The Effects of Interferons on Allogeneic T Cell Response in GVHD: The Multifaced Biology and Epigenetic Regulations

Type 2 hypersensitivity disorders, including systemic lupus erythematosus, Sjögren's syndrome, Graves' disease, myasthenia gravis, immune thrombocytopenia, autoimmune hemolytic anemia, dermatomyositis, and graft-versus-host disease, are THαβ-dominant autoimmune diseases

The THαβ host immunological pathway contributes to the response to infectious particles (viruses and prions). Furthermore, there is increasing evidence for associations between autoimmune diseases, and particularly type 2 hypersensitivity disorders, and the THαβ immune response. For example, patients with systemic lupus erythematosus often produce anti-double stranded DNA antibodies and anti-nuclear antibodies and show elevated levels of type 1 interferons, type 3 interferons, interleukin-10, IgG1, and IgA1 throughout the disease course. These cytokines and antibody isotypes are associated with the THαβ host immunological pathway. Similarly, the type 2 hypersensitivity disorders myasthenia gravis, Graves' disease, graft-versus-host disease, autoimmune hemolytic anemia, immune thrombocytopenia, dermatomyositis, and Sjögren's syndrome have also been linked to the THαβ pathway. Considering the potential associations between these diseases and dysregulated THαβ immune responses, therapeutic strategies such as anti-interleukin-10 or anti-interferon α/β could be explored for effective management.

Multi-omics analysis reveals a feedback loop amplifying immune responses in acute graft-versus-host disease due to imbalanced gut microbiota and bile acid metabolism

Acute graft-versus-host disease (aGVHD) is primarily driven by allogeneic donor T cells associated with an altered composition of the host gut microbiome and its metabolites. The severity of aGVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is not solely determined by the host and donor characteristics; however, the underlying mechanisms remain unclear. Using single-cell RNA sequencing, we decoded the immune cell atlas of 12 patients who underwent allo-HSCT: six with aGVHD and six with non-aGVHD. We performed a fecal microbiota (16SrRNA sequencing) analysis to investigate the fecal bacterial composition of 82 patients: 30 with aGVHD and 52 with non-aGVHD. Fecal samples from these patients were analyzed for bile acid metabolism. Through multi-omic analysis, we identified a feedback loop involving "immune cell-gut microbes-bile acid metabolites" contributing to heightened immune responses in patients with aGVHD. The dysbiosis of the gut microbiota and disruption of bile acid metabolism contributed to an exaggerated interleukin-1 mediated immune response. Our findings suggest that resistin and defensins are crucial in mitigating against aGVHD. Therefore, a comprehensive multi-omic atlas incorporating immune cells, gut microbes, and bile acid metabolites was developed in this study and used to propose novel, non-immunosuppressive approaches to prevent aGVHD.

Tetramerization of pyruvate kinase M2 attenuates graft-versus-host disease by inhibition of Th1 and Th17 differentiation

Lethal graft-versus-host disease (GVHD) is the major complication of allogeneic hematopoietic stem-cell transplantation (Allo-HSCT). Pyruvate kinase M2 (PKM2) is essential for CD4+ T-cell differentiation. Using the well-characterized mouse models of Allo-HSCT, we explored the effects of TEPP-46-induced PKM2 tetramerization on GVHD and graft-versus-leukemia (GVL) activity. TEPP-46 administration significantly improved the survival rate of GVHD. The severity of GVHD and histopathological damage of GVHD-targeted organs were obviously alleviated by PKM2 tetramerization. Additionally, tetramerized PKM2 inhibited the activation of NF-κB pathway and decreased the inflammation level of GVHD mice. PKM2 tetramerization blocked Th1 and Th17 cell differentiation and secretion of pro-inflammatory cytokine (IFN-γ, TNF-α, and IL-17). Meanwhile, differentiation of Treg cells and IL-10 secretion were promoted by tetramerized PKM2. These findings demonstrated that PKM2 enhanced the augment of Th1 and Th17 cells to accelerate the progression of GVHD, and allosteric activation of PKM2 targeted Th1 and Th17 cells attenuated GVHD. Furthermore, we also confirmed that TEPP-46 administration did not compromise GVL activity and resulted in slightly improvement of leukemia-free survive. Thus, targeting Th1 and Th17 cell response with PKM2 allosteric activator may be a promising therapeutic strategy for GVHD prevention while preserving the GVL activity in patients receiving Allo-HSCT.

