Graft-versus-host Research Articles

Multimodal analysis identifies microbiome changes linked to stem cell transplantation-associated diseases

BackgroundAllogeneic hematopoietic stem cell transplantation (allo-HSCT) is one of the most efficient therapeutic options available to cure many hematological malignancies. However, severe complications derived from this procedure, including graft-versus-host disease (GVHD) and infections, can limit its success and negatively impact survival. Previous studies have shown that alterations in the microbiome are associated with the development of allo-HSCT-derived complications. However, most studies relied on single techniques that can only analyze a unique aspect of the microbiome, which hinders our ability to understand how microbiome alterations drive allo-HSCT-associated diseases.ResultsHere, we have applied multiple “omic” techniques (16S rRNA and shotgun sequencing, targeted and un-targeted metabolomics) in combination with machine learning approaches to define the most significant microbiome changes following allo-HSCT at multiple modalities (bacterial taxa, encoded functions, and derived metabolites). In addition, multivariate approaches were applied to study interactions among the various microbiome modalities (the interactome). Our results show that the microbiome of transplanted patients exhibits substantial changes in all studied modalities. These include depletion of beneficial microbes, mainly from the Clostridiales order, loss of their bacterial encoded functions required for the synthesis of key metabolites, and a reduction in metabolic end products such as short chain fatty acids (SCFAs). These changes were followed by an expansion of bacteria that frequently cause infections after allo-HSCT, including several Staphylococcus species, which benefit from the reduction of bacteriostatic SCFAs. Additionally, we found specific alterations in all microbiome modalities that distinguished those patients who subsequently developed GVHD, including depletion of anti-inflammatory commensals, protective reactive oxygen detoxifying enzymes, and immunoregulatory metabolites such as acetate or malonate. Moreover, extensive shifts in the homeostatic relationship between bacteria and their metabolic products (e.g., Faecalibacterium and butyrate) were detected mainly in patients who later developed GVHD.ConclusionsWe have identified specific microbiome changes at different modalities (microbial taxa, their encoded genes, and synthetized metabolites) and at the interface between them (the interactome) that precede the development of complications associated with allo-HSCT. These identified microbial features provide novel targets for the design of microbiome-based strategies to prevent diseases associated with stem cell transplantation.Bx_7phuTozz8yFUTR9cZV4Video

Narrative Review: Advancing Dysbiosis Treatment in Onco-Hematology with Microbiome-Based Therapeutic Approach

This review explores the complex relationship between gut dysbiosis and hematological malignancies, focusing on graft-versus-host disease (GvHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. We discuss how alterations in microbial diversity and composition can influence disease development, progression, and treatment outcomes in blood cancers. The mechanisms by which the gut microbiota impacts these conditions are examined, including modulation of immune responses, production of metabolites, and effects on intestinal barrier function. Recent advances in microbiome-based therapies for treating and preventing GvHD are highlighted, with emphasis on full ecosystem standardized donor-derived products. Overall, this review underscores the growing importance of microbiome research in hematology–oncology and its potential to complement existing treatments and improve outcomes for thousands of patients worldwide.

Effect of NK cell receptor genetic variation on allogeneic stem cell transplantation outcome and in vitro NK cell cytotoxicity

Natural killer (NK) cells recognize and may kill malignant cells via their cell surface receptors. Killer cell immunoglobulin-like receptor (KIR) genotypes of donors have been reported to adjust the risk of relapse after allogeneic stem cell transplantation (HSCT), particularly in patients with acute myeloid leukemia. To test whether non-KIR NK cell receptors have a similar effect, we screened 1,638 genetic polymorphisms in 21 non-KIR NK cell receptor genes for their associations with relapse and graft-versus-host disease (GVHD) after HSCT in 1,491 HSCT donors (from Finland, the UK, Spain, and Poland), divided into a discovery and replication cohort. Eleven polymorphisms regulating or located in CD226, CD244, FCGR3A, KLRD1, NCR3, and PVRIG were associated with the risks for relapse and GVHD. These associations could not be confirmed in the replication cohort. Blood donor NK cells carrying alleles showing genetic protection for relapse had a higher in vitro NK cell killing activity than non-carriers whereas those with alleles genetically protective for GVHD had lower cytotoxicity, potentially indicating functional effects. Taken together, these results show no robust effects of genetic variation in the tested non-KIR NK cell receptors on the outcome of HSCT.

