Current Immunosuppressive Strategies Research Articles

Anti-CD19 CAR-T cells are effective in severe idiopathic Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome (LEMS) is an autoantibody-mediated disease of the neuromuscular junction characterized by muscular weakness. Autoantibodies to presynaptic P/Q-type voltage-gated calcium channels (VGCCs) induce defective neuromuscular function. In severe cases, current immunosuppressive and immunomodulatory treatment strategies are often insufficient. First reports show beneficial effects of anti-CD19 chimeric antigen receptor (CAR)-T cell therapy in patients with autoantibody-mediated myasthenia gravis. We report a patient with isolated idiopathic LEMS treated with autologous anti-CD19-CAR-T cells. In this patient, CAR-T infusion leads to expansion of predominantly CD4+ CAR-T cells with a terminally differentiated effector memory cells re-expressing CD45RA (TEMRA)-like phenotype indicating cytotoxic capabilities and subsequent B cell depletion. VGCC antibody titers decrease, resulting in a clinical improvement of LEMS symptoms, e.g., 8-fold increase in walking distance. The patient does not show relevant side effects except for cytokine release syndrome grade 2 and intermittent neutropenia suggesting that anti-CD19 CAR-T cell therapy may be a treatment option in patients with LEMS.

Comparative Ability of Various Immunosuppressants as Adjuvants on the Activity of T1D Vaccine

Background: Type 1 diabetes (T1D) is an autoimmune disorder characterised by the destruction of insulin-producing beta cells in the pancreatic islets, resulting from a breakdown in immunological tolerance. Currently, T1D treatment primarily relies on insulin replacement or immunosuppressive therapies. However, these approaches often have significant drawbacks, including adverse effects, high costs, and limited long-term efficacy. Consequently, there is a pressing need for innovative immunotherapeutic strategies capable of inducing antigen-specific tolerance and protecting beta cells from autoimmune destruction. Among the various antigens, β-cell antigens like 65 kDa glutamic acid decarboxylase (GAD65) have been explored as vaccine candidates for T1D. Despite their potential, their effectiveness in humans remains modest, necessitating the use of appropriate adjuvants to enhance the vaccine’s protective effects. Methods: In this study, we evaluated the therapeutic potential of kynurenine (KYN), dexamethasone (DXMS), tacrolimus (FK506), and aluminium hydroxide (Alum) in combination with the GAD65 phage vaccine as adjuvants. Results: Our findings demonstrate that KYN, when used in conjunction with the GAD65 vaccine, significantly enhances the vaccine’s immunosuppressive effects. Compared to dexamethasone, FK506, and Alum adjuvants, KYN more effectively reduced the incidence and delayed the onset of T1D, preserved β-cell function, and promoted the induction of regulatory T cells and antigen-specific tolerance. These results suggest that KYN combined with vaccines could offer superior preventive and therapeutic benefits for T1D compared to existing treatments. Additionally, we investigated the dose-dependent effects of the GAD65 vaccine by including a low-dose group in our study. The results indicated that reducing the vaccine dose below 1010 plaque-forming units (pfu) did not confer any protective advantage or therapeutic benefit in combination with KYN. This finding underscores that 1010 pfu is the minimum effective dose for the GAD65 vaccine in achieving a protective response. In conclusion, KYN shows considerable promise as an adjuvant for the GAD65 vaccine in T1D therapy, potentially offering a more effective and durable treatment option than current immunosuppressive strategies.

Elucidating immune cell dynamics in chronic lung allograft dysfunction: A comprehensive single-cell transcriptomic study

