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Background: Jehovah's Witnesses (JWs) refuse blood transfusions due to religious issues. This situation may impact kidney transplantation (KT) outcomes in case of hemorrhagic complications. We evaluated demographic characteristics of this population, hematologic safety, and graft outcomes., Methods: This was a retrospective, single-center study comparing KT outcomes in JW patients versus a non-JW control group. Hematologic endpoints included clinical indication for blood transfusion (hemoglobin <7 g/dL), decrease of hemoglobin >2 g/dL or hematocrit >5% in the first week after KT, hemorrhagic complications requiring surgery, and de novo prescription of erythropoiesis-stimulating agents. Secondary endpoints included delayed graft function, treated biopsy-proven acute rejection, renal function, mortality, and graft survival at 12 months., Results: From January 1989 to September 2018, we identified 143 JW (10 pediatric) and selected 142 matched control (non-JW) patients. There were no differences in the incidence of clinical indication for transfusion (13.3% versus 11.3%, P = 0.640), but a higher proportion of non-JW patients received transfusions (2.1% versus 9.2%, P = 0.010). There were no differences in the proportion of patients with decreased hemoglobin concentration, in reinterventions due to hemorrhagic complications, in the use of erythropoiesis-stimulating agents at hospital discharge, in the incidence of acute rejection, in renal function, and in mortality or graft survival rate at 12 months., Conclusions: In summary, this matched control cohort study suggests that, when clinically indicated, blood transfusions can be safely avoided in the majority of JW kidney transplant, who achieve and maintain comparable hemoglobin concentrations during the first year after transplantation compared with non-JW patients., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Autocrine activation of the complement receptors C3aR and CD46 by complement activation components C3a and C3b produced through C3 cleavage by the protease cathepsin L (CTSL) during T cell stimulation is a requirement for IFN-γ production and Th1 induction in human CD4 + T cells. Thus, lack of autocrine CD46 activation, such as in CD46-deficient patients, is associated with defective Th1 responses and recurrent infections. We have identified LGMN [the gene coding for legumain, also known as asparaginyl endopeptidase (AEP)] as one of the key genes induced by CD46 co-stimulation during human CD4 + T cell activation. AEP processes and activates a range of proteins, among those α1-thymosin and CTSL, which both drive intrinsically Th1 activity-but has so far not been described to be functionally active in human T cells. Here we found that pharmacological inhibition of AEP during activation of human CD4 + T cells reduced CTSL activation and the CTSL-mediated generation of intracellular C3a. This translated into a specific reduction of IFN-γ production without affecting cell proliferation or survival. In line with these findings, CD4 + T cells isolated from Lgmn -/- mice also displayed a specific defect in IFN-γ secretion and Th1 induction. Furthermore, we did not observe a role for AEP-driven autocrine α1-thymosin activation in T cell-derived IFN-γ production. These data suggest that AEP is an "upstream" activator of the CTSL-C3-IFN-γ axis in human CD4 + T cells and hence an important supporter of human Th1 induction.

Unlabelled: Defective immune regulation plays a permissive role enabling effector cells to initiate and perpetuate tissue damage, eventually resulting in autoimmune disease. Numerical and functional regulatory T-cell (Treg) impairment has been previously reported in autoimmune liver disease (AILD; including autoimmune hepatitis and autoimmune sclerosing cholangitis ASC). However, in these early reports, Tregs were phenotypically defined as CD4(+) CD25(+) or CD4(+) CD25(high) cells. In the current study, we reexamined phenotypic and functional properties of Tregs by adopting a more refined definition of these cells that also includes negativity or low level of expression of CD127. We studied 43 AILD patients and 22 healthy subjects (HSs) and found that CD4(+) CD25(+) CD127(-) Tregs were decreased in the former. This decrease was more marked in patients with active disease than in those in remission. In AILD, Treg frequencies correlated inversely with parameters of disease activity and were not affected by immunosuppressive treatment. We also document, for the first time, that, in AILD, bona-fide Tregs produce less interleukin (IL)-10 and are impaired in their ability to suppress CD4(+) CD25(-) target cell proliferation, a feature that in HSs, but not in AILDs, is dependent, at least in part, on IL-10 secretion. Decreased IL-10 production by Tregs in AILD is linked to poor responsiveness to IL-2 and phospho signal transducer and activator of transcription 5 up-regulation., Conclusion: Tregs are numerically impaired in AILD, this impairment being more prominent during active disease. Notably, defective IL-10 production, resulting from low Treg responsiveness to IL-2, contributes to Treg functional impairment., (© 2015 by the American Association for the Study of Liver Diseases.)