Cause Of Graft Rejection Research Articles

Study protocol for the development and validation of a questionnaire evaluating predisposition to immunosuppressant medication non-adherence of kidney pre-transplant patients. The KATITA project.

Non-adherence to immunosuppressive medication after kidney transplant is an important cause of graft rejection and loss. Approaches to minimization of non-adherence have focused on the identification of episodes of medication non-adherence, but by then irreparable harm to the graft may already have occurred, and a more effective approach would be to adopt preventive measures in patients who may have difficulty in adhering to medication. The aim of this study protocol is to develop and validate a clinical questionnaire for assessing, in kidney transplant candidate patients in the pre-transplant setting, the predisposition to non-adherence to immunosuppressive medication. In this multicenter, prospective study, a pilot questionnaire in Brazilian Portuguese language, composed of Likert-scaled statements expressing patients' beliefs, behaviors and barriers regarding medication taking will be assembled from a literature review, from focus groups, and an expert panel. The pilot questionnaire will be administered to a minimum of 300 patients in kidney transplant waiting lists and exploratory factor analysis will be used for development of the definitive questionnaire. A random subsample of a minimum of 60 patients will have the scale re-administered after one month for evaluation of test-retest reliability. A multicenter, external validation study will include 364 kidney transplant candidates who will be evaluated immediately before surgery and at months 3, 6 and 12 post-transplant for assessment of concurrent validity, by comparison with two scales that assess medication non-adherence, and for determination of predictive validity using a triangulation method for assessment of medication non-adherence. Structural validity will be assessed with confirmatory factor analysis using structural equation modeling. Cross-cultural generalizability and validity will be assessed by a multicenter study, in which a translation of the scale to another language will be administered to kidney transplant candidate patients from a different culture, with a subsample being selected for test-retest. This study will be conducted in Spain with a Spanish translation of the scale.

Biological parameters for quality evaluation of allografts from the Brazilian National Institute of Traumatology and Orthopedics tissue bank.

Bone allografts are clinically used in a variety of surgical procedures, and tissue banks are responsible for harvesting, processing, quality testing, storing, and delivering these materials for transplantation. In tissue banks, the bone is processed for the removal of all organic content, remaining only the tissue structure (scaffold). However, several studies have shown that even after using different processing methods, viable cells, functional proteins, and DNA may still persist in the tissue, which constitute the main causes of graft rejection. Therefore, the objective of this study was to establish techniques and biological parameters for quality validation of allografts. To this end, we propose the use of 3 combined methods such as microscopy, histology, and molecular biology techniques to evaluate the quality of allografts harvested and processed by the Brazilian National Institute of Traumatology and Orthopedics (INTO) tissue bank according to the donation criteria of the Brazilian National Health Surveillance Agency and the Brazilian National Transplant System. Bone fragments from different processing stages showed no viable cells on histology, an intact extracellular matrix on scanning electron microscopy, and gradual reduction in DNA amount. Different techniques were used to demonstrate the quality of allografts produced by the INTO tissue bank and to establish biological parameters for ensuring the safety and quality of these products. Future studies need to be undertaken to assess and validate the efficacy of the decellularization process in larger bone grafts with diverse architectural configurations.

Consequences of Organ Transplant in Donors and Recipients

Organ Transplant has developed marvelously at a rapid pace and has become a major lifeguard. It has increased the survival rate of patients but certain complications are worth not ignorance .They should be treated as soon as possible for betterment of lifestyle, which otherwise may land up in life threatening conditions. A combined multiorgan transplant may offer a lower rate of graft rejection and lesser dependence on immunosuppressants. After transplant course can be followed by a few complications that can be early, late, and severe. Nevertheless, keeping a watch , regular follow ups and managing can determine the post operative cause of graft rejection. However, there has been a major increase in the demand for potential organs which is unable to met with the limited supply of donors. This hassle has left more patients in the country helpless. The shortage of existing organ crisis has deprived a lot of people from leading a better life and that gave rise to life time dependence on costly medical procedures like dialysis. Implementation of certain procedures of awareness and educational approach to people, about donating more organs on their consent, rewarding a gift of life to the people in need. This review has jotted down a few complications , that can arise post operative from the donor and recipient point of view, alongside the benefits associated with it . There’s no doubt Organ Transplant is a boon and a curse, but it has increased the life style of patients, family and friends.

