Acute Gastrointestinal Graft-versus-host Disease Research Articles

Safety of Probiotics Among High-Risk Pediatric Hematopoietic Stem Cell Transplant Recipients.

IntroductionIncreased diversity of the intestinal microbiome has been significantly associated with lower mortality after hematopoietic stem cell transplant (HSCT). Probiotics, such as Lactobacillus species with defined probiotic potential, may have beneficial properties including restoration of commensal species to the intestinal tract, anti-microbial effects, and healing of the intestinal mucosa. However, the use of probiotics in immune-compromised patients raises concerns, specifically regarding the risk for possible Lactobacillus bacteremia. Risk of bacteremia is an even greater concern in HSCT patients with breakdown of mucosal barriers, specifically patients with Clostridium difficile infection (CDI) or gastrointestinal graft-versus-host disease (GVHD). Minimal data have been reported on the safety of probiotics in these high-risk HSCT populations.MethodsWe performed a retrospective study of allogeneic HSCT recipients at our institution between 2011 and 2016, and identified 14 patients (median age 7 years) prescribed probiotics, 10 of whom received probiotics prior to day 100 after HSCT.ResultsEight of ten patients were diagnosed with acute GVHD, four of whom (40%) specifically had acute GVHD involving the gastrointestinal tract. Five patients (50%) on probiotics prior to day 100 were diagnosed with CDI (median onset at day 13 post-transplant). There were no cases of Lactobacillus bacteremia, including in patients with GVHD or CDI.ConclusionThis small case series supports the safe use of probiotics in a high-risk population of pediatric HSCT patients with compromised intestinal mucosal integrity. Further studies are needed to determine if probiotics have benefit in preventing and treating gastrointestinal GVHD or CDI.

α4β7 Integrin Is Upregulated on CD8+ Effector Memory T-Cells in Children with Gut Gvhd Prior to Clinical Symptoms and Represents a Therapeutic Target in Pediatric Allogeneic HSCT Patients

Background α4β7 integrin is expressed on T-cells which migrate to gut-associated lymphoid tissues. Expression of α4β7 integrin is elevated on memory T-cells in adult hematopoietic stem cell transplant (HSCT) recipients at diagnosis of GI GVHD. No pediatric data exist regarding α4β7 integrin expression before or at onset of GVHD. We hypothesized that α4β7 integrin expression on effector memory T-cells (TEMs) would be elevated in patients before acute GI GVHD symptoms compared to patients without GVHD and may be a useful therapeutic target for the prevention of acute GI GVHD. Methods Cryopreserved T-cells were characterized in 48 children who developed acute GI GVHD (n=22), isolated skin GVHD (n=12) and no GVHD (n=14). In patients with GVHD, T-cells were characterized prior to HSCT, one week before GVHD and at GVHD diagnosis. In patients without GVHD, samples were analyzed at baseline and day+30 after HSCT. Samples were incubated with fluorochrome conjugated monoclonal antibodies directed against CD3, CD8, CCR7, α4β7 integrin and CD45RA. TEMs were defined as CD3+, CCR7-, CD45RA- lymphocytes. Co-expression of trafficking markers implicated in GI GVHD (CCR5, CCR9), and liver GVHD (CXCR6 and CCR5) were also assessed. Samples were analyzed on an LSR Fortessa flow cytometer (BD Biosciences). Data were analyzed using FCS Express (De Novo Software). Surface expression of all markers were compared using the Mann Whitney U-test. Patients with skin GVHD and no GVHD were grouped for analysis. Patients with at least 200 absolute CD8+ T-cell events were deemed evaluable. Results Twenty patients with GI GVHD, 8 with skin GVHD and 10 patients without GVHD had at least 200 absolute CD8+ events and were evaluable. Demographics of patients are shown in Figure 1. Expression of α4β7 integrin on CD8+ TEMs was upregulated in patients with GI GVHD compared to the No GI GVHD (skin GVHD + no GVHD) group one week prior to clinical symptoms (p=0.02; Figure 2A). Co-expression of CCR5 and CCR9 with α4β7 integrin was also higher on CD8+ TEM cells in the GI GVHD group compared to No GI GVHD group (p Conclusion α4β7 integrin is elevated on CD8+ TEMs prior to acute GI GVHD symptoms and co-expression of intestinal trafficking-specific markers such as CCR5 and CCR9 are also elevated prior to acute GVHD in pediatric patients. Our data suggest a rationale for the blockade of α4β7 integrin or the dual blockade of α4β7 integrin and CCR5 with clinically available therapeutics (maraviroc and vedolizumab) for acute GI GVHD prevention in pediatric allogeneic HCT patients.

