Recruitment of Donor T Cells to the Eyes During Ocular GVHD in Recipients of MHC-Matched Allogeneic Hematopoietic Stem Cell Transplants

Epidemiology and risk factors for the development of cicatrizing conjunctivitis in chronic ocular graft-versus-host disease

PURPOSE

To evaluate the incidence of chronic cicatrizing conjunctivitis (CCC) and its associated risk factors in the context of chronic ocular graft-vs-host disease (coGVHD).

METHODS

A retrospective chart review of individuals diagnosed with coGVHD following hematopoietic stem cell transplantation (HSCT) who were seen at the Bascom Palmer Eye Institute between May 2010 and November 2021 was performed. Data regarding baseline demographic characteristics, systemic co-morbidities, lid margin abnormalities, ocular cicatricial changes, transplant information, immunosuppressive therapy, and GVHD severity assessments were collected. The incidence of cicatricial conjunctivitis was estimated with Kaplan-Meier survival analysis. A Cox regression model was used to assess the contribution of demographic and systemic variables to the development of CCC.

RESULTS

167 individuals were included (53.9 ± 14.7 years old; 60.5 % male). 65 individuals presented with features suggestive of CCC an average of 60.9 ± 53.8 months after HSCT, with 60-month and 120-month incidences of 29.3 % and 48.9 %, respectively. Multivariable analysis demonstrated that age younger than 50 at the time of the first eye visit was associated with a higher chance of CCC development (Hazard Ratio (HR): 2.14, 95 % Confidence Interval (CI): 1.16-3.97, p = 0.02).

CONCLUSION

Clinically detected cicatrizing conjunctivitis is an ocular manifestation of coGVHD, with an incidence that increases over time. Younger individuals may be at higher risk for CCC development.

Immunopathological mechanisms and clinical manifestations of ocular graft-versus-host disease following hematopoietic stem cell transplantation

Graft-versus-host disease is among the most common clinical complications following allogeneic hematopoietic stem cell transplantation. It causes inflammation-mediated destruction and dysfunction of various organ systems including ocular tissues in 60-90% of the patients and is termed ocular GVHD (oGVHD). In oGVHD, donor-derived T-cells recognize host antigens as foreign, resulting in immune dysregulation, inflammation and fibrosis of lacrimal glands, meibomian glands, cornea, and conjunctiva. The clinical presentation in oGVHD patients range from mild dry eye symptoms to catastrophic inflammation mediated pathological changes which can cause corneal perforation and blindness. In this review article, we provide detailed insights into the impact of mucosal barrier disruption, the afferent and efferent phases of immunological response involving activation of antigen presenting cells and T cells, respectively. We evaluate the evidence outlining the effector phase of the disease leading to cellular destruction and eventually fibrosis in patients with oGVHD. Finally, we discuss the well-established criteria for the diagnosis of oGVHD.

Understanding Ocular Graft-Versus-Host Disease to Facilitate an Integrated Multidisciplinary Approach

Ocular Graft-versus-Host Disease (oGVHD) remains a challenging and potentially devastating complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). It significantly impacts the quality of life of affected survivors, however, is often underrecognized particularly during the early stages. Targeting all providers in the HSCT community who see patients regularly and frequently for their post-allo-HSCT care, this review and opinion piece introduces the basic concepts of ocular surface pathophysiology, dissects the different stages of clinical presentation of oGVHD, explains why the current diagnostic criteria tend to capture the late disease stages, highlights the warning signs of early disease development, in hope to facilitate prompt referral of oGVHD suspects for ocular specialist care. In addition to introducing a comprehensive list of treatment options, this review emphasizes basic therapeutic strategy and options that are safe and effective to be initiated by any care provider. We believe in empowering the patients as well as the care providers beyond disciplinary boundaries, in order to provide the most cohesive and integrated care to our patients in a multidisciplinary approach.

A Novel Murine Model for Lupus-Like Ocular Chronic Graft-Versus-Host Disease

Purpose

Lupus-like chronic graft-versus-host disease (cGVHD) has been previously described, but the ocular findings have not been elucidated. Recipient mice in a lupus-like cGVHD model manifested notable and persistent ocular surface phenotypes. Herein, we further explored immunopathogenic mechanisms underlying these ocular phenotypes.

Methods

A previously described lupus-like cGVHD model was established by intraperitoneal injection of splenocytes from bm12 mice into C57BL/6J mice. Systemic findings were evaluated for the presence of splenomegaly, proteinuria, and autoantibodies. Comprehensive evaluations were conducted on ocular manifestations and immunopathological features in this model.

Results

The lupus-like cGVHD model was successfully constructed 2 weeks post-transplantation. The recipient mice developed lupus-like phenotypes, including splenomegaly, proteinuria, and increased autoantibodies, and their ocular presentations included corneal epithelial defects and decreased tear secretion. Histological analysis revealed a reduction in corneal nerve fiber density and corneal endothelial cells, along with conjunctival fibrosis and loss of goblet cells. Moreover, cGVHD induced progressive aggravation of immune cell infiltration and fibrosis in the lacrimal glands. RNA-Sequencing (RNA-seq) results of the lacrimal glands demonstrated that the differentially expressed genes (DEGs) between the control and cGVHD groups were associated with GVHD pathways. Immune infiltration analysis using RNA-seq and flow cytometry confirmed that CD8+ T lymphocytes predominantly constituted the inflammatory infiltrating cells within the lacrimal glands.

Conclusions

This lupus-like cGVHD model (bm12→C57BL/6J) exhibited persistent ocular surface manifestations, characterized by immune infiltration of CD8+ T lymphocytes in the lacrimal glands. Thus, this ocular cGVHD model may be used to explore the underlying mechanisms and discover novel therapeutic interventions.

Recombinant Deoxyribonuclease I Eye Drops for Ocular Graft Versus Host Disease: Results of a Randomized Clinical Trial

OBJECTIVE

We have previously shown that neutrophil extracellular traps (NETs) are present on the ocular surface of patients with ocular graft versus host disease (oGVHD), contributing to inflammation and surface disease. Therefore, we performed a clinical trial using deoxyribonuclease I (DNAase) eye drops to test the hypothesis that reducing the abundance of NETs from the ocular surface will reduce signs and symptoms of oGVHD.

METHODS

A prospective, phase I or II, randomized, placebo-controlled, double-masked clinical trial was performed to determine the safety and preliminary efficacy of DNAase (0.1%) eye drops four times daily for 8 weeks in patients with oGVHD (n=58). Intent-to-treat analysis was performed to determine the change in safety outcome measures (drug tolerability and proportion of adverse events) and efficacy outcome measures (ocular surface disease index [OSDI] score and corneal staining) between baseline and week 8.

