Short-term Immunosuppression Research Articles

Low-molecular-weight fucoidan increases telomere length and immunostimulatory effects on NK-92 cells following inhaled anesthetic injury

Inhaled anesthetics, such as isoflurane, may cause side effects, including short-term immunosuppression and DNA damage. In contrast, low molecular weight fucoidan (LMF), derived from brown seaweed, exhibits promising immunomodulatory effects. In this study, we determined the effect of isoflurane on telomeres and examined the potential of LMF to ameliorate the harmful effects of isoflurane. Male Lewis rats, the mouse lymphoma cell line YAC-1, and the human nature killer cell line NK-92 MI were exposed to isoflurane. The relative telomere length (T/S) ratio and mRNA expression were determined by quantitative PCR. The viability assay was used to assess cell viability. In vivo, 2% isoflurane exposure, which is a clinically relevant concentration, reduced telomere length, and correlated with exposure frequency and duration. Isoflurane concentrations above 2% shortened YAC-1 telomeres, with minimal impact on cell viability. LMF pre-treatment enhanced NK-92 MI cell survival resulting from isoflurane exposure and exerted superior telomere protection compared with LMF post-treatment. Furthermore, adding LMF during isoflurane exposure resulted in a significant increase in IFN-γ, TNF-α, and IL-10 mRNA compared with the untreated group. LMF protected against isoflurane-induced telomere shortening, enhanced NK cell viability, and modulated cytokine expression, thus mitigating postoperative immune suppression and risk of tumor metastasis.

The Synergistic Effect of Full-Spectrum Light Therapy and Transient Immunosuppressants Prolonged Allotransplant Survival.

The lifelong administration of immunosuppressants remains the largest drawback in vascularized composite allotransplantation (VCA). Therefore, developing alternative strategies to minimize the long-term use of immunosuppressive agents is crucial. This study investigated whether full-spectrum bright light therapy (FBLT) combined with short-term immunosuppressant therapy could prolong VCA survival in a rodent hindlimb model. Hindlimb allotransplantation was conducted from Brown-Norway to Lewis rats, and the rats were divided into 4 groups. Group 1 did not receive treatment as a rejection control. Group 2 received FBLT alone. Group 3 was treated with short-term antilymphocyte serum (ALS) and cyclosporine A (CsA). Group 4 was administered short-term ALS/CsA combined with FBLT for 8 weeks. Peripheral blood and transplanted tissues were collected for analysis. The results revealed median survival time of FBLT alone (group 2) did not increase allograft survival compared with the control (group 1). However, in group 4, FBLT combined with short-term ALS/CsA, median composite tissue allograft survival time (266 days) was significantly prolonged compared with groups 1 (11 days), 2 (10 days), and 3 (41 days) ( P < 0.01). Group 4 also showed a significant increase in regulatory T cells ( P = 0.04) and transforming growth factor-β1 levels ( P = 0.02), and a trend toward a decrease in interleukin-1β levels ( P = 0.03) at 16 weeks after transplantation as compared with control (group 1). FBLT combined with short-term immunosuppressants prolonged allotransplant survival by modulating T-cell regulatory functions and antiinflammatory cytokine expression. This approach could be a potential strategy to increase VCA survival. Full-spectrum light therapy could be a potential strategy to increase vascularized composite allotransplant survival.

Autologous haematopoietic stem cell transplantation for multiple sclerosis: a position paper and registry outline.

While substantial progress has been made in the development of disease-modifying medications for multiple sclerosis (MS), a high percentage of treated patients still show progression and persistent inflammatory activity. Autologous haematopoietic stem cell transplantation (AHSCT) aims at eliminating a pathogenic immune repertoire through intense short-term immunosuppression that enables subsequent regeneration of a new and healthy immune system to re-establish immune tolerance for a long period of time. A number of mostly open-label, uncontrolled studies conducted over the past 20 years collected about 4000 cases. They uniformly reported high efficacy of AHSCT in controlling MS inflammatory disease activity, more markedly beneficial in relapsing-remitting MS. Immunological studies provided evidence for qualitative immune resetting following AHSCT. These data and improved safety profiles of transplantation procedures spurred interest in using AHSCT as a treatment option for MS. To develop expert consensus recommendations on AHSCT in Germany and outline a registry study project. An open call among MS neurologists as well as among experts in stem cell transplantation in Germany started in December 2021 to join a series of virtual meetings. We provide a consensus-based opinion paper authored by 25 experts on the up-to-date optimal use of AHSCT in managing MS based on the Swiss criteria. Current data indicate that patients who are most likely to benefit from AHSCT have relapsing-remitting MS and are young, ambulatory and have high disease activity. Treatment data with AHSCT will be collected within the German REgistry Cohort of autologous haematopoietic stem CeLl trAnsplantation In MS (RECLAIM). Further clinical trials, including registry-based analyses, are urgently needed to better define the patient characteristics, efficacy and safety profile of AHSCT compared with other high-efficacy therapies and to optimally position it as a treatment option in different MS disease stages.