Inferior Overall Survival After Haploidentical Donor Lymphocyte Infusions in Relapsed Myeloid Neoplasms.

Allogeneic hematopoietic stem cell transplantation (HSCT) effectively treats high-risk myeloid neoplasms, but relapses post-HSCT, particularly in acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS), pose significant challenges. Donor lymphocyte infusion (DLI) has been utilized, but its effectiveness, especially in haploidentical settings, remains insufficiently clarified, and graft-versus-host disease (GvHD) poses a substantial risk. In this retrospective cohort study, 57 patients with AML or MDS who received DLI after allogeneic HSCT at our center from 2002 to 2023 were analyzed. Herein, only preemptively or therapeutically applied DLI were included, and endpoints included overall survival (OS), progression-free survival (PFS), and GvHD incidence post-DLI. Median OS after DLI was 517 days, with a 1-year OS of 62.5%. Factors associated with longer OS included patient age, HLA-identical donor, post-HSCT treatment naivety, and preemptive DLI indication. Haploidentical DLI was associated with inferior OS compared to HLA-identical DLI; however, PFS and GvHD incidence post-DLI did not differ significantly. Our study findings indicate that OS rate is inferior in patients with relapsed AML or MDS treated with haploidentical DLI in comparison to those who received HLA-identical DLI. Given the limitations of haploidentical DLI, alternative strategies, such as higher cell doses or combination treatment approaches, warrant further investigation.

Preclinical characterization of MTX-101: a novel bispecific CD8 Treg modulator that restores CD8 Treg functions to suppress pathogenic T cells in autoimmune diseases

IntroductionRegulatory CD8 T cells (CD8 Treg) are responsible for the selective killing of self-reactive and pathogenic CD4 T cells. In autoimmune disease, CD8 Treg may accumulate in the peripheral blood but fail to control the expansion of pathogenic CD4 T cells that subsequently cause tissue destruction. This CD8 Treg dysfunction is due in part to the expression of inhibitory killer immunoglobulin-like receptors (KIR; KIR2DL isoforms [KIR2DL1, KIR2DL2, and KIR2DL3]); these molecules serve as autoimmune checkpoints and limit CD8 Treg activation.MethodsHere we describe the pre-clinical characterization of MTX-101, a bispecific antibody targeting inhibitory KIR and CD8. Using human peripheral blood mononuculear cells (PBMC) derived from healthy donors and autoimmune patients, humanized mouse models, and human derived tissue organoids, we evaluated the molecular mechanisms and functional effects of MTX-101.ResultsBy binding to KIR, MTX-101 inhibited KIR signaling that can restore CD8 Treg ability to eliminate pathogenic CD4 T cells. MTX-101 bound and activated CD8 Treg in human peripheral blood mononuclear cells (PBMC), resulting in increased CD8 Treg cytolytic capacity, activation, and prevalence. Enhancing CD8 Treg function with MTX-101 reduced pathogenic CD4 T cell expansion and inflammation, without increasing pro-inflammatory cytokines or activating immune cells that express either target alone. MTX-101 reduced antigen induced epithelial cell death in disease affected tissues, including in tissue biopsies from individuals with autoimmune disease (i.e., celiac disease, Crohn’s disease). The effects of MTX-101 were specific to autoreactive CD4 T cells and did not suppress responses to viral and bacterial antigens. In a human PBMC engrafted Graft versus Host Disease (GvHD) mouse model of acute inflammation, MTX-101 bound CD8 Treg and delayed onset of disease. MTX-101 induced dose dependent binding, increased prevalence and cytolytic capacity of CD8 Treg, as well as increased CD4 T cell death. MTX-101 selectively bound CD8 Treg without unwanted immune cell activation or increase of pro-inflammatory serum cytokines and exhibited an antibody-like half-life in pharmacokinetic and exploratory tolerability studies performed using IL-15 transgenic humanized mice with engrafted human lymphocytes, including CD8 Treg at physiologic ratios.ConclusionCollectively, these data support the development of MTX-101 for the treatment of autoimmune diseases.

