• belumosudil
• cGVHD
• chronic graft-versus-host-disease
• ibrutinib
• oral cGVHD
• oral chronic graft-versus-host-disease
• ruxolitinib

• Graft vs Host Disease/diagnosis
• Graft vs Host Disease/etiology
• Graft vs Host Disease/therapy
• Humans
• Hematopoietic Stem Cell Transplantation/adverse effects
• Chronic Disease
• Mouth Diseases/etiology
• Mouth Diseases/therapy
• Mouth Diseases/diagnosis
• Transplantation, Homologous

• T cell
• infection
• malignancy
• organ transplantation
• posttransplant complications
• rejection

• Basic and Applied Basic Research Foundation of Guangdong Province
• National Natural Science Foundation of China

• T lymphocyte
• graft-versus-host disease
• graft-versus-leukemia
• hematopoietic stem cell transplantation
• memory T cells
• virus-specific T cells

• graft-versus-host disease
• medical dermatology
• transplantation

• Humans
• Bronchiolitis Obliterans Syndrome
• Graft vs Host Disease/diagnosis
• Graft vs Host Disease/epidemiology
• Graft vs Host Disease/etiology
• Quality of Life
• Hematopoietic Stem Cell Transplantation/adverse effects
• Hematopoietic Stem Cell Transplantation/methods
• Skin/pathology
• Chronic Disease

• ZIA AR041227 Intramural NIH HHS

• Humans
• Consensus
• Precision Medicine
• Graft vs Host Disease/therapy
• Graft vs Host Disease/drug therapy
• Bronchiolitis Obliterans Syndrome
• Biology

• P01 AI056299 NIAID NIH HHS
• R37 AI034495 NIAID NIH HHS
• R01 HL155114 NHLBI NIH HHS
• R01 HL056067 NHLBI NIH HHS
• R01 CA168814 NCI NIH HHS
• P01 HL158505 NHLBI NIH HHS

• T cell infiltrate
• allogeneic hematopoietic stem cell transplantation
• chip cytometry
• gastrointestinal biopsies
• graft-versus-host disease
• microbiome
• multimodal immune cell phenotyping
• multiplexed tissue imaging
• single-cell RNA sequencing

• Allogeneic hematopoietic stem cell transplantation
• Chronic graft-versus-host disease
• IL-12
• IL-39

• CCR7
• CTLA-4
• CXCR3
• GVHD
• GVL
• ICOS
• Itk
• PD-1
• SLP76pTYR
• Tregs
• canonical Tregs
• noncanonical Tregs

• Animals
• Disease Models, Animal
• Enzyme-Linked Immunosorbent Assay/methods
• Enzyme-Linked Immunosorbent Assay/statistics & numerical data
• Erythrocytes/metabolism
• Interleukin-2/metabolism
• Interleukin-2/pharmacology
• Mice
• Mice, Inbred C57BL/genetics
• Mice, Inbred C57BL/metabolism
• Signal Transduction/drug effects
• T-Lymphocytes, Regulatory/drug effects
• T-Lymphocytes, Regulatory/physiology

• L32 MD010106 NIMHD NIH HHS
• K22 AI130182 NIAID NIH HHS
• Howard Hughes Medical Institute
• R35 ES028244 NIEHS NIH HHS
• R01 AI120701 NIAID NIH HHS
• R35 GM138097 NIGMS NIH HHS
• R21 AI129422 NIAID NIH HHS
• 1146249-1-075632 Upstate Medical University Cancer center
• R01 AI138570 NIAID NIH HHS
• T32 HL007775 NHLBI NIH HHS