RESULTS

Tolerability and adverse events were similar in the vehicle and DNAase groups. Within the DNAase group (but not the vehicle group), corneal staining showed a statistically significant and clinically meaningful reduction at week 8 (3.50 [2.75; 5.00]) compared with baseline (5.00 [3.00; 7.00]). The OSDI score also showed a statistically significant clinically meaningful reduction of 18.4 (9.16; 33.1) ( P <0.001) at week 8 compared with baseline (45.5 [31.8; 50.0]) within the DNAase group. The proportion of eyes that had improvement in subjective global assessment (SGA) and mucous discharge was significantly greater in the DNAase group (55.6% and 57.7% at weeks 4 and 8, respectively; P <0.0001 at both time points) as compared with the vehicle group (35.7% and 34.0% at weeks 4 and 8, respectively).

CONCLUSIONS

Treatment of patients with oGVHD using DNAase eye drops is safe and demonstrates preliminary efficacy. Deoxyribonuclease I eye drops can potentially reduce the severity of signs and symptoms of ocular surface disease in patients with oGVHD.

Lessons Learned From Ocular Graft versus Host Disease: An Ocular Surface Inflammatory Disease of Known Time of Onset

ABSTRACT

The ocular surface inflammatory disorders (OSIDs) comprise a group of conditions characterized by persistent inflammation of the ocular surface and adnexal tissues. Systemic autoimmune diseases and hypersensitivity reactions cause them, and, if left untreated, can result in severe inflammatory dry eye, corneal damage, and vision loss. Ocular graft-versus-host disease (oGVHD) forms part of the ocular surface inflammatory disease umbrella. It is a condition occurring after allogeneic hematopoietic stem cell or bone marrow transplantation, usually in chronic graft-versus-host disease. oGVHD can virtually affect any ocular adnexal tissue, especially the meibomian glands, and cause persistent inflammation, tissue fibrosis, and subsequent chronic, severe dry eye disease. Among the OSIDs, oGVHD has the particularity that it has a "time zero," meaning we know when the disease started. As such, preclinical models have leveraged this to investigate the molecular mechanisms involved in the damage oGVHD causes to the ocular surface. In oGVHD, establishing a "time zero" allows for predicting the clinical course and establishing adequate treatment. This is also possible because the inflammatory infiltration occurs in ocular surface tissues, which are readily accessible. Using oGVHD, we might be able to understand the immune response mechanisms in other OSIDs better (i.e., Sjögren syndrome, Stevens-Johnson syndrome, among others). This review presents an up-to-date overview of the pathogenesis, clinical presentation, and treatment of oGVHD. In addition, we will discuss the value of the "time zero" concept in the study of oGVHD.

How does ocular graft-versus-host disease fit under the dry eye umbrella? A review

Graft-versus-host disease (GVHD) is a systemic disease that can affect multiple organs as a consequence of an allogeneic haematopoietic stem cell transplant. One organ system that is often affected in GVHD is the eyes. Ocular GVHD (oGVHD) may involve various structures within the eye including the lacrimal glands, eyelids, conjunctiva, cornea, and nasolacrimal ducts, and is a source of morbidity in patients with GVHD. Common presenting features of GVHD overlap with dry eye disease (DED), including decreased tear production, epithelial disruption, and Meibomian gland dysfunction (MGD). In this review, we aim to compare oGVHD and DED to better understand the similarities and differences between the conditions, with a focus on pathophysiology, risk factors, clinical features, and treatments.

Infectious and Noninfectious Corneal Ulcers in Ocular Graft-Versus-Host Disease: Epidemiology, Clinical Characteristics, and Outcomes

PURPOSE

To evaluate the incidence, clinical characteristics, microbiological profile, and therapeutic outcomes of corneal ulcers in individuals with chronic ocular graft-vs-host disease (coGVHD).

DESIGN

Retrospective clinical cohort study.

METHODS

Review of individuals diagnosed with coGVHD following hematopoietic stem cell transplantation (HSCT) who were seen at the Bascom Palmer Eye Institute between May 2010 and November 2021. Baseline demographics, clinical characteristics, microbiological profile, risk factors for corneal ulceration, and treatment outcomes were collected. Etiology was deemed infectious in individuals with a positive culture or appropriate clinical scenario (presence of stromal infiltrate or hypopyon); otherwise, ulcers were presumed to be noninfectious. Treatment success was defined as reepithelialization with infiltrate resolution, and treatment failure as progression to corneal perforation or keratoplasty. Kaplan-Meier survival analysis estimated the incidence of ulceration. Cox regression analyses examined demographic and risk factors. Infectious and noninfectious ulcer groups were compared using 2-way independent t tests, 1-way analysis of variances, and χ2 tests, as appropriate.

RESULTS

173 individuals were included (53.7±14.4 years old; 59.0% male). Thirty-three individuals developed an ulcer 74.5±54.3 months after HSCT, with estimated 5- and 10-year incidences of 14% and 30%, respectively. Twenty-two (66.6%) ulcers were deemed infectious (15 microbiologically confirmed, 7 clinically) and 11 (33.3%) were deemed noninfectious. Risk factors for corneal ulceration included Black race (hazards ratio [HR] 2.89, 95% CI 1.30-6.42, P < .01), previous ocular surgery (HR 9.16, 95% CI 3.86-21.72, P < .01), eyelid margin abnormalities (HR 3.44, 95% CI 1.69-6.99, P < .01), and topical steroid use (HR 2.74, 95% CI 1.33-5.62, P < .01). Conversely, contact lens use reduced the risk of corneal ulceration (HR 0.29, 95% CI 0.13-0.66, P < .01). Infectious ulcers had a significantly higher frequency of treatment failure than noninfectious ulcers (57.1% vs 20.0%, P = .04).

CONCLUSION

Corneal ulceration is a potential complication of coGVHD, with several clinical features identified as risk factors. Infectious ulcers had worse outcomes than noninfectious ulcers.

Murine models of graft versus host disease (GVHD): Focus on ocular GVHD

Graft versus host disease (GVHD) remains a major and serious complication of allogeneic hematopoietic stem cell transplantation. Based on the time of onset, clinical phenotypes, progression kinetics, and pathophysiology, GVHD is stratified into acute, chronic, and overlapping types. The eyes are among the most commonly affected organs in GVHD. Mouse models have played an important role in understanding the several key elements of GVHD pathobiology. The current review discusses the immunology, pathology, and key phenotypic features of mouse models of systemic GVHD. Furthermore, a critical appraisal of mouse models of ocular GVHD (oGVHD) is provided. The disease mechanisms underlying the ocular surface, meibomian gland, and lacrimal gland injury in these models are reviewed, and the relevance of oGVHD murine models to clinical oGVHD is also included.