Soluble CD64 Is a Novel Marker of Steroid Refractory Acute Gastrointestinal Graft Versus Host Disease in Pediatric Allogeneic Hematopoietic Stem Cell Transplant

Background CD64 is expressed on neutrophils and monocytes and is upregulated by mediators of inflammation such as interferon-gamma, G-CSF, infection or tissue injury. Soluble CD64 is elevated in new onset Crohn's disease and is a marker of intestinal inflammation. In Crohn's disease, elevated surface expression of CD64 has been associated with infliximab loss of response. The role of CD64 is not described in pediatric gastrointestinal graft versus host disease (GI GVHD). We hypothesized that CD64 would be elevated at diagnosis in children with acute GI GVHD at diagnosis. Methods Plasma CD64 was measured by ELISA in 40 patients (GI GVHD n=20, No GVHD n=20) at the following time points: before BMT and at diagnosis of acute GVHD or a comparable time point after BMT in controls (∼ day+35). Values were compared to new onset pediatric Crohn's disease (n=47) and non-inflammatory bowel disease (IBD) pediatric controls (n=42). Neutrophil CD64, measured by flow cytometry, was assessed in an independent group of 27 consecutive pediatric allogeneic BMT patients at diagnosis of GVHD or comparable time points in patients without GVHD. Results Patient demographics are shown in Table 1. Soluble CD64 was elevated in patients with GI GVHD at diagnosis compared to transplant patients without GVHD (p=0.003), Crohn's disease (p Nine of the 27 patients in the independent consecutive patient cohort had acute GVHD. Four patients had GI GVHD, 3 steroid refractory and one responsive. Median CD64 expression on neutrophils by flow cytometry was 14.3% in the GI GVHD patients compared to 4.92% in patients without GVHD (p=0.2) (Figure 2). Conclusion CD64 is a novel biomarker which could portend refractory acute gut GVHD in children. These findings need to be validated in a larger independent cohort.

Effectiveness of intra-arterial steroid administration for the treatment of steroid-refractory acute gastrointestinal graft-versus-host disease

To retrospectively assess the clinical effectiveness of intra-arterial steroid administration (IASA) treatment in adult patients who developed steroid-refractory gastrointestinal acutegraft-versus-host disease (GI-aGvHD) (≥stage II) following haematopoietic stem cell transplantation. Clinical data of 10 consecutive adult patients (age range, 19-61 years; mean age, 42 years) of a single centre with GI-aGvHD (≥stage II) who showed no response to intravenous methylprednisolone and received IASA into the superior (SMA) and/or inferior mesenteric arteries (IMA) were analysed. The severity of aGvHD was determined as the volume of diarrhoea (stages 0-IV) and the Glucksberg grading system before and 12±3 SD, 27±4 and 54±6 days after IASA treatment. Median follow-up was 65 days (range, 22-370 days). Six out of 10 patients at 12 days, 8/10 patients at 27 days, 6/10 patients at 54 days after IASA showed gastrointestinal response. Among them, 1/10 patients at 12 days, 4/10 patients at 27 days, and the same 4/10 patients at 54 days showed complete resolution of GI-aGvHD. The 4/10 patients who reached complete resolution of GI-aGvHD at day 12 or 27 showed a sustained symptom-free state. One in 10 patient showed only a temporary response, 5/10 patients died between days 22 and 67. IASA seems to be a potentially useful second-line therapy for intravenous steroid-refractory GI-aGvHD.

Targeted Molecular Imaging of Translocator Protein (TSPO) Using 18FGE180-PET for the Diagnosis of Gastrointestinal Graft Versus host Disease (GI-GVHD)

Introduction:Acute Gastrointestinal Graft Versus Host Disease (GI-GVHD) is a life-threatening complication following haematopoietic progenitor cell transplantation (HPCT). Recent data suggest that the current gold standard diagnostic test (endoscopic biopsy) fails to identify 26% of those patients requiring treatment. The mitochondrial translocator protein TSPO is upregulated in activated macrophages and inflammatory bowel diseases, and thus may be a biomarker of acute GI-GVHD. 18FGE180 is a novel TSPO-targeting radioligand for use in positron emission tomography imaging (18FGE180-PET).Methods:We performed a prospective observational pilot study evaluating 18FGE180-PET in adults with clinically suspected acute GI-GVHD occurring within 100 days following HPCT. Participants underwent a baseline 18FGE180-PET within 7 days of diagnostic endoscopy, and a follow-up 18FGE180-PET 1-4 weeks later. Tissue avidity was assessed visually in four sections of the gastrointestinal tract (GIT; stomach, duodenum, sigmoid and rectum) and rated by standardised uptake variable (SUV), with “positive” defined by SUV greater than mediastinal blood pool (MBP). Imaging findings were correlated with patient demographics, symptom severity (defined by modified Glucksberg stage), endoscopic findings, and histologic diagnosis. For patients in whom GI-GVHD treatment was initiated (defined as minimum prednisone 1mg/kg or equivalent), the clinical response was correlated with GIT avidity during the second 18FGE180-PET.Results:Six (6) patients were recruited, with median age 57 years (range 53-68 years), at a median 66 days post HPCT (range 26-95 days). Median Glucksberg stage of presumptive GI-GVHD was 2 (range 1-3). The histological diagnosis was GI-GVHD in 4 (66%) patients, and drug toxicity in the remaining two patients. Concordance between histological findings and 18FGE180-PET avidity by GIT section were 50% (stomach), 100% (duodenum), 100% (sigmoid) and 80% (rectum). 18FGE180-PET was highly accurate in duodenum and sigmoid (sensitivity 100%, specificity 100%), moderately accurate in rectum (sensitivity 66%, specificity 100%), and non-specific in stomach (sensitivity 100%, specificity 25%). Five (83%) patients subsequently underwent treatment for GI-GVHD, and of these 4 (80%) underwent repeat 18FGE180-PET for response assessment, seven days after the first. In these patients, high concordance between clinical response and 18FGE180-PET avidity was demonstrated in sigmoid (100%), rectum (100%) and duodenum (75%), compared with poor concordance in stomach (25%). The final patient, whose biopsies were negative for GI-GVHD and did not undergo GVHD treatment, was non-avid at all sites on both initial and subsequent 18FGE180-PET.Conclusion:18FGE180-PET appears to show utility in the diagnosis of GI-GVHD in small and large bowel. Larger prospective studies, correlating with histological TSPO expression, are warranted. DisclosuresNo relevant conflicts of interest to declare.