• Tregs
• aGVHD

Acute graft-versus-host disease (aGVHD) remains a significant and severe complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Due to the occurrence of aGVHD, allo-HSCT significantly increases the mortality rate compared with autologous hematopoietic stem cell transplantation (auto-HSCT). In this study, auto-HSCT and allo-HSCT aGVHD mouse models were built to detect the difference in CD4⁺ lymphocyte in different tissues based on ribonucleic acid sequencing (RNA-Seq) analysis. Clustering analysis, functional annotation, and pathway enrichment analysis were performed on differentially expressed genes (DEGs). The protein-protein interaction (PPI) network was used to find hub genes. CD4⁺T cells were activated by MLR and cytokine stimulation. Cells were sorted out by a flow cell sorter. The selected genes were verified by qRT-PCR, histology, and immunofluorescence staining. The GSE126518 GEO dataset was used to verify the hub genes. Enrichment analysis revealed four immune-related pathways that play an important role in aGVHD, including immunoregulatory interactions between a lymphoid and a nonlymphoid cell, chemokine receptors binding chemokines, cytokine and cytokine receptor interaction, and the chemokine signaling pathway. At the same time, with the PPI network, 11 novel hub genes that were most likely to participate in immunoregulation in aGVHD were identified, which were further validated by qRT-PCR and the GSE126518 dataset. Besides, the protein expression level of Cxcl7 was consistent with the sequencing results. In summary, this study revealed that immunoregulation-related DEGs and pathways played a vital role in the onset of aGVHD. These findings may provide some new clues for probing the pathogenesis and treatment of aGVHD.

Chronic graft-versus-host disease (cGVHD) is one of the most common reasons of late non-relapse morbidity and mortality of patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT). While acute GVHD is considered driven by a pathogenic T cell dominant mechanism, the pathogenesis of cGVHD is much complicated and involves participation of a variety of immune cells other than pathogenic T cells. Existing studies have revealed that antigen presenting cells (APCs) play crucial roles in the pathophysiology of cGVHD. APCs could not only present auto- and alloantigens to prime and activate pathogenic T cells, but also directly mediate the pathogenesis of cGVHD via multiple mechanisms including infiltration into tissues/organs, production of inflammatory cytokines as well as auto- and alloantibodies. The studies of this field have led to several therapies targeting different APCs with promising results. This review will focus on the important roles of APCs and their contributions in the pathophysiology of cGVHD after allo-HSCT.

• allogeneic hematopoietic stem cell transplantation
• antigen presenting cells
• chronic graft versus host disease
• immune regulation
• immune tolerance

• Immune tolerance
• Immunotherapy
• Inflammation
• Microbiota
• Treg

• Carbapenems
• Febrile neutropenia
• Gut microbiome
• Piperacillin-tazobactam

• Complication
• Donor response
• GvHD
• Immunosuppression
• Multiorgan disease

• Allogeneic hematopoietic stem cell transplantation
• acute graft-vs-host disease
• adoptive Treg therapy
• chronic graft-vs-host disease
• interleukin-2
• regulatory T cell

Accumulating evidence suggests that a reduction in the number of Foxp3⁺ regulatory T cells (Tregs) contributes to the pathogenesis of acute graft-versus-host disease (aGVHD), which is a major adverse complication that can occur after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the precise features and mechanism underlying the defects in Tregs remain largely unknown. In this study, we demonstrated that Tregs were more dramatically decreased in bone marrow compared with those in peripheral blood from aGVHD patients and that bone marrow Treg defects were negatively associated with hematopoietic reconstitution. Tregs from aGVHD patients exhibited multiple defects, including the instability of Foxp3 expression, especially in response to IL-12, impaired suppressor function, decreased migratory capacity, and increased apoptosis. Transcriptional profiling revealed the downregulation of Lkb1, a previously identified critical regulator of murine Treg identity and metabolism, and murine Lkb1-regulated genes in Tregs from aGVHD patients. Foxp3 expression in human Tregs could be decreased and increased by the knockdown and overexpression of the Lkb1 gene, respectively. Furthermore, a loss-of-function assay in an aGVHD murine model confirmed that Lkb1 deficiency could impair Tregs and aggravate disease severity. These findings reveal that Lkb1 downregulation contributes to multiple defects in Tregs in human aGVHD and highlight the Lkb1-related pathways that could serve as therapeutic targets that may potentially be manipulated to mitigate aGVHD.