An ocular Th1 immune response promotes corneal nerve damage independently of the development of corneal epitheliopathy

Proper sight is not possible without a smooth, transparent cornea, which is highly exposed to environmental threats. The abundant corneal nerves are interspersed with epithelial cells in the anterior corneal surface and are instrumental to corneal integrity and immunoregulation. Conversely, corneal neuropathy is commonly observed in some immune-mediated corneal disorders but not in others, and its pathogenesis is poorly understood. Here we hypothesized that the type of adaptive immune response may influence the development of corneal neuropathy. To test this, we first immunized OT-II mice with different adjuvants that favor T helper (Th)1 or Th2 responses. Both Th1-skewed mice (measured by interferon-γ production) and Th2-skewed (measured by interleukin-4 production) developed comparable ocular surface inflammation and conjunctival CD4+ T cell recruitment but no appreciable corneal epithelial changes upon repeated local antigenic challenge. Th1-skewed mice showed decreased corneal mechanical sensitivity and altered corneal nerve morphology (signs of corneal neuropathy) upon antigenic challenge. However, Th2-skewed mice also developed milder corneal neuropathy immediately after immunization and independently of ocular challenge, suggestive of adjuvant-induced neurotoxicity. All these findings were confirmed in wild-type mice. To circumvent unwanted neurotoxicity, CD4+ T cells from immunized mice were adoptively transferred to T cell-deficient mice. In this setup, only Th1-transferred mice developed corneal neuropathy upon antigenic challenge. To further delineate the contribution of each profile, CD4+ T cells were polarized in vitro to either Th1, Th2, or Th17 cells and transferred to T cell-deficient mice. Upon local antigenic challenge, all groups had commensurate conjunctival CD4+ T cell recruitment and macroscopic ocular inflammation. However, none of the groups developed corneal epithelial changes and only Th1-transferred mice showed signs of corneal neuropathy. Altogether, the data show that corneal nerves, as opposed to corneal epithelial cells, are sensitive to immune-driven damage mediated by Th1 CD4+ T cells in the absence of other pathogenic factors. These findings have potential therapeutic implications for ocular surface disorders.

Meibomian Gland Dysfunction: A Route of Ocular Graft-Versus-Host Disease Progression That Drives a Vicious Cycle of Ocular Surface Inflammatory Damage

PURPOSE

To investigate the role of aggressive meibomian gland dysfunction (MGD) in the immune pathogenesis of ocular graft-vs-host disease (GVHD).

METHODS

In mice, an allogeneic GVHD model was established by transferring bone marrow (BM) and purified splenic T cells from C57BL/6J mice into irradiated C3-SW.H2b mice (BM+T). Control groups received BM only. Mice were scored clinically across the post-transplantation period. MGD severity was categorized using the degree of atrophy on harvested lids. Immune disease was analyzed using flow cytometry of tissues along with fluorescent tracking of BM cells onto the ocular surface. In humans, parameters from 57 patients with ocular GVHD presenting to the Duke Eye Center were retrospectively reviewed. MGD was categorized using the degree of atrophy on meibographs. Immune analysis was done using high-parameter flow cytometry on tear samples.

RESULTS

Compared with BM only, BM+T mice had higher systemic disease scores that correlated with tear fluid loss and eyelid edema. BM+T had higher immune cell infiltration in the ocular tissues and higher CD4+-cell cytokine expression in draining lymph nodes. BM+T mice with worse MGD scores had significantly worse corneal staining. In patients with ocular GVHD, 96% had other organs affected. Patients with ocular GVHD had abnormal parameters on dry eye testing, high matrix metalloproteinase-9 positivity (92%), and abundance of immune cells in tear samples. Ocular surface disease signs were worse in patients with higher MGD severity scores.

CONCLUSIONS

Ocular GVHD is driven by a systemic, T-cell-dependent process that causes meibomian gland damage and induces a robust form of ocular surface disease that correlates with MGD severity. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Challenges and concepts in the diagnosis and management of ocular graft-versus-host disease

Graft-versus-host disease (GVHD) is characterized by tissue inflammation in the host following an allogeneic hematopoietic cell transplantation (HCT). The pathophysiology is complex and only incompletely understood yet. Donor lymphocyte interaction with the histocompatibility antigens of the host plays a crucial role in the pathogenesis of the disease. Inflammation may affect multiple organs and tissues, e.g., the gastrointestinal tract, liver, lung, fasciae, vaginal mucosa, and the eye. Subsequently, alloreactive donor-derived T and B lymphocytes may lead to severe inflammation of the ocular surface (i.e., cornea and conjunctiva) and the eyelids. Furthermore, fibrosis of the lacrimal gland may lead to severe dry eye. This review focuses on ocular GVHD (oGVHD) and provides an overview of current challenges and concepts in the diagnosis and management of oGVHD. Ophthalmic manifestations, diagnostic procedures, grading of severity and recommendations for ophthalmic examination intervals are provided. Management of ocular surface disease with lubricants, autologous serum eye drops, topical anti-inflammatory agents and systemic treatment options are described based on the current evidence. Ocular surface scarring and corneal perforation are severe complications of oGVHD. Therefore, ophthalmic screening and interdisciplinary treatment approaches are highly relevant to improve the quality of life of patients and to prevent potentially irreversible visual loss.

Recent advances in ocular graft-versus-host disease

Ocular graft-versus-host-disease (GVHD) remains a significant clinical complication after allogeneic hematopoietic stem cell transplantation. Impaired visual function, pain, and other symptoms severely affect affected individuals' quality of life. However, the diagnosis of and therapy for ocular GVHD involve a multidisciplinary approach and remain challenging for both hematologists and ophthalmologists, as there are no unified international criteria. Through an exploration of the complex pathogenesis of ocular GVHD, this review comprehensively summarizes the pathogenic mechanism, related tear biomarkers, and clinical characteristics of this disease. Novel therapies based on the mechanisms are also discussed to provide insights into the ocular GVHD treatment.

Ocular Surface Inflammatory Disorders (OSID): A Collective of Systemic Etiologies Which Cause or Amplify Dry Eye Syndrome

The ocular surface inflammatory disorders (OSID) are caused by systemic disorders that conduct a persistent inflammatory reaction in the ocular adnexal connective tissues, such as the conjunctiva, lacrimal gland (LG) and meibomian glands (MGs), which cause an inflammatory dry eye. The etiologies of OSID are a subset of systemic pathologies such as graft versus host disease, Sjögren’s syndrome, allergies, cicatrizing conjunctivitis, and more. These cause a purely inflammatory dry eye syndrome as a consequence of the persistent surrounding inflammation in the adnexal tissues, which is distinct from the age-related dry eye disease. A limitation toward management of these conditions is the lack of available biomarkers that can detect presence of inflammation and quantify damage on the conjunctiva and LG, even though these are considered to be drivers of the inflammatory milieu. The OSID and dry eye syndrome are caused by different immune cells which are not exclusively limited to T cell lymphocytes, but rather derive from an orchestrated multicellular immunologic response. Recognition of this syndrome is crucial to direct research in a direction that clarifies the potential role of inflammation and its associated immune phenotype on the conjunctiva and adnexal ocular tissues in OSID and dry eye syndrome. On this paper, we review the basic and clinical research evidence for the existence of OSID with focus on the different immune cells involved, the target tissues and potential consequences and OSIDs diagnostic and therapeutic implications.