Interferon-γ-induced HLA Class II expression on endothelial cells is decreased by inhibition of mTOR and HMG-CoA reductase.

In organ transplantation, donor‐specific HLA antibody (DSA) is considered a major cause of graft rejection. Because DSA targets primarily donor‐specific human leukocyte antigen (HLA) expressed on graft endothelial cells, the prevention of its expression is a possible strategy for avoiding or salvaging DSA‐mediated graft rejection. We examined the effect of various clinically used drugs on HLA class II expression on endothelial cells. Interferon‐γ (IFN‐γ)‐induced HLA class II DR (HLA‐DR) was downregulated by everolimus (EVR, 49.1% ± 0.8%; P < 0.01) and fluvastatin (FLU, 33.8% ± 0.6%; P < 0.01). Moreover, the combination of EVR and FLU showed a greater suppressive effect on HLA‐DR expression. In contrast, cyclosporine, tacrolimus, mycophenolic acid, and prednisolone did not exhibit any significant suppressive effect. FLU, but not EVR, suppressed mRNA of HLA‐DR. Imaging analysis revealed that HLA‐DR expressed in cytosol or on the cell surface was repressed by EVR (cytosol: 58.6% ± 4.9%, P < 0.01; cell surface: 80.9% ± 4.0%, P < 0.01) and FLU (cytosol: 19.0% ± 3.4%, P < 0.01; cell surface: 48.3% ± 4.8%, P < 0.01). These data indicated that FLU and EVR suppressed IFN‐γ‐induced HLA‐DR expression at the transcriptional and post‐translational level, respectively, suggesting a potential approach for alleviating DSA‐related issues in organ transplantation.

Next-generation sequencing shows marked rearrangements of BK polyomavirus that favor but are not required for polyomavirus-associated nephropathy

BackgroundBKPyV is associated with polyomavirus-associated nephropathy (PVAN), a major cause of graft rejection in kidney transplant recipients (KTRs). Mutations occur in the transcriptional control region (TCR) of BKPyV, but whether they are required for the development of PVAN is not completely understood. To this end, we characterized BKPyV TCRs from KTRs to assess whether TCR mutations are associated with PVAN. Study designWe analyzed urine and plasma samples of fifteen KTRs with biopsy-confirmed PVAN, presumptive PVAN, or probable PVAN in order to explore the contents of the BKPyV virome. BKPyV TCRs were amplified and deep sequenced to characterize the viral strains. Alterations in block structures and transcription factor binding sites were investigated. ResultsThe majority of sequences in both urine and plasma samples represented archetype BKPyV TCR. Minor populations harboring rearranged TCRs were detected in all patient groups. In one biopsy-confirmed PVAN patient rearranged TCRs predominated, and in another patient half of all reads represented rearranged sequences. ConclusionsAlthough archetype BKPyV predominated in most patients, highest proportions and highest numbers of rearranged strains were detected in association with PVAN. TCR mutations seem not necessary for the development of PVAN, but immunosuppression may allow increased viral replication giving rise to TCR variants with enhanced replication efficiency.

Generating hESCs with reduced immunogenicity by disrupting TAP1 or TAPBP.

Human embryonic stem cells (hESCs) are thought to be a promising resource for cell therapy, while it has to face the major problem of graft immunological rejection. Major histocompatibility complex (MHC) class I expressed on the cell surface is the major cause of graft rejection. Transporter associated with antigen presentation 1 (TAP1) and TAP-associated glycoprotein (TAPBP) play important roles in regulating MHC class I expression. In this study, we generated TAP1- and TAPBP-deficient hESC lines, respectively, using transcription activator-like effector nucleases technique. These cells showed deficient expression of MHC class I on the cell surface and reduced immunogenicity compared with wild types, but maintained normal pluripotency, karyotypes, and differentiation ability. Thus, our findings are instrumental in developing a universal cell resource with both pluripotency and hypo-immunogenicity for transplantation therapy in the future.

