Acute Graft-versus-host Disease In Patients Research Articles

Clinical Effects of Tacrolimus Blood Concentrations Early after Allogeneic Hematopoietic Stem Cell Transplantation

Tacrolimus (TAC) plus short-term methotrexate (stMTX) is used for graft-versus-host disease (GVHD) prophylaxis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). TAC blood concentrations are frequently adjusted to enhance the graft-versus-leukemia/lymphoma effect or attenuate severe GVHD. Limited information is available on the clinical impact of these adjustments and the optimal time to perform them in order to achieve good clinical outcomes. We retrospectively analyzed 211 patients who underwent allo-HSCT at our institutes. Higher TAC concentrations in week 3 correlated with a significantly higher cumulative incidence of relapse (CIR) (p=0.03) and lower non-relapse mortality (p=0.04). The clinical impact of high TAC concentrations in week 3 on CIR was detected in the refined disease risk index: low/intermediate (p=0.04) and high (p<0.01), and conditioning regimens other than cyclophosphamide/total body irradiation and busulfan/cyclophosphamide (p=0.07). Higher TAC concentrations in week 1 correlated with a lower grade 2-4 acute GVHD rate (p=0.01). Higher TAC concentrations in weeks 2 and 3 correlated with slightly lower (p=0.05) and significantly lower (p=0.02) grade 3-4 acute GVHD rates, respectively. Higher TAC concentrations in weeks 1 and 3 were beneficial for severe acute GVHD in patients with a human leukocyte antigen-matched donor (p=0.03 and p<0.01, respectively), not treated with anti-thymocyte globulin (p=0.02 and p=0.02, respectively), and receiving three stMTX doses (p=0.03 and p=0.02, respectively). The clinical impact of TAC concentrations varied according to patient characteristics, including disease malignancy, conditioning regimens, donor sources, and GVHD prophylaxis. These results suggest that TAC management needs to be based on patient profiles.

Monocyte Subpopulations and Their Expression of HLA-DR and CD300e after Allogeneic Stem Cell Transplantation in Patients with or without GvHD

Introduction: Graft versus host disease (GvHD) is a complex immune process that can affect up to 50% of patients undergoing allogeneic stem cell transplantation (allo-SCT). Even though prophylactic immunosuppressive regimens have been established over the last decades, GvHD is still one of the main causes of morbidity and mortality among these patients. Monocytes are cells of the innate immune system, that represent, as professional antigen-presenting cells, a connection to the adaptive immune system, and play a role in several autoimmune disorders. They are classified according to the expression of CD14 and CD16 into classical (CD14++/CD16-), intermediate (CD14++/CD16+), and non-classical (CD14+/CD16++) monocytes. Previous research has shown higher levels of intermediate monocytes in pediatric patients with GvHD. Furthermore, non-classical monocytes in allogenic bone marrow grafts have also been correlated with the development of GvHD. The expression of other surface markers such as HLA-DR and CD300e (IREM-2) are related to monocyte function and engagement in inflammatory processes. Nevertheless, the role of CD300e in GvHD remains unclear. Here, we present a description of monocyte subgroups and their expression of HLA-DR and CD300e in allo-SCT patients with or without GvHD as well as in healthy subjects. Methods: Transversal observational study with patients undergoing allo-SCT. Peripheral blood of patients was collected once after engraftment. Both acute and chronic GvHD patients were enrolled. Five healthy volunteers served as controls. Flow cytometry was performed to determine the immunophenotype of monocytes according to their expression of CD14 and CD16 stratifying into classical, intermediate, and non-classical subgroups as described above. In addition, the expression of HLA-DR and CD300e was analyzed for all monocytes and individual subgroups. Clinical characteristics are described in the table below. Statistical analysis was performed using GraphPad Prism 9. Comparisons between groups were made using non-parametrical tests and tests for multiple comparisons (Mann-Whitney and Kruskal-Wallis respectively). Results: 29 patients were enrolled. Two patients with GvHD were excluded due to neutropenia. 19 patients presented GvHD grade II or higher. Of those, ten had acute GvHD, five had prolonged acute GvHD, two had late onset acute GvHD, and two had chronic GvHD. Eight patients did not show GvHD or had only mild skin disease (grade one). The mean age was 60 years for all patients, 62.5 and 58.5 years among GvHD and non-GvDH patients, respectively. The image summarizes patient characteristics and comparisons. We compared transplant recipients with and without GvHD which each other and with healthy controls. In single comparisons, patients with GvHD showed significantly lower percentages of total monocytes as well as CD14+/HLA-DR+, total HLA-DR+, and intermediate monocytes compared to patients without GvHD. In addition, we observed a trend toward lower levels of CD16+/HLA-DR+ and CD300e-expressing monocytes in GvHD patients. When compared to healthy controls, allogeneic recipients without GvHD showed significantly higher levels of total monocytes, intermediate monocytes, and CD16+/HLA-DR+ monocytes and lower levels of classical and non-classical monocytes. Compared to controls, patients with GvHD showed significantly lower levels of total monocytes expressing CD300e (also true in all subgroups) as well as lower levels of classical monocytes, but higher levels of intermediate and non-classical monocytes. P values are shown in Table 1. Means and ranges for all groups are represented in Image 1. Conclusions: In our cohort, patients with GvHD showed higher levels of intermediate and non-classical monocytes compared to controls, however, these populations were lower when compared to allogeneic recipients without GvHD. This could indicate a consumption process similar to that observed in COVID-19 patients and a direct involvement of these monocytes in the GvHD process. In addition, we report for the first time the involvement of CD300e in GvHD, which was significantly lower expressed in the GvHD patients, compared to controls. However, there was only a strong trend compared to transplanted non-GvHD patients. This indicates a possible contribution of CD300e in the pathogenesis of GvHD. Further studies are needed in order to confirm these findings.

