Ocular graft-versus-host disease (oGVHD): From A to Z

Tear fluid derived extracellular vesicles for new biomarker discovery

Various cell types release extracellular vesicles (EVs) containing proteins, DNA, and RNA essential for intercellular communication. The bioactive molecules from EVs can reflect disease status and monitor progression, while their communication abilities suggest therapeutic potential. We will review various EV isolation methods, EV-enriched fluids, and studies analyzing differential mi-RNA and protein levels extracted from EVs. Specifically, tear-derived EVs, which protect their molecular content and allow for real-time monitoring of ocular conditions such as Dry Eye Disease (DED), Sjögren's disease (SJD), Ocular graft-versus-host disease (oGVHD), and Diabetic Retinopathy (DR), which all currently remain undiagnosed in patients. EVs also provide potential as carriers for gene transfer, and mesenchymal stem cell (MSCs)-derived EVs are shown to be immunomodulatory, demonstrating promise for autoimmune ocular diseases. Through the multi-omic analysis of tear-fluid content, EVs are promising biomarkers and therapeutic agents in ocular diseases.

Desiccation stress triggers and exacerbates experimental ocular Graft-versus-host-disease

INTRODUCTION

Chronic ocular graft-versus-host disease (oGVHD) is one of the most common complications after allogeneic hematopoietic stem cell transplantation (aHSCT). Recent studies indicate that desiccating stress by air-conditioning in transplantation wards increases the incidence of oGVHD. To test the hypothesis that experimental desiccating stress is a risk factor for oGVHD a mouse model of oGVHD was subjected to experimental desiccating stress.

MATERIALS/METHODS

A previously established chemo-induced minor-mismatch mouse model of oGVHD was used. One group was challenged with desiccating stress for 18 days and compared to non-desiccated GVHD animals. Clinical phenotyping was performed weekly and ocular tissue and regional lymph nodes were collected on days 7 and 28 for flow-cytometry, tear film cytokine analysis, histology for corneal lymphatics and dendritic cell counts, and corneal gene expression.

RESULTS

Desiccating stress leads to significant earlier and more severe systemic and oGVHD accompanied by higher numbers of activated corneal dendritic cells, higher expression of TNF in tear film and earlier corneal lymphangiogenesis. Gene expression analysis suggests that systemic GVHD severity may influence oGVHD. Different inflammatory pathways are upregulated at d28 following desiccating stress in contrast to non-desiccated GVHD.

CONCLUSIONS

The data presented strengthens the hypothesis, that desiccating stress during aHSCT is a risk factor for oGVHD. Together with already published clinical data, there is increasing evidence that implicates protecting patients from desiccation during the engraftment of allogeneic hematopoietic stem cells. Furthermore, specific prophylactic therapies should be developed and tested to reduce the incidence and severity of oGVHD.

Severe corneal manifestations of graft-versus-host disease: Experience of a tertiary referral center

PURPOSE

Graft-versus-host disease (GVHD) is a common complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). GVHD may affect several organs, including ocular manifestations, ranging from dry eye syndrome to sight-threatening corneal ulceration or perforation. Limited information is available about characteristics and treatments of ocular GVHD and its relation to general prognosis.

METHODS

We retrospectively analyzed data from 140 patients from a tertiary ophthalmological center and confronted it with systemic data from a national bone marrow transplantation database.

RESULTS

Most patients were treated with artificial tears, vitamin A ointment, topical anti-inflammatory agents (mostly cyclosporin and steroid drops), autologous serum eye drops, scleral lenses and punctal silicone plugs. We identified a high proportion of severe ocular manifestations, such as corneal ulceration or perforation (33 patients, 23.6 %), occurring with a median of 39 months (interquartile range (IQR): 16-96) after transplantation. Overall survival did not differ in patients with severe to non-severe ocular GVHD (5-year mortality of 8 % without and 13 % with severe ocular involvement, p = 0.53 for survival curves comparisons). Multivariate analysis revealed that male patients and HLA mismatch allo-HSCT were independently associated with an increased risk of severe ocular manifestations. Moreover, a high proportion of complications occurred after non-steroidal anti-inflammatory drug (NSAID) treatments.

