Possible involvement of cytokines, chemokines and chemokine receptors in the initiation and progression of chronic GVHD

Oral Chronic Graft-Versus-Host Disease: Pathogenesis, Diagnosis, Current Treatment, and Emerging Therapies

Chronic graft-versus-host disease (cGvHD) is a multisystem disorder that occurs in recipients of allogeneic hematopoietic (alloHCT) stem cell transplants and is characterized by both inflammatory and fibrotic manifestations. It begins with the recognition of host tissues by the non-self (allogeneic) graft and progresses to tissue inflammation, organ dysfunction and fibrosis throughout the body. Oral cavity manifestations of cGVHD include mucosal features, salivary gland dysfunction and fibrosis. This review synthesizes current knowledge on the pathogenesis, diagnosis and management of oral cGVHD, with a focus on emerging trends and novel therapeutics. Data from various clinical studies and expert consensus are integrated to provide a comprehensive overview.

Immunomodulation of salivary gland function due to cancer therapy

Functional salivary glands (SG) are essential for maintaining oral health, and salivary dysfunction is a persistent major clinical challenge. Several cancer therapies also have off-target effects leading to SG dysfunction. Recent advances highlight the role of SG immune populations in homeostasis, dysfunction and gland regeneration. Here, we review what is known about SG immune populations during development and postnatal homeostasis. We summarize recent findings of immune cell involvement in SG dysfunction following cancer treatments such as irradiation (IR) for head and neck cancers, immune transplant leading to graft-versus-host-disease (GVHD) and immune checkpoint inhibitor (ICI) treatment. The role of immune cells in SG in both homeostasis and disease, is an emerging field of research that may provide important clues to organ dysfunction and lead to novel therapeutic targets.

Immunohistopathology of oral mucosal chronic graft-versus-host disease severity and duration

OBJECTIVE

Chronic graft-versus-host disease (cGVHD) is the main cause of late non-relapse mortality following hematopoietic cell transplantation. Oral mucosal (om-) cGVHD is common, but diagnosis and assessment rely on clinical interpretation and patient-reported symptoms. We investigated immunohistopathological profiles with respect to om-cGVHD severity disease duration.

MATERIAL AND METHODS

Ninety-four transplant patients and 15 healthy controls (n = 212 biopsies) were investigated by quantitative immunohistochemistry for T cells (CD4, CD8, and CD5), B cells (CD19 and CD20), macrophages (CD68), and Langerhans cells (CD1a).

RESULTS

We found significant increases in T (CD4, CD8) and monocytic (CD68) cells in om-cGVHD, and a notable absence of B (CD19 and CD20) cells. Histopathological activity correlated with increased CD4, CD8 and CD68. However, CD4 was associated with mild om-cGVHD, whereas CD8 and CD68 were found to be elevated in severe om-cGVHD. CD8 and CD68 levels were raised at disease onset, but during late phase, the predominant CD68 population was accompanied by CD4.

CONCLUSION

Oral cGVHD is a heterogenous clinical disorder, but our knowledge of the underlying biology remains limited. We highlight the importance of CD4, CD8 and CD68 immune profiling, together with histological grading for the staging of oral cGVHD, to broaden our understanding of the biology and individual disease course.

Perspectives on oral chronic graft-versus-host disease from immunobiology to morbid diagnoses