Inflammatory Change of FoxP3 + Regulatory T Cells in Human Acute Graft-Versus-Host Disease: Implication in Immunopathogenesis

FoxP3 + regulatory T (Treg) cells are a subset of CD4 + T cells that are requisite for control of immune responses in various settings, thereby preventing excessive inflammation and maintaining homeostasis of the immune system. Paradoxically, in several autoimmune disorders, it has been suggested that Treg cells undergo inflammatory conversion to produce effector cytokines promoting tissue inflammation. Although Treg cells are known to play an important role in the pathogenesis of acute graft-versus-host disease (GvHD) following allogeneic stem cell transplantation (SCT), such inflammatory changes have not been focused on so far especially in the setting of human acute GvHD. Herein, in a prospective cohort of patients with hematologic malignancies who were treated with allogeneic SCT, we investigated the quantitative and qualitative changes of Treg cells in subjects with acute GvHD, including production of inflammatory cytokines from Treg cells. We also studied a cellular mechanism for production of effector cytokines by Treg cells and clinical significance of inflammatory changes of Treg cells. We first determined the frequency of Treg cells in the peripheral blood of patients with acute GvHD and compared it with that of patients who did not develop acute GvHD. Percentage of CD25 hiCD127 loFoxP3 + Treg cells among CD4 + T cells was significantly lower in patients with acute GvHD. When we analyzed for the composition of Treg cell subsets in more detail, we observed that the proportion of CD45RA -FoxP3 hi (actively suppressive) Treg cells was decreased and the proportion of CD45RA -FoxP3 lo (cytokine-producing non-suppressive) Treg cells was increased in patients with acute GvHD. Next, we assessed the production of inflammatory cytokines from Treg cells following T cell receptor (TCR) stimulation of peripheral blood lymphocytes with anti-CD3/CD28 antibody, using intracellular cytokine staining. As a result, we found that a remarkable proportion of CD4 +CD25 hiFoxP3 + Treg cells of acute GvHD patients produced TNF-α upon TCR stimulation. Interestingly, a significant proportion of TNF-α-producing Treg cells also secreted IL-17A simultaneously. These findings are consistent with the increased CD45RA -FoxP3 lo fraction among the Treg cell subsets. To explore a potential mechanism underlying inflammatory change of Treg cells, we quantified a variety of soluble factors in systemic circulation before and after onset of acute GvHD. The concentration of IL-6 and IL-21 was significantly higher in the serum drawn after onset of acute GvHD compared to baseline, suggesting that these Th17-polarizing cytokines might be responsible for the inflammatory conversion of Treg cells during acute GvHD. We further checked the suppressive activity of TNF-α-producing CD4 +CD25 hiFoxP3 + Treg cells of acute GvHD patients. TNF-α + Treg cells of acute GvHD patients expressed lower level of FoxP3 than the TNF-α - counterpart. Similarly, the percentage of CD39 + cells was lower in TNF-α + Treg cells than in the TNF-α - counterpart. In fact, Treg cell suppressive activity during acute GvHD was significantly reduced compared with that of pre-SCT control when non-Treg CD4 + T cells or CD8 + T cells were used as responder cells. Finally, we examined the clinical significance of TNF-α-producing CD4 +CD25 hiFoxP3 + Treg cells in acute GvHD patients. The frequency of TNF-α + cells among circulating Treg cells significantly correlated with the severity of acute GvHD, with higher proportion of TNF-α + Treg cells in patients with the higher grade of acute GvHD. This result indicates that the pathologic conversion of Treg cells to produce TNF-α contributes to immune-mediated tissue injury during acute GvHD. Taken together, during human acute GvHD, Treg cells undergo functional alteration to produce proinflammatory cytokines including TNF-α and IL-17A and to exhibit the reduced suppressive activity. TNF-α production by Treg cells is closely associated with the clinical severity of acute GvHD.

Novel therapies for graft versus host disease with a focus on cell therapies.

Graft versus host disease (GVHD) can occur at any period post allogeneic hematopoietic stem cell transplantation as a common clinical complication contributing to significant morbidity and mortality. Acute GVHD develops in approximately 30-50% of patients receiving transplants from matched related donors. High doses of steroids are used as first-line treatment, but are unsuccessful in around 40% of patients, resulting in the diagnosis of steroid-refractory acute GVHD. Consensus has yet to develop for the management of steroid-refractory acute GVHD, and prognosis at six months has been estimated at around 50%. Thus, it is critical to find effective treatments that increase survival of steroid-refractory acute GVHD. This article describes the currently known characteristics, pathophysiology, and treatments for GVHD, with a special focus on recent advances in cell therapies. In particular, a novel cell therapy using decidua stromal cells (DSCs) was recently shown to have promising results for acute GVHD, with improved effectiveness over previous treatments including mesenchymal stromal cells. At the Karolinska Institute, severe acute GVHD patients treated with placenta-derived DSCs supplemented with either 5% albumin or 10% AB plasma displayed a one-year survival rate of 76% and 47% respectively. Furthermore, patients with steroid-refractory acute GVHD, displayed survival rates of 73% with albumin and 31% with AB plasma-supplemented DSCs, compared to the 20% survival rate in the mesenchymal stromal cell control group. Adverse events and deaths were found to be attributed only to complications of hematopoietic stem cell transplant and GVHD, not to the study intervention. ASC Therapeutics, Inc, in collaboration with the Karolinska Institute, will soon initiate a phase 2 multicenter, open-label study to further assess the efficacy and safety of intravenous DSC treatment in sixty patients with Grade II-IV steroid-refractory acute GVHD. This novel cell therapy represents a promising treatment to combat the poor prognosis that steroid-refractory acute GVHD patients currently face.

Differential protein expression in endothelial cells exposed to serum from patients with acute graft-vs-host disease, depending on steroid response.