Clinical application status and prospect of the combined anti-tumor strategy of ablation and immunotherapy.

Image-guided tumor ablation eliminates tumor cells by physical or chemical stimulation, which shows less invasive and more precise in local tumor treatment. Tumor ablation provides a treatment option for medically inoperable patients. Currently, clinical ablation techniques are widely used in clinical practice, including cryoablation, radiofrequency ablation (RFA), and microwave ablation (MWA). Previous clinical studies indicated that ablation treatment activated immune responses besides killing tumor cells directly, such as short-term anti-tumor response, immunosuppression reduction, specific and non-specific immune enhancement, and the reduction or disappearance of distant tumor foci. However, tumor ablation transiently induced immune response. The combination of ablation and immunotherapy is expected to achieve better therapeutic results in clinical application. In this paper, we provided a summary of the principle, clinical application status, and immune effects of tumor ablation technologies for tumor treatment. Moreover, we discussed the clinical application of different combination of ablation techniques with immunotherapy and proposed possible solutions for the challenges encountered by combined therapy. It is hoped to provide a new idea and reference for the clinical application of combinate treatment of tumor ablation and immunotherapy.

Systemic and Intraocular Methotrexate for the Prevention and Treatment of Proliferative Vitreoretinopathy in Children With Rhegmatogenous Retinal Detachment and Underlying Inflammatory Disease.

This index study highlights the efficacy and safety of a combined surgical and medical therapy (with intraocular and systemic methotrexate) of pediatric rhegmatogenous retinal detachments (RRD) complicated by proliferative vitreoretinopathy (PVR). Three pediatric patients with RRD complicated by PVR in the setting of underlying atopic dermatitis and/or uveitis who were treated with a combination of vitreoretinal surgery and intraoperative intravitreal methotrexate (MTX) (40mg) infusion, followed by at least one injection of 200 μg of MTX into the silicone oil-filled vitreous cavity, are reported. In addition, the patients received short-term systemic immunosuppression with systemic (oral or subcutaneous 20 mg weekly MTX for 12 weeks) and/or steroids. Retinal reattachment with improvement in visual acuity was achieved in all eyes following a single surgery and remained to the final follow-up examination after oil removal. There were no observed side effects of intraocular or systemic MTX. The safety and efficacy of this combination therapy suggests that it could be a successful strategy for treating pediatric patients with RRD with or without PVR in the presence or absence of underlying inflammatory diseases.

Effects of transport stress on immune response, physiological state, and WSSV concentration in the red swamp crayfish Procambarus clarkii

Transport is an essential part of the aquaculture and research of the main freshwater aquaculture crayfish Procambarus clarkii in China. However, transport is often accompanied by a low survival rate. Assessing the physiological state of P. clarkii before and after transport may discover the cause of this high mortality rate. In this study, ice-cold and exposed-to-air transport methods were compared using an array of parameters, including relative expression level of heat shock protein 70 (HSP70), content of serum glucose and cortisol, immune parameters (enzyme and immune-related genes), and white spot syndrome virus (WSSV) concentration were investigated to understand the physiological state of P. clarkii before and after transport, as well as the cause of dying crayfish on days 5 and 7 after transport stress. Histological sections of hepatopancreas, gills, and intestines reflected pathological changes. The survival rate of crayfish with ice-cold transport was significantly higher than that with exposed-to-air transport, and mortality peaked at 3–9 days after transport stress. A prolonged response to oxidative stress and short-term immunosuppression was present after transport, and the trend of the WSSV concentration in the hepatopancreas was similar to the mortality rate of P. clarkii. The contents of serum glucose and cortisol, antioxidant enzymes and immune-related indexes, and the concentration of WSSV in hepatopancreas of dying crayfish were significantly higher than those of vibrant crayfish on the 5th and 7th days after transport. The hepatopancreas, intestines, and gills of dying crayfish had varying degrees of damage, and the hepatopancreas and intestines were severely damaged. The results suggested that the death of P. clarkii after transport stress is caused by oxidative stress, the imbalance of reactive oxygen species regulation, and decreased WSSV resistance, which eventually led to irreversible tissue damage. The increase of WSSV in the body of crayfish might be the direct cause of crayfish death.

