Altered balance between Th1 and Th17 cells in circulation is an indicator for the severity of murine acute GVHD

B Lymphocyte Chemoattractant (CXCL13) Is an Indicator of Acute Gastrointestinal GVHD in Murine Model

Gastrointestinal acute graft-vs.-host disease (GI aGVHD) remains a significant obstacle to the success of allogeneic hematopoietic cell transplantation and is a major cause of morbidity and mortality. In addition, GI aGVHD is often clinically indistinguishable from other causes of GI dysfunction such as conditioning regimen toxicity, infections, or medications, which complicates the diagnosis. Thus, specific biomarkers are needed to help improve diagnosis and obtain a deeper understanding of the cytokine changes in GI aGVHD. An MHC-mismatched model of aGVHD was established by transplanting 1 × 10⁷ bone marrow nuclear cells and 3 × 10⁷ spleen cells from C57/Bl6 mice or from BALB/c mice into lethally irradiated BALB/c recipients. The mice in the allogeneic transplantation group were intraperitoneally treated with 20 mg kg^-1 day^-1 cyclosporin A after aGVHD developed. Five micrograms of lipopolysaccharide were administered intraperitoneally daily to syngeneic recipients at day 11 to imitate infection; the same volume of phosphate-buffered saline was administered to control mice. The mice were killed at the indicated time points. Forty molecules derived from the GI tract were screened cytokine array. The data demonstrated that the expression of B lymphocyte chemoattractant (CXCL13) was increased by ~10-, 12-, and 16-fold upon the occurrence of aGVHD compared with infection, aGVHD after treatment, and the syngeneic control group, respectively. Thus, the elevation of BLC (CXCL13) is an indicator of acute GI GVHD.

Phase 1 clinical trial evaluating abatacept in patients with steroid-refractory chronic graft-versus-host disease

Costimulatory blockade using abatacept represents a novel therapeutic approach for the treatment of cGVHD. Abatacept resulted in a clinical response in 44% of patients with both decreased prednisone use and T-cell PD-1 expression in responders.

Plasma vascular non-inflammatory molecule 3 is associated with gastrointestinal acute graft-versus-host disease in mice

Background

Gastrointestinal acute graft-versus-host disease (GI aGVHD) is a lethal complication following allogeneic hematopoietic stem cell transplantation (HSCT). However, it is still very difficult to make a diagnosis of GI aGVHD in practice. To date, no consensus plasma biomarker of GI aGVHD can be used to help make a diagnosis. Here, we attempted to identify GI aGVHD associated plasma proteins in murine model, which can help make a diagnosis of GI aGVHD.

Methods

We used 8-plex isobaric tags for relative and absolute quantitation (8-plex iTRAQ) to screen out proteins in plasma samples taken from murine models before and after allogeneic HSCT. Next mRNA expressions were validated by quantitative real-time polymerase chain reaction in mouse intestinal epithelial samples.

Results

We found that five proteins were increased at least 2-fold in the allogeneic group at day 7 compared with days 0, 3 and 15 (after Cyclosporin A treatment) and the syngeneic group at day 7. These 5 proteins were VNN3, ZNF746, C4BP, KNG1 and FETUB, and they were consistent with results from negative labeling with 8-plex iTRAQ. Furthermore, increase in mRNA level of VNN3 was confirmed in murine intestinal epithelial samples with aGVHD.

Conclusions

Our results demonstrate that plasma VNN3 protein is associated with GI aGVHD in murine model.

Electronic supplementary material

The online version of this article (10.1186/s12950-017-0178-z) contains supplementary material, which is available to authorized users.

The P2X7 receptor antagonist Brilliant Blue G reduces serum human interferon-γ in a humanized mouse model of graft-versus-host disease

Graft-versus-host disease (GVHD) remains a major problem after allogeneic haematopoietic stem cell transplantation, a curative therapy for haematological malignancies. Previous studies have demonstrated a role for the adenosine triphosphate (ATP)-gated P2X7 receptor channel in allogeneic mouse models of GVHD. In this study, injection of human peripheral blood mononuclear cells (PBMCs) into immunodeficient non-obese diabetic-severe combined immunodeficiency-interleukin (NOD-SCID-IL)-2Rγ^null (NSG) mice established a humanized mouse model of GVHD. This model was used to study the effect of P2X7 blockade in this disease. From five weeks post-PBMC injection, humanized mice exhibited clinical signs and histopathology characteristic of GVHD. The P2X7 antagonist, Brilliant Blue G (BBG), blocked ATP-induced cation uptake into both murine and human cells in vitro. Injection of BBG (50 mg/kg) into NSG mice did not affect engraftment of human leucocytes (predominantly T cells), or the clinical score and survival of mice. In contrast, BBG injection reduced circulating human interferon (IFN)-γ significantly, which was produced by human CD4⁺ and CD8⁺ T cells. BBG also reduced human T cell infiltration and apoptosis in target organs of GVHD. In conclusion, the P2X7 antagonist BBG reduced circulating IFN-γ in a humanized mouse model of GVHD supporting a potential role for P2X7 to alter the pathology of this disease in humans.