Graft-versus-host disease (GVHD) is a complication of allogeneic haematopoietic cell transplantation. Endothelial injury is crucial as pathophysiological substrate for GVHD. GVHD first-line treatment is high-dose corticosteroids, although some patients are steroid-refractory. Through the present study, we compared the endothelial proteomic profiles in response to serum from steroid-refractory acute GVHD (SR-aGVHD) and steroid-sensitive acute GVHD (SS-aGVHD) patients. Blood samples from SR-aGVHD (n= 4) and SS-aGVHD (n= 8) patients were collected at aGVHD diagnosis. Endothelial cell cultures were exposed (48 h) to patients' serum. Protein extraction and proteomic analysis were performed. Differences were statistically evaluated by multivariate analysis. Forty-four proteins contributed to separate all samples into the two study groups, among which 15 participated significantly (p< 0.05), 10 exhibiting a fold change >1.2. Differentially expressed proteins were mainly associated with oxidative phosphorylation (Cytochrome C oxidase subunit 6B1, CX6B1), inflammation and angiogenesis (Apolipoprotein D, APOD), cell survival (Rapamycin-insensitive companion of mTOR, RICTR), and oxidative stress (Riboflavin kinase, RIFK). This pilot study used a novel approach to distinguish the aGVHD response to steroid treatment. The proteins differentially expressed could constitute potential biomarkers for steroid-treatment response. These findings signify a step forward to identify the mechanisms of response to steroids, of high clinical relevance considering the SR-aGVHD elevated mortality.

Allogeneic hematopoietic stem cell transplant outcomes in adults with inherited myeloid malignancies.

There is increasing recognition that pathogenic germ line variants drive the development of hematopoietic cancers in many individuals. Currently, patients with hereditary hematologic malignancies (HHMs) receive similar standard therapies and hematopoietic stem cell transplant (HSCT) approaches as those with sporadic disease. We hypothesize that patients with myeloid malignancies and deleterious germ line predisposition variants have different posttransplant outcomes than those without such alleles. We studied 472 patients with myeloid neoplasms, of whom 26% had deleterious germ line variants and 34% underwent HSCT. Deleterious germ line variants in CHEK2 and DDX41 were most commonly seen in American and Australian cohorts, respectively. Patients with deleterious germ line DDX41 variants had a higher incidence of severe (stage 3-4) acute graft-versus-host disease (GVHD) (38%) than recipients with deleterious CHEK2 variants (0%), other HHM variants (12%), or patients without such germ line variants (9%) (P= .002). Importantly, the use of posttransplant cyclophosphamide reduced the risk of severe acute GVHD in patients receiving HSCT for deleterious germ line DDX41-associated myeloid neoplasms (0% vs 53%, P= .03). Based on these results, we advocate the use of posttransplant cyclophosphamide when individuals with deleterious germ line DDX41 variants undergo allogeneic HSCT for myeloid malignancies, even when transplantation has been performed using wild-type donors.

CD73-Expressing Microbiota-Reactive DP8α Regulatory T Cells Are Lacking in Acute GvHD Patients and Prevent Disease Development in a Pre-Clinical In Vivo Humanized Mouse Model of GvHD

Allogeneic stem cell transplantation (allo-HSCT) to treat hematological malignancies can induce life-threatening complications, such as graft-versus-host disease (GvHD). Steroids remain the first-line treatment for acute GvHD (aGvHD). Nevertheless, new treatments are needed to, not only, treat steroid-resistant patients and improve allo-HSCT outcomes, but also reduce steroid complications. Increasing evidences strongly suggest that gut microbiota composition and the activity of regulatory T cells (Tregs) could be involved in GvHD prevention. We have identified a novel FoxP3-negative IL-10-secreting Treg subset, named DP8α, enriched in the colonic mucosa and present in blood. These cells display a TCR-specificity for the gut ClostridiumIV bacterium Faecalibacterium prausnitzii. Sizable fractions of these cells also expressed the membrane-bound ectonucleotidases CD39 and CD73, which are directly involved in their suppressive activity in vitro. In vivo, these enzymes play key regulatory roles by both degrading proinflammatory extracellular ATP and inducing the production of immunosuppressive adenosine. An alteration in this adenosine/purinergic pathway has also been linked to GvHD occurrence. Altogether, these data prompted us to hypothesize that F. prausnitzii-reactive DP8α Tregs, whose suppressive activity is driven by the purinergic pathway, could bridge microbiota dysbiosis and GvHD incidence in allo-HSCT patients. Moreover, decreased levels of Clostridia, especially Faecalibacteriumspp, in patient's stools, have been associated with aGvHD risk, and mice gavaged with Treg-inducing Clostridia displayed milder GvHD and improved survival. Therefore, we addressed a potential role for DP8α Tregs in the prevention of aGvHD. We first analyzed cells from 63 patients with hematological malignancies, who received allo-HSCT, among whom a third developed aGvHD. We quantified their circulating DP8α Tregs and their CD39 and CD73 expression pre- and post-allo-HSCT. While the percentage of CD73-expressing DP8α Tregs within CD3+ T cells before HSCT was not different, a strikingly deficiency of CD73-expressing DP8α Tregs was strongly associated with aGvHD development (p<.001) at 1-month post-transplant, as compared to aGvHD-free patients (Fig.1). Importantly, CD73 expression was not affected on any other T cell subset analyzed. CD73 decrease on DP8α Tregs did not result from corticotherapy since it was 1/ equally observed before and after treatment in aGvHD patients and 2/ not observed following in vitro treatment of PBMCs with methylprednisolone. Moreover, the decrease of CD73-expressing DP8α Tregs in aGvHD patients was observed across all treatment conditions, which were heterogeneous, and therefore appears relevant and likely related to the aGvHD condition itself. Altogether, these data strongly suggest that a CD73-dependent functional alteration of DP8α Tregs could, at least in part, be involved in aGvHD occurrence and/or development. We next evaluated the therapeutic efficacy of CD73+ DP8α Tregs in a pre-clinical model of acute xeno-GvHD induced through human PBMC injection in irradiated NSG recipient mice. In vitro-expanded CD73+ DP8α Treg injected i.v. drastically protected mice against xeno-GvHD (Log-rank, p<.0001; Fig.2) without preventing the development of human chimerism. Moreover, these in vivo experiments, repeated 4 times using different PBMC donors, all confirmed the potent protective role of CD73+ DP8α Tegs in this model. Accordingly, serum inflammatory human cytokines and tissue infiltration by human cells were significantly lower in mice treated with CD73+ DP8α Tregs, as compared to untreated mice. In addition, the colon was rapidly populated with the injected DP8α Tregs and well-preserved in treated mice, while clearly damaged in untreated mice. Altogether, these results strongly support a role for CD73+ DP8α Tregs in aGVHD prevention and advocate for the use of these cells to both predict aGvHD risks and give rise to the development of innovative therapeutic strategies to preclude GvHD-related inflammation. Such therapeutic approaches would be based on the infusion of DP8α Tregs and/or their in vivo stimulation, e.g., with F. prausnitzii-derived antigens or probiotics. Of note, DP8α Tregs display an uniquely high proliferating potential and stable immunosuppressive functions in vitro, a key feature to implement such therapeutics. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P1382: RUXOLITINIB USE IN A REAL WORLD ACUTE AND CHRONIC GRAFT VERSUS HOST DISEASE COHORT IN THE NETHERLANDS: A RETROSPECTIVE STUDY