CONCLUSIONS

Patients with GVHD should therefore undergo close ophthalmological monitoring and they should not, in any case, be treated with local ocular NSAIDs, due to the severity of potential complications.

Label-free quantitative imaging of conjunctival goblet cells

PURPOSE

To introduce and validate quantitative oblique back-illumination microscopy (qOBM) as a label-free, high-contrast imaging technique for visualizing conjunctival goblet cells (GCs) and assessing their functional changes.

METHODS

qOBM was developed in conjunction with moxifloxacin-based fluorescence microscopy (MBFM), which was used for validating GC imaging. Initial validation was conducted with polystyrene beads, followed by testing on normal mouse conjunctiva under both ex-vivo and in-vivo conditions. Longitudinal qOBM imaging was performed on ex-vivo mouse conjunctiva exposed to hyperosmotic stress (induced by 1000 mOsm/kg NaCl solution) and normal saline (300 mOsm/kg balanced salt solution, BSS). Imaging was conducted at baseline and at 15- and 30-min instillation. Results were compared to those of MBFM and periodic acid-Schiff (PAS) staining. A similar longitudinal study was performed in-vivo, and the outcomes were analyzed.

RESULTS

qOBM accurately imaged polystyrene beads, with measured phase delays matching theoretical predictions. In normal mouse conjunctiva, qOBM visualized GCs in high contrast, confirmed by MBFM, and the average phase delay was 0.59 ± 0.25 radians. Under hyperosmotic stress, qOBM detected a significant reduction in GC phase delays, decreasing to levels of the surrounding tissue (-0.07 ± 0.14 radians). In normal conditions, no notable changes were observed in GCs. In-vivo imaging results were consistent with ex-vivo findings. Statistical analysis further characterized these changes. The results were consistent with MBFM and PAS staining.

CONCLUSIONS

qOBM is a high-contrast, label-free imaging modality that enables the functional assessment of GCs. This technique holds significant potential for advancing research and clinical diagnostics related to ocular surface diseases.

A review of the application of in-vivo confocal microscopy on conjunctival diseases

Over the past few decades, the expanded applications of in-vivo confocal microscopy (IVCM) have greatly enhanced the knowledge of a variety of conjunctival diseases. IVCM allows non-invasively detailed observation of tarsal, palpebral and bulbar conjunctiva, from the superficial to the substantia propria at the cellular level. IVCM has been shown as a powerful tool for the assessment of morphological changes in both physiological and pathological conditions. High-resolution images of different cellular phenotypes, together with quantifiable results, open new insights into understanding the mechanisms of conjunctival diseases, as well as provide valuable and longitudinal information for the diagnosis and therapeutic evaluation. This review aims to provide an overview of the current knowledge on the applications of IVCM on conjunctival disorders, including aging changes, dry eye-related morphological changes, glaucoma and glaucoma surgery-related morphological changes, conjunctival neoplasm, pterygium, allergic conjunctivitis, trachomatous scarring, and the conjunctiva-associated lymphoid tissue (CALT) changes. In this review, we highlight the key findings of previous studies and discusses the current limitations and challenges of IVCM in assessing the structural characteristics of the conjunctiva. Furthermore, we consider possible future directions for unlocking the full potential of IVCM applications. The insights presented here will contribute to a more comprehensive understanding of the applications of IVCM in conjunctival diseases.

Concurrent Limbal Stem Cell Deficiency and Mild Neurotrophic Keratopathy in Graft-Vs-Host Disease

PURPOSE

The purpose of this study was to delineate the concurrence of limbal stem cell deficiency (LSCD) and neurotrophic keratopathy in patients with ocular graft-vs-host disease (oGVHD).