• Lkb1
• Treg
• acute graft-versus-host disease (aGVHD)
• allogeneic hematopoietic stem cell transplantation (allo-HSCT)

• IL-2
• graft-versus-host disease
• immunotherapy
• rapamycin
• treg cells

• Animals
• Autoimmune Diseases/immunology
• Autoimmune Diseases/therapy
• Disease Models, Animal
• Graft vs Host Disease/immunology
• Graft vs Host Disease/therapy
• Humans
• Immunotherapy, Adoptive/methods
• Lymphocyte Activation/immunology
• Lymphocyte Transfusion/methods
• T-Lymphocytes, Regulatory/immunology
• T-Lymphocytes, Regulatory/transplantation

• P30 CA008748 NCI NIH HHS
• R01 AI034206 NIAID NIH HHS

Delayed immune reconstitution and the consequently high rates of leukemia relapse and infectious complications are the main limitations of haploidentical hematopoietic stem cell transplantation. Donor T cell addback can accelerate immune reconstitution but the therapeutic window between graft-vs.-host disease and protective immunity is very narrow in the haploidentical transplant setting. Hence, strategies to improve the safety and efficacy of adoptive T cell transfer are particularly relevant in this setting. Adoptive T cell transfer strategies in haploidentical transplantation include the use of antigen-specific T cells, allodepletion and alloanergy induction, immune modulation by the co-infusion of regulatory cell populations, and the use of safety switch gene-modified T cells. Whilst common principles apply, there are features that are unique to haploidentical transplantation, where HLA-mismatching directly impacts on immune reconstitution, and shared vs. non-shared HLA-allele can be an important consideration in antigen-specific T cell therapy. This review will also present an update on safety switch gene-modified T cells, which can be conditionally deleted in the event of severe graft- vs.-host disease or other adverse events. Herpes Virus Simplex Thymidine Kinase (HSVtk) and inducible caspase-9 (iCasp9) are safety switches that have undergone multicenter studies in haploidentical transplantation with encouraging results. These gene-modified cells, which are trackable long-term, have also provided important insights on the fate of adoptively transferred T cells. In this review, we will discuss the biology of post-transplant T cell immune reconstitution and the impact of HLA-mismatching, and the different cellular therapy strategies that can help accelerate T cell immune reconstitution after haploidentical transplantation.

• T cell immune reconstitution
• adoptive T cell therapy
• antigen-specific T cells
• gene modification
• haploidentical transplant
• safety switch

Excessive inflammatory environment in a course of chronic graft-versus-host disease (cGvHD) is associated with T-cell trafficking into inflamed tissues. This study focused on the identification of IL-17-producing cells in the tissue biopsies of cGvHD patients. Forty-one biopsy specimens of cGvHD lesions of the skin (n = 27), gastrointestinal tract (n = 9) and oral mucosa (n = 5), examined in 24 patients, were morphologically defined according to the NIH criteria and analyzed for the presence of cellular infiltrations including: IL-17⁺, FOXP3⁺ and CCR6⁺ cells. IL-17⁺ cells were identified in 26/27 skin and in all gut and oral mucosa biopsies, being more frequent in mucosa lesions than in the skin (11/14 vs 14/26, respectively; NS: not significant). Double staining documented that CD138⁺/IL-17⁺ cells were commonly seen in the gut than in the skin (5/8 vs 3/11, respectively; NS). In the skin, cells expressing trafficking receptor CCR6⁺ were more frequent than IL-17⁺ cells compared to the mucosa (23/26 vs 2/13, respectively; p < 0.0001). CCR6 was present on a majority of IL-17⁺ cells in all examined skin biopsies but only in 6 out of 11 digestive tract biopsies (p = 0.0112). FOXP3⁺ cells were identified only in five patients (with mild lesions) at least in one biopsy. In this study group, results documented that local expansion of IL-17-producing cells in the digestive tract correlate with moderate and severe clinical symptoms of cGvHD, in contrast to the skin, where IL-17⁺ cells are rather scarcely present (p = 0.0301) and the course of cGvHD is slowly progressing with final organ deterioration.