Real-World Efficacy of Anti-Fungal Prophylaxis in Patients Treated for Acute Gastrointestinal Graft-Versus-host Disease (GI-GVHD)

AimAllogeneic progenitor cell transplant (HPCT) recipients who develop acute gastrointestinal graft-versus-host disease (GI-GVHD) are at increased risk of developing invasive fungal infections (IFI). Randomised control trial data supports the use of mould-active fungal prophylaxis in HPCT patients with grade II-IV GVHD (Ullman et al. 2007). We aimed to assess our unit's use of anti-fungal prophylaxis and describe the incidence and species of breakthrough IFI in patients with GI-GVHD.MethodWe conducted a retrospective audit of patients who underwent HPCT at our institution between 2011-2016 and identified those who were treated for acute GI-GVHD using a minimum of prednisone 1mg/kg or equivalent. For those patients the following details were collected: presence of any prior IFIs, anti-fungal prophylaxis before and after initiation of steroids, and the incidence of new IFIs within 6 months of commencing steroids.ResultOf the 551 HPCT performed during this period, 74 evaluable patients were treated for GI-GVHD. All patients received anti-fungal prophylaxis prior to steroid commencement (66.2% received fluconazole, 10.8% posaconazole, 20.2% voriconazole and 2.7% other). Post steroids 35.1% remained on fluconazole, 21.6% received posaconazole, 35.1% received voriconazole, and 8.1% received other anti-fungals. Of the 26 patients remaining on fluconazole, 9 were transitioned to mould-active prophylaxis at a later time.Twelve patients (16.2%) experienced a breakthrough IFI (6 definite and 6 probable). In the 42 patients receiving posaconazole or voriconazole, 7 (16.7%) experienced breakthrough IFI, compared with 3 (11.5%) in the fluconazole cohort. Two other cases occurred in patients who received caspofungin. Notably, patients receiving mould-active fungal prophylaxis developed mucormycosis, Fusarium and Scedosporium infections whereas fluconazole lead to invasive aspergillosis.ConclusionDespite anti-fungal prophylaxis, real-world GI-GVHD patients remain at particularly increased risk of developing IFI. Anti-mould prophylaxis is associated with lower incidence of invasive aspergillosis but higher incidence of non-Aspergillus mould. Further studies investigating optimal anti-mould strategies are warranted. DisclosuresNo relevant conflicts of interest to declare.

Safety and Effectiveness of Vedolizumab in Patients with Steroid-Refractory Gastrointestinal Acute Graft-versus-Host Disease: A Retrospective Record Review

Allogeneic hematopoietic cell transplantation (allo-HCT) can be curative in patients with hematologic malignancies but carries a significant risk of graft-versus-host disease (GVHD). There are no standard treatments for steroid-refractory (SR) gastrointestinal (GI) acute GVHD (aGVHD). This multicenter, international, retrospective medical record review aimed to evaluate the off-label use of vedolizumab, a gut-selective immunomodulator, for treating SR GI aGVHD. Data were collected from patients' medical records; criteria for extraction included no more than 1 allo-HCT and at least 1 dose of vedolizumab as treatment for SR GI aGVHD (ie, stage 1 to 4 GI aGVHD following ≥1 previous treatment regimen(s) containing ≥1mg/kg methylprednisolone or equivalent). Descriptive analyses of response rate, overall survival (OS), and serious adverse effects (SAEs) were performed. Twenty-nine patients were identified from 7 sites who had received 1 to 10 doses of vedolizumab 300mg i.v. (median 3 doses) as treatment for SR GI aGVHD. The overall response rate at 6 to 10 weeks after vedolizumab initiation was 64%, and OS at 6 months was 54%. There were 29 SAEs, including 12 infections; 3 SAEs were considered possibly related to vedolizumab, 2 of which were infections. Thirteen SAEs were fatal, 1 of which was possibly vedolizumab-related. There were 8 nonserious infections and 1 serious infection with confirmed GI origin in 8 patients; there was no apparent pattern in the timing of these infections relative to the initiation of vedolizumab treatment. Further data on the efficacy and safety of vedolizumab in this setting from prospective trials are needed.

Gastrointestinal Graft-versus-Host Disease Is a Risk Factor for Postengraftment Bloodstream Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Bloodstream infection (BSI) is a well-known cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. Here, we conducted a retrospective study to assess the morbidity, etiology, risk factors, and outcomes of BSI in the postengraftment period (PE-BSI) after allo-HSCT. Forty-three of 316 patients (13.6%) developed 57 PE-BSI episodes, in which 62 pathogens were isolated: Gram-positive bacteria, gram-negative bacteria, and fungi, respectively, accounted for 54.8%, 35.5%, and 9.7% of the isolates. Multivariate analysis revealed methylprednisolone use for graft-versus-host disease (GVHD) prophylaxis (odds ratio [OR], 6.49; 95% confidence interval [CI], 1.49 to 28.2; P = .013) and acute gastrointestinal GVHD (GI-GVHD) (OR, 8.82; 95% CI, 3.99 to 19.5; P < .0001) as risk factors for developing PE-BSI. This finding suggested that GI-GVHD increases the risk of bacterial translocation and subsequent septicemia. Moreover, among patients with GI-GVHD, insufficient response to corticosteroids, presumably related to an intestinal dysbiosis, significantly correlated with this complication. Patients with PE-BSI presented worse outcome compared with those without (3-year overall survival, 47.0% versus 18.6%; P < .001). Close microbiologic monitoring for BSIs and minimizing intestinal dysbiosis may be crucial to break the vicious cycle between GI-GVHD and bacteremia and to improve transplant outcomes especially in patients who require additional immunosuppressants.