Chronic Graft-versus-Host Disease (cGVHD) is a major long-term complication, associated with morbidity and mortality in patients following allogenic hematopoietic cell transplantation (HCT) for immune hematopoietic disorders. The mouth is one of the most frequently affected organs after HCT (45-83%) and oral cGVHD, which may appear as the first visible sign. Manifestations present with mucosal lichenoid lesions, salivary gland dysfunction and limited oral aperture. Diagnosis of oral cGVHD severity is based on mucosal lesions with symptoms of sensitivity and pain and reduced oral intake. However, diagnostic difficulties arise due to subjective definitions and low specificity to cover the spectrum of oral cGVHD. In recent years there have been significant improvements in our understanding of the underlying oral cGVHD disease mechanisms. Drawing upon the current knowledge on the pathophysiology and biological phases of oral cGVHD, we address oral mucosa lichenoid and Sjogren's Syndrome-like sicca syndromes. We consider the response of alloreactive T-cells and macrophages to recipient tissues to drive the pathophysiological reactions and biological phases of acute inflammation (phase 1), chronic inflammation and dysregulated immunity (phase 2), and subsequent aberrant fibrotic healing (phase 3), which in time may be associated with an increased malignant transformation rate. When formulating treatment strategies, the pathophysiological spectrum of cGVHD is patient dependent and not every patient may progress chronologically through the biological stages. As such there remains a need to address and clarify personalized diagnostics and management to improve treatment descriptions. Within this review, we highlight the current state of the art knowledge on oral cGVHD pathophysiology and biological phases. We address knowledge gaps of oral cGVHD, with a view to facilitate clinical management and improve research quality on lichenoid biology and morbid forms of oral cGVHD.

Salivary gland function, development, and regeneration

Salivary glands produce and secrete saliva, which is essential for maintaining oral health and overall health. Understanding both the unique structure and physiological function of salivary glands, as well as how they are affected by disease and injury, will direct the development of therapy to repair and regenerate them. Significant recent advances, particularly in the OMICS field, increase our understanding of how salivary glands develop at the cellular, molecular, and genetic levels: the signaling pathways involved, the dynamics of progenitor cell lineages in development, homeostasis, and regeneration, and the role of the extracellular matrix microenvironment. These provide a template for cell and gene therapies as well as bioengineering approaches to repair or regenerate salivary function.

Gene expression profile of chronic oral graft-versus-host disease

Among the complications observed after allogeneic hematopoietic stem cell transplantation, graft-versus-host disease (GVHD) is the primary cause of post-transplant mortality. The oral cavity is the second most affected organ target in chronic GVHD. Tissue damage results from the upregulation of inflammatory mediators, which play a critical role in the immunopathogenesis of the disease. This case series observational study aims to evaluate the participation of cytokines, chemokines, transcription factors, and heat shock proteins in the pathogenesis of oral GVHD (oGVHD), describing the mRNA expression of 28 genes selected. Peripheral blood mononuclear cells were isolated from six participants with oGVHD and two without GVHD, and relative expression of transcripts with established roles as inflammatory mediators was determined in triplicate using the human RT² Profiler™ PCR Array. The gene expression levels in the group with oGVHD were mainly up-regulated compared to those without GVHD. PBMC from oGVDH expressed consistently higher IFN-γ, TNF, IL-1β, CCL2, HSP60 (HSPD1) and HSP90 (HSP90B1). These results can provide a basis for developing new molecular diagnostics and targets therapies for the clinical management of oGVHD.

Secondary Oral Cancer after Systemic Treatment of Hematological Malignancies and Oral GVHD: A Systematic Review

(1) Purpose: In this article, the authors decided to systematically review the available literature to identify potential correlations regarding secondary oral carcinoma occurring after hematological systemic treatment and oral chronic graft-versus-host disease. (2) Methods: Medline (PubMed) and Scopus (Elsevier) databases were searched, including articles from the years 2002-2022. The 33 unique results were assessed by a PRISMA flowchart, and we rejected 24 papers and included 9 articles in the review. (3) Results: The majority of patients suffered from the oral form of chronic graft-versus-host disease before the diagnosis of oral malignancy. Two common cancer sites were the tongue and buccal mucosa. The exact percentage of secondary oral carcinoma after hematopoietic stem cell transplantation could not be estimated due to a lack of data. (4) Conclusions: Every physician taking part in the follow-up of patients after hematological treatment should be aware of the possibility of secondary neoplastic disease in the oral cavity, especially in patients with oral graft-versus-host disease. Proper follow-up protocols and monitoring are needed in this patient group as the cause of these cancers appears to be multifactorial.