IL-22 promoted CD3+ T cell infiltration by IL-22R induced STAT3 phosphorylation in murine acute graft versus host disease target organs after allogeneic bone marrow transplantation

Graft versus host disease (GVHD) is a life threatening complication of bone marrow stem cell transplantation, in which considerable numbers of proinflammatory cytokines secreted by allo-reactive donor T cells are involved. We and other previous studies have found that interleukin-22 (IL-22) was able to aggravate the target organs damage of GVHD. However, the mechanism and the signal pathway of IL-22 in murine acute GVHD was not clear. Here, we observed that compared with GVHD group, more serious pathological damage and more CD3(+) T cells infiltrated in GVHD target organs were detected in the mice injected with IL-22. Meanwhile, transcription factor T-bet, RORγt and AhR respectively associated with Th1, Th17 and Th22 cells changed in varying degrees in different GVHD target organs. Furthermore, the increased expression of IL-22R and its downstream protein P-STAT3 were detected in GVHD mice with IL-22 treated. These results suggested that the pathological role of IL-22 in GVHD target organs contribute to exogenous injected IL-22 as well as secreted IL-22 from the infiltrated allo-reactive effector T cells. In addition, the IL-22R-STAT3 pathway may play important role in GVHD tissue injury and target this way may yield new approaches for reduction of GVHD.

High expression of heme oxygenase-1 in target organs may attenuate acute graft-versus-host disease through regulation of immune balance of TH17/Treg

The high incidence of acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Grades III and IV aGVHD are the leading causes of death in allo-HSCT recipients. Heme oxygenase-1(HO-1) has anti-inflammatory and immune-regulatory functions. In this study, we evaluated the none GVHD and grade I-IV patients samples which were collected at the first re-examination after successful allo-HSCT, we found that expressions of HO-1 mRNA in the bone marrow and peripheral blood mononuclear cells of allo-HSCT recipients who had subsequent non-GVHD and grade I aGVHD were significantly higher than those in patients with Grade III-IV aGVHD. We then demonstrated that enhanced expression of HO-1 in target organs by infusing HO-1-gene-modified Mesenchymal stem cells (MSCs) alleviated the clinical and histopathological severity of aGVHD in experimental mice. Flow cytometry revealed a higher expression of Treg cells and a lower expression of TH17 cells in splenic and lymph node tissues of mice with enhanced HO-1 expression, as compared to that in the aGVHD mice. This was further substantiated by lower expression levels of ROR-Υt and IL-17A mRNA, and higher levels of Foxp3 mRNA in the splenic tissue of mice with enhanced HO-1 expression. Our results indicate that high expression of HO-1 may reduce the severity of aGVHD by regulation of the TH17/Treg balance.

Cellular and molecular mechanisms in graft-versus-host disease

Graft-versus-host disease is a complication in patients undergoing hematopoietic stem cell transplantation. Graft-versus-host disease includes acute graft-versus-host disease and chronic graft-versus-host disease. Host APCs (e.g., dendritic cells and macrophages), effector T cells (e.g., Th1, Th17, and abnormal Th17:regulatory T cell ratio), B cells, and NK cells are implicated in graft-versus-host disease physiopathology. Proinflammation cytokines (e.g., IL-17, IL-1β, and TNF-α) are increased in graft-versus-host disease . Costimulatory molecules play an important role in inducing graft-versus-host disease . Pattern-recognition receptors, such as TLRs and nucleotide-binding oligomerization domain-like receptors, are critically involved in the pathogenesis of graft-versus-host disease . Complement system C3 mediates Th1/Th17 polarization in human T cell activation and skin graft-versus-host disease. Accumulation of CD26 T cells in graft-versus-host disease target organs was found. As a therapeutic target, soluble CD83 molecules or antibodies have been demonstrated to have therapeutic effects against graft-versus-host disease, and signaling molecules promote the inflammatory and immune process of graft-versus-host disease . These immune cells and molecules could be the predictors of graft-versus-host disease development and the drug targets of the treatments for graft-versus-host disease. This article focuses on major advances on cellular and molecular mechanisms in graft-versus-host disease.