METHODS

Medical records of patients with oGVHD were reviewed. Parameters collected included corneal sensitivity measured by using a noncontact esthesiometer, corneal fluorescein staining score (National Eye Institute grading scale), tear volume (Schirmer I test), and subbasal nerve density and limbal structure assessed by in vivo confocal microscopy.

RESULTS

Twenty-eight patients (mean age: 60.8 ± 10.4 years) with oGVHD were included; 50% (n = 14) had partial LSCD (P-LSCD), and 32% (n = 9) had complete LSCD (C-LSCD). Patients with C-LSCD showed significantly reduced total nerve density and branch nerve density compared with those with P-LSCD ( P < 0.02, P < 0.04) and no LSCD ( P < 0.01, P = 0.02). Dendritic cell density was significantly higher in the C-LSCD group compared with the no LSCD group ( P < 0.05). Corneal sensitivity was significantly reduced in patients with C-LSCD compared with those with P-LSCD ( P = 0.01) and no LSCD ( P < 0.02). Patients with C-LCSD had higher corneal fluorescein staining scores than patients with P-LSCD ( P < 0.01) and no LSCD ( P = 0.02).

CONCLUSIONS

This study highlights a significant concurrence of LSCD and neurotrophic keratopathy in patients with oGVHD, underscoring the link between inflammation, neurodegeneration, and loss of stem cell function.

Advances in the ocular complications after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) has benefited an increasing number of patients with hematological disease in the clinic. It is a curative therapy for malignant and nonmalignant hematological diseases. With the advancement and further clinical application of HSCT in recent years, the life expectancy of patients has increased, but complications have become more common. The occurrence of ocular complications is receiving increasing attention because they can seriously affect the quality of life of patients. Ocular complications require increased attention from clinicians because of their negative impact on patients and increasing incidence. Most of recent reports on posttransplant ocular complications involve ocular manifestations of graft-versus-host disease (GVHD), and a few ocular complications that do not originate from GVHD have also been reported. This review summarizes the diagnosis, scoring criteria, pathophysiology, and clinical manifestations of and common therapies for ocular graft-versus-host disease(oGVHD) after HSCT, and includes a description of some rare cases and novel therapies.

Delayed diagnosis of ocular graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

PURPOSE

To investigate the delayed diagnosis of chronic ocular graft-versus-host disease (coGVHD) after allogeneic hematopoietic stem cell transplantation (alloHCT), and further analyze potential confounding factors.

METHODS

This cross-sectional study included 118 patients newly diagnosed as coGVHD after alloHCT at Zhongshan Ophthalmic Center, Sun Yat-sen University. All participants finished the flow path of medical history taking, detailed ophthalmological examination and questionnaire-based survey. coGVHD was diagnosed and graded by International Chronic Ocular GVHD Consensus Group (ICOGCG) criteria. Lag time of diagnosis was defined as interval between noting of ocular symptoms and confirmed diagnosis of coGVHD (TN-D). We further compared the clinical parameters between groups categorized by the median TN-D as medium and long delay groups.

RESULTS

The median TN-D was 6.3 [IQR 2.8-14.5] months. Most coGVHD patients underwent delayed diagnosis of coGVHD longer than 3 months (70 %, 83 of 118), with 90 of 118 diagnosed as severe coGVHD (76 %). The long delay group exhibited higher ICOGCG scores (10 [IQR 9-10.5] vs. 9 [IQR 8-10], P = 0.039) and more pronounced ocular signs, including conjunctival injection, meibomian gland loss, fibrotic tarsal conjunctiva, symblepharon, and corneal complications (all P < 0.05). Delayed diagnosis was strikingly correlated with seeking ophthalmic medical care twice or more prior to diagnosis (adjusted OR = 5.42, 95%CI: 1.40-21.06, P = 0.015) and accurate knowledge of ocular discomfort symptoms in coGVHD (adjusted OR = 0.29, 95%CI: 0.08-1.00, P = 0.050).