Chronic Lung Allograft Dysfunction (CLAD) is a critical post-transplant complication that predominantly determines the long-term survival rates and quality of life of patients undergoing lung transplantation. The limited efficacy of current immunosuppressive strategies underscores our incomplete understanding of the immunological aspects of CLAD. Hence, there is an urgent need for more comprehensive and targeted research to unravel the complex interplay of immune cells in the development and progression of CLAD. This study conducts an in-depth analysis of the immune environment in CLAD. By examining the gene expression profiles of T cells, natural killer cells, B cells, macrophages, and monocytes, we have elucidated a unique immunological landscape in CLAD compared to healthy controls. We highlight the heterogeneity within the immune populations and provide a comprehensive understanding of the immune mechanisms driving CLAD. Enrichment analysis identified specific pathways that are either overactive or suppressed in CLAD, revealing potential molecular targets for therapeutic intervention. Our findings emphasize the crucial role of T cells in the pathophysiology of CLAD, coordinating the immune response and revealing an amplified immune cell network, potentially leading to maladaptive tissue responses. By integrating a comprehensive cellular and molecular portrait of the immune environment, our research not only deepens our understanding of the pathogenesis of CLAD but also lays a foundational approach for the development of targeted therapies.

Ferroptosis contributes to multiple sclerosis and its pharmacological targeting suppresses experimental disease progression

Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by central nervous (CNS) demyelination resulting in axonal injury and neurological deficits. Essentially, MS is driven by an auto-amplifying mechanism of inflammation and cell death. Current therapies mainly focus on disease modification by immunosuppression, while no treatment specifically focuses on controlling cell death injury. Here, we report that ferroptosis, an iron-catalyzed mode of regulated cell death (RCD), contributes to MS disease progression. Active and chronic MS lesions and cerebrospinal fluid (CSF) of MS patients revealed several signs of ferroptosis, reflected by the presence of elevated levels of (labile) iron, peroxidized phospholipids and lipid degradation products. Treatment with our candidate lead ferroptosis inhibitor, UAMC-3203, strongly delays relapse and ameliorates disease progression in a preclinical model of relapsing-remitting MS. In conclusion, the results identify ferroptosis as a detrimental and targetable factor in MS. These findings create novel treatment options for MS patients, along with current immunosuppressive strategies.

Risks and ways of preventing kidney dysfunction in drug-induced immunosuppression in solid organ recipients

Immunosuppressive therapy (IMT) is the cornerstone of treatment after transplantation. The goal of immunosuppression is to prevent acute and chronic rejection while maximizing patient survival and long-term graft function. However, the expected effects of IMT must be balanced against the major adverse effects of these drugs and their toxicity. The purpose of this review is to summarize world experience on current immunosuppressive strategies and to assess their effects on renal function.

Donor Macrophages Modulate Rejection After Heart Transplantation.

Cellular rejection after heart transplantation imparts significant morbidity and mortality. Current immunosuppressive strategies are imperfect, target recipient T cells, and have adverse effects. The innate immune response plays an essential role in the recruitment and activation of T cells. Targeting the donor innate immune response would represent the earliest interventional opportunity within the immune response cascade. There is limited knowledge about donor immune cell types and functions in the setting of cardiac transplantation, and no current therapeutics exist for targeting these cell populations. Using genetic lineage tracing, cell ablation, and conditional gene deletion, we examined donor mononuclear phagocyte diversity and macrophage function during acute cellular rejection of transplanted hearts in mice. We performed single-cell RNA sequencing on donor and recipient macrophages and monocytes at multiple time points after transplantation. On the basis of our imaging and single-cell RNA sequencing data, we evaluated the functional relevance of donor CCR2+ (C-C chemokine receptor 2) and CCR2- macrophages using selective cell ablation strategies in donor grafts before transplant. Last, we performed functional validation that donor macrophages signal through MYD88 (myeloid differentiation primary response protein 88) to facilitate cellular rejection. Donor macrophages persisted in the rejecting transplanted heart and coexisted with recipient monocyte-derived macrophages. Single-cell RNA sequencing identified donor CCR2+ and CCR2- macrophage populations and revealed remarkable diversity among recipient monocytes, macrophages, and dendritic cells. Temporal analysis demonstrated that donor CCR2+ and CCR2- macrophages were transcriptionally distinct, underwent significant morphologic changes, and displayed unique activation signatures after transplantation. Although selective depletion of donor CCR2- macrophages reduced allograft survival, depletion of donor CCR2+ macrophages prolonged allograft survival. Pathway analysis revealed that donor CCR2+ macrophages are activated through MYD88/nuclear factor kappa light chain enhancer of activated B cells signaling. Deletion of MYD88 in donor macrophages resulted in reduced antigen-presenting cell recruitment, reduced ability of antigen-presenting cells to present antigen to T cells, decreased emergence of allograft-reactive T cells, and extended allograft survival. Distinct populations of donor and recipient macrophages coexist within the transplanted heart. Donor CCR2+ macrophages are key mediators of allograft rejection, and deletion of MYD88 signaling in donor macrophages is sufficient to suppress rejection and extend allograft survival. This highlights the therapeutic potential of donor heart-based interventions.