In Vivo Confocal Microscopy in Different Types of Dry Eye and Meibomian Gland Dysfunction

In vivo confocal microscopy (IVCM) imaging is increasingly popular in ocular surface disease diagnosis and management. We conducted a systematic review to update the use of IVCM in the diagnosis and treatment of dry eye and meibomian gland dysfunction (MGD). A literature review was conducted on IVCM studies in MGD, dry eye disease, systemic disease causing dry eye, dry eye in glaucoma patients, contact lens-associated ocular conditions, graft-versus-host disease, and Sjogren’s syndrome-related dry eye. The articles were identified through PubMed and a total number of 63 eligible publications were analyzed in detail. All primary research studies on confocal microscopy on dry eye and related conditions from 2017 onwards were included. The reports were reviewed for their contribution to the existing literature as well as potential biases and drawbacks. Despite limitations such as small field of view, lack of population-based norms, and lack of standardization of image acquisition, interpretation, and quantification, IVCM is useful as a complementary technique for clinical diagnosis in various ocular surface disorders related to dry eye. With advances in hardware and software in the near future, it has the potential for further practical impact.

Fungi of the human eye: Culture to mycobiome

The focus of the current review is multi-fold and compares the diversity and abundance of fungi on the ocular surface by the conventional culture-based method with the more sensitive, high throughput, culture-independent NGS method. The aim is to highlight the existence of a core ocular mycobiome and explore the transition of the ocular fungal microbiota from the normal eye to the diseased eye. PubMed, Google Scholar and Medline were used to search for publications and reviews related to cultivable fungi and the mycobiome of the normal and diseased eye. The conventional cultivable approach and the NGS approach confirm that the eye has its own mycobiome and several confounding factors (age, gender, ethnicity etc.) influence the mycobiome. Further, dysbiosis in the mycobiome appears to be associated with ocular diseases and thus impacts the health of the human eye. Considering that the mycobiome of the eye is influenced by several confounding factors and also varies with respect to the disease status of the eye there is a need to extensively explore the mycobiome under different physiological conditions, different ethnicities, geographical regions etc. Such studies would unravel the diversity and abundance of the mycobiomes and contribute to our understanding of ocular health. Research focused on ocular mycobiomes may eventually help to build a targeted and individualized treatment.

miR-204-containing exosomes ameliorate GVHD-associated dry eye disease

Graft-versus-host disease (GVHD)–associated dry eye disease is characterized by extensive inflammatory destruction in the ocular surface and causes unbearable pain and visual impairment. Current treatments provide limited benefits. Here, we report that exosomes from mesenchymal stromal cells (MSC-exo) administered as eye drops notably alleviate GVHD-associated dry eye disease by suppressing inflammation and improving epithelial recovery in mice and humans. In a prospective clinical trial, 28 eyes with refractory GVHD–dry eye disease exhibited substantial relief after MSC-exo treatment, showing reduced fluorescein scores, longer tear-film breakup time, increased tear secretion, and lower OSDI scores. Mechanistically, MSC-exo reprogramed proinflammatory M1 macrophages toward the immunosuppressive M2 via miR-204–mediated targeting of the IL-6/IL-6R/Stat3 pathway. Blockade of miR-204 abolished the effects of MSC-exo, while overloading L929-exo with miR-204 markedly attenuated dry eye. Thus, this study suggests that MSC-exo are efficacious in treating GVHD-associated dry eye disease and highlights miR-204 as a potential therapeutic agent.

Analyses and Correlation of Pathologic and Ocular Cutaneous Changes in Murine Graft versus Host Disease

Graft versus host disease (GVHD) is initiated by donor allo-reactive T cells activated against recipient antigens. Chronic GVHD (cGVHD) is characterized by immune responses that may resemble autoimmune features present in the scleroderma and Sjogren's syndrome. Unfortunately, ocular involvement occurs in approximately 60-90% of patients with cGVHD following allo-hematopoietic stem cell transplants (aHSCT). Ocular GVHD (oGVHD) may affect vision due to ocular adnexa damage leading to dry eye and keratopathy. Several other compartments including the skin are major targets of GVHD effector pathways. Using mouse aHSCT models, the objective was to characterize cGVHD associated alterations in the eye and skin to assess for correlations between these two organs. The examination of multiple models of MHC-matched and MHC-mismatched aHSCT identified a correlation between ocular and cutaneous involvement accompanying cGVHD. Studies detected a "positive" correlation, i.e., when cGVHD-induced ocular alterations were observed, cutaneous compartment alterations were also observed. When no or minimal ocular signs were detected, no or minimal skin changes were observed. In total, these findings suggest underlying cGVHD-inducing pathological immune mechanisms may be shared between the eye and skin. Based on the present observations, we posit that when skin involvement is present in aHSCT patients with cGVHD, the evaluation of the ocular surface by an ophthalmologist could potentially be of value.

Topical neurokinin-1 receptor antagonist Fosaprepitant ameliorates ocular graft-versus-host disease in a preclinical mouse model

PURPOSE

to assess the effect of topical administration of the Neurokin-1 receptor (NK1R) antagonist Fosaprepitant in a pre-clinical model of ocular Graft-versus-Host disease (GVHD).

METHODS

BALB/c mice were pre-conditioned by myeloablative total body irradiation and subjected to allogeneic bone marrow transplantation and mature T cell infusion (BM + T). BM-transplanted mice (BM) were used as controls. Ocular GVHD was specifically assessed by quantifying corneal epithelial damage, tear secretion, blepharitis and phimosis, 3 times/week for 28 days post-transplantation. A group of BM + T mice received Fosaprepitant 10 mg/mL, 6 times/day, topically, from day 7-29 after transplantation. After sacrifice, the expression of NK1R, CD45, CD3, and CXCL10 was quantified in the cornea, conjunctiva, and lacrimal gland by immunohistochemistry.

RESULTS

BM + T mice developed corneal epithelial damage (day 0-29, p < 0.001), blepharitis (day 0-29, p < 0.001), and phimosis (day 0-29, p < 0.01), and experienced decreased tear secretion (day 21, p < 0.01) compared to controls. NK1R was found upregulated in corneal epithelium (p < 0.01) and lacrimal gland (p < 0.01) of BM + T mice. Fosaprepitant administration significantly reduced corneal epithelial damage (p < 0.05), CD45⁺ (p < 0.05) and CD3⁺ (p < 0.01) immune cell infiltration in the cornea and conjunctiva (p < 0.001 and p < 0.001, respectively). In addition, Fosaprepitant reduced the expression of CXCL10 in the cornea (p < 0.05) and in the lacrimal gland (p < 0.05).

CONCLUSIONS

Our results suggest that NK1R represents a novel druggable pathway for the therapy of ocular GVHD.