Dynamic regulation of effector IFN-γ-producing and IL-17-producing T cell subsets in the development of acute graft-versus-host disease

Graft-versus-host disease (GVHD) as the predominant complication of allogeneic hematopoietic stem cell transplantation remains to be fully understood. It is known that the cytokines produced by allogeneic reactive effector CD4+ and CD8+ T cells are involved in GVHD. However, the regulation and coordination of IFN-γ-producing and IL-17-producing effector T cells remain unclear. The present study aimed to investigate the dynamic changes of alloantigen-specific effector CD4+ T and CD8+ T cell subsets by flow cytometry, which produce inflammatory cytokines involved in the multistep GVHD pathogenesis progress. The results demonstrated that IL-17-producing CD8+ T (Tc17) cells and IFN-γ+CD8+ T (Tc1) cells were detected in the early stage of GVHD. The differentiation of CD4+ T cells into Th1 cell (IFN-γ+CD4+ T) and Th17 (IL-17+CD4+ T) cells was later than that of the Tc1 and Tc17 cells. The effector CD4+ T and CD8+ T cell subsets either became exhausted or became memory cells, exhibiting a CD62L-CD44+ phenotype following marked expansion during GVHD. Furthermore, T cell-associated type I (IL-2 and IFN-γ) and type II (IL-4 and IL-10) classical cytokines exhibited coordinated dynamic regulation. It was concluded that the differentiation of cytokine-producing Tc1 and Tc17 cells may be the key step in the initiation of GVHD, whereas CD4+ effector Th1 and Th17 cells are considered to be pathophysiological factors leading to the continuous aggravation of GVHD.

Interleukin-22 aggravates murine acute graft-versus-host disease by expanding effector T cell and reducing regulatory T cell

Graft-versus-host disease (GVHD) as a major complication after allogeneic hematopoietic stem cell transplantation is not well prevented now. We have observed that interleukin-22 (IL-22) produced by Th22, Th1, and Th17 cells participated in GVHD development in our previous study. However, the role of IL-22 in GVHD is still ambiguous. The aim of this study was to illuminate the pathological or protective function and the potential mechanism of IL-22 in the GVHD process. In the present study, we found that compared with mice cotransferred with bone marrow and spleen cells (BS mice) without IL-22 administration, more serious tissue damage and higher GVHD clinical score were observed in BS+IL-22 mice. IL-22 administration was a benefit to early recovery of thymus after irradiation-induced injury. Administration of IL-22 could promote Th1 and Tc1 cell expansion in mesenteric lymph nodes but reduce CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cell number. Levels of systemic inflammatory cytokines (IFN-γ and TNF-α) were upregulated, while the level of immunosuppressive cytokine IL-10 was downregulated in recipients with IL-22 injection. In conclusion, IL-22, which exacerbates both local immune responses and systemic inflammation of recipients, plays a pathogenic role in the GVHD process. The potential mechanism of IL-22 in GVHD may attribute to increased alloreactive effector Th1 and Tc1 cells and decreased inhibitory Treg cell.

Current data on IL-17 and Th17 cells and implications for graft versus host disease

Human interleukin 17 was first described in 1995 as a new cytokine produced primarily by activated T CD4+ cells that stimulate the secretion of IL-6 and IL-8 by human fibroblasts, besides increasing the expression of ICAM-1. Various authors have reported that IL-17A has a role in the protection of organisms against extracellular bacteria and fungi due to the capacity of IL-17A to recruit neutrophils to the areas of infection, evidencing a pathological role in various models of autoimmune diseases, such as experimental autoimmune encephalitis and arthritis. The participation of IL-17A has also been described in the acute rejection of organ transplants and graft versus host disease. However, the greatest revolution in research with IL-17 happened in 2000, when it was proposed that IL-17 cannot be classified as Th1 or Th2, but rather, simply as a new lineage of IL-17-producing T-cells. These findings modified the previously established Th1/Th2 paradigm, leading to the definition of the CD3+ CD4+ Th17 cellular subtype and establishment of a new model to explain the origin of various immune events, as well as its implication in the graft versus host disease that is discussed in depth in this article.