Immunosuppressive calcineurin inhibitor cyclosporine A induces proapoptotic endoplasmic reticulum stress in renal tubular cells

Current immunosuppressive strategies in organ transplantation rely on calcineurin inhibitors cyclosporine A (CsA) or tacrolimus (Tac). Both drugs are nephrotoxic, but CsA has been associated with greater renal damage than Tac. CsA inhibits calcineurin by forming complexes with cyclophilins, whose chaperone function is essential for proteostasis. We hypothesized that stronger toxicity of CsA may be related to suppression of cyclophilins with ensuing endoplasmic reticulum (ER) stress and unfolded protein response (UPR) in kidney epithelia. Effects of CsA and Tac (10 µM for 6 h each) were compared in cultured human embryonic kidney 293 (HEK 293) cells, primary human renal proximal tubule (PT) cells, freshly isolated rat PTs, and knockout HEK 293 cell lines lacking the critical ER stress sensors, protein kinase RNA–like ER kinase or activating transcription factor 6 (ATF6). UPR was evaluated by detection of its key components. Compared with Tac treatment, CsA induced significantly stronger UPR in native cultured cells and isolated PTs. Evaluation of proapoptotic and antiapoptotic markers suggested an enhanced apoptotic rate in CsA-treated cells compared with Tac-treated cells as well. Similar to CsA treatment, knockdown of cyclophilin A or B by siRNA caused proapoptotic UPR, whereas application of the chemical chaperones tauroursodeoxycholic acid or 4-phenylbutyric acid alleviated CsA-induced UPR. Deletion of protein kinase RNA–like ER kinase or ATF6 blunted CsA-induced UPR as well. In summary, inhibition of cyclophilin chaperone function with ensuing ER stress and proapoptotic UPR aggravates CsA toxicity, whereas pharmacological modulation of UPR bears potential to alleviate renal side effects of CsA.

Assessment and Comparison of the Efficacy of Methotrexate, Prednisolone, Adalimumab, and Tocilizumab on Multipotency of Mesenchymal Stem Cells.

Mesenchymal stem cell (MSC)–based articular regeneration might be beneficial for both protecting and rebuilding cartilaginous tissues in the management of rheumatoid arthritis. However, it is unclear how current immunosuppressive strategies influence the multipotency of MSCs. The present study was undertaken to profile the direct effectiveness of major antirheumatic drugs including methotrexate, prednisolone, adalimumab, and tocilizumab on the multipotency of MSCs, with a special focus on chondrogenesis. The inhibitory effects of methotrexate on adipogenesis, osteogenesis, and chondrogenesis were observed to occur in a dose-dependent manner in an in vitro differentiation system. Prednisolone enhanced adipogenesis, but reduced alkaline phosphatase activity in osteoprogenitors and suppressed the formation of chondrospheroids. Adalimumab suppressed alkaline phosphatase activity, while tocilizumab diminished osteogenesis and chondrogenesis of MSCs in vitro. Chondrogenesis of antirheumatic drug-treated MSCs was also evaluated in vivo using a scaffolded spheroid-engrafted murine model. The biologics examined appeared to be relatively safe for cartilaginous formation, but methotrexate and prednisolone exhibited opposing influences on chondrogenesis. Taken together, these results reveal the direct efficacy of major antirheumatic agents on the multipotency of MSCs. Therefore, our findings suggest that optimization of medication protocols is further required for therapeutic approaches involving cartilaginous tissue engineering.

Current Practice in Immunosuppression in Pediatric Liver Transplantation.