A ferret model of immunosuppression induced with dexamethasone

Ferrets are nowadays frequently used as animal models for biomedical purposes; in many cases, immunosuppression of experimental animals is necessary. The aim of this study was to evaluate the effect of intramuscular dexamethasone administration (2 mg/kg as the initiation dose continued with 1 mg/kg q 12 h applied 5 times) on ferret’s immune system. In comparison with ferrets which received the saline (n = 5), significantly lower total counts of leukocytes (P < 0.01), lymphocytes (P < 0.01) and monocyte (P < 0.05), as well as absolute numbers of CD4+CD8- (P < 0.01) and CD4-CD8+ (P < 0.01) subsets were noted in dexamethasone treated ferrets (n = 5) the first day after the treatment (D1). Absolute number of CD79+ lymphocytes remained unchanged throughout the experiment. The proliferation activity of lymphocytes in dexamethasone treated ferrets was lower only in D1 using concanavalin A (conA), phytohemagglutinin (PHA) and pokeweed mitogen (PWM); statistical significance was noted using PHA 40 (P < 0.05) and PWM 10 (P < 0.01). Lower neutrophil activity (P < 0.01) was detected in D1 after the dexamethasone treatment in both production of reactive oxygen species (chemiluminescence test) and ingestion of particles (phagocytosis assay). The dexamethasone treatment proved to be useful for short-term immunosuppression in ferrets. The results closely resembled data previously reported in human studies and indicate classification of ferrets as steroid-resistant species.

Prophylactic vaccination with a live-attenuated herpes zoster vaccine in lung transplant candidates

Herpes zoster (HZ) is caused by the reactivation of varicella-zoster virus (VZV). Patients with lung transplants are at high risk for HZ owing to their immunocompromised status and the need for lifelong immunosuppression. In this study, patients on the waiting list for lung transplantation were vaccinated by a live-attenuated HZ vaccine (Zostavax, Merck Sharp & Dohme), and the safety and immunogenicity of this vaccine were studied. In total, 105 patients with end-stage pulmonary disease (ESPD) were enrolled (68 participants received 1 dose of Zostavax and 37 participants were enrolled as unvaccinated controls). Among them, 43 patients underwent lung transplantation and were followed up for further analysis. VZV immunoglobulin G antibody titers and VZV-specific cell-mediated immunity (CMI) on multiple time points before and after vaccination and before and after transplantation were measured. Immune response to Zostavax was higher in younger patients, highest within 3 months after vaccination, and not influenced by gender or type of ESPD. Age, cytomegalovirus serostatus, and immunity to VZV at baseline impacted the subsequent immune response to the vaccine. Short-term immunosuppressant treatment had strong effects on VZV CMI levels, which returned to a high level at 6 months after transplantation in vaccinated patients. Zostavax did not impact infection or rejection rate after transplantation. Zostavax was safe and induced a robust humoral and cellular response for patients awaiting lung transplantation regardless of the type of ESPD. Patients younger than the recommended vaccination age of over 50 years showed a strong response and could also benefit from pre-transplant immunization.

A highly effective and practical desensitization regimen: Results in comparable clinical outcomes for multiple myeloma patients with skin rash after immunomodulatory drugs.