A new bioinformatics analysis can reveal intestinal infection as a cause of graft rejection in islet xenotransplantation in non-human primate. (TRAN1P.940)

Abstract Pancreatic islet transplantation is one of the most attractive treatment modality for select type 1 diabetes patients suffering from frequent hypoglycemia unawareness. However, because of the shortage of human donor organs, xenotransplantation is becoming more highlighted. Under this circumstance, we have recently achieved reproducible and consistent survivals of adult porcine islet for more than 180 days in the liver of five diabetic monkeys under immunosuppression regimen base on anti-CD154. Interestingly, among five monkeys, one has exhibited graft failure after having experienced severe intestinal infections. Because the porcine islets were exposed to direct blood flow from the intestine, intestinal infection would exert detrimental effect on porcine islets. To test this hypothesis, we performed RNA-seq with peripheral blood from graft maintaining monkey or rejecting monkey after intestinal infections. By using novel bioinformatics tool called Time-series RNA-seq analysis package, we demonstrated highly relevant activated immunologic pathway in graft rejecting monkey, but not in well maintaining monkey. Consistent with this notion, we further confirmed that porcine islets were indeed rejected by CD8+ T cells by immunohistochemistry. Taken together, we for the first time showed that a new bioinformatics analysis using peripheral blood RNA-seq data can pinpoint intestinal infection as a cause of graft rejection in intraportal islet xenotransplantation.

Reactivation of BKV and AdV infections during post-transplant immunosuppressive therapy

Introduction. Viral infections are an important problem in transplantology. Infections in recipients may develop as a result of the original infection or reactivation of a latent infection. Many viruses have the ability to enter into a latent state without symptoms. The most common groups of viruses causing infections in patients after transplantations are herpersviruses, hepatotropic viruses, retroviruses, adenoviruses and poliomaviruses. Objectives. The aim of the presented study is to analyze the incidence of infections caused by BKV and AdV in a group of patients after kidney and bone marrow transplant. Material and methods. The study group consisted of 13 patients after bone marrow transplantation and a group of 10 patients after kidney transplantation. DNA was isolated from urine and serum and analysed with PCR auto-nested reaction. The amplification products were separated in agarose gel. Results. A positive result for AdV was recorded in 7 patients after bone marrow transplant and 5 patients after renal transplant. BK virus was detected in the urine of 13 patients, and in the blood sample of 5 patients. Discussion. Reactivation of a virus during immunosuppression is a frequent cause of graft rejection. In addition, in patients with impaired immune system, mixed infections with various types of viruses are becoming a serious problem. This study confirm that infections with BKV and AdV viruses are a major problem in the field of transplantation. Conclusion. BKV and AdV are common causes of infections affecting patients after renal and bone marrow transplantation. BKV infections are often accompanied by human adenovirus infection. Adenovirus infections are a more common cause of infection in bone marrow transplant patients than in patients after renal transplantation.

Generating Hypoimmunogenic Human Embryonic Stem Cells by the Disruption of Beta 2-Microglobulin

Immune rejection hinders the application of human embryonic stem cells (hESCs) in transplantation therapy. Human leukocyte antigens (HLAs) on the cell surface are the major cause of graft rejection. In this study, we generated HLA class I-deficient hESCs via disruption of beta 2-microglobulin (β2m), the light chain of HLA Class I. We found that HLA class I proteins were not present on the cell surface of β2m-null hESCs. These cells showed the same pluripotency as wildtype hESCs and demonstrated hypoimmunogenicity. Thus, HLA class I-deficient hESCs might serve as an unlimited cell source for the generation of universally compatible "off-the-shelf" cell grafts, tissues or organs in the future.