CONCLUSIONS

Delayed diagnosis of coGVHD, associated with disease severity, was common among alloHCT recipients in southern China. Improving patient education and the awareness of ophthalmologists may facilitate early diagnosis of coGVHD.

Current Approaches for the Prevention and Treatment of Acute and Chronic GVHD

Whereas aGVHD has strong inflammatory components, cGVHD displays autoimmune and fibrotic features; incidence and risk factors are similar but not identical; indeed, the aGVHD is the main risk factor for cGVHD. Calcineurin Inhibitors (CNI) with either Methotrexate (MTX) or Mycophenolate (MMF) still represent the standard prophylaxis in HLA-matched allogeneic stem cell transplantation (HSCT); other strategies focused on ATG, Post-Transplant Cyclophosphamide (PTCy), Abatacept and graft manipulation. Despite the high rate, first-line treatment for aGVHD is represented by corticosteroids, and Ruxolitinib is the standard second-line therapy; investigational approaches include Microbiota transplant and the infusion of Mesenchymal stem cells. GVHD is a pleiotropic disease involving any anatomical district; also, Ruxolitinib represents the standard for steroid-refractory cGVHD in this setting. It is a pleiotropic disease involving any anatomical district; also, Ruxolitinib represents the standard for steroid-refractory cGVHD in this setting. Extracorporeal Photopheresis (ECP) is still an option used for steroid refractoriness or to achieve a steroid-sparing. For Ruxolitinib-refractory cGVHD, Belumosudil and Axatilimab represent the most promising agents. Bronchiolitis obliterans syndrome (BOS) still represents a challenge; among the compounds targeting non-immune effectors, Alvelestat, a Neutrophil elastase inhibitor, seems promising in BOS. Finally, in both aGVHD and cGVHD, the association of biological markers with specific disease manifestations could help refine risk stratification and the availability of reliable biomarkers for specific treatments.

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). Although oGVHD significantly impacts the quality of life of affected survivors, it often goes unrecognized, particularly in 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, and highlights the warning signs of early disease development to facilitate prompt referral of oGVHD suspects for ocular specialist care. Along with introducing a comprehensive list of treatment options, this review emphasizes basic therapeutic strategy and options that can be safely and effectively initiated by any care provider. We believe in empowering patients as well as care providers beyond disciplinary boundaries to provide the most cohesive and integrated care in a multidisciplinary approach.

Advances in Extracellular-Vesicles-Based Diagnostic and Therapeutic Approaches for Ocular Diseases

Extracellular vesicles (EVs) are nanoscale membrane vesicles of various sizes that can be secreted by most cells. EVs contain a diverse array of cargo, including RNAs, lipids, proteins, and other molecules with functions of intercellular communication, immune modulation, and regulation of physiological and pathological processes. The biofluids in the eye, including tears, aqueous humor, and vitreous humor, are important sources for EV-based diagnosis of ocular disease. Because the molecular cargos may reflect the biology of their parental cells, EVs in these biofluids, as well as in the blood, have been recognized as promising candidates as biomarkers for early diagnosis of ocular disease. Moreover, EVs have also been used as therapeutics and targeted drug delivery nanocarriers in many ocular disorders because of their low immunogenicity and superior biocompatibility in nature. In this review, we provide an overview of the recent advances in the field of EV-based studies on the diagnosis and therapeutics of ocular disease. We summarized the origins of EVs applied in ocular disease, assessed different methods for EV isolation from ocular biofluid samples, highlighted bioengineering strategies of EVs as drug delivery systems, introduced the latest applications in the diagnosis and treatment of ocular disease, and presented their potential in the current clinical trials. Finally, we briefly discussed the challenges of EV-based studies in ocular disease and some issues of concern for better focusing on clinical translational studies of EVs in the future.

Early intervention with oral mucosal barrier Protective agents in chronic oral graft-versus-host disease: a retrospective cohort study

BACKGROUND

Preventing the progression of chronic oral graft-versus-host disease (cGVHD) is essential for maintaining oral health, improving quality of life, minimizing functional impairment, reducing systemic complications, and addressing treatment challenges.