Background: Preclinical data showed that Janus Kinase (JAK) signaling plays an important role in the pathogenesis of Graft versus Host Disease (GVHD) and several clinical studies showed remarkable clinical efficacy in both acute and/or chronic steroid-refractory (SR)-GVHD patients. However, these clinical results have not yet been repeated in real world cohorts with long term follow-up. Furthermore, infectious complications have not been highlighted in published clinical trials whilst these remain a significant problem in daily practice. Aims: To assess the response of acute and/or chronic SR-GVHD patients to ruxolitinib treatment and to assess side-effects of ruxolitinib treatment occurring in adult acute and/or chronic SR-GVHD patients. Methods: We performed a retrospective analysis of 121 consecutive patients treated with ruxolitinib for either acute or chronic GVHD. Patients were included from 3 academic centers in the Netherlands from 2014 to 2019. Patients provided written informed consent, with the exception of deceased patients in accordance with the local ethics committee. Patient data were extracted by personnel from an independent CRO to minimize reviewer bias. Patient data were anonymized. Results: 121 patients were included in the study of whom 54 were diagnosed with acute and 67 patients with chronic GVHD. Selected baseline characteristics are depicted in Table 1. The overall response rate at day 28 of acute GVHD was 70% (38/54) with a complete response in 50% of patients (27/54). At timepoint 6 months after initiation of ruxolitinib for chronic GVHD, the majority of patients showed stable disease. The overall response rate at 6 months in chronic GVHD was 28% (19/67) with a complete response in 13% of patients (9/67). Ruxolitinib use was mainly complicated by infections and hematological toxicity. Of the reported (S)AE’s possibly related to ruxolitinib, 38% were infectious and 13% were hematological. Severity of infections ranged from grade 1 to grade 5, median grade 2. Most infections were viral (43%), followed by bacterial (19%) and fungal or mould infections (14%). During follow up mortality was 14,9% (18 patients) of which 6 cases were due to uncontrolled GVHD, 5 cases due to infections and 3 patients died of relapse of their primary malignancy, 4 patients died of other causes. Image:Summary/Conclusion: In a real world cohort of GVHD patients treated with ruxolitinib we observed in patients with acute GVHD a complete response rate at day 28 of 50%. Overall response rate at 6 months in cGVHD patients was 28%. Infectious adverse events were common in both acute and chronic GVHD patients and were mainly caused by viral pathogens.

Naive T Cells in Graft Versus Host Disease and Graft Versus Leukemia: Innocent or Guilty?

The outcome of allogeneic hematopoietic cell transplantation (allo-HCT) largely depends on the development and management of graft-versus-host disease (GvHD), infections, and the occurrence of relapse of malignancies. Recent studies showed a lower incidence of chronic GvHD and severe acute GvHD in patients receiving naive T cell depleted grafts compared to patients receiving complete T cell depleted grafts. On the other hand, the incidence of acute GvHD in patients receiving cord blood grafts containing only naive T cells is rather low, while potent graft-versus-leukemia (GvL) responses have been observed. These data suggest the significance of naive T cells as both drivers and regulators of allogeneic reactions. The naive T cell pool was previously thought to be a quiescent, homogenous pool of antigen-inexperienced cells. However, recent studies showed important differences in phenotype, differentiation status, location, and function within the naive T cell population. Therefore, the adequate recovery of these seemingly innocent T cells might be relevant in the imminent allogeneic reactions after allo-HCT. Here, an extensive review on naive T cells and their contribution to the development of GvHD and GvL responses after allo-HCT is provided. In addition, strategies specifically directed to stimulate adequate reconstitution of naive T cells while reducing the risk of GvHD are discussed. A better understanding of the relation between naive T cells and alloreactivity after allo-HCT could provide opportunities to improve GvHD prevention, while maintaining GvL effects to lower relapse risk.

Pre-transplantation vitamin E levels and acute graft-versus-host disease after non-myeloablative allogeneic hematopoietic cell transplantation

BackgroundLow pre-transplantation plasma vitamin E levels have been associated with increased risk of acute graft-versus-host disease (GvHD) after myeloablative allogeneic hematopoietic cell transplantation (allo-HCT). We aimed to investigate the association between pre-transplantation plasma vitamin E levels and acute GvHD in patients undergoing allo-HCT with non-myeloablative conditioning. MethodsIn a cohort of 194 adults who underwent non-myeloablative allo-HCT at Rigshospitalet between July 2015 and December 2019, we measured pre-transplantation plasma vitamin E levels by high-performance liquid chromatography in stored plasma samples. Univariable ordinary least squares linear models were used to investigate associations between vitamin E levels and patient characteristics. A multivariable logistic regression model was used to estimate the association between vitamin E levels and grade II–IV acute GvHD, adjusted for recipient age, donor age, female-male donor-recipient pairing, and donor type. ResultsThe median (Q1, Q3) pre-transplantation plasma vitamin E level was 32.3 (26.4, 40.4) μmol/L. No patients had a vitamin E level below the normal reference range. Vitamin E levels were higher in females (mean difference: 8.0 μmol/L, 95% confidence interval [CI]: 4.9, 11.1 μmol/L) and in patients transplanted for acute leukemia (mean difference: 6.2 μmol/L, CI: 3.0, 9.4 μmol/L). Grade II–IV acute GvHD developed in 33 (17%) patients. Patients who developed acute GvHD had similar pre-transplantation vitamin E levels compared with patients who did not develop grade II–IV acute GvHD (mean difference: 0.7 μmol/L, bootstrap CI: −3.3, 4.7 μmol/L). In the adjusted logistic regression model, an increase in the pre-transplantation vitamin E level from 26.4 (Q1) to 40.4 (Q3) μmol/L was associated with an odds ratio of grade II–IV acute GvHD of 1.17 (CI: 0.64, 2.12). ConclusionsContrary to the previously reported association between pre-transplantation vitamin E levels and acute GvHD after myeloablative allo-HCT, we did not find support for an association in patients who received non-myeloablative conditioning. The potential protective effects of vitamin E may not be efficacious in the reduced inflammatory response following non-myeloablative conditioning.