Flow Cessation Triggers Endothelial Dysfunction During Organ Cold Storage Conditions: Strategies for Pharmacologic Intervention

Vascular pathologies constitute a major cause of graft rejection after organ transplantation. Recent studies have documented an improvement in transplant outcome when organs are preserved through pulsatile perfusion; however, the underlying mechanisms of these observations are poorly characterized. We hypothesized that the temporary absence of flow occurring in the context of organ cold storage conditions disrupts endothelial vasoprotective programs, and that this consequence of stasis may be a target for pharmacological modulation. The expression of the transcription factor Kruppel-like factor 2 (KLF2) and its vasoprotective target genes were assessed during cold storage conditions in cultured human endothelial cells and murine aortic segments. In addition, we evaluated the effect of simvastatin used as a supplement in a cold preservation solution on the expression of vasoprotective genes, and on endothelial activation and apoptosis. The expression of endothelial KLF2 and its vasoprotective transcriptional targets were rapidly lost during cold preservation in vitro and ex vivo. Importantly, simvastatin treatment blocked the decay of KLF2, sustaining a vasoprotective phenotype, and preventing endothelial activation and apoptosis. Flow stasis leads to acute endothelial dysfunction and apoptosis in the context of cold storage conditions. Supplementation of organ preservation solutions with pharmacologic agents that restore endothelial vasoprotective programs, by upregulating KLF2, may represent a significant advancement of current organ preservation techniques.

Impact of Human Cytomegalovirus Infection UL55-Nested Polymerase Chain Reaction Method in Hematopoietic Stem Cell Transplant Donors and Recipients

Human cytomegalovirus (HCMV) is one of the most important and critical viral causes of graft rejection among hematopoietic stem cell transplant (HSCT) recipients. Monitoring of this viral infection has a critical role in the management of HSCT clinical complications. In this retrospective cohort, blood (plasma and buffy coat) and urine samples were collected from 110 HSCT patients and 95 donors pretransplantation and weekly for 100 days posttransplantation. An HCMV-optimized UL55-nested polymerase chain reaction (PCR) method was used to detect HCMV infection. Genotyping of the HCMV UL55 gene was performed for all UL55-nested, PCR-positive samples. HSCT donor and recipient laboratory and clinical data were statistically analyzed using SPSS version 15 software. UL55-nested, PCR-positive results were obtained in 3540/4950 (71.5%), 3634/4950 (73.4%), and 3292/4950 (66.5%) of these plasma, buffy coat, and urine samples, respectively. Twenty-five percent of transplant donors were infected with HCMV. An increase in HCMV infection was observed from pre- to post-HSCT conditions. Detection of the gB2 UL55 genotype in most transplant patient samples suggested the need to examine the possible impact of HCMV UL55 genotypes and HCMV infections among stem cell transplant recipients.

TRUE MYCOTIC ARTERITIS BY CANDIDA ALBICANS IN 2 KIDNEY TRANSPLANT RECIPIENTS FROM THE SAME DONOR

Although the frequency of fungal infections in kidney transplant recipients has decreased in the last 2 decades, candidal infection is still a major nonimmunological cause of graft rejection and transplant nephrectomy. We report on 2 patients with candidal arteritis, which evolved into a “true” mycotic aneurysm in one and an external iliac artery rupture in the other. Both patients received a kidney from the same donor. To our knowledge we report the first cases of candidal arteritis in 2 kidney transplant recipients.

Polyomaviruria in renal transplant patients is not correlated to the cold ischemia period or to rejection episodes.

Polyomaviruria was observed in one-third of all renal transplant patients, irrespective of whether their renal grafts came from a living or cadaver donor, and was not correlated to graft rejection episodes. This suggests that the renal graft ischemia period is not the major cause of polyomavirus reactivation and that reactivation of polyomavirus is not a dominant cause of graft rejection.