12104 Background: Immunomodulatory drugs (IMiDs) are backbone of myeloma therapy for patients with Multiple Myeloma (MM). The incidence of IMiD-associated rash is up to 27% in some reports impeding maximal benefit of this agent. The optimal management of IMiDs-associated skin is unclear. The concurrent weekly Dexamethasone (Dex) does not diminish the incidence of skin eruptions with IMiDs (Sviggum, et al. 2006), therefore we designed a low dose daily and tapering corticosteroid regimen to tame this immune response upon restarting IMiDs and allow desensitization and reinstitution of the same IMiD. Furthermore, we assessed the impact of this desensitization regimen on clinical outcome. Methods: A total of 160 patients were evaluated. The incidence of rash was found to be 13% (n = 21). A cohort of age- and gender-matched without rash (n = 39) was randomly selected. The effects of rash on overall and progression free survival (OS and PFS) were further estimated using Cox regression controlling the effects of age and gender. Results: Median time to development of rash after IMiD initiation was 28 days (range, 2-232). Rashes were graded as low (I-II) in 89% (n = 17) and high (III-IV) in 19% of pts. All pts were managed by temporary treatment interruption and upon clearance of rash, re-institution of the same IMiD concomitantly with a standardized 3-week steroid rash prophylaxis protocol (prednisone at 10 mg daily for 10 days, followed by 5 mg daily for 10 days, followed by 5 mg on alternate days for 10 days). As a result, all patients were able to restart the same IMiD with none re-experiencing any dermatologic adverse effect afterward. Comparing to no-rash controls, there was no significant difference in PFS (0.13) or OS (p = 0.12) in multivariate regression model. Conclusions: Proposed 3-week corticosteroid regimen showed 100% success rate in reinstituting IMiDs in our cohort. It may provide a highly effective and practical short term immunosuppression required to enable patients to restart IMiDs and enjoy comparable outcome to pts without skin rash.

Transplant chimerism in porcine structural vascularized bone allotransplants

BackgroundBone allotransplant viability can be maintained long-term by implanting arteriovenous (AV) bundles and creating an autogenous neoangiogenic circulation. Only short-term immunosuppression is required. This study investigates the origin of viable osteocytes observed in areas of active bone remodeling in orthotopically transplanted tibiae in a Yucatan mini-pig model. MethodsSegmental tibial defects created in female Yucatan minipigs (N = 14) were reconstructed with a matched vascularized composite allotransplant from a male donor. The circulation was microsurgically restored, with simultaneous autogenous AV-bundle implantation in group 1 (N = 7). A ligated AV-bundle was implanted as a no-angiogenesis control in group 2 (N = 7). After 20-weeks, repopulation of the allotransplant was assessed by real-time qPCR measurement of relative copy numbers of a Y chromosome-specific gene (SRY) and an autosomal housekeeping gene, ribosomal protein L4 (RPL4). A lower SRY/RPL4 ratio demonstrates replacement of male allogeneic cells with female, autogenous cells in the sample. Genomic DNA was extracted from cross-sections of the allotransplant, liver and spleen. Additionally, areas of new bone formation within the allotransplant were sampled by laser capture microdissection. A comparison was made between groups as well as male control samples. RNA was extracted from bone as well, as a measure of metabolically active cells. ResultsLaser-captured areas of new bone formation in animals with both normal and ligated AV-bundles were found to have significantly lower relative copy numbers of SRY (p = 0.03) than control specimens from male bone, indicating replacement by female (autogenous) bone-forming cells. Analysis of an entire segment of the allotransplant from Group 1 was similarly reduced (p = 0.04), unlike that from Group 2. RNA expression of SRY was observed in both groups. No chimerism could be found in non-bone tissues (liver and spleen). ConclusionWe observed a significant level of transplant chimerism in areas of new bone formation sampled by laser capture microdissection. The migration of autogenous cells including osteocytes was seen in both groups. Survival of some allogeneic (male) cells was also demonstrable. No microchimerism was found in liver and spleen.

A Highly Effective and Practical Corticosteroid Regimen to Overcome Skin Rash Associated with Immunomodulatory Drugs Allowing Reinstitution of Therapy