Vitamin D Supplementation: Association With Serum Cytokines in Pediatric Hematopoietic Stem Cell Transplantation

Vitamin D deficiency is prevalent in pediatric patients presenting for hematopoietic stem cell transplantation (HSCT) and has been linked to poor clinical outcomes. Using the data from a randomized control trial, in this paper we explore the effects of vitamin D supplementation on circulating cytokine levels during pediatric HSCT (www.clinicaltrials.gov as NCT03176849). A total of 41 children, 20 received Stoss therapy and 21 children received standard of care vitamin D supplementation. Levels of 25(OH)D and 20 cytokines were assessed at baseline and day +30. Significantly (P < 0.05) higher levels of mostly proinflammatory cytokines, FGF, GCSF, TNFα, IL-2, IL-6, IP10 were detected pre-transplant for patients with low compared to those with normal vitamin D levels. In sex stratified models that compare changes in cytokines between Stoss vs. standard of care, females in the Stoss group show greater changes in mostly pro -inflammatory cytokines- IP-10 (P = 0.0047), MIG (P = 0.009), and RANTES (P = 0.0047), IL-2R (P = 0.07) and IL-6(P = 0.069). Despite a small sample size, these findings suggest vitamin D deficiency affects the pre-transplant cytokine milieu and higher doses of vitamin D (Stoss therapy) appears to influence proinflammatory cytokine responses in a sex specific manner during pediatric HSCT. Larger clinical trials are warranted to validate these results.

Cross-talk between CXC chemokine ligand 10-CXC chemokine receptor 3 axis and CC chemokine ligand 17-CC chemokine receptor 4 axis in the pathogenesis of oral lichen planus

OBJECTIVES

This study aimed to determine whether a correlation existed between CXC chemokine ligand 10 (CXCL10)-CXC chemokine receptor 3 (CXCR3) and CC chemokine ligand 17 (CCL17)-CC chemokine receptor 4 (CCR4) in the pathogenesis of oral lichen planus (OLP).

METHODS

Peripheral blood of OLP patients (non-erosive and erosive groups) and healthy controls were collected, and T cells were isolated and purified. T cells were co-cultured with three groups: blank, anti-CXCR3, and anti-CCR4. CXCR3 and CCR4 expression were detected by flow cytometry, and CXCL10 and CCL17 were detected by enzyme-linked immunosorbent assay, respectively.

RESULTS

The purities of T cells were all >95% in the three groups (P>0.05). Receptor expression showed that CXCR3 and CCR4 in the anti-CXCR3 group was downregulated in OLP compared with the blank group (P>0.05). The level of CCR4 in the anti-CCR4 group was significantly downregulated (P<0.05), and CXCR3 was upregulated (P>0.05). Ligand analysis results showed that CXCL10 in the anti-CXCR3 group was significantly downregulated in OLP compared with the blank group (P<0.05), and CCL17 was also downregulated (P>0.05). CCL17 in the anti-CCR4 group was significantly downregulated (P<0.05), and CXCL10 was upregulated (P>0.05). The trend of receptors and ligands in controls was consistent with OLP, but no significant difference existed between the antagonistic and the blank groups (P>0.05).

CONCLUSIONS

Two axes interact with each other in the pathogenesis of OLP and may play different roles in its occurrence and development.

Functional Contributions of Antigen Presenting Cells in Chronic Graft-Versus-Host Disease

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.