Tocilizumab for the treatment of severe steroid-refractory acute graft-versus-host disease of the lower gastrointestinal tract.

Steroid-refractory (SR) acute gastrointestinal (GI) graft-versus-host disease (GVHD) is associated with significant mortality in allogeneic hematopoietic cell transplantation recipients. We retrospectively evaluated the efficacy of tocilizumab for the treatment of SR biopsy-proven acute lower GI GVHD in 16 consecutive adult transplant recipients between October 2015 and July 2016. Tocilizumab 8 mg/kg was administered every 2 weeks until achievement of complete response, defined as resolution of all manifestations of GI GVHD, or until patients had progression or initiation of other therapy. Ten of 16 patients (62.5%; 95% CI, 0.39-82) achieved a complete response after a median time of 11 days (range, 2-28 days) from tocilizumab initiation. The median time to response onset (improvement in stage by at least 1) was 1 day (range, 1-4 days). Tocilizumab was administered at a median of 9 days (range, 3-75 days) from GVHD diagnosis and 10 days (range, 3-75 days) from initiation of high-dose steroids. At a median follow-up of 7.6 months (range, 0.8-27.7 months) from initiation of tocilizumab, 6/16 (37.5%) patients are alive and free of their underlying hematologic malignancy. Tocilizumab appears to be a highly active agent for the treatment of severe SR lower GI acute GVHD.

Third-party fecal microbiota transplantation following allo-HCT reconstitutes microbiome diversity

AbstractWe hypothesized that third-party fecal microbiota transplantation (FMT) may restore intestinal microbiome diversity after allogeneic hematopoietic cell transplantation (allo-HCT). In this open-label single-group pilot study, 18 subjects were enrolled before allo-HCT and planned to receive third-party FMT capsules. FMT capsules were administered no later than 4 weeks after neutrophil engraftment, and antibiotics were not allowed within 48 hours before FMT. Five patients did not receive FMT because of the development of early acute gastrointestinal (GI) graft-versus-host disease (GVHD) before FMT (n = 3), persistent HCT-associated GI toxicity (n = 1), or patient decision (n = 1). Thirteen patients received FMT at a median of 27 days (range, 19-45 days) after HCT. Participants were able to swallow and tolerate all FMT capsules, meeting the primary study endpoint of feasibility. FMT was tolerated well, with 1 treatment-related significant adverse event (abdominal pain). Two patients subsequently developed acute GI GVHD, with 1 patient also having concurrent bacteremia. No additional cases of bacteremia occurred. Median follow-up for survivors is 15 months (range, 13-20 months). The Kaplan-Meier estimates for 12-month overall survival and progression-free survival after FMT were 85% (95% confidence interval, 51%-96%) and 85% (95% confidence interval, 51%-96%), respectively. There was 1 nonrelapse death resulting from acute GI GVHD (12-month nonrelapse mortality, 8%; 95% confidence interval, 0%-30%). Analysis of stool composition and urine 3-indoxyl sulfate concentration indicated improvement in intestinal microbiome diversity after FMT that was associated with expansion of stool-donor taxa. These results indicate that empiric third-party FMT after allo-HCT appears to be feasible, safe, and associated with expansion of recipient microbiome diversity. This trial was registered at www.clinicaltrials.gov as #NCT02733744.

Impact of route and adequacy of nutritional intake on outcomes of allogeneic haematopoietic cell transplantation for haematologic malignancies

Allogeneic haematopoietic cell transplantation (HCT) is often associated with poor oral intake due to painful mucositis and gastrointestinal sequalae that occur following a preparative regimen of intensive chemotherapy and/or total body radiation. Although attractive to assume that optimal nutrition improves HCT outcomes, there are limited data to support this. It is also unclear whether artificial nutrition support should be provided as enteral tube feeding or parenteral nutrition (PN). We analysed day-100 non-relapse mortality (NRM), incidence of acute graft-versus-host disease (GvHD), acute gastrointestinal GvHD, 5-year survival and GvHD-free/relapse-free survival (GRFS) according to both route and adequacy of nutritional intake prior to neutrophil engraftment, together with other known prognostic factors, in a retrospective cohort of 484 patients who underwent allogeneic HCT for haematologic malignancy between 2000 and 2014. Multivariate analyses showed increased NRM with inadequate nutrition (hazard ratio (HR) 4.1; 95% confidence interval (CI) 2.2-7.2) and adequate PN (HR 2.9; 95% CI 1.6-5.4) compared to adequate enteral nutrition (EN) both P<.001. There were increased incidences of gastrointestinal GvHD of any stage and all GvHD≥grade 2 in patients who received PN (odds ratio (OR) 2.0; 95% CI 1.2-3.3; P=.006, and OR 1.8; 95% CI 1.1-3.0; P=.018, respectively), compared to adequate EN. Patients who received adequate PN and inadequate nutrition also had reduced probabilities of survival and GRFS at 5 years. Adequate EN during the early transplantation course is associated with reduced NRM, improved survival and GRFS at 5 years. Furthermore, adequate EN is associated with lower incidence of overall and gut acute GvHD than PN, perhaps because of its ability to maintain mucosal integrity, modulate the immune response to intensive chemo/radiotherapy and support the gastrointestinal tract environment, including gut microflora.