PURPOSE

To evaluate the effectiveness of early intervention with oral mucosal barrier protective agents in preventing the progression of cGVHD and its impact on oral health, quality of life, and treatment response.

METHODS

This retrospective cohort study included 75 participants, with 34 in the non-oral mucosal barrier protective agent group and 41 in the oral mucosal barrier protective agent group. Baseline characteristics, oral mucosal health parameters, quality of life assessments, and curative effect data were collected and compared between the two study groups.

RESULTS

The group receiving oral mucosal barrier protectants (n = 41) exhibited significantly lower severity of oral mucositis compared to the group without such protectants (n = 34) (2.12 ± 0.48 vs. 2.56 ± 0.63, P = 0.001) and the incidence of complications was significantly lower in the group receiving oral mucosal barrier protectants (P < 0.05). Additionally, the quality of life assessment showed marked improvements in somatization, emotional management, and social reintegration in the oral mucosal barrier protectant group compared to the group without these protectants (P < 0.05). Furthermore, the assessment of treatment efficacy revealed significantly higher rates of both complete and partial responses in the oral mucosal barrier protectant group, along with a notable reduction in disease progression compared to the group without these protectants (P < 0.001).

CONCLUSION

Early intervention with oral mucosal barrier protective agents was associated with improved oral health parameters, enhanced quality of life, and a more favorable treatment response in the context of cGVHD.

Remarkable improvement of symptoms and signs of severe dry eye treated by ocular immersion hydrotherapy

Key Clinical Message

Traditional treatment options are often insufficient in treating severe dry eyes caused by systemic diseases. This case demonstrates that ocular immersion hydrotherapy significantly alleviated symptoms and ocular surface inflammation in ocular graft-versus-host disease. Based on these findings, we propose it as a promising option for managing severe dry eye disease.

Abstract

This case report investigates the efficacy of ocular immersion hydrotherapy (OIH) in treating severe dry eye secondary to ocular graft-versus-host disease (oGVHD). A 35-year-old female with a history of acute myeloid leukemia-M2 and subsequent hematopoietic stem cell transplantation (HSCT) developed high-intensity oGVHD unresponsive to conventional treatments, including topical corticosteroids and lubricants. We introduced OIH, utilizing sterilized swimming goggles filled with intraocular irrigating solutions, providing a moist microenvironment for the ocular surface. Symptoms were significantly relieved after treatment. Corneal filaments and epithelial defects were significantly reduced, and in vivo confocal microscopy (IVCM) demonstrated resolution of inflammation and reappearance of corneal nerves. This case indicates that OIH could be a promising therapeutic approach for severe dry eye conditions arising from oGVHD, particularly for patients refractory to traditional treatments. Further studies are warranted to elucidate the long-term benefits and mechanisms of OIH in oGVHD management.

The Application of Umbilical Cord Blood-derived Platelet Gel for Skin Ulcers Associated With Chronic Graft-Versus-Host Disease in Pediatrics: A Randomized Trial