Piezo1 restrains proinflammatory response but is essential in T cell-mediated immunopathology.

Piezo1 is a mechanosensitive, nonselective Ca2+ channel which is broadly expressed in CD4+ T cells. Using lineage-specific Piezo1 knockout mice (Piezo1cKO), we show that loss of Piezo1 in CD4+ T cells significantly increased IFNγ and IL-17 production in vitro under TH1 and TH17 polarizing conditions, respectively. Despite their intrinsic proinflammatory phenotype, Piezo1cKO T cells are incapable of establishing disease in vivo in three separate adoptive transfer (AT) T cell-mediated inflammatory mouse models, including experimental autoimmune encephalomyelitis, inflammatory bowel disease (IBD), and graft versus-host disease. These phenomena coincided with a decreased effector memory (CD44hiCD62Llo) CD4+ T cell pool derived from donor Piezo1cKO T cells, an observation that is related to intrinsic T-cell fitness, as co-transfer IBD mouse model revealed a deficiency in the CD4+ effector memory population derived only from the naïve Piezo1cKO but not co-infused Piezo1WT CD4+ T cell source. Taken together, our results support Piezo1 as restraining proinflammatory T cell differentiation while contributing to the generation and persistence of the effector memory pool during CD4+ T cell-mediated immunopathology.

Time to Rethink Bronchiolitis Obliterans Syndrome Following Lung or Hematopoietic Cell Transplantation in Pediatric Patients

Background: Similar in histological characteristics and clinical manifestations, bronchiolitis obliterans syndrome (BOS) can develop following lung transplantation (LTx) or hematopoietic cell transplantation (HCT). In contrast to lung transplantation, where BOS is restricted to the lung allograft, HCT-related systemic graft-versus-host disease (GVHD) is the root cause of BOS. Because lung function declines following HCT, diagnosis becomes more difficult. Given the lack of proven effective medicines, treatment is based on empirical evidence. Methods: Cross-disciplinary learning is crucial, and novel therapies are under investigation to improve survival and avoid LTx. Recent advances have focused on updating the understanding of the etiology, clinical features, and pathobiology of BOS. It emphasizes the significance of learning from experts in other transplant modalities, promoting cross-disciplinary knowledge. Results: Our treatment algorithms are derived from extensive research and expert clinical input. It is important to ensure that immunosuppression is optimized and that any other conditions or contributing factors are addressed, if possible. Clear treatment algorithms are provided for each condition, drawing from the published literature and consensus clinical opinion. There are several novel therapies currently being investigated, such as aerosolized liposomal cyclosporine, Janus kinase inhibitors, antifibrotic therapies, and B-cell-directed therapies. Conclusions: We urgently need innovative treatments that can greatly increase survival rates and eliminate the need for LTx or re-transplantation.

Venous thromboembolism incidence and risk factors in patients undergoing hematopoietic stem cell transplantation