67 - Phase II Trial of Natalizumab (Tysabri®) with Corticosteroids as Initial Treatment of Gastrointestinal Acute Graft Versus Host Disease

Abstract Background: Graft-vs.-host disease (GVHD) is caused by allorecognition of host antigens by tissue-specific donor lymphocytes. We have previously demonstrated that α4s7 integrin is upregulated on both naive and memory T cell subsets in patients who subsequently developed intestinal acute GVHD (Chen, BMT 2013). This integrin interacts with endothelial cell adhesion molecules and mediates homing of lymphocytes to the gastrointestinal (GI) tract. Natalizumab (Tysabri®, Biogen Inc.) is a selective adhesion molecule inhibitor, acting directly against the α4 subunit of α4 integrins. Given the poor outcomes of GI GVHD when treated with corticosteroids alone, we initiated a phase II study to determine the safety and efficacy of natalizumab in combination with corticosteroids for the initial treatment of acute GI GVHD. Methods: Subjects with new-onset, acute GVHD of the lower GI tract were eligible to participate. Other organ involvement was permitted but not required. Biopsy confirmation of GI GVHD and exclusion of infectious causes of diarrhea were required. Natalizumab was given at a dose of 300 mg IV, with a second dose permitted 4 weeks later in the event of an incomplete response. An initial corticosteroid dose of 2 mg/kg of methylprednisolone was suggested, but dosing and dose reductions were at the discretion of the treating physician. Steroids could be initiated up to 7 days prior to the initiation of natalizumab while biopsy and infectious disease specimens were being analyzed. The primary endpoint was GVHD-free survival rate 56 days from enrollment. Secondary endpoints included response rates at day 28 and 56, steroid dose at days 28, 56, 100, 180 and 365, incidence of systemic infections at day 56 and 180, and overall survival. Results: 18 subjects were enrolled and received at least one dose of natalizumab. Subjects had a median age of 63.5 years, and 12 were male. Fifteen had a non-myeloablative transplant, 12 had a matched unrelated donor, and all had received PBSCs. All subjects had newly diagnosed acute GI GVHD at time of enrollment; 4 had concomitant cutaneous and 1 had concomitant hepatic involvement. Stage 1, 2, 3, and 4 GI involvement was noted in 7, 4, 4, and 3 subjects respectively, corresponding to overall grade II GVHD in 7 and grade III in 11 subjects. Sixteen patients had data for response assessment. The day 56 GVHD-free survival rate was 37.5%. The overall response rate (PR+CR) for GI GVHD at day 28 and day 56 was 75% and 62.5% respectively. All surviving subjects except one achieved steroid dose reduction by day 56, with a median reduction of 61.6%. Three patients experienced treatment-related toxicity possibly related to natalizumab; one subject had grade 2 hepatic toxicity, one had grade 4 encephalopathy, and one developed hepatic failure. Three subjects have developed chronic GVHD. Four subjects had documented infections with bacteria (2), yeast (1), and viral pathogens (1- polyomavirus). Six subjects had measurable JC viremia prior to initiation of natalizumab and 8 subjects had measurable JC viremia at day 56, although only 1 subject had a viral load greater than 1000 copies/ml. No subject has developed JC-associated disease. Seven subjects have died. Causes of death include GVHD (2), disease relapse (2), and organ failure (3). With a median follow-up of 180 days, the 6 month overall survival was 52% (95% CI 25-74%). Conclusion: Natalizumab in combination with corticosteroids as initial treatment of acute gastrointestinal GVHD is feasible and well tolerated. These early results suggest a higher rate of response at day 56 than is typically observed with steroids alone. Inhibition of T-cell homing to the GI tract may improve GI GVHD response and potentially mitigate progression of acute GVHD. Disclosures Koreth: Kadmon Corp: Membership on an entity's Board of Directors or advisory committees; Amgen Inc.: Consultancy; Prometheus Labs: Research Funding; Takeda Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Millennium Pharmaceuticals: Research Funding. Armand: Bristol-Myers Squibb: Consultancy, Research Funding; Tensha: Research Funding; Affimed: Research Funding; Sequenta/Adaptive: Research Funding; Merck & Co., Inc.: Consultancy, Research Funding; Roche: Research Funding; Genmab: Consultancy; Pfizer: Consultancy, Research Funding; Infinity: Consultancy; Otsuka: Research Funding; Sigma Tau: Research Funding. Antin: Gentium SpA/Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Cutler: Pfizer: Consultancy; Pharmacyclics: Consultancy; Kite: Consultancy; Bristol-Myers Squibb: Consultancy; Incyte: Consultancy; Astellas: Consultancy.