Oral Complications of Chronic Graft-Versus-Host Disease

The increasing clinical indications for hematopoietic stem cell transplantation (HSCT) and improved clinical care throughout and following HSCT have led to not only long-term survival but also to an increasing incidence and prevalence of graft-versus-host disease (GVHD). Chronic GVHD (cGVHD) affects almost 50% of adult patients post-HSCT, with increasing incidence in pediatric patients as well. Oral cGVHD specifically has a reported prevalence ranging from 45% to 83% in patients who develop cGVHD and is more extensive in adult patients than in children. Oral cGVHD affects patients through clinically significant oral symptoms that may lead to significantly decreased caloric intake, oral infections, and increased health service utilization, and may thus affect overall health and survival. The most commonly used therapy for mucosal involvement of oral cGVHD is topical high-dose and ultra-high potency corticosteroids, and calcineurin inhibitors. This review of oral complications of cGVHD presents the clinical significance of oral cGVHD to HSCT survivors, our current understanding of the pathobiology of oral cGVHD and gaps in this evidence, and the global targeted interdisciplinary clinical research efforts, including the National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease. Current challenges regarding the management of oral cGVHD and strategies to advance our scientific understanding of this clinically significant chronic oral disease are presented.

Targeting the Complement Alternative Pathway Permits Graft Versus Leukemia Activity while Preventing Graft Versus Host Disease

PURPOSE

Application of allogeneic hematopoietic cell transplantation (allo-HCT) for patients with hematologic disorders is limited by the development of GVHD. Separation of GVHD and graft-versus-leukemia (GVL) remains a great challenge in the field. We investigated the contribution of individual pathways involved in the complement cascade in GVH and GVL responses to identify specific targets by which to separate these two processes.

EXPERIMENTAL DESIGN

We used multiple preclinical murine and human-to-mouse xenograft models involving allo-HCT recipients lacking components of the alternative pathway (AP) or classical pathway (CP)/lectin pathway (LP) to dissect the role of each individual pathway in GVHD pathogenesis and the GVL effect. For translational purposes, we used the AP-specific complement inhibitor, CR2-fH, which localizes in injured target organs to allow specific blockade of complement activation at sites of inflammation.

RESULTS

Complement deposition was evident in intestines of mice and patients with GVHD. In a preclinical setting, ablation of the AP, but not the CP/LP, significantly improved GVHD outcomes. Complement activation through the AP in host hematopoietic cells, and specifically dendritic cells (DC), was required for GVHD progression. AP deficiency in recipients decreased donor T-cell migration and Th1/Th2 differentiation, while increasing the generation of regulatory T cells. This was because of decreased activation and stimulatory activity of recipient DCs in GVHD target organs. Treatment with CR2-fH effectively prevented GVHD while preserving GVL activity.

CONCLUSIONS

This study highlights the AP as a new therapeutic target to prevent GVHD and tumor relapse after allo-HCT. Targeting the AP by CR2-fH represents a promising therapeutic approach for GVHD treatment.

The Biological and Clinical Relevance of G Protein-Coupled Receptors to the Outcomes of Hematopoietic Stem Cell Transplantation: A Systematized Review

Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment for several malignant and non-malignant diseases at the cost of serious treatment-related toxicities (TRTs). Recent research on extending the benefits of HSCT to more patients and indications has focused on limiting TRTs and improving immunological effects following proper mobilization and engraftment. Increasing numbers of studies report associations between HSCT outcomes and the expression or the manipulation of G protein-coupled receptors (GPCRs). This large family of cell surface receptors is involved in various human diseases. With ever-better knowledge of their crystal structures and signaling dynamics, GPCRs are already the targets for one third of the current therapeutic arsenal. The present paper assesses the current status of animal and human research on GPCRs in the context of selected HSCT outcomes via a systematized survey and analysis of the literature.