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative strategy against a variety of malignant and nonmalignant disorders. However, acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively) commonly complicate this approach, culminating in substantial morbidities and mortalities. The integumentary system is the preponderant organ involved in cGVHD, and its response to existing treatments, including well-versed immunosuppressants and novel targeted therapies, is not desirable. Despite the rarity, ulcers of sclerotic skin cGVHD are treatment-refractory and associated with significant morbidities and an exaggerated risk of infectious complications. Platelet-rich plasma (PRP) and its derivatives are endowed with growth factors and proangiogenic molecules and hold regenerative potential. This study aimed to assess the safety and efficacy of the application of platelet gel-containing dressing against ulcerative skin cGVHD in pediatric patients. This randomized trial is conducted at the hematopoietic stem cell transplantation unit of the Children's Medical Center Hospital in Tehran, Iran. Twenty-one pediatric patients (aged between 5 and 15 years) were initially enrolled, and 16 met the inclusion criteria. All cases (4 females) were recipients of allo-HSCT who had been complicated with symmetrically or near-symmetrically ulcerative sclerotic skin cGVHD. Fresh umbilical cord blood (UCB) was obtained from healthy donors and underwent centrifugation using a novel PRP preparation kit in a single-step process. Platelet gel was produced by adding thrombin to the isolated buffy coat layer. Two similar ulcers of each patient were randomized to receive either conventional dressing or platelet gels up to 6 times. At each time point evaluation, ulcer size and its relative reduction compared to the basal size were recorded. Included patients received a total of 80 platelet gel-containing dressings. While the mean sizes of randomized ulcers at the beginning of the study were similar, their differences became significant 15 days after the initiation of intervention (P = .019). In addition, the mean reduction in the ulcers' surface area (in comparison to their baseline values) was significantly higher for the intervention arm at all evaluation points (P = .001 for day 5 and P < .001 for subsequent time points). At the end of the trial, the number of ulcers with a more than 50% reduction in size was 14 (87.5%) in the intervention arm (including 6 completely healed ulcers) versus 1 (6.25%, which was not completely healed) in the control arm (P < .001). None of the patients exhibited any localized or systemic treatment-related adverse events. In this study, using a relatively large number of cases, we showed that UCB-derived platelet gel is a safe, feasible, and effective curative approach for skin ulcers of sclerotic skin cGVHD in pediatric patients. Designing upcoming trials on the efficacy of this therapeutic approach for ocular, mucosal, and acute skin GVHD is prudent. Retrospectively registered at the Iranian Registry of Clinical Trials (registration number IRCT20190101042197N1) on August 24, 2020.

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.

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.

Molecular Biomarkers in Ocular Graft-versus-Host Disease: A Systematic Review

Ocular graft-versus-host disease (oGVHD) affects ~50% of post-stem cell transplant patients and is the only form of GVHD diagnosed without a biopsy. As it must be distinguished from other dry eye diseases, there is a need to identify oGVHD biomarkers to improve diagnosis and treatment. We conducted a systematic review of 19 scholarly articles published from 2018 to 2023 including articles focused on adult patients diagnosed with oGVHD following allogeneic hematopoietic stem cell transplant and used biomarkers as the outcome measure. Articles that were not original investigations or were not published in English were excluded. These clinical investigations explored different molecular oGVHD biomarkers and were identified on 3 October 2023 from the Scopus, PubMed, and Embase databases by using search terms including ocular graft-versus-host disease, biomarkers, cytokines, proteomics, genomics, immune response, imaging techniques, and dry-eye-related key terms. The Newcastle-Ottawa scale for case-control studies was used to assess bias. From the 19 articles included, cytokine, proteomic, lipid, and leukocyte profiles were studied in tear film, as well as ocular surface microbiota and fluorescein staining. Our findings suggest that cytokine profiling is the most studied oGVHD biomarker. Additionally, variations correlating these biomarkers with disease state may lead to a more targeted diagnosis and therapeutic approach. Limitations include language bias, publication bias, and sampling bias, as well as a lack of appropriate controls for included studies.

Corneal Descemetocele Management with Multi-Layer Amniotic Membrane Transplantation in an Ocular Graft-versus-Host Disease Case

Background: Chronic ocular graft-versus-host disease (oGVHD) is a common ocular complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT), characterized by progressive inflammation of the ocular surface and refractory dry eye. In severe cases, sterile corneal perforation can occur, which poses a significant challenge, due to the low survival rate of grafts after corneal transplantation. Case Presentation: A 47-year-old female presented to our hospital with persistent dryness, foreign body sensation, and blurred vision in her left eye. Diagnosis of graft-versus-host disease with corneal descemetocele in the left eye was made after detailed history review and thorough examination. Multi-layer amniotic membrane transplantation was performed in the affected eye, resulting in amelioration of the patient's symptoms. This amelioration of symptoms provided the patient with a level of comfort that permitted additional time while awaiting corneal transplantation. Conclusions: We report a successful case of multi-layer amniotic membrane transplantation for the management of corneal descemetocele following allo-HSCT.