Gut microbiome in allogeneic hematopoietic stem cell transplantation and specific changes associated with acute graft vs host disease

Allogeneic hematopoietic stem cell transplantation (aHSCT) is a standard validated therapy for patients suffering from malignant and nonmalignant hematological diseases. However, aHSCT procedures are limited by potentially life-threatening complications, and one of the most serious complications is acute graft-versus-host disease (GVHD). During the last decades, DNA sequencing technologies were used to investigate relationship between composition or function of the gut microbiome and disease states. Even if it remains unclear whether these microbiome alterations are causative or secondary to the presence of the disease, they may be useful for diagnosis, prevention and therapy in aHSCT recipients. Here, we summarized the most recent findings of the association between human gut microbiome changes and acute GVHD in patients receiving aHSCT.

Prognostic Value of Elafin in Acute Graft-Versus-Host Disease

Prognostic Value of Elafin in Acute Graft-Versus-Host Disease

Safety and Efficacy of Pembrolizumab Prior to Allogeneic Stem Cell Transplantation for Acute Myelogenous Leukemia

Programmed death 1 (PD-1) is an integral component of acute myelogenous leukemia (AML) immune evasion, chemotherapy resistance, and disease progression. PD-1 inhibitors are being investigated as treatment for AML in combination with hypomethylating agents and cytotoxic chemotherapy with encouraging findings. Although allogeneic stem cell transplantation (alloSCT) remains the most established curative treatment for patients with relapsed and refractory AML in complete remission, there are limited data on the clinical outcomes and safety of immune checkpoint inhibitors (ICIs) prior to alloSCT in AML. In the present study, we compared clinical outcomes of 9 patients with AML receiving high-dose cytarabine followed by pembrolizumab in a phase II clinical trial (NCT02768792) prior to alloSCT versus a historical control group of 18 AML patients who underwent alloSCT without prior ICI exposure. The nonparametric Jonckheere-Terpstra test was used to test for a difference in the ordered severity categories of acute graft-versus-host disease (GVHD) within 100 days of transplantation. Time-to-event estimates for overall survival and relapse-free survival were calculated using the Kaplan-Meier method and compared using a log-rank test. One-year survival was not significantly different between the treatment groups (67% versus 78%; P=.34). 100-day mortality was 0% in the ICI group versus 17% in the control group, and there was no increase in grade III-IV acute GVHD in patients treated with pembrolizumab prior to alloSCT. No chronic GVHD was seen in patients treated with pembrolizumab prior to alloSCT and who received post-transplantation cyclophosphamide (PTCy) as part of their conditioning regimen. These findings reinforce the safety and feasibility of ICI therapy prior to alloSCT in patients with AML, and suggest that PTCy may abrogate GVHD risk and severity in patients who receive ICI prior to undergoing alloSCT for AML.

Evaluation of Elafin as a Prognostic Biomarker in Acute Graft-versus-Host Disease

Acute graft-versus-host disease (GVHD) is a major cause of mortality in patients undergoing hematopoietic cell transplantation (HCT) for hematologic malignancies. The skin is the most commonly involved organ in GVHD. Elafin, a protease inhibitor overexpressed in inflamed epidermis, was previously identified as a diagnostic biomarker of skin GVHD; however, this finding was restricted to a subset of patients with isolated skin GVHD. The main driver of nonrelapse mortality (NRM) in HCT recipients is gastrointestinal (GI) GVHD. Two biomarkers, Regenerating islet-derived 3a (REG3α) and Suppressor of tumorigenesis 2 (ST2), have been validated as biomarkers of GI GVHD that predict long-term outcomes in patients treated for GVHD. We undertook this study to determine the utility of elafin as a prognostic biomarker in the general population of acute GVHD patients in whom GVHD may develop in multiple organs. We analyzed serum elafin concentrations as a predictive biomarker of acute GVHD outcomes and compared it with ST2 and REG3α in a large group of patients treated at multiple centers. A total of 526 patients from the Mount Sinai Acute GVHD International Consortium (MAGIC) who had received corticosteroid treatment for skin GVHD and who had not been previously studied were analyzed. Serum concentrations of elafin, ST2, and REG3α were measured by ELISA in all patients. The patients were divided at random into equal training and validation sets, and a competing-risk regression model was developed to model 6-month NRM using elafin concentration in the training set. Additional models were developed using concentrations of ST2 and REG3α or the combination of all 3 biomarkers as predictors. Receiver operating characteristic (ROC) curves were constructed using the validation set to evaluate the predictive accuracy of each model and to stratify patients into high- and low-risk biomarker groups. The cumulative incidence of 6-month NRM, overall survival (OS), and 4-week treatment response were compared between the risk groups. Unexpectedly, patients in the low-risk elafin group demonstrated a higher incidence of 6-month NRM, although the difference was not statistically significant (17% versus 11%; P=.19). OS at 6 months (68% versus 68%; P > .99) and 4-week response (78% versus 78%; P=.98) were similar in the low-risk and high-risk elafin groups. The area under the ROC curve (AUC) was 0.55 for elafin and 0.75 for the combination of ST2 and REG3α. The addition of elafin to the other 2 biomarkers did not improve the AUC. Our data indicate that serum elafin concentrations measured at the initiation of systemic treatment for acute GVHD did not predict 6-month NRM, OS, or treatment response in a multicenter population of patients treated systemically for acute GVHD. As seen in previous studies, serum concentrations of the GI GVHD biomarkers ST2 and REG3α were significant predictors of NRM, and the addition of elafin levels did not improve their accuracy. These results underscore the importance of GI disease in driving NRM in patients who develop acute GVHD.