The impact of cytokine gene polymorphisms on the outcome of HLA matched sibling hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is the major complication of allogeneic hematopoietic stem cell transplantation (HSCT); cytokines are recognized as important mediators in its pathogenesis. In this study we investigated the role of cytokine gene polymorphisms on HSCT outcome. A total of 106 patient and 98 donors were genotyped by polymerase chain reaction sequence specific primers (PCR-SSP) based assay for tumor necrosis factor-α-308 (TNFα -308), interleukin (IL)-6-174, IL-10-1082, -819, -592, Interferon-γ+874 (IFN-γ+874), and transforming growth factor-β1 (TGF-β1) codon10 and 25 polymorphisms. Except one in each category, all patients and donors were TNFα -308 high producers and the majority were IL-6-174 high producers (93.3% and 90.8% respectively); a pattern that would alleviate any potential biological impact. Patient's IFN-γ+874 showed significant association with the development of chronic GVHD. Patients with IFN-γ +874 high producer showed an 8 folds likelihood to develop chronic GVHD as compared to those with IFN-γ+874 low producer predicted phenotype (95% CI: 1.59-40.2, p = 0.01). Patient's TGFβ1-codon 10 and 25 high/intermediate producers showed a lower incidence of acute GVHD though it did not achieve statistical significance (p = 0.065) on account of the low frequency of this genotype in our patients and donors (11.4 and 8.2% respectively). Other factors contributing to risk of GVHD included older age for both acute and chronic (p = 0.01 and 0.02 respectively) with age 24 as the best discriminating cutoff; CD34+ cell dose for chronic GVHD (p = 0.045) with a dose of 8 × 10⁶/kg as the best discriminating cutoff; and conditioning regimen with Flu/Bu associated with the lowest incidence of acute GVHD (p = 0.003) and no impact on chronic GVHD. In conclusion the current study further indicates a potential role of some cytokine gene polymorphisms in the development of GVHD. The relative distribution of high and low producer genotypes in different ethnic groups contributes to their biological impact in different populations.

Myeloid dendritic cells stimulated by thymic stromal lymphopoietin promote Th2 immune responses and the pathogenesis of oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory disease characterized by subepithelial T-cell infiltration. Recent studies reported that specific T helper (Th) subsets, especially Th2 cells, are involved in the pathogenesis of OLP. Thymic stromal lymphopoietin (TSLP) is mainly secreted by epithelial cells and potently activates myeloid dendritic cells (mDCs) to induce Th2-mediated inflammation. Here, we investigated the expression of TSLP and related molecules in OLP. Buccal mucosa specimens from patients with OLP, hyperkeratosis, and ulcer were analyzed by immunohistochemistry for expression of TSLP, its receptor (TSLPR), and inflammatory cells. TSLP was detected in/around the epithelium of patients with OLP and hyperkeratosis, whereas TSLPR, CD11c (mDC), and GATA3 (Th2) were strongly expressed in the subepithelial layer only in OLP patients. Double immunofluorescence staining showed that TSLPR expression mainly co-localized with CD11c. Moreover, the number of CD11c- and GATA-3 positive cells was correlated in OLP patients. In lesions selectively extracted by laser microdissection, the mRNA expression of Th2 (IL-4, MDC, TARC, GATA3)- and Th17 (IL-17, RORγt)-related molecules in OLP patients was significantly higher than in other groups. These results suggest that CD11c⁺ mDCs expressing TSLPR contribute to aberrant Th2 immune responses and the pathogenesis of OLP via TSLP stimulation.

CD8+ T cells drive autoimmune hematopoietic stem cell dysfunction and bone marrow failure

Bone marrow (BM) failure syndrome encompasses a group of disorders characterized by BM stem cell dysfunction, resulting in varying degrees of hypoplasia and blood pancytopenia, and in many patients is autoimmune and inflammatory in nature. The important role of T helper 1 (Th1) polarized CD4⁺ T cells in driving BM failure has been clearly established in several models. However, animal model data demonstrating a functional role for CD8⁺ T cells in BM dysfunction is largely lacking and our objective was to test the hypothesis that CD8⁺ T cells play a non-redundant role in driving BM failure. Clinical evidence implicates a detrimental role for CD8⁺ T cells in BM failure and a beneficial role for Foxp3⁺ regulatory T cells (Tregs) in maintaining immune tolerance in the BM. We demonstrate that IL-2-deficient mice, which have a deficit in functional Tregs, develop spontaneous BM failure. Furthermore, we demonstrate a critical role for CD8⁺ T cells in the development of BM failure, which is dependent on the cytokine, IFNγ. CD8⁺ T cells promote hematopoietic stem cell dysfunction and depletion of myeloid lineage progenitor cells, resulting in anemia. Adoptive transfer experiments demonstrate that CD8⁺ T cells dramatically expedite disease progression and promote CD4⁺ T cell accumulation in the BM. Thus, BM dysregulation in IL-2-deficient mice is mediated by a Th1 and IFNγ-producing CD8⁺ T cell (Tc1) response.