Diagnostic Utility of Endoscopy and Biopsy in Suspected Acute Gastrointestinal Graft-versus-Host Disease after Hematopoietic Progenitor Cell Transplantation

Acute gastrointestinal graft-versus-host disease (GI-GVHD) after hematopoietic progenitor cell transplantation (HPCT) is a common and life-threatening complication. Endoscopic biopsy of the GI tract (GIT) is required for diagnosis. However, clear evidence to optimize this diagnostic approach is lacking, leading to variation in diagnostic sensitivity between institutions. We aimed to assess the clinical, endoscopic, and histologic findings of endoscopies performed for suspected acute GI-GVHD at our institution to better define the optimal use of this strategy. We performed a retrospective cohort study of adults who had undergone endoscopy for suspected acute GI-GVHD within 180 days after allogeneic HPCT for hematologic malignancy between 2011 and 2016. Details included symptoms at time of referral for endoscopy, type of procedure performed, macroscopic findings on endoscopy, and histologic findings after gut biopsy. Correlation was made with clinical GVHD severity scores. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated and compared for each procedure. Predictors of histologic GVHD and overall survival were also compared. Of the 123 patients included, acute GI-GVHD occurred in 59 (48%). Lower endoscopy demonstrated greater sensitivity than upper endoscopy (50% versus 39%). Single upper endoscopy for upper symptoms alone had the lowest yield of GI-GVHD (14%). Combination upper and lower endoscopy demonstrated strong histologic concordance between upper and lower procedures. The addition of upper endoscopy to lower endoscopy only identified an extra 2 (4%) cases of GVHD. Advanced age and the presence of lower GIT symptoms were the only pre-endoscopy predictors of histologic GVHD on multivariate analysis. Patients with isolated upper histologic GVHD showed similar survival to patients with negative biopsies. Endoscopy and biopsy only identified 74% of those ultimately requiring treatment for acute GI-GVHD. Acute GI-GVHD remains a clinical diagnosis supported by available histologic evidence. Isolated upper GI-GVHD is rare, and in the absence of lower GIT symptoms, routine upper endoscopy does not significantly improve diagnostic yield for histologic GVHD. Overall, endoscopy and biopsy underdiagnoses 26% of clinical GI-GVHD, highlighting a need for research into novel diagnostic strategies.

Computed tomography imaging of acute gastrointestinal graft-versus-host disease after haematopoietic stem cell transplantation in children.

Aim of the studyTo evaluate computed tomography (CT) findings of gastrointestinal graft-versus-host disease (GI-GVHD) occurring in children after haematopoietic stem-cell transplantation (HSCT).Material and methodsFrom February 2013 to May 2018, 225 paediatric patients underwent HSCT. Sixty-eight patients (30%) presented with clinical diagnosis of acute GI-GVHD in the first 100 days after HSCT. Thirty-five (18 girls, 17 boys; age range, 2–18 years; mean age, 10.3 years) of 68 patients had abdominopelvic CT and included in study.ResultsIntestinal CT abnormalities were present in 33 (94%) and extra-intestinal CT findings were in 30 (86%) patients. Thickening of the bowel wall was the most common finding (31 patients, 89%), which involved the small bowel in 29 patients (83%), colon in 16 patients (46%), and both in 15 patients (43%). Oesophageal wall thickening was present in three patients (9%), and gastric wall thickening was in eight patients (23%). Bowel dilatation was detected in 13 patients (37%). Mucosal enhancement of the bowel wall was observed in 28 patients (80%). The prevalence of the extra-intestinal CT findings were: periportal oedema in nine (26%), ascites in 15 (43%), wall thickening and enhancement of gall bladder in 13 (37%), pericholecystic fluid in six (17%), hepatomegaly in 13 (37%), and splenomegaly in nine (26%) patients. One patient (3%) demonstrated free intraperitoneal air due to intestinal perforation.ConclusionsCT is useful to support the clinical diagnosis of acute GVHD in children with GI symptoms after HSCT. Radiological evaluation is important because early diagnosis and treatment affect the prognosis of GI-GVHD.

Human Gastro-Intestinal Graft-Versus-Host Disease Is Mediated By Retinoic Acid-Responsive CD8+ Effector T-Cells Under IL-23 Polarising Conditions