BackgroundMalignancy is a well-known risk factor for venous thromboembolism (VTE), and the Khorana risk score is effective for screening solid tumor patients. However, there is a lack of validated screening tools and established risk factors for patients undergoing hematopoietic stem cell transplant (HCT). Current literature reports VTE incidence in HCT patients ranging from 2.5% to 8.5%. Anticoagulation is difficult to manage post-transplant given prolonged thrombocytopenia and the likelihood of bleeding. By identifying risk factors, a predictive model may be developed to prospectively test prophylaxis strategies in patients at the highest thromboembolic event (TE) risk. ObjectivesThis study evaluated the cumulative incidence of TE at 6 months following allogeneic and autologous HCTs. This study also aimed to identify risk factors for developing TE, to evaluate time from HCT to TE, and to compare one-year survival following HCT between patients experiencing TE and those who did not. Study DesignThis is a retrospective single-center study evaluating the incidence of TE events in adult subjects undergoing HCT between March 2014 and December 2019. ICD-9 and ICD-10 codes were used to determine cancer diagnosis, TE events up 180 days after HCT, and comorbidities of interest. Each subject was reviewed for data accuracy by manual retrospective chart review. The study employed statistical tests such as the cumulative incidence method with competing risks, Gray's test, and univariate and multivariate Cox proportional hazards models to analyze the time to first thromboembolic (TE) event, evaluate risk factors, and assess 1-year survival post-HCT in relation to TE events within 180 days of HCT. Variables examined included age, sex, body mass index (BMI), transplant type, hospital length of stay, history of TE prior to transplant, active infections, graft-versus-host disease (GVHD), veno-occlusive disorder (VOD), cytomegaly virus (CMV) and other factors. ResultsThe study included 636 evaluable patients; the majority were male (57.9%), white (68.7%), and underwent an autologous HCT (68.4%). Twenty-nine patients (4.6%) experienced a TE event within 180 days post-transplant. TE events were more common in the allogeneic transplant group (n=13/201, 6.5%) than the autologous transplant group (n=16/435, 3.7%) (p=0.122). The cumulative incidence of TE was higher in patients who developed an active infection than those who did not (7.6% vs 3.1%, P=.011). Hospital LOS [HR 1.03, 95% CI 1.0-1.06, p=0.036] and active infection [HR 2.34, 95% CI 1.1-4.95, p=0.027] were significantly associated with TE in the univariate analysis but were not retained in the final multivariate model. There was no difference in one-year survival among all patients who experienced a TE event and those who did not; however, in the autologous HCT subgroup, one-year survival rate was significantly lower in those with TE compared to those without TE (Figure 3c, 80.4% vs 95.3%, P=.01). Examined variables, including history of TE event and GVHD, were not associated with TE event risk. ConclusionWhile the overall incidence of TE in our study was low, many patients received pharmacologic or mechanical prophylaxis, suggesting such strategies may be effective in mitigating TE risk. Factors such as infection and hospital LOS may further increase TE risk. Providers should continuously monitor for risk factors and signs and symptoms of TE post-transplant. It is also imperative to consider chemical prophylaxis if counts are recovered while hospitalized.

Representativeness of Blood and Marrow Transplant Clinical Trials Network (BMT CTN) trial participants

Underrepresentation by race and ethnicity in oncology clinical trials, including hematopoietic cell transplantation (HCT), is a known challenge. This analysis studied accrual on Blood and Marrow Transplant Clinical Trials Network (BMT CTN) trials conducted in 2014-20 by race/ethnicity, age, and sex comparing these characteristics with those of potentially eligible patients identified from SEER and CIBMTR databases for the disease, age, and years of interest of BMT CTN studies. Five BMT CTN trials met inclusion criteria, including one autologous and four allogeneic HCT trials. Two studies focused on multiple myeloma (BMT CTN 1302 and 1401), two studies on graft versus host disease (GVHD) treatment (BMT CTN 1301 and 1501), and one study on post-HCT maintenance therapy in FLT3+ acute myelogenous leukemia (BMT CTN 1506). A decline in the proportion of patients from minority racial and ethnic groups was seen from the SEER population to trial enrollees, with the largest drop seen between the SEER population and all patients transplanted (on or off trial) in US transplant centers. Allogeneic HCT trials which allowed alternate donor graft sources had less decrease from the SEER population. No decrease was seen in clinical trial enrollment with respect to older age and female HCT recipients. This study provides insights into the underrepresentation of racial and ethnic minority patients in BMT CTN clinical trials, largely due to lack of access to HCT in general. Pathways expanding access to donors and improving the outreach of HCT programs to underserved populations are needed to improve access to clinical trials.

Harnessing Chimeric Antigen Receptor-engineered Invariant Natural Killer T Cells: Therapeutic Strategies for Cancer and the Tumor Microenvironment.