• Chronic GvHD
• Graft-versus-host disease
• IL-17-producing cells
• Skin and mucosa

• A(2A) receptor
• CGS 21680
• Cytokine
• Humanised mice
• T regulatory cell
• Weight loss
• Xenogeneic graft-versus-host disease

• WNT signalling
• haematopoietic stem cell transplantation
• mesenchymal stromal cells
• nuclear hormone transcription factors
• prostaglandins

• Animals
• Cyclooxygenase 2/immunology
• Female
• Hematopoietic Stem Cells/immunology
• Hematopoietic Stem Cells/pathology
• Humans
• Leukemia, Myeloid, Acute/immunology
• Leukemia, Myeloid, Acute/pathology
• Male
• Mesenchymal Stem Cells/immunology
• Mesenchymal Stem Cells/pathology
• Mice
• Mice, Inbred NOD
• Mice, Knockout
• Mice, SCID
• Neoplasm Proteins/immunology
• Nuclear Receptor Subfamily 4, Group A, Member 1/immunology
• Nuclear Receptor Subfamily 4, Group A, Member 2/immunology
• Wnt Signaling Pathway/immunology

• P20 GM121322 NIGMS NIH HHS
• U54 GM104942 NIGMS NIH HHS

• biomarkers
• chronic graft-versus-host disease
• oral mucosa
• topical therapy

• Administration, Topical
• Adult
• Aged
• Antigens, CD/metabolism
• Dexamethasone/therapeutic use
• Female
• Forkhead Transcription Factors/metabolism
• Glucocorticoids/therapeutic use
• Graft vs Host Disease/drug therapy
• Graft vs Host Disease/immunology
• Graft vs Host Disease/pathology
• Humans
• Immunohistochemistry
• Immunomodulation
• Immunosuppressive Agents/therapeutic use
• Macrophages/metabolism
• Male
• Middle Aged
• Mouth Diseases/drug therapy
• Mouth Diseases/immunology
• Mouth Diseases/pathology
• T-Lymphocytes/metabolism
• Tacrolimus/therapeutic use
• Young Adult

• P01 CA142106 NCI NIH HHS
• R01 CA183559 NCI NIH HHS

Graft-versus-host disease (GVHD) is an important cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Many studies have suggested that human herpesvirus-6B (HHV-6B) plays a role in acute GVHD (aGVHD) after HCT. Our objective was to systematically summarize and analyze evidence regarding HHV-6B reactivation and development of aGVHD. PubMed and EMBASE databases were searched using terms for HHV-6, HCT, and aGVHD, yielding 865 unique results. Case reports, reviews, articles focusing on inherited chromosomally integrated HHV-6, poster presentations, and articles not published in English were excluded. The remaining 467 articles were reviewed for the following requirements: a statistical analysis of HHV-6B reactivation and a GVHD was described, HHV-6B reactivation was defined by PCR, and blood (plasma, serum, or peripheral blood mononuclear cells) was used for HHV-6B PCR. Data were abstracted from publications that met these criteria (n = 33). Publications were assigned to 1 of 3 groups: (1) HHV-6B reactivation was analyzed as a time-dependent risk factor for subsequent aGVHD (n = 14), (2) aGVHD was analyzed as a time-dependent risk factor for subsequent HHV-6B reactivation (n = 1), and (3) analysis without temporal specification (n = 18). A statistically significant association (P < .05) between HHV-6B reactivation and aGVHD was observed in 10 of 14 studies (71%) in group 1, 0 of 1 study (0%) in Group 2, and 8 of 18 studies (44.4%) in Group 3. Of the 14 studies that analyzed HHV-6B as a risk factor for subsequent aGVHD, 11 performed a multivariate analysis and reported a hazard ratio, which reached statistical significance in 9 of these s tudies. Meta-analysis of these 11 studies demonstrated a statistically significant association between HHV-6B and subsequent grades II to IV aGVHD (hazard ratio, 2.65; 95% confidence interval, 1.89 to 3.72; P < .001).HHV-6B reactivation is associated with aGVHD, and when studies have a temporal component to their design, HHV-6B reactivation is associated with subsequent aGVHD. Further research is needed to investigate whether antiviral prophylaxis reduces incidence or severity of aGVHD.