Keeping an 'eye' on ocular GVHD

Ocular graft versus host disease (GVHD) is a common manifestation in patients undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT). Ocular GVHD affects approximately 10% of patients with acute GVHD and more than 50% of patients with chronic GVHD. Symptoms of dry eye disease are one of the clinical hallmarks of ocular GVHD, and inflammatory changes to the ocular surface, cornea, conjunctiva, eyelids and lacrimal glands have been observed. Less commonly, the posterior segment of the eye is involved in the form of microvascular retinopathy, scleritis or intraretinal and vitreous haemorrhage. Although ocular GVHD does not usually result in permanent visual loss, it often impairs the patient's quality of life and activities of daily living. Regular and more consistent ocular assessment of allo-HSCT patients, including screening prior to transplantation will allow for the earlier detection and treatment of ocular complications associated with GVHD and potentially prevent more severe outcomes. The implementation of additional screening including corneal endothelial cell density assessment and non-invasive analysis of tear biomarkers may be valuable additions to current clinical testing and assist in better detection and clinical intervention in patients with GVHD. This review describes the clinical features, diagnostic criteria and clinical scoring of ocular GVHD, as well as current treatment strategies and potential ophthalmic screening tools for common ocular complications. Further, we describe the clinical and histopathological features of ocular GVHD in preclinical mouse models.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IV. The 2020 Highly morbid forms report

Chronic graft-versus-host disease (GVHD) can be associated with significant morbidity, in part because of nonreversible fibrosis, which impacts physical functioning (eye, skin, lung manifestations) and mortality (lung, gastrointestinal manifestations). Progress in preventing severe morbidity and mortality associated with chronic GVHD is limited by a complex and incompletely understood disease biology and a lack of prognostic biomarkers. Likewise, treatment advances for highly morbid manifestations remain hindered by the absence of effective organ-specific approaches targeting "irreversible" fibrotic sequelae and difficulties in conducting clinical trials in a heterogeneous disease with small patient numbers. The purpose of this document is to identify current gaps, to outline a roadmap of research goals for highly morbid forms of chronic GVHD including advanced skin sclerosis, fasciitis, lung, ocular and gastrointestinal involvement, and to propose strategies for effective trial design. The working group made the following recommendations: (1) Phenotype chronic GVHD clinically and biologically in future cohorts, to describe the incidence, prognostic factors, mechanisms of organ damage, and clinical evolution of highly morbid conditions including long-term effects in children; (2) Conduct longitudinal multicenter studies with common definitions and research sample collections; (3) Develop new approaches for early identification and treatment of highly morbid forms of chronic GVHD, especially biologically targeted treatments, with a special focus on fibrotic changes; and (4) Establish primary endpoints for clinical trials addressing each highly morbid manifestation in relationship to the time point of intervention (early versus late). Alternative endpoints, such as lack of progression and improvement in physical functioning or quality of life, may be suitable for clinical trials in patients with highly morbid manifestations. Finally, new approaches for objective response assessment and exploration of novel trial designs for small populations are required.

Ocular Graft-versus-Host Disease in a Chemotherapy-Based Minor-Mismatch Mouse Model Features Corneal (Lymph-) Angiogenesis

Ocular graft-versus-host disease (oGVHD) is a fast progressing, autoimmunological disease following hematopoietic stem cell transplantation, leading to severe inflammation of the eye and destruction of the lacrimal functional unit with consecutive sight-threatening consequences. The therapeutic “window of opportunity” is narrow, and current treatment options are limited and often insufficient. To achieve new insights into the pathogenesis and to develop new therapeutic approaches, clinically relevant models of oGVHD are desirable. In this study, the ocular phenotype was described in a murine, chemotherapy-based, minor-mismatch GVHD model mimicking early-onset chronic oGVHD, with corneal epitheliopathy, inflammation of the lacrimal glands, and blepharitis. Additionally, corneal lymphangiogenesis was observed as part of oGVHD pathogenesis for the first time, thus opening up the investigation of lymphangiogenesis as a potential therapeutic and diagnostic tool.

Cascade of Inflammatory, Fibrotic Processes, and Stress-Induced Senescence in Chronic GVHD-Related Dry Eye Disease

Ocular graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation. Ocular GVHD affects recipients' visual function and quality of life. Recent advanced research in this area has gradually attracted attention from a wide range of physicians and ophthalmologists. This review highlights the mechanism of immune processes and the molecular mechanism, including several inflammation cascades, pathogenic fibrosis, and stress-induced senescence related to ocular GVHD, in basic spectrum topics in this area. How the disease develops and what kinds of cells participate in ocular GVHD are discussed. Although the classical immune process is a main pathological pathway in this disease, senescence-associated changes in immune cells and stem cells may also drive this disease. The DNA damage response, p16/p21, and the expression of markers associated with the senescence-associated secretory phenotype (SASP) are seen in ocular tissue in GVHD. Macrophages, T cells, and mesenchymal cells from donors or recipients that increasingly infiltrate the ocular surface serve as the source of increased secretion of IL-6, which is a major SASP driver. Agents capable of reversing the changes, including senolytic reagents or those that can suppress the SASP seen in GVHD, provide new potential targets for the treatment of GVHD. Creating innovative therapies for ocular GVHD is necessary to treat this intractable ocular disease.

Update on ocular graft-versus-host disease

Ocular graft-versus-host disease (oGVHD) occurs as a complication following hematopoietic stem cell transplantation and is associated with significant ocular morbidity resulting in a marked reduction in the quality of life. With no current consensus on treatment protocols, management becomes challenging as recurrent oGVHD often refractory to conventional treatment. Most authors now diagnose and grade the disease based on criteria provided by the National Institutes of Health Consensus Conference (NIH CC) or the International Chronic oGVHD (ICCGVHD) consensus group. This article will provide an insight into the diagnostic criteria of oGVHD, its classification, and clinical severity grading scales. The inflammatory process in oGVHD can involve the entire ocular surface including the eyelids, meibomian gland, corneal, conjunctiva, and lacrimal system. The varied clinical presentations and treatment strategies employed to manage them have been discussed in the present study. The recent advances in ocular surface imaging in oGVHD patients such as the use of meibography and in vivo confocal microscopy may help in early diagnosis and prognostication of the disease. Researching tear proteomics and identification of novel potential tear biomarkers in oGVHD patients is an exciting field as they may help in objectively diagnosing the disease and monitoring the response to treatment.

IL-37 As a Potential Biotherapeutics of Inflammatory Diseases

Interleukin-37 (IL-37) was discovered as a new member of pro-inflammatory IL-1 superfamily. However, further studies suggested that IL-37 plays a critical anti-inflammatory role in innate and adaptive immunity. IL-37 may suppress the inflammatory process via intracellular SMAD family member 3 (SMAD3) and extracellular IL-18 Receptor alpha (IL-18Rα) signaling pathway, respectively. Meanwhile, the abnormal expression of IL-37 was observed in immune-mediated inflammatory diseases, such as inflammatory bowel disease, rheumatoid arthritis, atherosclerosis, systemic lupus erythematosus, asthma, and multiple sclerosis, which suggest IL-37 is a potential therapeutic target for these diseases. In this review, we summarize the anti-inflammatory mechanism of IL-37 and discuss the critical roles of IL-37 in the pathogenesis of these diseases. Further studies are required to confirm the effectiveness of IL-37 as a novel target for these inflammatory diseases.