Chimeric antigen receptor (CAR)-engineered T (CAR-T) cell therapy has emerged as a revolutionary approach for cancer treatment, especially for hematologic cancers. However, CAR-T therapy has some limitations, including cytokine release syndrome (CRS), immune cellassociated neurologic syndrome (ICANS), and difficulty in targeting solid tumors and delivering allogeneic cell therapy due to graft-versus-host disease (GvHD). Therefore, it is important to explore other cell sources for CAR engineering. Invariant natural killer T (iNKT) cells are a potential target, as they possess powerful antitumor ability and do not recognize mismatched major histocompatibility complexes (MHCs) and protein antigens, thus avoiding the risk of GvHD. CAR-engineered iNKT (CAR-iNKT) cell therapy offers a promising new approach to cancer immunotherapy by overcoming the drawbacks of CAR-T cell therapy while retaining potent antitumor capabilities. This review summarizes the current CAR-iNKT cell products, their functions and phenotypes, and their potential for off-the-shelf cancer immunotherapy.

Post-transplant cyclophosphamide separates graft-versus host disease and graft versus leukemia effects after HLA-matched stem-cell transplantation for acute myeloid leukemia.

The association of graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effects after allogeneic stem-cell transplantation (SCT) is well-established but was not confirmed in the modern era and following post-transplant cyclophosphamide (PTCy). We assessed GVHD/ GVL association in AML patients following HLA-matched SCT with standard calcineurin-based (n = 12,653, 57% with additional in-vivo T-cell depletion) or PTCy-based (n = 508) GVHD prophylaxis. Following standard prophylaxis, acute GVHD grade II-IV and III-IV, chronic GVHD, and extensive chronic GVHD rates were 23.8%, 7.5%, 37.0%, and 16.3%, respectively. Acute GVHD grade II and III-IV were associated with lower relapse [hazard-ratio (HR) 0.85, P = 0.002; HR 0.76, P = 0.003, respectively)], higher non-relapse mortality (NRM) (HR 1.5, P < 0.001; HR 6.21, P < 0.001) and lower overall survival (OS) (HR 1.49, P < 0.001; HR 6.1, P < 0.001). Extensive chronic GVHD predicted lower relapse (HR 0.69, P < 0.001), higher NRM (HR 2.83, P < 0.001), and lower OS (HR 2.74, P < 0.001). Following PTCy, GVHD rates were 22.8%, 6.2%, 35.5%, and 17.7%, respectively. Acute GVHD was not associated with relapse (HR 1.37, P = 0.15) but predicted higher NRM (HR 3.34, P < 0.001) and lower OS (HR 1.92, P = 0.001). Chronic GVHD was not prognostic for these outcomes. In conclusion, GVHD and GVL are strongly associated with contemporary SCT. However, following PTCy, GVHD is not associated with reduced relapse.

Emerging Frontiers in Cancer Immunotherapy: Recent Advances in CAR-NK Cell and CAR-Macrophage Therapies

Chimeric antigen receptor (CAR) cell therapies have revolutionized the field of cancer treatment with the breakthrough successes of CAR-T cell therapy in hematological malignancies. However, CAR-T cell efficacy in solid tumors has been limited by challenges such as the immunosuppressive tumor microenvironment (TME) and safety concerns like cytokine release syndrome (CRS) and graft-versus-host disease (GvHD). This review focuses on the latest advancements in CAR-NK cell and CAR-macrophage therapies, which offer potential solutions to these limitations. CAR-NK cells exhibit natural cytotoxicity and MHC-independent tumor targeting, providing a safer profile with lower risks of GvHD and CRS compared to CAR-T cells. Innovations in CAR-NK cell therapy includes structural optimizations, gene editing with CRISPR-Cas9, and the development of multispecific CARs, all contributing to enhanced anti-tumor efficacy, especially in solid tumors. Meanwhile, CAR-macrophages are effective in remodeling the TME through phagocytosis and immune activation, addressing the challenges of solid tumor infiltration. This review compares the mechanisms of action, clinical applications, and safety profiles of CAR-NK cells and CAR-macrophages, highlighting the synergistic potential of these therapies. Although clinical research on both therapies is still in its early stages, the promising preclinical and early clinical trial results underscore their potential as alternative immunotherapies for refractory cancers. Future research will focus on overcoming challenges in production scalability, improving in vivo persistence, and personalizing CAR therapies through precision medicine approaches. These two therapies will likely play pivotal roles in the next generation of cancer immunotherapies.