Introduction Immunomodulatory drugs (IMiDs) are backbone of myeloma therapy in induction and maintenance therapy after transplant for patients (pts) with Multiple Myeloma (MM). The incidence of IMiD-associated rash is up to 27% (Nardone, et al, Clinical Lymphoma Myeloma and Leukemia. 2013) and importantly heralds a favorable prognosis (Kojima, et al. Blood. 2016) suggesting more robust immune stimulation by this class of drugs; however, lack of optimal management strategy of this toxicity can deprive large subset of pts from maintenance therapy after transplant and lead to potential detrimental impact on survivals. The concurrent weekly dexamethasone (Dex) does not diminish the incidence of skin eruptions with IMiDs (Sviggum, et al. Archives of dermatology. 2006), therefore we designed a low dose daily and tapering corticosteroid regimen to tame this immune response upon restarting IMiDs and allow desensitization and reinstitution of the same IMiD which may not be achieved by standard weekly Dex. Here, we present our experience with this regimen. Methods In this retrospective study, pts with MM treated with lenalidomide and pomalidomide were reviewed for any IMiD-associated dermatologic toxicity. We followed the same corticosteroid regimen for all IMiD-related rash in our clinic without changing Dex dosing. Result A total of 160 pts were evaluated. The incidence of rash was found to be 13% (n=21). IMiDs were instituted as part of induction regimen in 71% (n=15) and as maintenance therapy after transplant in 29% (n=6) of pts. Median time to development of rash after IMiD initiation was 28 days (range, 2-232). The rashes were characterized as morbilliform in 86% (n=18), urticaria in 9.5% (n=2) and blisters in 5% (n=1) of pts. Pruritis or pain was associated with 86% of rashes (n=15). According to NCI-CTCAE, rashes were graded as low (I-II) in 89% (n=17) and high (III-IV) in 19% of pts. All pts were managed by temporary treatment interruption and upon clearance of rash, re-institution of the same IMiD concomitantly with a standardized 3-week steroid rash prophylaxis protocol (prednisone at 10 mg daily for 10 days, followed by 5 mg daily for 10 days, followed by 5 mg on alternate days for 10 days). As a result, all pts were able to restart the same IMiD either at same (n=5, 24%) or reduced (n=16, 76%) dose with none re-experiencing any dermatologic adverse effect afterward. There was no association between rash development and changes in creatinine clearance (p=0.42). Median eosinophil count at rash development was observed to be significantly higher as compared to eosinophil count at IMiD initiation (380 × 106 vs 130 × 106 respectively, p=0.01). Conclusion The proposed 3-week corticosteroid regimen showed 100% success rate in terms of reinstituting IMiDs, therefore it may provide a highly effective and practical short term immunosuppression required to enable pts to restart IMiDs.

Neo-Angiogenesis, Transplant Viability, and Molecular Analyses of Vascularized Bone Allotransplantation Surgery in a Large Animal Model.

Vascularized composite allotransplantation of bone is a possible alternative treatment for large osseous defects but requires life-long immunosuppression. Surgical induction of autogenous neo-angiogenic circulation maintains transplant viability without this requirement, providing encouraging results in small animal models [1-3]. A preliminary feasibility study in a swine tibia model demonstrated similar findings [4, 5]. This study in swine tibial allotransplantation tests its applicability in a pre-clinical large animal model. Previously, we have demonstrated bone vascularized composite allotransplantation (VCA) survival was not the result of induction of tolerance nor an incompetent immune system [1]. Fourteen tibia vascularized bone allotransplants were microsurgically transplanted orthotopically to reconstruct size-matched tibial defects in Yucatan miniature swine. Two weeks of immunosuppression was used to maintain allotransplant pedicle patency during angiogenesis from a simultaneously implanted autogenous arteriovenous bundle. The implanted arteriovenous bundle was patent in group 1 and ligated in group 2 (a neo-angiogenesis control). At twenty weeks, we quantified the neo-angiogenesis and correlated it with transplant viability, bone remodeling, and gene expression. All patent arteriovenous bundles maintained patency throughout the survival period. Micro-angiographic, osteocyte cell count and bone remodeling parameters were significantly higher than controls due to the formation of a neo-angiogenic autogenous circulation. Analysis of gene expression found maintained osteoblastic and osteoclastic activity as well as a significant increase in expression of endothelial growth factor-like 6 (EGFL-6) in the patent arteriovenous bundle group. Vascularized composite allotransplants of swine tibia maintained viability and actively remodeled over 20 weeks when short-term immunosuppression is combined with simultaneous autogenous neo-angiogenesis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:288-296, 2020.

Outcomes of Vascularized Bone Allotransplantation with Surgically Induced Autogenous Angiogenesis in a Large Animal Model: Bone Healing, Remodeling, and Material Properties.