The graft versus leukemia effect: donor lymphocyte infusions and cellular therapy

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for many hematologic malignancies as well as non-malignant conditions. Part of the curative basis underlying HSCT for hematologic malignancies relies upon induction of the graft versus leukemia (GVL) effect in which donor immune cells recognize and eliminate residual malignant cells within the recipient, thereby maintaining remission. GVL is a clinically evident phenomenon; however, specific cell types responsible for inducing this effect and molecular mechanisms involved remain largely undefined. One of the best examples of GVL is observed after donor lymphocyte infusions (DLI), an established therapy for relapsed disease or incipient/anticipated relapse. DLI involves infusion of peripheral blood lymphocytes from the original HSCT donor into the recipient. Sustained remission can be observed in 20-80% of patients treated with DLI depending upon the underlying disease and the intrinsic burden of targeted cells. In this review, we will discuss current knowledge about mechanisms of GVL after DLI, experimental strategies for augmenting GVL by manipulation of DLI (e.g. neoantigen vaccination, specific cell type selection/depletion) and research outlook for improving DLI and cellular immunotherapies for hematologic malignancies through better molecular definition of the GVL effect.

How can Cytokine-induced killer cells overcome CAR-T cell limits

The successful treatment of patients affected by B-cell malignancies with Chimeric Antigen Receptor (CAR)-T cells represented a breakthrough in the field of adoptive cell therapy (ACT). However, CAR-T therapy is not an option for every patient, and several needs remain unmet. In particular, the production of CAR-T cells is expensive, labor-intensive and logistically challenging; additionally, the toxicities deriving from CAR-T cells infusion, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), have been documented extensively. Alternative cellular therapy products such as Cytokine-induced killer (CIK) cells have the potential to overcome some of these obstacles. CIK cells are a heterogeneous population of polyclonal CD3+CD56+ T cells with phenotypic and functional properties of NK cells. CIK cell cytotoxicity is exerted in a major histocompatibility complex (MHC)-unrestricted manner through the engagement of natural killer group 2 member D (NKG2D) molecules, against a wide range of hematological and solid tumors without the need for prior antigen exposure or priming. The foremost potential of CIK cells lies in the very limited ability to induce graft-versus-host disease (GvHD) reactions in the allogeneic setting. CIK cells are produced with a simple and extremely efficient expansion protocol, which leads to a massive expansion of effector cells and requires a lower financial commitment compared to CAR-T cells. Indeed, CAR-T manufacturing involves the engineering with expensive GMP-grade viral vectors in centralized manufacturing facilities, whereas CIK cell production is successfully performed in local academic GMP facilities, and CIK cell treatment is now licensed in many countries. Moreover, the toxicities observed for CAR-T cells are not present in CIK cell-treated patients, thus further reducing the costs associated with hospitalization and post-infusion monitoring of patients, and ultimately encouraging the delivery of cell therapies in the outpatient setting. This review aims to give an overview of the limitations of CAR-T cell therapy and outline how the use of CIK cells could overcome such drawbacks thanks to their unique features. We highlight the undeniable advantages of using CIK cells as a therapeutic product, underlying the opportunity for further research on the topic.

CARs: a new approach for the treatment of autoimmune diseases

The development of chimeric antigen receptor (CAR)-based therapeutic interventions represented a breakthrough in cancer treatment. Following the success of the CAR-T-cell strategy, this novel therapeutic approach has been applied to other diseases, including autoimmune diseases. Using CAR-T cells to deplete pathological immune cells (i.e., B cells, autoreactive B or T cells, and accessory antigen-presenting cells (APCs)) has resulted in favorable outcomes in diseases characterized by excessive autoantibody levels or hyperactive lymphocyte cell numbers. The importance of immunosuppressive regulatory T cells (Tregs) in restoring immune tolerance has been well established, and CAR-Tregs have shown promising therapeutic potential in treating autoimmune diseases. Moreover, prior experience from the cancer field has provided sufficient paradigms for understanding how to optimize the structure and function of CARs to improve their function, persistence, stability and safety. In this review, we describe the potential application of CAR-T cells and CAR-Tregs in the treatment of autoimmune diseases, and we summarize the currently available strategies of gene editing and synthetic biological tools that have improved the practical application of CAR-based therapies.

Graft-versus-Host Disease Modulation by Innate T Cells

Allogeneic cell therapies, defined by genetically mismatched transplantation, have the potential to become a cost-effective solution for cell-based cancer immunotherapy. However, this type of therapy is often accompanied by the development of graft-versus-host disease (GvHD), induced by the mismatched major histocompatibility complex (MHC) between healthy donors and recipients, leading to severe complications and death. To address this issue and increase the potential for allogeneic cell therapies in clinical practice, minimizing GvHD is a crucial challenge. Innate T cells, encompassing subsets of T lymphocytes including mucosal-associated invariant T (MAIT) cells, invariant natural killer T (iNKT) cells, and gamma delta T (γδ T) cells, offer a promising solution. These cells express MHC-independent T-cell receptors (TCRs), allowing them to avoid MHC recognition and thus GvHD. This review examines the biology of these three innate T-cell populations, evaluates research on their roles in GvHD modulation and allogeneic stem cell transplantation (allo HSCT), and explores the potential futures for these therapies.