Gallic acid enhances GVL effects of T cells without exacerbating GVHD after haematopoietic stem cell transplantation.

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is an effective therapy for acute myeloid leukaemia (AML), predominantly due to its potent graft-versus-leukaemia (GVL) effect. However, leukaemia relapse remains a major obstacle to the success of allo-HSCT. In this study, we demonstrated that gallic acid (GA), a natural dietary compound, can enhance T-cell-mediated GVL effects both invitro and invivo. GA-treated T cells exhibited increased activation and elevated secretion of cytotoxic cytokines, leading to the apoptosis of AML cells in co-culture systems invitro. In a non-irradiated leukaemia mouse model, we showed that GA treatment prolonged the survival of leukaemic mice and reduced leukaemia cell infiltration. Further analysis revealed that GA treatment increased T-cell activation and tumour necrosis factor-α secretion. Moreover, integrated transcriptomic and proteomic analyses indicated that GA augments T-cell-mediated GVL effects through the activation of the MAPK and NF-κB pathways. Blocking these pathways individually diminished the protective effect of GA in AML model mice. Importantly, GA administration did not accelerate graft-versus-host disease (GVHD) progression in a mouse model. In conclusion, our study revealed that GA can enhance the GVL effects of T cells without exacerbating GVHD, offering insights into its potential to improve outcomes for patients after HSCT.

Concurrent hypoxia and apoptosis imparts immune programming potential in mesenchymal stem cells: Lesson from acute graft-versus-host-disease model

BackgroundMesenchymal stem cells (MSCs) have emerged as promising candidates for immune modulation in various diseases that are associated with dysregulated immune responses like Graft-versus-Host-Disease (GVHD). MSCs are pleiotropic and the fate of MSCs following administration is a major determinant of their therapeutic efficacy.MethodsHuman MSCs were derived from bone marrow (BM) and Wharton’s Jelly (WJ) and preconditioned through exposure to hypoxia and induction of apoptosis, either sequentially or simultaneously. The immune programming potential of preconditioned MSCs was evaluated by assessing their effects on T cell proliferation, induction of Tregs, programming of effector T-cell towards Th2 phenotype, macrophage polarization in the direct co-culture of MSCs and aGVHD patients-derived PBMNCs. Additionally, efferocytosis of MSCs and relative change in the expression of immunomodulatory soluble factors were examined.ResultsOur study demonstrated that hypoxia preconditioned apoptotic MSCs (BM-MSCs, WJ-MSCs) bear more immune programming ability in a cellular model of acute Graft-versus-Host-Disease (aGVHD). Our findings revealed that WJ-MSCsHYP+APO were superior to BM-MSCsHYP+APO for immune regulation. These induced the differentiation of CD4+T-cell into Tregs, enhanced Th2 effector responses, and simultaneously mitigated Th1- and Th17 responses. Additionally, this approach led to the polarization of M1 macrophages toward an M2 phenotype.ConclusionOur study highlights the potential of WJ-MSCs conditioned with hypoxia and apoptosis concurrently, as a promising therapeutic strategy for aGVHD. It underscores the importance of considering MSC apoptosis in optimizing MSCs-based cellular therapy protocols for enhanced therapeutic efficacy in aGvHD.Graphical

First reported case of thymoma-associated multiorgan autoimmunity induced by COVID-19.

Thymoma-associated multiorgan autoimmunity (TAMA) presents with skin symptoms similar to those of graft-versus-host disease (GVHD), liver dysfunction, and enteritis, in the absence of a history of hematopoietic stem cell or bone marrow transplantation. TAMA is a type of paraneoplastic syndrome associated with thymoma. Its etiology is unclear but is thought to be a result of breakdown of immune tolerance. Histopathologically, TAMA is characterized by epidermal acanthosis with parakeratosis, individual cell keratinization, liquefaction degeneration, and intraepidermal infiltration of CD8-positive lymphocytes. A 64-year-old female patient with a history of myasthenia gravis and thymoma treated with prednisolone (10 mg/day) and cyclosporine (150 mg/day) experienced erythema on her trunk after coronavirus disease 2019 (COVID-19) onset. A psoriatic drug eruption was suspected and the possible causative drug was discontinued, but the skin rash failed to improve. A skin biopsy demonstrated GVHD-like histopathological findings. Diarrhea, abdominal pain, and duodenal perforation occurred concurrently, leading to the diagnosis of TAMA. Thereafter, the patient continued prednisolone and cyclosporine in the same doses as the TAMA treatment and added topical steroids. During the disease course, candida fungemia and cytomegalovirus infection developed, resulting in the patient's death. The TAMA was considered to have been caused by the release of inflammatory cytokines, autoreactive T cell activation, and regulatory T cell dysfunction induced by COVID-19.

