC and target cells in a cognate fashion determined the inhibition of cell proliferation via engagement of the inhibitory molecule programmed death 1 (PD-1) to its ligands PD-L1 and PD-L2, leading the target cells to modulate the expression of different cytokine receptors and transduction molecules for cytokine signaling. Soluble factors present on supernatants of BMSC cultures were effective in suppressing proliferation of B cells to a mitogenic stimulus. Taken together, these results highlight the complexity of the role of BMSC in regulating the immune response, asserting the possibility of their therapeutic application in transplantation and autoimmune diseases.

Rabbit antithymocyte globulin versus basiliximab in renal transplantation.

Abstract: Background Induction therapy reduces the frequency of acute rejection and delayed graft function after transplantation. A rabbit antithymocyte polyclonal antibody or basiliximab, an interleukin-2 receptor monoclonal antibody, is most commonly used for induction. Methods In this prospective, randomized, international study, we compared short courses of antithymocyte globulin and basiliximab in patients at high risk for acute rejection or delayed graft function who received a renal transplant from a deceased donor. Patients taking cyclosporine, mycophenolate mofetil, and prednisone were randomly assigned to receive either rabbit antithymocyte globulin (1.5 mg per kilogram of body weight daily, 141 patients) during transplantation (day 0) and on days 1 through 4 or basiliximab (20 mg, 137 patients) on days 0 and 4. The primary end point was a composite of acute rejection, delayed graft function, graft loss, and death. Results At 12 months, the incidence of the composite end point was similar in the two groups (P=0.34). The antithymocyte globulin group, as compared with the basiliximab group, had lower incidences of acute rejection (15.6% vs. 25.5%, P=0.02) and of acute rejection that required treatment with antibody (1.4% vs. 8.0%, P=0.005). The antithymocyte globulin group and the basiliximab group had similar incidences of graft loss (9.2% and 10.2%, respectively), delayed graft function (40.4% and 44.5%), and death (4.3% and 4.4%). Though the incidences of all adverse events, serious adverse events, and cancers were also similar between the two groups, patients receiving antithymocyte globulin had a greater incidence of infection (85.8% vs. 75.2%, P=0.03) but a lower incidence of cytomegalovirus disease (7.8% vs. 17.5%, P=0.02). Conclusions Among patients at high risk for acute rejection or delayed graft function who received a renal transplant from a deceased donor, induction therapy consisting of a 5-day course of antithymocyte globulin, as compared with basiliximab, reduced the incidence and severity of acute rejection but not the incidence of delayed graft function. Patient and graft survival were similar in the two groups. (ClinicalTrials.gov number, NCT00235300 [ClinicalTrials.gov].).

Long-term survival and late deaths after allogeneic bone marrow transplantation. Late Effects Working Committee of the International Bone Marrow Transplant Registry.

Abstract: Background and Methods It is uncertain whether mortality rates among patients who have undergone bone marrow transplantation return to the level of the mortality rates of the general population. We analyzed the characteristics of 6691 patients listed in the International Bone Marrow Transplant Registry. All the patients were free of their original disease two years after allogeneic bone marrow transplantation. Mortality rates in this cohort were compared with those of an age-, sex-, and nationality-matched general population. Cox proportional-hazards regression was used to identify risk factors for death more than two years after transplantation (late death). Results Among patients who were free of disease two years after transplantation, the probability of living for five more years was 89 percent (95 percent confidence interval, 88 to 90 percent). Among patients who underwent transplantation for aplastic anemia, the risk of death by the sixth year after transplantation did not differ significantly from ...