Background: Gastro-intestinal (GI) graft-versus-host disease (GvHD) results in significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (AHSCT). Retinoic acid (RA), a metabolite of vitamin A, has diverse effects on immune cells. RA signaling promotes immune tolerance under steady state conditions. However in pro-inflammatory conditions RA increases Th1, Th17 CD4+ and Tc1 CD8+ T cell responses and is implicated in the pathogenesis of autoimmune inflammatory bowel disease. Furthermore, RA exposure and RA-receptor alpha (RARα) signaling in allogeneic T cells potentiates GI-GvHD in mice. Thus RA and cytokines that influence the effect of RA on T cells may represent potential therapeutic targets for GI-GvHD. However, the impact of RA at a tissue level in human GI-GvHD is unknown. We therefore investigated the role of RA-responsive T cells in human GvHD in vivo and human allogeneic T-cell responses in vitro .Methods: We scrutinized GI biopsies from 47 patients after AHSCT (36 with and 11 without GI-GvHD confirmed by conventional histological criteria). We also analysed skin biopsies from 11 AHSCT patients. We used conventional immunohistochemistry and a novel deep phenotyping method using sequential staining, stripping and re-probing on the same fixed embedded biopsy to determine cellular co-expression of multiple markers to identify RA-responsive T cells in human GvHD biopsies at sites of GvHD damage. Finally, we used an HLA-mismatched allogeneic mixed lymphocyte co-culture (MLRs) system, combining CFSE dye dilution and multi-parameter flow cytometry to enable the phenotyping of alloproliferative T cells after manipulation of RA signalling.Results: Firstly we observed thatthe number of cells expressing high levels of cytoplasmic RA binding proteins I/II (a surrogate marker of RA) was increased in gut biopsies in patients with GI-GvHD versus controls (median 155 vs 43 cells/mm2, p=0.056). Importantly the number of cells expressing RARα was also significantly increased (median 1315 vs 544 cells/mm2, p=0.001) consistent with RA-responsiveness. Crucially the number of RARα+ cells correlated with clinical stage of acute GI-GvHD with higher numbers in patients with severe (stage 3-4) versus less severe (stage 1-2) disease.Having demonstrated that RA-responsive cells were associated with both occurrence and severity of GI-GvHD we went on to identify potential RA-responsive T cell subsets. Additionally, as IL-23 and IL-33 direct RA-programming of T cells to either pro-inflammatory or tolerogenic phenotypes we also measured cellular expression of these cytokines and their receptors. CD8+ T cells co-localized with RARα+ cells and were present in significantly increased numbers in gut biopsies from patients with GI-GvHD, as were Tbet+ Th1/Tc1 cells. In contrast, numbers of RORγ+ Th17 cells were unchanged and CD4+ cells were decreased. IL-23p19+ and IL-23R+ cell numbers were significantly increased in GI-GvHD biopsies, whereas IL33R (ST2+)cells were unchanged.In order to determine if the RA-responsive, CD8+ and IL-23R+ cells represented a single effector subset, we used sequential stripping/re-probing to deep phenotype the T cells. We identified a unique single CD8+ T-cell population that co-expressed RARα+, T-bet and IL23R, present in significantly increased numbers in gut biopsies from patients with GI-GvHD versus controls. This is consistent with a RA-responsive, IL-23-dependent, inflammatory Tc1 effector cell mediating tissue damage in human gut GvHD. Importantly, there was no increase in this T cell subset in skin biopsies of skin GvHD patients demonstrating tissue-specificity.Finally we determined the impact of exogenous RA exposure on T cell alloresponses in MLRs. RA significantly increased the proportion of alloproliferative effector CD8+ T cells co-expressing Tbet and gut-homing molecules, confirming that RA can directly potentiate human alloreactive CD8 T cell responses with capacity to home to the GI tract.Conclusions: This is the first data to demonstrate a role for RA at a tissue level in human GI-GvHD. Furthermore we have identified a gut specific CD8+ T cell subset which co-expresses RARα, T-bet, and IL-23R localised in areas of GI-damage likely to represent the RA-responsive effector cell. Therapeutic blockade of IL-23R could target this cellular response to prevent or treat GI-GvHD. DisclosuresGribben:Acerta: Honoraria; Janssen: Honoraria; Kite: Honoraria; Celgene: Honoraria; TG Therapeutics: Honoraria; Karyopharm: Honoraria; Pharmacyclics: Honoraria; Genentech/Roche: Honoraria; Abbvie: Honoraria.

Associations between acute gastrointestinal GvHD and the baseline gut microbiota of allogeneic hematopoietic stem cell transplant recipients and donors.

Growing evidence suggests that host-microbiota interactions influence GvHD risk following allogeneic hematopoietic stem cell transplant. However, little is known about the influence of the transplant recipient's pre-conditioning microbiota nor the influence of the transplant donor's microbiota. Our study examines associations between acute gastrointestinal GvHD (agGvHD) and 16S rRNA fecal bacterial profiles in a prospective cohort of N=57 recipients before preparative conditioning, as well as N=22 of their paired HLA-matched sibling donors. On average, recipients had lower fecal bacterial diversity (P=0.0002) and different phylogenetic membership (UniFrac P=0.001) than the healthy transplant donors. Recipients with lower phylogenetic diversity had higher overall mortality rates (hazard ratio=0.37, P=0.008), but no statistically significant difference in agGvHD risk. In contrast, high bacterial donor diversity was associated with decreased agGvHD risk (odds ratio=0.12, P=0.038). Further investigation is warranted as to whether selection of hematopoietic stem cell transplant donors with high gut microbiota diversity and/or other specific compositional attributes may reduce agGvHD incidence, and by what mechanisms.

Acute graft-versus-host disease of the gut: considerations for the gastroenterologist.

Haematopoietic stem cell transplantation (HSCT) is central to the management of many haematological disorders. A frequent complication of HSCT is acute graft-versus-host disease (GVHD), a condition in which immune cells from the donor attack healthy recipient tissues. The gastrointestinal system is among the most common sites affected by acute GVHD, and severe manifestations of acute GVHD of the gut portends a poor prognosis in patients after HSCT. Acute GVHD of the gastrointestinal tract presents both diagnostic and therapeutic challenges. Although the clinical manifestations are nonspecific and overlap with those of infection and drug toxicity, diagnosis is ultimately based on clinical criteria. As reliable serum biomarkers have not yet been validated outside of clinical trials, endoscopic and histopathological evaluation continue to be utilized in diagnosis. Once a diagnosis of gastrointestinal acute GVHD is established, therapy with systemic corticosteroids is typically initiated, and non-responders can be treated with a wide range of second-line therapies. In addition to treating the underlying disease, the management of complications including profuse diarrhoea, severe malnutrition and gastrointestinal bleeding is paramount. In this Review, we discuss strategies for the diagnosis and management of acute GVHD of the gastrointestinal tract as they pertain to the practising gastroenterologist.