Visual and ocular surface benefits of mini-scleral contact lenses in patients with chronic ocular graft-versus-host disease (GvHD)

Graft-versus-Host disease is a major complication of allogeneic stem cell transplantation. The eyes are a frequently affected organ with a severe dry eye disease being the hallmark manifestation. This retrospective study evaluates the effect of mini-scleral contact lenses on visual acuity, eye-related quality of life and the ocular surface. 62 eyes of 31 patients were included and visual acuity, ocular surface disease index (OSDI) questionnaire results and Oxford grades before and after mini-scleral lens fitting were compared. Median Snellen fraction with mini-scleral lenses was 20/25 (1st 20/30/3rd 20/20) compared to 20/40 median Snellen fraction with spectacles (1st 20/60/3rd 20/25). Median OSDI scores improved from 73 (1st 41.6/3rd 89) before fitting to 27 (1st 14.5/3rd 56) with mini-scleral lenses. Median Oxford grade decreased from 3 before mini-scleral lens fitting (1st 1/3rd 4.75) to 1 after mini-scleral lens fitting (1st 0/3rd 4). Median time of follow up was 717.5 days. Seven patients (22.6%) discontinued therapy with mini-scleral lenses. Mini-scleral lenses are beneficial for most patients with ocular GvHD as they improve visual acuity, eye-related quality of life and the integrity of the corneal epithelium.

Gut microbiota and graft-versus-host disease in hematopoietic stem cell transplant patients

Background and Objectives: Graft-versus-host disease (GvHD) frequently complicates hematopoietic stem cell transplan- tation (HSCT). Emerging evidence suggests a correlation between gut microbiota and GvHD risk. This study aims to eluci- date the microbiota profiles in HSCT patients before and after transplantation and their association with GvHD. Materials and Methods: This study, conducted from December 2022 to December 2023, involved the collection of 15 stool samples from HSCT patients. Bacterial content was quantified using real-time PCR, while interleukin-6 levels were assessed via ELISA. Results: Among the 15 participants (8 male, 7 female), 9 underwent allogeneic HSCT (allo-HSCT) and 6 received autol- ogous HSCT. In the aGvHD group, there was a significant reduction in the abundance of Bacteroides and Bifidobacterium compared to those without aGvHD. Additionally, declines were observed in Clostridium and Firmicutes populations. The genus Blautia also showed reduced prevalence in the aGvHD group, whereas no significant differences were noted in the uncomplicated group. ELISA analysis revealed that interleukin-6 levels remained within the normal range (30-960 pg/ml) with no significant elevation in the aGvHD group. Conclusion: The study highlights a notable association between alterations in gut microbiota, specifically reductions in certain bacterial populations and the development of aGvHD following allo-HSCT.

Post-transplant cyclophosphamide with post-engraftment anti-thymocyte globulin reduce moderate to severe chronic graft-versus-host disease in peripheral stem cell transplantation from HLA-matched unrelated and haploidentical donors.