Bone vascularized composite allotransplantation (VCA) is a possible alternative for the treatment of large bone defects. Clinical application of VCAs is limited by the need for life-long immunosuppression (IS). We report an alternative method to maintain bone allotransplant viability in a large animal model without the need for life-long IS by using autogenous vessel implantation. Fourteen bone only VCAs were transplanted in a porcine tibia defect model with short-term IS. Two groups were used to evaluate the effect of the implantation of an autogenous arteriovenous (AV)-bundle, therefore the only difference between the groups was the patency of the AV-bundle. We radiographically evaluated bone healing and allogenic pedicle patency. AV-bundle patency and union were evaluated with micro-CT. Bone remodeling was assessed with histomorphometry and material properties were evaluated with axial compression testing and cyclic reference point indentation. Two subjects did not reach the final time point. Twelve tibiae healed proximally, and nine at the distal transplant-bone interface. Bone allotransplants showed their viability in the first 4 to 6 weeks by significant periosteal bridging arising from the transplant and maintained pedicle patency. Bone material properties were not affected by the implantation of an AV-bundle when compared with ligated AV-bundle controls, but diminished compared with normal bone. Significantly higher bone formation rates resulted from the implantation of a patent AV-bundle. New periosteal bone formation and subsequent bone healing result from blood flow through the microsurgically repaired nutrient blood supply, demonstrated by maintained allogenic pedicle patency. The implantation of a patent autogenous AV-bundle has no adverse effect on material properties, but a positive effect on bone remodeling of endosteal surfaces despite thrombosis of the allogenic pedicle. Bone material properties change after transplantation compared with normal bone, although 20-weeks survival time is relatively short for the final evaluation of bone material properties.

Survival and functionality of xeno-free human embryonic stem cell-derived retinal pigment epithelial cells on polyester substrate after transplantation in rabbits.

To study immunogenic properties of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) and to evaluate subretinal xenotransplantation of hESC-RPE on porous polyethylene terephthalate (PET) in rabbits. Human ESC-RPE cells were characterized by morphology, transepithelial electrical resistance (TER), protein expression and photoreceptor outer segment phagocytosis invitro. Expression of major histocompatibility complex (MHC) proteins was assessed in conventionally or xeno-free produced hESC-RPE±interferon-gamma (IFN-γ) stimulation (n=1). Xeno-free hESC-RPE on PET with TER<200Ω·cm2 >or PET alone were transplanted into 18 rabbits with short-term triamcinolone±extended tacrolimus immunosuppression. Rabbits were monitored by spectral domain optical coherence tomography. After 4weeks, the eyes were processed for histology and transmission electron microscopy. Upon invitro IFN-γ stimulation, xeno-free hESC-RPE expressed lower level of MHC-II proteins compared to the conventional cells. Outer nuclear layer (ONL) atrophy was observed over the graft in most cases 4weeks post-transplantation. In 3/4 animals with high TER hESC-RPE, but only in 1/3 animals with low TER hESC-RPE, ONL atrophy was observed already within 1week. Retinal cell infiltrations were more frequent in animals with high TER hESC-RPE. However, the difference was not statistically significant. In three animals, preservation of ONL was observed. Weekly intravitreal tacrolimus did not affect ONL preservation. In all animals, hESC-RPE cells survived for 4weeks, but without tacrolimus, enlarged vacuoles accumulated in hESC-RPE (n=1). Xenografted xeno-free hESC-RPE monolayers can survive and retain some functionality for 4weeks following short-term immunosuppression. The preliminary findings of this study suggest that further investigations to improve transplantation success of hESC-RPE xenografts in rabbits should be addressed especially toward the roles of hESC-RPE maturation stage and extended intravitreal immunosuppression.

Allograft and patient survival after sequential HSCT and kidney transplantation from the same donor-A multicenter analysis.