Evaluation of safety and efficacy of allogeneic adipose tissue-derived mesenchymal stem cells in pediatric bronchiolitis obliterans syndrome (BoS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT)

BACKGROUND

Allo-HSCT is a definite approach for the management of a wide variety of lethal and debilitating malignant and non-malignant disorders. However, its two main complications, acute and chronic graft-versus-host disease (GVHD), exert significant morbidities and mortalities. BoS, as a manifestation of chronic lung GVHD, is a gruesome complication of allo-HSCT, and for those with steroid-refractory disease, no approved second-line therapies exist. Mesenchymal stem cells (MSCs) exert anti-inflammatory and growth-promoting effects, and their administration against a wide range of inflammatory and neurologic disorders, as well as GVHD, has been associated with promising outcomes. However, literature on the safety and effectiveness of MSC therapy for BoS and pediatric cGVHD is scarce.

METHODS

We designed a single-arm trial to administer adipose tissue (AT)-derived MSCs to pediatric patients with refractory BoS after allo-HSCT. AT-MSCs from obese, otherwise healthy donors were cultured in an ISO class 1 clean room and injected into the antecubital vein of eligible patients with a dose of 1 × 106/kg. The primary endpoints included a complete or partial response to therapy [in terms of increased forced expiratory volume in one second (FEV1) values and steroid dose reduction] and its safety profile.

RESULTS

Four eligible patients with a median age of 6.5 years were enrolled in the study. Steroid-induced osteoporosis and myopathy were present in three cases. A partial response was evident in three cases after a single injection of AT-MSCs. The treatment was safe and tolerable, and no treatment-related adverse events were noted. Two patients developed manageable COVID-19 infections one and 4 months after AT-MSC injection. After a median follow-up duration of 19 months, all cases are still alive and have had no indications for lung transplantation.

CONCLUSIONS

AT-MSCs could be safely administered to our pediatric cases with BoS post-allo-HSCT. Considering their advanced stage of disease, their sub-optimal functional capacity due to steroid-induced complications, and COVID-19 infection post-treatment, we believe that AT-MSC therapy can have possible efficacy in the management of pediatric BoS. The conduction of further studies with larger sample sizes and more frequent injections is prudent for further optimization of AT-MSC therapy against BoS. Trial registration Iranian Registry of Clinical Trials (IRCT), IRCT20201202049568N2. Registered 22 February 2021, https://en.irct.ir/trial/53143 .

Pathological role of inflammation in ocular disease progress and its targeting by mesenchymal stem cells (MSCs) and their exosome; current status and prospect

Because of their unique capacity for differentiation to a diversity of cell lineages and immunosuppressive properties, mesenchymal stem cells (MSC) are being looked at as a potential new treatment option in ophthalmology. The MSCs derived from all tissue sources possess immunomodulatory attributes through cell-to-cell contact and releasing a myriad of immunomodulatory factors (IL-10, TGF-β, growth-related oncogene (GRO), indoleamine 2,3 dioxygenase (IDO), nitric oxide (NO), interleukin 1 receptor antagonist (IL-1Ra), prostaglandin E2 (PGE2)). Such mediators, in turn, alter both the phenotype and action of all immune cells that serve a pathogenic role in the progression of inflammation in eye diseases. Exosomes from MSCs, as natural nano-particles, contain the majority of the bioactive components of parental MSCs and can easily by-pass all biological barriers to reach the target epithelial and immune cells in the eye without interfering with nearby parenchymal cells, thus having no serious side effects. We outlined the most recent research on the molecular mechanisms underlying the therapeutic benefits of MSC and MSC-exosome in the treatment of inflammatory eye diseases in the current article.