Outcome of Children with Acute Leukemia Given Allogeneic HSCT Either from an Unrelated Donor or from an HLA-Partially Matched Relative after αβ-T Cell/B-Cell Depletion: A Multicenter, Retrospective, Comparative Analysis of the AIEOP Network

IntroductionFor patients in need of an allograft and lacking an HLA-identical sibling, hematopoietic stem cell transplantation (HSCT) from an unrelated donor (UD) is the standard of care. In the recent few years, αβ T-cell and B-cell depleted HLA-haploidentical HSCT (αβhaplo-HSCT) is becoming a widely employed alternative to UD-HSCT in patients with acute leukemia. We, thus, decided to conduct a retrospective analysis on the outcome of patients given either αβhaplo-HSCT or UD HSCT in the same time period, namely October 2010-December 2015, in one of the 13 centers affiliated with the Italian-HSCT pediatric network.Methods: Included in the study were 97 αβhaplo-HSCT recipients and 244 patients receiving UD-HSCT in the same period. Six centers performed both αβhaplo-HSCT and UD-HSCT, while only this latter procedure was performed in the remaining 7 centers. All children were transplanted in morphological complete remission (CR) after a fully myeloablative conditioning regimen. The UD was selected using high-resolution typing for the HLA-loci A, B, C, DRB1. The UD was 8/8 HLA-matched with the recipient in 52% of cases, while the remaining 48% of patients were transplanted from a donor with either 1 or 2 HLA-disparities. Details on patient characteristics of the 2 groups are shown in the Table; recipients of αβhaplo-HSCT were transplanted in more advanced phase and received more frequently a TBI-based regimen than UD-HSCT patients. Patients given αβhaplo-HSCT did not receive any post-transplantation pharmacological prophylaxis of graft-versus-host disease (GvHD), while the combination of anti-T lymphocyte globulin (ATLG), cyclosporine-A and short-term methotrexate was employed for preventing GvHD occurrence in all UD-HSCT recipients. ATLG was also infused before transplantation in all children treated with αβhaplo-HSCT to prevent both graft rejection and GvHD.Results: Two (2%) and 4 (2%) patients experienced graft failure in the αβhaplo-HSCT and UD-HSCT groups, respectively. Median time to neutrophil and platelet recovery was shorter in children given αβhaplo-HSCT (13 and 11 days vs. 19 and 23 days, respectively, P < 0.001 in both cases). The cumulative incidence (CI) of grade II-IV and grade III-IV acute GvHD in patients given αβhaplo-HSCT was 16% and 0%, as compared to 39% and 12% in UD-HSCT recipients (P < 0.001 and < 0.0005, respectively). Children treated with αβhaplo-HSCT benefited also from a lower incidence of both overall and extensive chronic GvHD (6% and 1%, respectively, vs 20% and 7% in UD-HSCT recipients, P < 0.01 and < 0.05, respectively), especially when compared with 7/8 and 6/8 UD-HSCT recipients. Forty-eight patients died for transplant-related complications: 9 (9%) and 40 (16%) in the αβhaplo-HSCT and UD-HSCT group, respectively, the CI of non-relapse- mortality (NRM) being 9% and 17% (P = N.S.). While the probability of NRM is superimposable in αβhaplo-HSCT and 8/8 UD-HSCT, 7/8 and 6/8 UD-HSCT had a higher risk of mortality (25% and 37%, respectively). Seventy-three children relapsed at a median time of 190 days (range 40-1603) after the allograft; no statistically significant difference for the CI of disease recurrence was observed between the 2 groups (25% vs 20%, respectively). With a median follow-up of 3.3 years (range 0.5-5 years for surviving patients) the 3-year probability of overall survival for patients given either αβhaplo-HSCT or UD-HSCT is 68% and 64%, respectively (P = N.S.), while that of event-free survival is 63% and 62%, respectively (P = N.S.). The 3-year chronic GvHD-free/relapse-free survival (GRFS) in the 2 groups is 59% and 48%, respectively (P = 0.03). GRFS of αβhaplo-HSCT or 8/8 UD-HSCT recipients was superimposable.Conclusions: Patients givenαβhaplo-HSCT had a faster ANC/PLT recovery and a lower probability of acute GvHD in comparison to children transplanted from an UD donor. Moreover, they also had a lower risk of NRM and better probability of GRFS in comparison to patients transplanted from an UD with 1 or 2 HLA-disparities. αβhaplo-HSCT is associated with a CI of disease recurrence comparable to that of children transplanted from an UD. Altogether, these data indicate that αβhaplo-HSCT is a competitive alternative to UD-HSCT, especially in the absence of a fully-matched donor. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Current practice in nutrition after allogeneic hematopoietic stem cell transplantation – Results from a survey among hematopoietic stem cell transplant centers

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is frequently associated with impaired oral intake and malnutrition, which potentially increases morbidity and mortality. Therefore, nutrition is one of the major challenges in the post-transplant period. To document the current clinical approach in nutritional treatment, we designed a questionnaire concerning the current practice in nutrition after alloHSCT and distributed it to German speaking centers performing alloHSCT in Germany, Austria and Switzerland between November 2018 and March 2020. Twenty-eight (39%) of 72 contacted centers completed the survey, 23 from Germany, two from Austria and three from Switzerland, representing 50% of alloHSCT activity within the participating countries in 2018. All centers reported having nutritional guidelines for patients undergoing alloHSCT, whereby 86% (n=24) provided a low-microbial diet during the neutropenic phase. The criteria to start parenteral nutrition (PN) directly after alloHSCT seemed to be consistent, 75% (n=21) of the corresponding centers started PN if the oral nutritional intake or the bodyweight dropped below a certain limit. In the setting of intestinal graft-versus-host disease (GvHD) the current practice appeared to be more heterogenous. About 64% (n=18) of the centers followed a special diet, added food stepwise modulated by GvHD symptoms, while only four centers regularly stopped oral intake completely (intestinal GvHD grade >1). Half of the centers (54%, n=15) applied a lactose-free diet, followed by 43% (n=12) which provided fat- and 18% (n=5) gluten-free food in patients with intestinal GvHD. Supplementation of micronutrients in acute intestinal GvHD patients was performed by 54% (n=15) of the centers, whereas vitamin D (89%, n=25) and vitamin B12 (68%, n=19) was added regularly independently of the presence of GvHD. Only 5 (18%) participating centers ever observed a food-associated infection during hospitalization, whereas food-associated infections were reported to occur more often in the outpatient setting (64%, n=18). The survey documented a general consensus about the need for nutritional guidelines for patients undergoing alloHSCT. However, the nutritional treatment in clinical practice (i.e. lactose-, gluten- or fat-free in intestinal GvHD) as well as the use of food supplements was very heterogeneous. In line with current general recommendations the centers seemed to focus on safe food handling practice rather than providing a strict neutropenic diet. More high-quality data are required to provide evidence-based nutrition to patients during and after alloHSCT.