• Graft-versus-host disease
• Human herpesvirus-6
• Risk factor

• antigen-presenting cell
• exosome
• graft-versus-host disease
• mesenchymal stromal cell
• regulatory T cells

It has rarely been studied that how the blood level of CsA affect the incidence of chronic GVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

A total of 183 patients who underwent allo-HSCT from an HLA-matched or haplo matched family donors between 2006 and 2014 were reviewed.

The average monthly CsA blood concentration (CsA^avr, ng/ml) was calculated in each patient: 0-1, 1-2, and 2-3 months after allo-HSCT. CsA^avr at the first month showed significant association with the occurrence of moderate to severe cGVHD in multivariate analysis adjusted for gender, age, total body irradiation, anti-thymocyte globulin, acute GVHD ≥ grade 2 and CsA^avr levels of other periods. The risk of cGVHD development was lowest in patients with CsA^avr of 200-250 ng/ml when compared to those with CsA^avr of ≥ 250 or < 200 ng/ml (p=0.003).

CsA level between 200 and 250 mg/ml during the first month after transplantation was significantly associated with the decreased risk of moderate to severe cGVHD.

• blood level
• chronic graft versus host disease
• cyclosporine

• CD4 stimulation
• cellular therapy
• graft-versus-host disease
• regulatory T cell
• tolerance

Polyclonal anti-human thymocyte globulins (ATG) have been recently shown to significantly reduce the incidence of graft versus host disease (GVHD) post allogeneic stem cell transplantation (HSCT) from both sibling and unrelated donors. Induction of regulatory T cells has been suggested as one of the possible mechanisms. The aim of current study was to further characterize the T cell populations induced by ATG treatment and to delineate the mechanisms involved in ATG-induced tolerance. Phenotypic characterization revealed a significant increase in the expression of FoxP3, GITR, CD95, PD-1 and ICOS as well as the complement inhibitory molecules CD55, CD58 and CD59 on CD4+CD25+ T cells upon ATG treatment. Addition of ATG-treated cells to autologous and allogeneic peripheral blood mononuclear cells (PBMCs) stimulated with anti-CD3/anti-CD28 antibodies resulted in significant inhibition of proliferation. Moreover, T-cell activation and IFNγ secretion were reduced in the presence of ATG-induced Treg cells. The CD4+CD25+CD127-low Treg fraction sorted from ATG-treated culture demonstrated greater suppressive potency than negative fraction. Conditioned medium produced by ATG-treated but not IgG-treated cells contained TGFβ and suppressed T cell proliferation and activation in a TGFβ receptor-dependent manner. TGFβ receptor kinase inhibitor SB431542 interfered with the suppressive activity of ATG-primed cells, enabling partial rescue of proliferation and IFNγ secretion. Moreover, SB431542 prevented Treg phenotype induction upon ATG treatment. Altogether, our data reveal the role of TGFβ signaling in ATG-mediated immunosuppression and further support the use of ATG, a potent inducer of regulatory T cells, for prevention of GVHD post HSCT and potentially other therapeutic applications.

• ATG
• Immune response
• Immunity
• Immunology and Microbiology Section
• TGFβ
• Treg

Supplemental Digital Content is available in the text.

Antibiotic therapy is a major risk factor for the development of diarrhea and colitis with varying severity. Often the origin of antibiotic-associated gastrointestinal deterioration remains elusive and no specific infectious agents could be discerned.