High incidence of extensive chronic graft-versus-host disease in patients with the REG3A rs7588571 non-GG genotype.

Regenerating islet-derived protein 3 alpha (REG3A) is a biomarker of lower gastrointestinal graft-versus-host disease (GVHD); however, the biological role of REG3A in the pathophysiology of GVHD is not understood. Here, we examined the association between a single nucleotide polymorphism in the REG3A gene, rs7588571, which is located upstream and within 2 kb of the REG3A gene, and transplant outcomes including the incidence of GVHD. The study population consisted of 126 adult Japanese patients who had undergone bone marrow transplantation from a HLA-matched sibling. There was no association between rs7588571 polymorphism and the incidence of acute GVHD. However, a significantly higher incidence of extensive chronic GVHD was observed in patients with the rs7588571 non-GG genotype than in those with the GG genotype (Odds ratio 2.6; 95% confidence interval, 1.1–6.0; P = 0.029). Semi-quantitative reverse transcription PCR demonstrated that the rs7588571 non-GG genotype exhibited a significantly lower REG3A mRNA expression level than the GG genotype (P = 0.032), and Western blot analysis demonstrated that the rs7588571 non-GG genotype exhibited a trend toward lower REG3A protein expression level than the GG genotype (P = 0.053). Since REG proteins have several activities that function to control intestinal microbiota, and since intestinal dysbiosis is in part responsible for the development of GVHD, our findings lead to the novel concept that REG3A could have some protective effect in the pathogenesis of GVHD through the regulation of gut microbiota.

The association between acute graft-versus-host disease and antimicrobial peptide expression in the gastrointestinal tract after allogeneic stem cell transplantation.

Intestinal microbiota disruption is associated with acute gastrointestinal (GI) Graft-versus-Host Disease (GvHD) and poor outcome after allogeneic stem cell transplantation (ASCT). Here, in a retrospective analysis of 200 patients undergoing ASCT at the Regensburg University Medical Center, we assessed the relative expression of Paneth cell antimicrobial peptides (AMPs), Human Defensins (HD) 5 and 6 and regenerating islet-derived 3α (Reg3α), in 292 human intestinal biopsies as well as Reg3α serum levels in relation to acute GI GvHD. In the absence of GI GvHD, the relative expression of Paneth cell AMPs was significantly higher in the small intestine (duodenum to ileum) than in the stomach and large intestine (cecum to rectum) for Reg3α (p≤0.001), HD5 (p≤0.002) and HD6 (p≤0.02). Acute stage 2–4 GI GvHD was associated with reduced expression of AMPs in the small intestine (p≤0.01) in comparison to stage 0–1 disease, accompanied by a decrease in Paneth cell count in case of severe acute GI GvHD (p<0.001). The opposite held true for the large intestine as we found stage 2–4 GI GvHD correlated with significantly higher expression of HD5, HD6, and Reg3α compared to mild or no acute GI GvHD (p≤0.002). Severe GI GvHD in both the lower and the upper GI tract also correlated with higher serum concentrations of Reg3α (p = 0.002). As indirect markers of intestinal microbiome diversity low levels of urinary 3-indoxyl sulfate levels were associated with severe stages of acute GI GvHD compared to mild stage or no acute GI GvHD (p = 0.05). In conclusion, acute GI GvHD correlates with intestinal expression of HD5, HD6 and Reg3α as well as Reg3α serum levels and is associated with intestinal dysbiosis.

Clinical impact of pre-transplant gut microbial diversity on outcomes of allogeneic hematopoietic stem cell transplantation

Post-transplant microbial diversity in the gastrointestinal tract is closely associated with clinical outcomes following allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, little is known about the impact of the fecal microbiota before allo-HSCT. We analyzed fecal samples approximately 2weeks before conditioning among 107 allo-HSCT recipients between 2013 and 2015. Microbial analysis was performed using 16S rRNA gene sequencing. Operational taxonomic unit-based microbial diversity was estimated by calculating the Shannon index. Patients were classified into three groups based on the diversity index: low (<2), intermediate (2, 3), and high (>3) diversity (18 (16.8%), 48 (44.9%), and 41 (38.3%) patients, respectively). There were no significant differences in the 20-month overall survival, cumulative incidence of relapse, and non-relapse mortality among three groups. The cumulative incidence of grade II to IV acute graft-versus-host disease (aGVHD) was similar among the three groups (low 55.6%; intermediate 35.4%; high 48.8%, p=0.339, at day 100). Furthermore, we found no differences in the cumulative incidence of grade II to IV acute gastrointestinal GVHD among the three groups (low 38.9%; intermediate 21.3%; high 24.4%, p=0.778, at day 100). Regarding the composition of microbiota before allo-HSCT, aGVHD patients showed a significantly higher abundance of phylum Firmicutes (p<0.01) and a lower tendency for Bacteroidetes (p=0.106) than non-aGVHD patients. Maintenance of Bacteroidetes throughout allo-HSCT may be a strategy to prevent aGVHD.