The last decades have witnessed a significant improvement in the field of pediatric liver transplantation (LT), resulting in longer patient and graft survival; adequate graft selection, surgical refinement, the use of live donors and optimal postoperative care are among the reasons why pediatric recipients are living longer. With this new condition, pediatric recipients are now more exposed to the deleterious effects of immunosuppression, including metabolic, infectious and neoplastic complications, nephrotoxicity and neurotoxicity. Due to all those particularities, the approach to avoid overimmunosuppression or underimmunosuppression may be more difficult in children than in adult recipients. Moreover, pediatric recipients are exposed to growth issues and specific problems during adolescence, like nonadherence to immunosuppressive therapy. This article highlights the current immunosuppressive strategies for pediatric liver transplant recipients.

CCR4 expression on host T cells is a driver for alloreactive responses and lung rejection.

Despite current immunosuppressive strategies, long-term lung transplant outcomes remain poor due to rapid allogenic responses. Using a stringent mouse model of allo-airway transplantation, we identify the CCR4-ligand axis as a central node driving secondary lymphoid tissue homing and activation of the allogeneic T cells that prevent long-term allograft survival. CCR4 deficiency on transplant recipient T cells diminishes allograft injury and when combined with CTLA4-Ig leads to an unprecedented long-term lung allograft accommodation. Thus, we identify CCR4-ligand interactions as a central mechanism driving allogeneic transplant rejection and suggest it as a potential target to enhance long-term lung transplant survival.

Microbiota and Graft-versus Host disease: a double-edged sword.

Microbiota and Graft-versus Host disease: a double-edged sword.

T Follicular Regulatory Cells and Antibody Responses in Transplantation.

De novo donor-specific antibody (DSA) formation is a major problem in transplantation, and associated with long-term graft decline and loss as well as sensitization, limiting future transplant options. Forming high-affinity, long-lived antibody responses involves a process called the germinal center (GC) reaction, and requires interaction between several cell types, including GC B cells, T follicular helper (Tfh) and T follicular regulatory (Tfr) cells. T follicular regulatory cells are an essential component of the GC reaction, limiting its size and reducing nonspecific or self-reactive responses.An imbalance between helper function and regulatory function can lead to excessive antibody production. High proportions of Tfh cells have been associated with DSA formation in transplantation; therefore, Tfr cells are likely to play an important role in limiting DSA production. Understanding the signals that govern Tfr cell development and the balance between helper and regulatory function within the GC is key to understanding how these cells might be manipulated to reduce the risk of DSA development.This review discusses the development and function of Tfr cells and their relevance to transplantation. In particular how current and future immunosuppressive strategies might allow us to skew the ratio between Tfr and Tfh cells to increase or decrease the risk of de novo DSA formation.

TAK1 inhibition ameliorates survival from graft-versus-host disease in an allogeneic murine marrow transplantation model.

Acute graft-versus-host disease(GVHD) isa major cause of morbidity and mortality in allogeneic hematopoietic cell transplantation (allo-HCT). Majority of the current immunosuppressive strategies targeting donor T cells to prevent or treat acute GVHD are only partially effective, and often require escalated immunosuppressive therapy. Recent studies have revealed that activation of antigen-presenting cells in the proinflammatory milieu is important for the priming and promotion of GVHD. This activation is mediated by innate immune signaling pathways, which therefore potentially represent new targets in addressing GVHD. Using gene expression analysis of peripheral monocytes from patients' post-allo-HCT, we detected an upregulation of TGF-β-activated kinase 1 (TAK1), a key regulator of the toll-like receptor signaling pathway. 5Z-7-oxozeaenol, a selective inhibitor of TAK1, reduced proinflammatory cytokine production by activated monocytes under lipopolysaccharide stimulation and T cell proliferation in allogeneic-mixed leukocyte reactions with monocyte-derived dendritic cells. In an experimental mouse model of GVHD, 5Z-7-oxozeaenol administration after allo-HCT ameliorated GVHD severity and mortality, with significant reduction in serum TNFα, IL-1β, and IL-12 levels. Our findings suggest that altering the activation status of innate immune cells by TAK1 inhibition may be a novel therapeutic approach for acute GVHD.

