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Application of Stem Cell and Exosome-Based Therapy in COVID-19
Published in Debmalya Barh, Kenneth Lundstrom, COVID-19, 2022
Suleyman Gokhan Kara, Ayla Eker Sariboyaci
Both allogeneic and autologous MSCs are used in clinical studies. Many studies have shown that allogeneic MSC treatments do not stimulate significant alloimmune reactions, and do not show more severe side effects than autologous MSC treatments. The main advantage of the allogeneic treatment is that it can be used immediately in acute cases without waiting for the production process.
Recurrent pregnancy loss
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Christine E. Ryan, Danny J. Schust
Alloimmune disorders are purported to cause pregnancy loss via an abnormal cell-mediated maternal immune response to placental or fetal antigens. One hypothesis for alloimmune RPL holds that in normal pregnancies, maternal production of a blocking factor prevents rejection of the fetus and that these factors are missing in women experiencing RPL (87). Evidence used to support this theory includes (i) the tendency for RPL partners to share human leukocyte antigens, (ii) the fact that females experiencing RPL often do not produce purported serum blocking factors, and (iii) the fact that women with a history of RPL commonly produce anti-leukocytotoxic antibodies against paternal leukocytes (2). The blocking factor hypothesis has been widely studied, but is poorly supported.
Immunopathogenesis of Vanishing Bile Duct Syndromes
Published in Gianfranco Alpini, Domenico Alvaro, Marco Marzioni, Gene LeSage, Nicholas LaRusso, The Pathophysiology of Biliary Epithelia, 2020
John M. Vierling, Marius Braun, Haimei Wang
Both CGVHD and HAR result from alloimmune reactions of T-cells to nonself MHC or minor histocompatibility antigens.99,100 In both entities, CD4 T-cells are obligatory. Alloimmune T-cell reactions can be activated by both direct and/or indirect mechanisms. In direct activation, TCRs are directly stimulated by allo-MHC molecules due to the molecular mimicry of allo-MHC-peptide antigen complexes with self-MHC-peptide antigen complexes. In contrast, indirect activation results from classical processing and presentation of allo-antigens by self-APCs. Allo-antigenic peptides presented by the indirect pathway may be derived from any protein, including allo-MHC molecules themselves.
Emerging local immunomodulatory strategies to circumvent systemic immunosuppression in cell transplantation
Published in Expert Opinion on Drug Delivery, 2022
Jocelyn Nikita Campa-Carranza, Jesus Paez-Mayorga, Corrine Ying Xuan Chua, Joan E. Nichols, Alessandro Grattoni
In this context, local delivery of immunomodulatory agents presents a unique opportunity to address the limitations of systemic delivery avoiding toxicity, rapid clearance, and off-target effects. For this, while biomaterials functionalization can provide transient therapeutic efficacy that is relevant in the short term against chronic rejection, platforms that allow for sustained, and potentially life-long immunomodulation are needed for extending life of the transplant. Here, simple mechanisms for drug refilling or supplementation may be fundamental for long-term clinical deployment. Nonetheless, it is still unclear if local therapeutic release is sufficient to regulate the alloimmune response. In addition, local confinement of immunosuppressants impose potential toxicity to the graft. Thus, safety profiles for local drug release are required as with systemically deployed agents.
Total pancreatectomy with intraportal islet autotransplantation for pancreatic malignancies: a literature overview
Published in Expert Opinion on Biological Therapy, 2022
Mohamed Ali Chaouch, Piera Leon, Gianluca Cassese, Caroline Aguilhon, Salah Khayat, Fabrizio Panaro
Despite the improvement in long-term metabolic outcomes, challenges regarding insulin independence still need to be overcome. Allogenic islets were, indeed, vulnerable to alloimmune rejection. Moreover, immunosuppressive drugs could lead to beta-cell toxicity. Islet autotransplantation (IAT) does not need immunosuppression. However, the quality and quantity of beta-cell mass that is available and extractable from a diseased organ may constitute a problem. Moreover, the possibility of tumor cell dissemination with IAT in an oncological setting presents serious concerns. However, there are different papers that support the oncological safety of IAT. Renaud et al. [11], in a preclinical murine model, assessed the risk of malignant dissemination after islet xenograft from the non-tumoral part of surgical specimen of pancreatic ductal adenocarcinoma (PDAC). They found neither local nor distant spreading of malignant cells after 6 weeks of follow-up when immunocompromised mice were sacrificed. Balzano et al. also reported on a multicenter experience of selected patients with neoplasm safely treated with IAT [12].
Comparison of outcomes of peritoneal dialysis between patients after failed kidney transplant and transplant-naïve patients: a meta-analysis of observational studies
Published in Renal Failure, 2021
Xiaohua Meng, Weifei Wu, Shuang Xu, Zhiqun Cheng
Perl et al. [7] in their retrospective review of 16 113 patients demonstrated that the use of peritoneal dialysis (PD), when compared to hemodialysis (HD), may improve the outcomes in patients after a failed kidney transplant. However, whether the PD outcomes in this cohort are different from those of transplant-naïve patients initiating PD remains unclear. Research indicates that mortality and morbidity in dialysis patients after allograft failure are high when compared to those of patients awaiting kidney transplants [8]. This has been attributed to the different characteristics between patients with failed transplants and transplant-naïve patients. Failed allografts can generate a persistent alloimmune reaction in affecting clinical outcomes. Moreover, the prolonged immunosuppressant therapy in patients with a kidney transplant, which sometimes is continued after graft failure, may also influence clinical outcomes [9].