Safety and Efficacy of Ruxolitinib in Steroid-Resistant Graft Versus Host Disease: A Systematic Review and Meta-Analysis

Introduction: Stem cell transplantation (SCT) is used to treat multiple malignancies, but a major complication of the procedure is graft versus host disease (GvHD), which is a significant cause of morbidity and death in SCT patients. Methylprednisolone is the first-line therapy of GvHD. Ruxolitinib is a Janus kinase (JAK) inhibitor that can dampen the effect of inflammatory cytokines involved in GvHD and may be used in patients refractory to steroid treatment. In this systematic review and meta-analysis, we assessed the safety and efficacy of Ruxolitinib in steroid-resistant (SR) acute (a) and chronic (c) GvHD. Methods: We performed a search on PubMed, Cochrane, Embase, and Web of Science. We used the keywords, "Ruxolitinib" AND "Graft vs Host Disease" from the inception of literature till 7/10/2020. We screened 694 articles and included 1 randomized clinical trial (RCT) (N=309), 4 non-randomized trials (NRCT) (N=232), and 13 observational studies (N=481) in this meta-analysis. We extracted data for efficacy (i-e, OS, CR, ORR) and safety (≥grade 3 treatment related adverse events (TRAE). We excluded case reports, case series, review articles, meta-analysis, and preclinical trials. We used the R programming language (version 4.0.2) to conduct a meta-analysis. Results: In the 18 included studies (N=1022), Ruxolitinib was used in patients with the age range of 6 months to 70 years. 417 participants had grade III-IV acute GvHD, and 272 participants had moderate to severe chronic GvHD (Table 1). In an RCT (N=309), patients aged between 12-73 years with SR aGVHD were randomized 1:1 to receive either Ruxolitinib or physician's choice drug. Overall response rate (ORR) and complete response (CR) were significantly higher in the Ruxolitinib group as compared to the physician's choice drug. The results were consistent for all grades of GvHD. Grade 3 or higher treatment-related adverse events (TRAEs) were 78% in the two groups. 22% of the patients died of GvHD related adverse events in the Ruxolitinib group vs. 25% of the patients in the control group. In 12 clinical trials and observational studies, among SR GvHD patients (N=443), pooled ORR was 0.74 (CI=0.65-0.81, I2=61%) with Ruxolitinib treatment. Similarly, pooled CR was 0.45 (CI=0.34-0.68, I2=81%). The most common adverse events were cytopenias, viral reactivation, and infections. (Fig 1, 2) In 9 early phase trials and observational studies (N=282) in SR- chronic GvHD patients, pooled ORR and pooled CR were 0.75 (CI=0.64-0.83, I2=64%) and 0.11 (CI=0.08-0.16, I2=0), respectively. The most common adverse events were cytopenias and viral reactivation (Fig 3, 4). In a non-randomized trial (N=64), Ruxolitinib was used in combination with Etanercept for SR- acute GvHD patients. The ORR and CR were 87.5% and 72%, respectively. High rates of hematological adverse events and infections were reported in these patients. In an observational study (N=18), Ruxolitinib was used in combination with Extracorporeal Photopheresis (ECP). The combination was well-tolerated, and ORR and CR were 55% and 44%, respectively (Table 1). Conclusion: Ruxolitinib was well tolerated by patients with acute or chronic SR-GvHD. Ruxolitinib showed a higher efficacy compared to the physician's choice drug in SR acute GvHD. Ruxolitinib was also effective in SR cGvHD patients. The addition of etanercept to Ruxolitinib increased the efficacy in SR-acute GvHD patients but resulted in an increased incidence of infections. Ruxolitinib with ECP was effective and well tolerated in SR-acute GvHD. Additional multicenter, randomized, double-blind clinical trials are needed to confirm these results. Disclosures Anwer: Incyte, Seattle Genetics, Acetylon Pharmaceuticals, AbbVie Pharma, Astellas Pharma, Celegene, Millennium Pharmaceuticals.: Honoraria, Research Funding, Speakers Bureau.

Allogeneic Bone Marrow Mesenchymal Stromal Cell Therapy in Patients with Steroid-Refractory Graft Versus Host Disease—a Pilot Study from Pakistan

Mesenchymal stromal cells (MSCs) have emerged as a promising candidate for the treatment of steroid-refractory graft-versus-host disease (GVHD). In this uncontrolled, pilot clinical study, we report safety and efficacy of allogeneic bone marrow MSCs administered intravenously to steroid-refractory GVHD patients. A total of 33 MSC infusions were given to 10 patients suffering from acute GVHD (n = 3), chronic GVHD (n = 5), and overlap syndrome (n = 2). Eight out of ten patients are alive after a median follow-up of 11 months with five having sustained complete remission (CR). Three patients with partial response received further doses to sustain the response. One of them died of lung infection while others are still alive. One out of the two non-responding patients died after 17 days of MSC therapy due to advanced liver GVHD while the other is having a stable disease course. The overall and GVHD-free survival was 80% and 50%, respectively. The patients developed no complication or toxicity related to MSC infusion. Luminex analysis revealed a modest drop after MSC infusion in pro-inflammatory cytokines like TNFα, IL-1β, and IL-6 whereas serum IL-10 levels were slightly raised. Allogeneic donor-derived bone marrow mesenchymal stromal cell therapy is a safe and feasible treatment for steroid-refractory GVHD patients (NCT02824653). We report the safety and efficacy of allogeneic bone marrow mesenchymal stromal cell therapy in 10 patients suffering from steroid-resistant graft-versus-host disease. Eight out of ten patients are alive after a median follow-up of 11 months with five having sustained CR. The response rate was better in acute GVHD patients compared to chronic GVHD patients. MSC therapy within 20 days of steroid-refractory acute GVHD resulted in sustained CR. Initial and sustained response was superior in pediatric patients compared to adults. The Luminex analysis showed a modest decrease in pro-inflammatory cytokines in those responding to MSC therapy.