We represent three cases of intractable high-volume diarrhea associated with combined antibiotic and steroid therapy in critically ill patients not fitting into established disease entities. Cases presented with severe apoptotic enterocolitis resembling acute intestinal graft-versus-host-disease. Microbiologic workup precluded known enteropathogens, but microbiota analysis revealed a severely depleted gut microbiota with concomitant opportunistic pathogen overgrowth.

Fecal microbiota transplantation, performed in one patient, was associated with correction of dysbiosis, rapid clinical improvement, and healing of enterocolitis.

Our series represents a severe form of antibiotic-associated colitis in critically ill patients signified by microbiota depletion, and reestablishment of a physiologic gastrointestinal microbiota might be beneficial for this condition.

• acute and chronic intestinal graft-versus-host disease
• confocal endomicroscopy
• in vivo histology

Regulatory T (Tregs) cells play a crucial role in immunoregulation and promotion of immunological tolerance. Adoptive transfer of these cells has therefore been of interest in the field of bone marrow and solid organ transplantation, autoimmune diseases and allergy medicine. In bone marrow transplantation, Tregs play a pivotal role in the prevention of graft-verus-host disease (GvHD). This has generated interest in using adoptive Treg cellular therapy in the prevention and treatment of GvHD. There have been several barriers to the feasibility of Treg cellular therapy in the setting of hematopoietic stem cell transplantation (HSCT) which include low Treg concentration in peripheral blood, requiring expansion of the Treg population; instability of the expanded product with loss of FoxP3 expression; and issues related to the purity of the expanded product. Despite these challenges, investigators have been able to successfully expand these cells both in vivo and in vitro and have demonstrated that they can be safely infused in humans for the prevention and treatment of GvHD with no increase in relapse risk or infections risk.

• CD4+CD25+FoxP3+ T cells
• Tregs
• adoptive cellular therapy
• graft versus host disease (GvHD)

CD4⁺ T-helper subsets drive autoimmune chronic graft-versus-host disease, a major complication after allogeneic bone marrow transplantation. However, it remains unclear how specific T-helper subsets contribute to chronic graft-versus-host disease. T-helper type 1 cells are one of the major disease-mediating T-cell subsets and require interferon-γ signaling and Tbet expression for their function. Regulatory T cells on the other hand can inhibit T-helper type 1 cell-mediated responses. Using an established murine model that isolates the autoimmune component of graft-versus-host disease, we hypothesized that T-helper type 1 cells would restrict FoxP3-driven regulatory T cells. Upon transfer into immune-deficient syngeneic hosts, alloreactive Tbx21^−/−CD4⁺ T cells led to marked increases in FoxP3⁺ cells and reduced clinical evidence of autoimmunity. To evaluate whether peripheral induction contributed to regulatory T-cell predominance, we adoptively transferred Tbx21^−/− T cells that consisted of fate mapping for FoxP3: recipients of flow-purified effector cells that were Foxp3⁻ and Tbx21^−/− had enhanced T-regulatory-cell predominance during autoimmune graft-versus-host disease. These data directly demonstrated that peripheral T-regulatory-cell induction was inhibited by Tbet. Finally, Tbx21^−/− T-regulatory cells cross-regulated autoimmune wild-type T-effector-cell cytokine production in vivo. The Tbet pathway therefore directly impairs T-regulatory-cell reconstitution and is consequently a feasible target in efforts to prevent autoimmune graft-versus-host disease.

• GVHD
• NK-T cells
• T-regulatory cells
• sirolimus

• Bone marrow
• GVHD
• Mobilization
• Treg

• graft-versus-host disease
• graft-versus-leukemia effect
• hematopoietic stem cell transplantation
• immune reconstitution
• infection

• bone marrow transplantation
• donor-specific regulatory T cells
• mixed chimerism
• small bowel transplantation
• transplantation tolerance