Trasplante cardiaco y soporte circulatorio mecánico para pacientes con insuficiencia cardiaca avanzada

Patients with advanced heart failure have a poor prognosis and heart transplant is still the best treatment option. However, the scarcity of donors, long waiting times, and an increasing number of unstable patients have favored the development of mechanical circulatory support. This review summarizes the indications for heart transplant, candidate evaluation, current immunosuppression strategies, the evaluation and treatment of rejection, infectious prophylaxis, and short and long-term outcomes. Regarding mechanical circulatory support, we distinguish between short- and long-term support and the distinct strategies that can be used: bridge to decision, recovery, candidacy, transplant, and destination therapy. We then discuss indications, risk assessment, management of complications, especially with long-term support, and outcomes. Finally, we discuss future challenges and how the widespread use of long-term support for patients with advanced heart failure will only be viable if their complications and costs are reduced.Full English text available from:www.revespcardiol.org/en

Heart Transplant and Mechanical Circulatory Support in Patients With Advanced Heart Failure

Patients with advanced heart failure have a poor prognosis and heart transplant is still the best treatment option. However, the scarcity of donors, long waiting times, and an increasing number of unstable patients have favored the development of mechanical circulatory support. This review summarizes the indications for heart transplant, candidate evaluation, current immunosuppression strategies, the evaluation and treatment of rejection, infectious prophylaxis, and short and long-term outcomes. Regarding mechanical circulatory support, we distinguish between short- and long-term support and the distinct strategies that can be used: bridge to decision, recovery, candidacy, transplant, and destination therapy. We then discuss indications, risk assessment, management of complications, especially with long-term support, and outcomes. Finally, we discuss future challenges and how the widespread use of long-term support for patients with advanced heart failure will only be viable if their complications and costs are reduced.

Chimeric Allografts Induced by Short-Term Treatment With Stem Cell Mobilizing Agents Result in Long-Term Kidney Transplant Survival Without Immunosuppression: II, Study in Miniature Swine.

Transplantation is now lifesaving therapy for patients with end-stage organ failure but requires lifelong immunosuppression with resultant morbidity. Current immunosuppressive strategies inhibit T cell activation and prevent donor-recipient engagement. Therefore, it is not surprising that few host cells are demonstrated in donor grafts. However, our recent small animal studies found large numbers of recipient stem cells present after transplantation and pharmacological mobilization, resulting in a chimeric, repopulated organ. We now confirm these findings in a well-characterized large animal preclinical model. Here, we show that AMD3100 and FK506 mobilization of endogenous stem cells immediately post kidney transplantation combined with repeat therapy at 1, 2, and 3 months led to drug-free long-term survival in maximally immunologically mismatched swine. Three long-term recipients have stable chimeric transplants, preserved antidonor skin graft responses, and normal serum creatinine levels despite withdrawal of all medication for 3 years.

Biologic agents in the treatment of glomerulonephritides.

Current immunosuppression strategies in the treatment of glomerulonephritides remain unsatisfactory, especially in glomerular diseases that are frequently relapsing or are resistant to treatment. Toxicities associated with the use of drugs with non-specific targets for the immune response result in treatment non-compliance, and increase morbidity and mortality in these patients. Advances in our understanding of the immunopathogenesis of glomerulonephritis and the availability of biologics have led to their successful use in the treatment of immune-mediated glomerular diseases. Biologics are usually very large complex molecules, often produced using recombinant DNA technology and manufactured in a living system such as a microorganism, or plant or animal cells. They are novel agents that can target specific immune cell types, cytokines or immune pathways involved in the pathogenesis of these disorders. It is attractive to consider that, given their specific mode of action, these agents can potentially offer a more directed and effective immunosuppression, with side-effect profiles that are much more desirable. However, there have been few randomized controlled trials comparing biologic agents to conventional immunosuppression, and in many of these studies the side-effect profiles have been disappointingly similar. In this review, we will examine the rationale, efficacy and safety of some commonly used biologics in the treatment of primary and secondary glomerulonephritides. We will also discuss some of the key challenges that may be encountered with the use of biologics in treating glomerulonephritis in the future.