Durable responses to ibrutinib in patients with relapsed CLL after allogeneic stem cell transplantation

Ibrutinib, a recently approved inhibitor of Bruton's tyrosine kinase (BTK), has shown great efficacy in patients with high-risk CLL. Nevertheless, there are few data regarding its use in patients who relapsed after allogeneic stem cell transplantation (alloSCT). We report clinical data from five CLL patients treated with ibrutinib for relapse after first or even second allogeneic transplantation. Additionally, we performed analyses on cytokine levels and direct measuring of CD4 Th1 and CD4 Th2 cells to evaluate possible clinically relevant immunomodulatory effects of ibrutinib. All patients achieved partial responses including one minimal residual disease (MRD)-negative remission. Within 1 year of follow-up, no relapse was observed. One patient died of severe pneumonia while on ibrutinib treatment. Beside this, no unexpected adverse events were observed. Flow cytometry and analyses of T cell-mediated cytokine levels (IL10 and TNFα) did not reveal substantial changes in T-cell distribution in favor of a CD4 Th1 T-cell shift in our patients. No acute exacerbation of GvHD was reported. In conclusion, these results support further evaluation of ibrutinib in CLL patients relapsing after alloSCT.

The effect of extracorporeal photopheresis on T cell response in chronic graft-versus-host disease

Extracorporeal photopheresis (ECP) is a safe and effective immunoregulatory therapy for steroid-refractory chronic graft-versus-host disease (cGVHD) but its mechanism of action is poorly understood. In this study, we evaluated the effect of ECP in a sample of cGVHD patients. Our data showed that ECP-treated patients had lower CD4 T and B cells, and substantially higher NK cells than untreated patients. T regulatory (Treg) cells were similar between the two groups of patients. Interestingly, Treg cells were higher in ECP-treated patients and ECP-responders who had no history of aGVHD or sclerosis, than in those who had one of them or both. These findings suggest that at least one of the mechanisms of immunomodulation by ECP targets the Treg cell population and that an increase in Treg cells may be associated with response in patients with cGVHD. Together, the results of ECP are different depending on the patients' clinical condition.

Role of Toll-like receptor 4 signaling in cutaneous chronic graft-versus-host disease

Cutaneous damage is one of the characterized manifestations in chronic graft-versus-host disease (cGVHD). When local effective immunity in the skin is altered to a dysimmune reaction, cutaneous injuries occur. Toll-like receptor 4 signaling is regarded as a central mediator of inflammation and organ injury. In this study, we found that TLR4 mRNA in peripheral blood from patients with cutaneous cGVHD was markedly increased compared with that from non-GVHD patients and healthy controls. In addition, NF-κB expression, TLR4 downstream signaling, and TLR4-mediated cytokines, including IL-6 and ICAM-1, were upregulated. Moreover, ICAM-1 was widely distributed in skin biopsies from patients with cutaneous cGVHD. We also found that LPS induced TLR4-mediated NF-κB activation and IL-6 and ICAM-1 secretion in human fibroblasts in vitro. Thus, TLR4, NF-κB, IL-6, and ICAM-1 contribute to the inflammatory response that occurs in cutaneous cGVHD, indicating the TLR4 pathway may be a novel target for cutaneous cGVHD therapy.