Tolerance induction through simultaneous hematopoietic stem cell and renal transplantation has shown promising results, but it is hampered by the toxicity of preconditioning therapies and graft‐versus‐host disease (GVHD). Moreover, renal function has never been compared to conventionally transplanted patients, thus, whether donor‐specific tolerance results in improved outcomes remains unanswered. We collected follow‐up data of published cases of renal transplantations after hematopoietic stem cell transplantation from the same donor and compared patient and transplant kidney survival as well as function with caliper‐matched living‐donor renal transplantations from the Austrian dialysis and transplant registry. Overall, 22 tolerant and 20 control patients were included (median observation period 10 years [range 11 months to 26 years]). In the tolerant group, no renal allograft loss was reported, whereas 3 were lost in the control group. Median creatinine levels were 85 μmol/l (interquartile range [IQR] 72‐99) in the tolerant cohort and 118 μmol/l (IQR 99‐143) in the control group. Mixed linear‐model showed around 29% lower average creatinine levels throughout follow‐up in the tolerant group (P < .01). Our data clearly show stable renal graft function without long‐term immunosuppression for many years, suggesting permanent donor‐specific tolerance. Thus sequential transplantation might be an alternative approach for future studies targeting tolerance induction in renal allograft recipients.

Vascular Delivery of Allogeneic MuStem Cells in Dystrophic Dogs Requires Only Short-Term Immunosuppression to Avoid Host Immunity and Generate Clinical/Tissue Benefits

Growing demonstrations of regenerative potential for some stem cells led recently to promising therapeutic proposals for neuromuscular diseases. We have shown that allogeneic MuStem cell transplantation into Golden Retriever muscular dystrophy (GRMD) dogs under continuous immunosuppression (IS) leads to persistent clinical stabilization and muscle repair. However, long-term IS in medical practice is associated with adverse effects raising safety concerns. Here, we investigate whether the IS removal or its restriction to the transplantation period could be considered. Dogs aged 4–5 months old received vascular infusions of allogeneic MuStem cells without IS (GRMDMU/no-IS) or under transient IS (GRMDMU/tr-IS). At 5 months post-infusion, persisting clinical status improvement of the GRMDMU/tr-IS dogs was observed while GRMDMU/no-IS dogs exhibited no benefit. Histologically, only 9-month-old GRMDMU/tr-IS dogs showed an increased muscle regenerative activity. A mixed cell reaction with the host peripheral blood mononucleated cells (PBMCs) and corresponding donor cells revealed undetectable to weak lymphocyte proliferation in GRMDMU/tr-IS dogs compared with a significant proliferation in GRMDMU/no-IS dogs. Importantly, any dog group showed neither cellular nor humoral anti-dystrophin responses. Our results show that transient IS is necessary and sufficient to sustain allogeneic MuStem cell transplantation benefits and prevent host immunity. These findings provide useful critical insight to designing therapeutic strategies.

Subcutaneous administration of a neutralizing IL-1β antibody prolongs limb allograft survival.

Cytokine‐expression profiles revealed IL‐1ß highly upregulated in rejecting skin of limb allografts. We investigate the effect of intragraft treatment with a neutralizing IL‐1β antibody in limb transplantation. Following allogenic hind‐limb transplantation, Lewis rats were either left untreated1 or treated with anti‐lymphocyte serum + tacrolimus (baseline)2; baseline immunosuppression + anti‐IL‐1β (1 mg/kg once/week, 6‐8 subcutaneous injections) into the transplanted3 or contralateral4 limb. Endpoint was rejection grade III or day 100. Graft rejection was assessed by histology, immunohistochemistry, flow cytometry phenotyping of immune cells, and monitoring cytokine expression. Anti‐IL‐1β injections into the allograft or contralateral limb resulted in a significant delay of rejection onset (controls: 58.60 ± 0.60; group 3: 75.80 ± 10.87, P = .044; group 4: 73.00 ± 6.49, P = .008) and prolongation of graft survival (controls: 64.60 ± 0.87; group 3: 86.60 ± 5.33, P = .002; group 4: 93.20 ± 3.82, P = .002), compared to controls. Although the phenotype of the graft infiltrating immune cells did not differ between groups, significantly decreased skin protein levels of IL‐1β, IL‐4, IL‐13, IP‐10, MCP‐1, and MCP‐3 in long‐term‐survivors indicate an overall decrease of chemoattraction and infiltration of immune cells as the immunosuppressive mechanism of anti‐IL‐1β. Inhibition of IL‐1β with short‐term systemic immunosuppression prolongs limb allograft survival and represents a promising target for immunosuppression in extremity transplantation.

Evaluation of Safe Systemic Immunosuppression Created with Dexamethasone in Prevention of Capsular Contracture: A Glance to Distinct Perspectives with Toll-Like Receptors.