Systematic Review of Patient-Reported Outcome Measures in Graft-versus-Host Disease.

Graft-versus-host disease (GVHD) is a major cause of morbidity and mortality after allogeneic stem cell transplantation. These patients face a unique challenge due to the complexity of GVHD and the toxicity of treatments received. GVHD has significant impact on quality of life (QOL), but this is not routinely evaluated formally. Despite the availability of patient-reported outcome measures (PROMs) to assess QOL, there is currently no consensus regarding the optimal PROMs that should be used to evaluate the impact of GVHD. We undertook a systematic review to determine the current evidence for the use of PROMs in assessment of QOL, symptom burden, and disease severity of patients with GVHD. A comprehensive systematic review based on the COSMIN guidelines was conducted to identify studies using PROMs (including those for QOL and symptom burden) in acute and chronic GVHD (cGVHD) patients. The following databases were searched: OVID Medline, AMED, CINAHL, Embase, PROQOLID, ProQuest, PsychINFO, and Social Sciences Citation Index from inception to May 2018. Hand searches updated the search to December 2018. Articles were screened by 2 independent reviewers, with discrepancies resolved by a third independent reviewer. Included articles were critically appraised using the COSMIN Risk of Bias tool, and relevant data on measurement properties for the included PROMs were extracted from within the target population. A total of 4545 articles were identified, and 64 articles reporting on 27 PROMs were included in this review. PROMs were separated into 5 groups; generic patient-reported measures (n=7), cancer-specific measures (n=4), bone marrow transplant-specific measures (n=2), cGVHD-specific measures (n=4), and dimension-specific measures (n=10). Three PROMs (Human Activity Profile, Lee Symptom Scale, National Institutes of Health Eleven Point Scale) had evidence to support strong reliability (including internal consistency), responsiveness, and aspects of validity within the cGVHD population. Only 5 included PROMs were used in patients with acute GVHD. This review summarizes the current evidence regarding the use of 27 included PROMs in the context of GVHD. The choice of the most optimal PROM depends on the clinical or research context of use. Future research should comprehensively validate these tools in the GVHD population, including the testing and possible development of a PROM for use in acute GVHD, which remains a current critical gap in the existing literature.

Significantly Increased Risk of Grade II-IV Acute Gvhd in Adolescent and Young Adult (AYA) Recipients (ages ≥13 years) Vs Childhood Recipients (ages 2-12 years) with Acute Leukemia Following Matched Unrelated Donor (MUD) Stem Cell Transplantation (SCT): The Children's Oncology Group Experience

<h3>Background</h3> Adolescent and young adult (AYA) acute leukemia patients have inferior outcomes in comparison to their younger counterparts, related to higher risk disease and increased toxicity (Hochberg J, et al., BJH, 2013). AYA recipient age (≥13 years) vs children (ages 2-12 years) has been associated with increased acute and chronic graft versus host disease (GVHD) in matched sibling donor SCT (Qayed M, et al., BBMT, 2017). <h3>Objective</h3> To determine the association between recipient age (age ≥13 years vs age 2-12 years) and risk of acute grade II-IV and chronic GVHD following MUD SCT in acute leukemia recipients. <h3>Methods</h3> We reviewed all pediatric and young adult recipients receiving a MUD SCT enrolled on Children's Oncology Group clinical trials ASCT0431, AAML03P1, AAML0531, AAML1031 from 2004-present. Variables assessed included age at transplant, sex, race, performance score, leukemia type (ALL vs AML), remission (CR1 vs CR2), stem cell source, donor/recipient ABO, CMV, and sex matching, GVHD prophylaxis, year of transplant, time from diagnosis to transplant. Overall survival (OS), event-free survival (EFS), acute and chronic GVHD were assessed with Kaplan-Meier curves, cumulative incidence curves, and multivariable Cox proportional hazard models. <h3>Results</h3> Four-hundred eighty-six children and young adults underwent transplant on these trials, including 205 patients undergoing MUD SCT. For the MUD population, 8% were under age 2 years, 58% were age 2-12, and 34% were age 13-29. Seventy-one percent of patients had AML in CR1; 8% had ALL in CR1; 21% had ALL in CR2. Stem cell source included bone marrow (48%), peripheral blood stem cells (14%), and cord blood (38%). Complete HLA match in 60%, 1 allele HLA mismatch in 27%, 2+ HLA mismatches in 13%. Five-year OS and EFS rates (± standard error) for MUD were 48.4±3.8% and 44.6±3.6%, respectively. In multivariable analysis, older recipient age was associated with a significant increase in grade II-IV acute GVHD, hazard ratio or HR (95% CI) =2.03(1.28, 3.22) for age ≥13 vs age 2-12, p=0.004 (see Figure 1). HLA mismatches (≥2) were associated with grade II-IV acute GVHD, HR=2.35(1.30, 4.24) for ≥2 HLA mismatches vs matched, p=0.039 (see Figure 2). Older recipient age was not associated with chronic GVHD (p=0.83). However, significant association was found between chronic GVHD vs leukemia type and remission status (p=0.007; see Figure 3), with ALL in CR2 having more chronic GVHD than did AML in CR1 (HR=3.54(1.56, 8.03)). Acute GVHD, as expected, was a risk factor for the development of chronic GVHD (HR=2.18(1.03, 4.60), p=0.040). <h3>Conclusion</h3> Older recipient age (ages ≥13 years vs ages 2-12 years) was associated with significantly increased risk of grade II-IV acute GVHD in patients with acute leukemia following MUD SCT. Further evaluations of differential toxicity of AYA vs younger pediatric patients undergoing MUD SCT are underway.