Experimental models of cardiac transplantation: design determines relevance.

Experimental models have contributed enormously to basic immunology. However, the use of reductionist experiments has produced results that are not always successfully translated into the clinic. Recently, incorporation of more realistic clinical parameters in experimental designs has produced new insights relevant to cardiac transplantation. Experiments in mice have provided crucial insights into the concept that T cell responses to pathogens generate memory cells with cross-reactive specificities for histocompatibility antigens. These memory T cells are resistant to current immunosuppressive strategies. Memory T cells infiltrate grafts within hours after transplantation, and grafts subjected to clinically relevant periods of cold ischemia are more susceptible to injury by this cellular infiltrate. Early immune responses now can be investigated with improved 'humanized' mice. Mice with multiple knock-in genes for human cytokines support development of human monocytes, macrophages and natural killer cells in increased numbers and with better function. Better and more clinically relevant experimental designs are providing animal models tailored to address clinic exigencies.

Costimulation-adhesion blockade is superior to cyclosporine A and prednisone immunosuppressive therapy for preventing rejection of differentiated human embryonic stem cells following transplantation.

Human embryonic stem cell (hESC) derivatives are attractive candidates for therapeutic use. The engraftment and survival of hESC derivatives as xenografts or allografts require effective immunosuppression to prevent immune cell infiltration and graft destruction. To test the hypothesis that a short-course, dual-agent regimen of two costimulation-adhesion blockade agents can induce better engraftment of hESC derivatives compared to current immunosuppressive agents. We transduced hESCs with a double fusion reporter gene construct expressing firefly luciferase (Fluc) and enhanced green fluorescent protein, and differentiated these cells to endothelial cells (hESC-ECs). Reporter gene expression enabled longitudinal assessment of cell engraftment by bioluminescence imaging. Costimulation-adhesion therapy resulted in superior hESC-EC and mouse EC engraftment compared to cyclosporine therapy in a hind limb model. Costimulation-adhesion therapy also promoted robust hESC-EC and hESC-derived cardiomyocyte survival in an ischemic myocardial injury model. Improved hESC-EC engraftment had a cardioprotective effect after myocardial injury, as assessed by magnetic resonance imaging. Mechanistically, costimulation-adhesion therapy is associated with systemic and intragraft upregulation of T-cell immunoglobulin and mucin domain 3 (TIM3) and a reduced proinflammatory cytokine profile. Costimulation-adhesion therapy is a superior alternative to current clinical immunosuppressive strategies for preventing the post-transplant rejection of hESC derivatives. By extending the window for cellular engraftment, costimulation-adhesion therapy enhances functional preservation following ischemic injury. This regimen may function through a TIM3-dependent mechanism.

Identification of clinical predictors of flare in systemic lupus erythematosus patients: a 24-month prospective cohort study

SLE has a relapsing-remitting course with disease activity flares over time. This study aims to identify clinical predictors of SLE flares. This prospective cohort study over 24 months included all SLE patients on follow-up at one academic lupus clinic. Flare was defined as an increase in SLEDAI-2K score ≥4 points. Baseline clinical and demographic parameters were compared using survival analysis for time-to-flare outcome with univariate log-rank tests. Variables with significant differences were further evaluated as predictors with multivariate Cox regression models adjusting for potential confounding or contributing factors and hazard ratio (HR) calculation. A total of 202 SLE patients were included. Over the follow-up period, 1083 visits were documented and 16.8% of patients presented with flares. In multivariate analysis, the following parameters emerged as flare predictors: SLE diagnosis up to 25 years of age (HR = 2.14, P = 0.03), lupus nephritis previous to baseline visit (HR = 4.78, P < 0.0001) and immunosuppressor treatment for severe SLE (HR = 3.22, P < 0.001). Baseline disease activity, disease duration and treatment with prednisone or HCQ were not predictive factors. Patients with an SLE diagnosis before age 25 years, lupus nephritis or immunosuppressor treatment for severe SLE present greater HRs for flares, suggesting the need for tighter clinical monitoring. Current immunosuppressive strategies seem to be inefficient in providing flare prevention.