The toll-like receptors (TLRs) stand at the interface of innate immune activation. We hypothesize to decrease the response of innate immunity activated by TLR4 by a safe, short-term, systemic immunosuppression. Two silicone block implants were placed into two dorsal subcutaneous pockets in 32 rats that were subdivided into four groups: The two study groups were the IV DEX group (single intravenous injection of dexamethasone 1h before surgery) and the IV DEX + IP DEX group (in addition to a single intravenous injection of dexamethasone 1h before surgery, intraperitoneal dexamethasone was administered for 10days after surgery), and the two control groups were the untreated control group and the saline-treated control group. After 10weeks, all animals were killed to determine capsular thickness, inflammatory cell density, presence of pseudoepitheliomatous hyperplasia, edema, necrosis, vascularization, TLR4 expression and myofibroblast proliferation. No significant difference was observed in any parameter between the untreated and saline-treated control groups (p > 0.05). Capsular thickness, myofibroblast proliferation, TLR4 expression density were statistically different amongstudy groupscompared to control (p < 0.05). This study demonstrates the relationship between toll-like receptors and fibrous capsule after implant surgery. Decreasing the innate immunity by a safe, short-term perioperative systemic immunosuppression resulted in decreased TLR4 expression and myofibroblast differentiation which could be a new research field in profibrotic pathophysiology underlying breast capsule formation. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Cladribine to Treat Relapsing Forms of Multiple Sclerosis.

Cladribine is a purine nucleoside analogue that selectively depletes peripheral lymphocytes without a major impact on cells of the innate immune system. An oral formulation of cladribine has been developed to be given as short courses over two annual cycles. Oral cladribine results in the peripheral depletion of lymphocytes that is gradual, occurring over several weeks, and is not associated with a cell lysis syndrome, has a greater impact on B cells than T cells, and is followed by gradual reconstitution of the peripheral lymphocyte counts over several months. Oral cladribine is effective in relapsing forms of multiple sclerosis. As a selective immune reconstitution therapy (SIRT), cladribine acts as a short-term immunosuppressant, relative to other maintenance immunosuppressive therapies that result in long-term immunosuppression. The main safety signal that has emerge relates primarily to herpes zoster infection, which was more common in patients with higher grades of lymphopenia, in particular grade 3 and 4 lymphopenia. Data from the oral cladribine extension trial and safety register, and reanalysis of the pivotal phase III trial has indicated that oral cladribine is unlikely to be associated with an increased short- to intermediate-term risk of malignancy.

Surgical Angiogenesis in Porcine Tibial Allotransplantation: A New Large Animal Bone Vascularized Composite Allotransplantation Model.

Segmental bone loss resulting from trauma, infection malignancy and congenital anomaly remains a major reconstructive challenge. Current therapeutic options have significant risk of failure and substantial morbidity. Use of bone vascularized composite allotransplantation (VCA) would offer both a close match of resected bone size and shape and the healing and remodeling potential of living bone. At present, life-long drug immunosuppression (IS) is required. Organ toxicity, opportunistic infection and neoplasm risks are of concern to treat such non-lethal indications. We have previously demonstrated that bone and joint VCA viability may be maintained in rats and rabbits without the need of long-term-immunosuppression by implantation of recipient derived vessels within the VCA. It generates an autogenous, neoangiogenic circulation with measurable flow and active bone remodeling, requiring only 2 weeks of IS. As small animals differ from man substantially in anatomy, bone physiology and immunology, we have developed a porcine bone VCA model to evaluate this technique before clinical application is undertaken. Miniature swine are currently widely used for allotransplantation research, given their immunologic, anatomic, physiologic and size similarities to man. Here, we describe a new porcine orthotopic tibial bone VCA model to test the role of autogenous surgical angiogenesis to maintain VCA viability. The model reconstructs segmental tibial bone defects using size- and shape-matched allogeneic tibial bone segments, transplanted across a major swine leukocyte antigen (SLA) mismatch in Yucatan miniature swine. Nutrient vessel repair and implantation of recipient derived autogenous vessels into the medullary canal of allogeneic tibial bone segments is performed in combination with simultaneous short-term IS. This permits a neoangiogenic autogenous circulation to develop from the implanted tissue, maintaining flow through the allogeneic nutrient vessels for a short time. Once established, the new autogenous circulation maintains bone viability following cessation of drug therapy and subsequent nutrient vessel thrombosis.