Post-transplantation cyclophosphamide (PTCy) has unique advantages for graft-versus-host disease (GVHD) prophylaxis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this single-center retrospective landmark analysis, we evaluated chronic GVHD (cGVHD) and clinical outcomes in patients receiving PTCy, tacrolimus, and post-engraftment low-dose anti-thymocyte globulin (PTCy-ATG) as GVHD prophylaxis after HLA-matched unrelated or haploidentical donor transplantation. Two historical patient groups receiving calcineurin inhibitor-based GVHD prophylaxis were used as control groups. A total of 71 patients with myeloid malignancies undergoing allo-HSCT with myeloablative conditioning regimens were included in the analysis. The 3-year cumulative incidences of cGVHD and moderate to severe cGVHD (M/S cGVHD) were 39.2% (95%CI 27.4%-51.0%) and 11.5% (95%CI 4.1%-18.9%), respectively, in the PTCy-ATG group, and only one instance of bronchiolitis obliterans (BO) was observed. The disease-free survival (DFS), overall survival (OS), and GVHD-free and relapse-free survival rates were 94.0% (95%CI 88.3%-99.7%), 93.0% (95%CI 87.1%-98.9%) and 83.8% (95%CI 75.0%-92.6%) respectively. Of note, the PTCy-ATG group presented with a significantly lower incidence of M/S cGVHD and BO, which translated into superior OS in multivariate analysis. In this retrospective analysis, we observed that PTCy-ATG-based GVHD prophylaxis was associated with a lower incidence of M/S cGVHD and better transplantation outcomes beyond day 100, which invites prospective evaluation.

Comparison of HLA-haploidentical donors with post-transplant cyclophosphamide versus HLA-matched unrelated donors in peripheral blood stem cell transplantation for acute myeloid leukaemia.

HLA-haploidentical haematopoietic cell transplantation with post-transplant cyclophosphamide (PTCy-haplo) is emerging as an effective alternative due to donor availability and safety. We conducted a nationwide retrospective study comparing the outcomes of PTCy-haplo with both anti-thymocyte globulin (ATG)-free and ATG-administered matched unrelated donors (MUD) transplantation, using peripheral blood stem cells as the first transplantation for acute myeloid leukaemia (AML). Our study showed a lower and slower haematopoietic recovery and a higher incidence of infection-related deaths after PTCy-haplo than after MUD transplantation. In addition, we revealed an increased risk of acute and chronic graft-versus-host disease (GVHD) in ATG-free MUD transplantation in comparison to PTCy-haplo. For grades III-IV acute GVHD, the hazard ratio (HR) was 2.71 (95% CI, 1.46-5.01), and for extensive chronic GVHD, the HR was 3.11 (95% CI, 2.07-4.68). There was no significant difference regarding overall survival amongst the groups. In addition, GVHD-free relapse-free survival (GRFS) was lower in ATG-free MUD transplantation than in PTCy-haplo (HR, 1.46; 95% CI, 1.17-1.82). Notably, ATG-administered MUD transplantation showed no significant difference in GRFS from PTCy-haplo, negating the advantage of PTCy. Our results suggest that PTCy-haplo could be viable for AML patients without an HLA-matched related donor.

Allogeneic stem cell Transplant in Hematological Disorders: A Decade of Experience

Background: Allogeneic hematopoietic cell transplantation (allo-HCT) is a complex procedure with the potential to provide curative treatment for various hematological disorders. This study aims to evaluate the outcomes of allo-HCT in hematological diseases and identify significant complications in a single-center setting. Materials and Methods: We conducted a retrospective analysis of 180 patients with hematological diseases who underwent allo-HCT between January 2011 and December 2021. Key outcomes, including indications for transplantation, overall survival, engraftment time, relapse rates, graft-versus-host disease (GVHD), and transplant-related mortality (TRM) were assessed. Results: The most common indications for allo-HCT were benign hematological diseases, particularly aplastic anemia, and thalassemia major. Despite the majority of patients receiving fully matched transplants, Acute GVHD was observed in 30% of the cohort. Graft failure occurred in 13 patients, with primary and secondary graft failure rates of 1.6% and 5.5%, respectively. Sepsis emerged as the primary cause of non-relapsed mortality at day 100 and beyond. The overall survival rate in this study was 62%, with 79% of patients disease-free on their last visit. Conclusion: This study provides valuable insights into the treatment strategies and patient care of allo-HCT for hematological disorders by offering a comprehensive overview of multiple relevant outcomes. The findings underscore the significance of addressing complications and risk factors associated with allogeneic transplantation, including GVHD and infections. Future research should focus on further optimizing transplantation techniques to minimize complications and enhance patient survival.