Meibomian Gland Dysfunction in Ocular Graft vs. Host Disease: A Need for Pre-Clinical Models and Deeper Insights

Despite decades of experience with hematopoietic stem cell transplantation, we are still faced with the delicate equipoise of achieving stable ocular health post-transplantation. This is because ocular graft-versus-host disease (oGvHD) following hematopoietic stem cell transplantation frequently occurs (≥50%) among transplant patients. To date, our understanding of the pathophysiology of oGvHD especially the involvement of the meibomian gland is still limited as a result of a lack of suitable preclinical models among other. Herein, the current state of the etiology and, pathophysiology of oGvHD based on existing pre-clinical models are reviewed. The need for additional pre-clinical models and knowledge about the involvement of the meibomian glands in oGvHD are emphasized.

Microbes of the human eye: Microbiome, antimicrobial resistance and biofilm formation

BACKGROUND

The review focuses on the bacteria associated with the human eye using the dual approach of detecting cultivable bacteria and the total microbiome using next generation sequencing. The purpose of this review was to highlight the connection between antimicrobial resistance and biofilm formation in ocular bacteria.

METHODS

Pubmed was used as the source to catalogue culturable bacteria and ocular microbiomes associated with the normal eyes and those with ocular diseases, to ascertain the emergence of anti-microbial resistance with special reference to biofilm formation.

RESULTS

This review highlights the genetic strategies used by microorganisms to evade the lethal effects of anti-microbial agents by tracing the connections between candidate genes and biofilm formation.

CONCLUSION

The eye has its own microbiome which needs to be extensively studied under different physiological conditions; data on eye microbiomes of people from different ethnicities, geographical regions etc. are also needed to understand how these microbiomes affect ocular health.

The role of Th17 immunity in chronic ocular surface disorders

Th17 cells have been implicated in the pathogenesis of numerous inflammatory and autoimmune conditions. At the ocular surface, Th17 cells have been identified as key effector cells in chronic ocular surface disease. Evidence from murine studies indicates that following differentiation and expansion, Th17 cells migrate from the lymphoid tissues to the eye, where they release inflammatory cytokines including, but not limited to, their hallmark cytokine IL-17A. As the acute phase subsides, a population of long-lived memory Th17 cells persist, which predispose hosts both to chronic inflammation and severe exacerbations of disease; of great interest is the small subset of Th17/1 cells that secrete both IL-17A and IFN-γ in acute-on-chronic disease exacerbation. Over the past decade, substantial progress has been made in deciphering how Th17 cells interact with the immune and neuroimmune pathways that mediate chronic ocular surface disease. Here, we review (i) the evidence for Th17 immunity in chronic ocular surface disease, (ii) regulatory mechanisms that constrain the Th17 immune response, and (iii) novel therapeutic strategies targeting Th17 cells.

Macrophage regulation of graft-vs-host disease

Hematopoietic stem cell transplantation has become a curative choice of many hematopoietic malignancy, but graft-vs-host disease (GVHD) has limited the survival quality and overall survival of hematopoietic stem cell transplantation. Understanding of the immune cells’ reaction in pathophysiology of GVHD has improved, but a review on the role of macrophages in GVHD is still absent. Studies have observed that macrophage infiltration is associated with GVHD occurrence and development. In this review, we summarize and analyze the role of macrophages in GVHD based on pathophysiology of acute and chronic GVHD, focusing on the macrophage recruitment and infiltration, macrophage polarization, macrophage secretion, and especially interaction of macrophages with other immune cells. We could conclude that macrophage recruitment and infiltration contribute to both acute and chronic GVHD. Based on distinguishing pathology of acute and chronic GVHD, macrophages tend to show a higher M1/M2 ratio in acute GVHD and a lower M1/M2 ratio in chronic GVHD. However, the influence of dominant cytokines in GVHD is controversial and inconsistent with macrophage polarization. In addition, interaction of macrophages with alloreactive T cells plays an important role in acute GVHD. Meanwhile, the interaction among macrophages, B cells, fibroblasts, and CD4+ T cells participates in chronic GVHD development.

Immunological considerations and concerns as pertinent to whole eye transplantation

PURPOSE OF REVIEW

The advent of clinical vascularized composite allotransplantation (VCA), offers hope for whole eye transplantation (WET) in patients with devastating vison loss that fails or defies current treatment options. Optic nerve regeneration and reintegration remain the overarching hurdles to WET. However, the realization of WET may indeed be limited by our lack of understanding of the singular immunological features of the eye as pertinent to graft survival and functional vision restoration in the setting of transplantation.

RECENT FINDINGS

Like other VCA, such as the hand or face, the eye includes multiple tissues with distinct embryonic lineage and differential antigenicity. The ultimate goal of vision restoration through WET requires optimal immune modulation of the graft for successful optic nerve regeneration. Our team is exploring barriers to our understanding of the immunology of the eye in the context of WET including the role of immune privilege and lymphatic drainage on rejection, as well as the effects ischemia, reperfusion injury and rejection on optic nerve regeneration.

SUMMARY

Elucidation of the unique immunological responses in the eye and adnexa after WET will provide foundational clues that will help inform therapies that prevent immune rejection without hindering optic nerve regeneration or reintegration.

Complement and CD4+ T cells drive context-specific corneal sensory neuropathy

Whether complement dysregulation directly contributes to the pathogenesis of peripheral nervous system diseases, including sensory neuropathies, is unclear. We addressed this important question in a mouse model of ocular HSV-1 infection, where sensory nerve damage is a common clinical problem. Through genetic and pharmacologic targeting, we uncovered a central role for C3 in sensory nerve damage at the morphological and functional levels. Interestingly, CD4 T cells were central in facilitating this complement-mediated damage. This same C3/CD4 T cell axis triggered corneal sensory nerve damage in a mouse model of ocular graft-versus-host disease (GVHD). However, this was not the case in a T-dependent allergic eye disease (AED) model, suggesting that this inflammatory neuroimmune pathology is specific to certain disease etiologies. Collectively, these findings uncover a central role for complement in CD4 T cell-dependent corneal nerve damage in multiple disease settings and indicate the possibility for complement-targeted therapeutics to mitigate sensory neuropathies.

Modeling Chronic Graft-versus-Host Disease in MHC-Matched Mouse Strains: Genetics, Graft Composition, and Tissue Targets

Graft-versus-host disease (GVHD) remains a major complication of allogeneic hematopoietic cell transplantation. Acute GVHD (aGVHD) results from direct damage by donor T cells, whereas the biology of chronic GVHD (cGVHD) with its autoimmune-like manifestations remains poorly understood, mainly because of the paucity of representative preclinical models. We examined over an extended time period 7 MHC-matched, minor antigen-mismatched mouse models for development of cGVHD. Development and manifestations of cGVHD were determined by a combination of MHC allele type and recipient strain, with BALB recipients being the most susceptible. The C57BL/6 into BALB.B combination most closely modeled the human syndrome. In this strain combination moderate aGVHD was observed and BALB.B survivors developed overt cGVHD at 6 to 12 months affecting eyes, skin, and liver. Naïve CD4⁺ cells caused this syndrome as no significant pathology was induced by grafts composed of purified hematopoietic stem cells (HSCs) or HSC plus effector memory CD4⁺ or CD8⁺ cells. Furthermore, co-transferred naïve and effector memory CD4⁺ T cells demonstrated differential homing patterns and locations of persistence. No clear association with donor Th17 cells and the phenotype of aGVHD or cGVHD was observed in this model. Donor CD4⁺ cells caused injury to medullary thymic epithelial cells, a key population responsible for negative T cell selection, suggesting that impaired thymic selection was an underlying cause of the cGVHD syndrome. In conclusion, we report for the first time that the C57BL/6 into BALB.B combination is a representative model of cGVHD that evolves from immunologic events during the early post-transplant period.