The identification and characteristics of IL-22-producing T cells in acute graft-versus-host disease following allogeneic bone marrow transplantation

Graft-versus-host disease (GVHD) remains the major obstacle for allogeneic bone marrow transplantation, in which many proinflammatory cytokines secreted by alloreactive donor T cells are involved. Role of IL-22 as a member of IL-10 family in GVHD is still disputed and the properties of IL-22-producing cells are unclear. We demonstrated here that CD4⁺ T cells but not CD8⁺ T cells involved in GVHD were the main cellular source of donor-derived IL-22. Th1 and Th17 cells were detected not only express classical cytokine IFN-γ or IL-17, but also contributed to IL-22 secretion in GVHD. Th22 cells characterized by the independent secretion of IL-22 were identified and occupied almost half percentage of IL-22-producing CD4⁺ T cells. The frequency of IL-22-producing CD4⁺ T cells showed dynamic changes with the development of GVHD. Finally, we observed that IL-22-producing CD4⁺ T cells in GVHD mouse carried CD62L⁻CD44(high/low) surface markers. In conclusion, we illuminate the characteristics of donor-derived IL-22-producing CD4⁺ T cells, which may have potent implication for further study of pathogenesis of GVHD.

Combination cell therapy using mesenchymal stem cells and regulatory T-cells provides a synergistic immunomodulatory effect associated with reciprocal regulation of TH1/TH2 and th17/treg cells in a murine acute graft-versus-host disease model

Mesenchymal stem cells (MSCs) have been considered to be an ideal cellular source for graft-versus-host disease (GVHD) treatment due to their unique properties, including tissue repair and major histocompatibility complex (MHC)-unmatched immunosuppression. However, preclinical and clinical data have suggested that the immunomodulatory activity of MSCs is not as effective as previously expected. This study was performed to investigate whether the immunomodulatory capacity of MSCs could be enhanced by combination infusion of regulatory T (Treg) cells to prevent acute GVHD (aGVHD) following MHC-mismatched bone marrow transplantation (BMT). For GVHD induction, lethally irradiated BALB/c (H-2(d)) mice were transplanted with bone marrow cells (BMCs) and spleen cells of C57BL/6 (H-2(b)) mice. Recipients were injected with cultured recipient-derived MSCs, Treg cells, or MSCs plus Treg cells (BMT + day 0, 4). Systemic infusion of MSCs plus Treg cells improved clinicopathological manifestations and survival in the aGVHD model. Culture of MSCs plus Treg cells increased the population of Foxp3(+) Treg cells and suppressed alloreactive T-cell proliferation in vitro. These therapeutic effects were associated with more rapid expansion of donor-type CD4(+)CD25(+)Foxp3(+) Treg cells and CD4(+)IL-4(+) type 2 T-helper (Th2) cells in the early posttransplant period. Furthermore, MSCs plus Treg cells regulated CD4(+)IL-17(+) Th17 cells, as well as CD4(+)IFN-γ(+) Th1 cells. These data suggest that the combination therapy with MSCs plus Treg cells may have cooperative effects in enhancing the immunomodulatory activity of MSCs and Treg cells in aGVHD. This may lead to development of new therapeutic approaches to clinical allogeneic hematopoietic cell transplantation.

The potential use of mesenchymal stem cells in hematopoietic stem cell transplantation

In the last 10 years, mesenchymal stem cells (MSCs) have emerged as a therapeutic approach to regenerative medicine, cancer, autoimmune diseases, and many more due to their potential to differentiate into various tissues, to repair damaged tissues and organs, and also for their immunomodulatory properties. Findings in vitro and in vivo have demonstrated immune regulatory function of MSCs and have facilitated their application in clinical trials, such as those of autoimmune diseases and chronic inflammatory diseases. There has been an increasing interest in the role of MSCs in allogeneic hematopoietic stem cell transplantation (HSCT), including hematopoietic stem cell engraftment and the prevention and treatment of graft-versus-host disease (GVHD), and their therapeutic potential has been reported in numerous clinical trials. Although the safety of clinical application of MSCs is established, further modifications to improve their efficacy are required. In this review, we summarize advances in the potential use of MSCs in HSCT. In addition, we discuss their use in clinical trials of the treatment of GVHD following HSCT, the immunomodulatory capacity of MSCs, and their regenerative and therapeutic potential in the field of HSCT.