Neutrophil extracellular traps (NETs) contribute to pathological changes of ocular graft-vs.-host disease (oGVHD) dry eye: Implications for novel biomarkers and therapeutic strategies

PURPOSE

To investigate the role of neutrophil extracellular traps (NETs) and NET-associated proteins in the pathogenesis of oGVHD and whether dismantling of NETs with heparin reduces those changes.

METHODS

Ocular surface washings from oGVHD patients and healthy subjects were analyzed. Isolated peripheral blood human neutrophils were stimulated to generate NETs and heparinized NETs. We performed in vitro experiments using cell lines (corneal epithelial, conjunctival fibroblast, meibomian gland (MG) epithelial and T cells), and in vivo experiments using murine models, and compared the effects of NETs, heparinized NETs, NET-associated proteins and neutralizing antibodies to NET-associated proteins.

RESULTS

Neutrophils, exfoliated epithelial cells, NETs and NET-associated proteins (extracellular DNA, Neutrophil Elastase, Myeloperoxidase, Oncostatin M (OSM), Neutrophil gelatinase-associated lipocalin (NGAL) and LIGHT/TNFSF14) are present in ocular surface washings (OSW) and mucocellular aggregates (MCA). Eyes with high number of neutrophils in OSW have more severe signs and symptoms of oGVHD. NETs (and OSM) cause epitheliopathy in murine corneas. NETs (and LIGHT/TNFSF14) increase proliferation of T cells. NETs (and NGAL) inhibit proliferation and differentiation of MG epithelial cells. NETs enhance proliferation and myofibroblast transformation of conjunctival fibroblasts. Sub-anticoagulant dose Heparin (100 IU/mL) dismantles NETs and reduces epithelial, fibroblast, T cell and MG cell changes induced by NETs.

CONCLUSION

NETs and NET-associated proteins contribute to the pathological changes of oGVHD (corneal epitheliopathy, conjunctival cicatrization, ocular surface inflammation and meibomian gland disease). Our data points to the potential of NET-associated proteins (OSM or LIGHT/TNFSF14) to serve as biomarkers and NET-dismantling biologics (heparin eye drops) as treatment for oGVHD.

Sjögren's Syndrome, Non-Sjögren's Syndrome, and Graft-Versus-Host Disease Related Dry Eye

I have reviewed available literature on dry eye related to Sjögren's syndrome (SS), non-Sjögren's syndrome (non-SS), and graft-versus-host disease (GVHD) to examine aqueous tear deficient dry eye as a subtype of dry eye. This section will focus on clinical studies regarding those subtypes of dry eye. I searched the PubMed database from 1990-2017 for discussion of clinical features, diagnostic criteria, and risk factors of SS, non-SS, and GVHD-related dry eye. In addition, therapeutic options for each subtype of dry eye are described. Although the clinical presentations of SS and chronic graft-versus-host disease (cGVHD) are similar, ocular surface fibrotic changes are characteristic of ocular GVHD but not SS- or non-SS-related dry eye. Recently, diagnostic criteria for each disease have been proposed and include the American College of Rheumatology/European League Against Rheumatism (ACR-EULAR) for SS and the International Chronic Ocular GVHD consensus criteria. Although there has been gradual progress, there are currently no specific therapies and few approved treatment options for these intractable diseases, including SS and GVHD. As judged by the findings, these subtypes of dry eye are different clinical entities from simple dry eye. Therefore, novel therapies, specific to these subtypes of dry eye, may be required in the future.

Longitudinal analysis of meibomian gland dropout in patients with ocular graft-versus-host disease

PURPOSE

To evaluate morphological changes in meibomian glands (MGs) over 1 year in patients diagnosed with chronic ocular graft-versus-host disease (GVHD), and to determine the association between MG loss and ocular surface parameters in such patients.

METHODS

This retrospective, observational study included 37 patients diagnosed with ocular GVHD who were followed-up for at least 1 year in the ophthalmology department. All patients received treatment during the follow-up period. The Ocular Surface Disease Index (OSDI) score, tear breakup time (TBUT), corneal staining score, lid margin score, Schirmer test I value, and noncontact infrared meibography findings were evaluated at baseline and after 1 year of follow-up for ocular GVHD. Both eyes were included in the analyses.

RESULTS

OSDI (p = 0.0391), corneal fluorescein scores (p = 0.0352 and 0.0181 for the right and left eyes, respectively), and upper and lower eyelid meiboscores (right eye: p = 0.0039 and 0.0156, respectively: left eye: p = 0.0273 and 0.0156, respectively) were significantly higher at 1 year than at baseline. Infrared meibography showed MG loss in 18.9% of eyes, improvement in 5.4% of eyes, and no changes in 75.7% of eyes, respectively. The Schirmer value for the right eye negatively correlated with the upper eyelid meiboscore at 1 year (p = 0.0103, r = -0.46), whereas the corneal fluorescein score for the left eye positively correlated with both upper and lower eyelid meiboscores at 1 year (p = 0.0368, r = 0.40; p = 0.0387, r = 0.39, respectively).

CONCLUSIONS

Rapid and aggressive MG destruction may occur in patients with ocular GVHD. Further studies with larger patient samples and longer follow-up periods are mandatory to validate these conclusions.

Subconjunctival injection of mesenchymal stromal cells protects the cornea in an experimental model of GVHD

PURPOSE

To evaluate the therapeutic effect of subconjunctival injection of human mesenchymal stromal cells (hMSCs) in the cornea of mice with graft versus host disease (GVHD).

METHODS

GVHD was induced in mice after hematopoietic stem cell transplantation (HSCT) between MHC-mismatched mouse strains. Subconjunctival injection of hMSCs was applied at day 10 post-HSCT. Infiltration of CD3⁺ cells in the cornea and epithelial alterations were analyzed by immunofluorescence. Tear was assessed using the PRT test and TearLab Osmolarity System. qPCR was used to evaluate changes in cytokines, Pax6 and Sprr1b expression. To evaluate the effect of irradiation, we analyzed the expression of these genes in TBI mice.

RESULTS

Immune cell invasion occurs in mice with GVHD, as shown by the presence of CD3⁺ cells in the cornea. Interestingly, eyes treated with hMSC did not present CD3⁺ cells. Tear osmolarity was increased in GVHD eyes, but not in treated eyes. TNFa expression was highly increased in all corneas except in Control and treated eyes. Pax6 in corneal epithelium showed a similar pattern in GVHD and Control mice, and its gene expression was enhanced in GVHD corneas. In contrast, Pax6 was reduced in GVHD + MSC corneas. We also found an increase in SPRR1B staining in GVHD eyes that was lower in GVHD + MSC mice, demonstrating that corneal keratinization is less frequent after treatment with hMSC.

CONCLUSIONS

The treatment with hMSCs by subconjunctival injection is effective in reducing corneal inflammation and squamous metaplasia in ocular GVHD (oGVHD). Local treatment with hMSCs is a promising strategy for oGVHD.

Ocular graft-versus-host disease after hematopoietic cell transplantation: Expert review from the Late Effects and Quality of Life Working Committee of the CIBMTR and Transplant Complications Working Party of the EBMT

Ocular graft-versus-host disease (GVHD) occurs in more than half of patients who develop chronic GVHD after allogeneic hematopoietic cell transplantation (HCT), causing prolonged morbidity, which affects activities of daily living and quality of life. Here we provide an expert review of ocular GVHD in a collaboration between transplant physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Recent updates in ocular GVHD, regarding pathophysiology, preclinical models, risk factors, prevention, screening, diagnosis, response criteria, evaluation measures, and treatment are discussed in this review. Ocular GVHD has at least three biological processes: lacrimal gland dysfunction, meibomian gland dysfunction, and corneoconjunctival inflammation. Preclinical models have found several novel pathogenic mechanisms, including renin angiotensin system and endoplasmic reticulum stress signaling that can be targeted by therapeutic agents. Many studies have identified reliable tests for establishing diagnosis and response assessment of ocular GVHD. Efficacy of systemic and topical treatment for ocular GVHD is summarized. It is important for all health professionals taking care of HCT recipients to have adequate knowledge of ocular GVHD for optimal care.

Ocular Graft-versus-Host Disease after Hematopoietic Cell Transplantation: Expert Review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

Ocular graft-versus-host disease (GVHD) occurs in more than one-half of patients who develop chronic GVHD after allogeneic hematopoietic cell transplantation (HCT), causing prolonged morbidity that affects activities of daily living and quality of life. Here we provide an expert review of ocular GVHD in a collaboration between transplantation physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Recent updates in ocular GVHD regarding pathophysiology, preclinical models, risk factors, prevention, screening, diagnosis, response criteria, evaluation measures, and treatment are discussed. Ocular GVHD involves at least 3 biological processes: lacrimal gland dysfunction, meibomian gland dysfunction, and corneoconjunctival inflammation. Preclinical models have identified several novel pathogenic mechanisms, including the renin angiotensin system and endoplasmic reticulum stress signaling, which can be targeted by therapeutic agents. Numerous studies have identified reliable tests for establishing diagnosis and response assessment of ocular GVHD. The efficacy of systemic and topical treatment for ocular GVHD is summarized. It is important that all health professionals caring for HCT recipients have adequate knowledge of ocular GVHD to provide optimal care.

Manifestation of Clinical Categories of Ocular Graft-versus-Host Disease

This study aims at improving the understanding of the subjective symptoms and signs of two different clinical categories of ocular graft-versus-host disease. After reviewing and screening 193 posthematopoietic stem cell transplantation (HSCT) patients of Peking University Third Hospital, we enrolled 148 (21 acute ocular GVHD, 127 chronic ocular GVHD). Patients' subjective symptoms, ocular parameters, and typical ocular signs were collected and evaluated at the same visit. Classic acute ocular GVHD patients had variable levels of conjunctival involvement but few had keratopathy; increased mucus secretion (21 of 21, 100.0%), red eye (19 of 21, 90.5%), and lacrimation (11 of 21, 52.4%) were the characteristic symptoms. The classic chronic ocular group had severe eye dryness and further corneal lesions, including filamentary keratitis, corneal ulcer, and corneal vascularization. Eye dryness (115 of 127, 90.6%), increased fibrous secretion (53 of 127, 41.7%), photophobia (50 of 127, 39.4%), and alacrimia (45 of 127, 35.4%) were the most common symptoms. Although 44.1% (56 of 127) of these patients had a history of acute ocular GVHD episodes, most were overlooked, so they did not receive stepwise evaluation and treatment. Management of ocular GVHD is very challenging and requires cooperation among disciplines.

Ocular Surface and Tear Film Characteristics in a Sclerodermatous Chronic Graft-Versus-Host Disease Mouse Model

PURPOSE

To report the characteristics of the ocular surface in a previously established sclerodermatous chronic graft-versus-host disease (cGVHD) mouse model.

METHODS

The ocular surface features and tear film parameters of the mouse model were assessed by histopathology, immunohistochemistry, electron microscopy, quantitative polymerase chain reaction, and flow cytometry.

RESULTS

The mice exhibited loss of body weight and decreased tear secretion (P < 0.001), mimicking the clinical features of patients with cGVHD. Ocular examination demonstrated significant corneal epithelial staining, conjunctival (P < 0.001), and eyelid (P = 0.015) fibrosis compared with the control mice. The density of both goblet cells (P = 0.043) and microvilli was lower (P < 0.001), and the microvilli were shorter (P = 0.007) in the conjunctiva of cGVHD mice than those of the controls. The immunohistochemical studies demonstrated greater expression of CD45, CD4, and CD8 cells in the conjunctiva and eyelid tissues compared with the controls (P < 0.05 for all). In addition, reduced Forkhead box P3 (Foxp3)+ cells were found in both the peripheral blood (P < 0.001) and conjunctiva (P = 0.042) of cGVHD mice compared with the controls.

CONCLUSIONS

The constellation of these findings suggests that the sclerodermatous cGVHD mouse model well recapitulates ocular manifestations of cGVHD in humans. This model can be used to study the mechanisms involved in the pathogenesis and treatment of chronic ocular graft-versus-host disease.

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

Novel Scoring Criteria for the Evaluation of Ocular Graft-versus-Host Disease in a Preclinical Allogeneic Hematopoietic Stem Cell Transplantation Animal Model

Ocular complications occur after transplantation in 60% to 90% of chronic graft-versus-host disease (GVHD) patients and significantly impair vision-related quality of life. Ocular surface inflammation and dry eye disease are the most common manifestations of ocular GVHD. Ocular GVHD can be viewed as an excellent preclinical model that can be studied to understand the immune pathogenesis of this common and debilitating disease. A limitation of this is that only a few experimental models mimic the ocular complications after hematopoietic stem cell transplantation (HSCT) and have focused on the acute GVHD process. To address this issue, we used a preclinical animal model developed by our group where ocular involvement was preceded by systemic GVHD to gain insight regarding the contributing immune mechanisms. Employing this "matched unrelated donor" model enabled the development of clinical scoring criteria, which readily identified different degrees of ocular pathology at both the ocular surface and adnexa, dependent on the level of conditioning before HSCT. As far as we are aware, we report for the first time that these clinical and immune responses occur not only on the ocular surface, but they also heavily involve the lid margin region. In total, the present study reports a preclinical scoring model that can be applied to animal models as investigators look to further explore GVHD's immunologic effects at the level of the ocular surface and eyelid adnexa compartments. We speculate that future studies will use this clinical scoring index in combination with what is recognized histologically and correlated with serum biomarkers identified in chronic/ocular GVHD.