Non-invasive diagnosis of acute intestinal graft-versus-host disease by a new scoring system using ultrasound morphology, compound elastography, and contrast-enhanced ultrasound

NIH Chronic Graft-versus-Host Disease Consensus Conference 2025 Update

In 2020, the third NIH Consensus Development Project on Criteria for Chronic Graft-versus-Host Disease (GVHD) Clinical Trials was held with the goals of identifying gaps in understanding, prevention and treatment of chronic graft-versus-host disease (GVHD) and making actionable recommendations that would advance the field. An interim meeting was held in October 2024 to review progress on the 2020 recommendations. Each group was charged with reviewing their previous recommendations, assessing whether the field is on track to eventually achieve the goals, and considering whether recommendations should be modified in light of new data or insufficient progress. This manuscript summarizes the Working Groups' reports and helps define the research agenda for future studies in chronic GVHD. Overall, modest progress has been made on most initiatives. Some studies in progress will address key recommendations and results are eagerly anticipated.

Is Contrast-Enhanced Ultrasonography a New, Reliable Tool for Early-Graft-versus-Host Disease Diagnosis?

Acute gastrointestinal graft-versus-host disease (GI aGVHD) is a significant and life-threatening complication in patients undergoing allogeneic stem cell transplantation (allo-SCT). Early diagnosis of GI aGVHD is crucial for improving patient outcomes, but it remains a challenge due to the condition's nonspecific symptoms and the reliance on invasive diagnostic methods, such as biopsies and endoscopic procedures. In recent years, interest in non-invasive diagnostic techniques for graft-versus-host disease has increased, with contrast-enhanced ultrasound (CEUS) being one of them. For this reason, we aimed to examine the potential of ultrasound as a non-invasive, safe, and cost-effective alternative for the early detection and monitoring of GI aGVHD in this review. Our narrative review aims to describe the use of multimodal US that includes conventional US (B-mode and Doppler US) and advanced ultrasound techniques such as CEUS and CRTE for the non-invasive diagnosis of GI GVHD. We browsed several databases, including PubMed, Scopus, Web of Science, and Google Scholar. The search spanned 2000 to the present, focusing on articles written in English that reviewed the use of these imaging techniques in the context of GI GVHD. Following our research, we noticed that CEUS offers several advantages, including the real-time visualization of the gastrointestinal wall, assessment of blood flow, and detailed microvascular analysis-all achieved without the use of ionizing radiation. This feature makes CEUS an appealing option for repeated assessments, which are often necessary in monitoring the progression of GI aGVHD. When used in conjunction with conventional gastrointestinal ultrasound (GIUS), CEUS provides a more comprehensive view of the structural and functional changes occurring in the GI tract, potentially enhancing diagnostic accuracy and allowing for earlier intervention. In comparison to traditional diagnostic methods like tissue biopsy or CT scans, CEUS is less invasive, quicker to perform, and better tolerated by patients, especially those in fragile health following allo-SCT. Its non-invasive nature and ability to provide immediate imaging results make it a valuable tool for clinicians, particularly in settings where minimizing patient discomfort and risk is paramount. However, despite these advantages, there are still gaps in the literature regarding CEUS's full diagnostic accuracy for GI aGVHD. Further research, including larger clinical trials and comparative studies, is needed to validate CEUS's role in routine clinical practice and to establish standardized protocols for its use. Nonetheless, CEUS shows considerable potential to transform the diagnostic approach to GI aGVHD by improving early detection, reducing the need for invasive procedures, and ultimately enhancing treatment outcomes for affected patients.

Diagnostic prediction of gastrointestinal graft-versus-host disease based on a clinical- CT- signs nomogram model

OBJECTIVE

Gastrointestinal graft-versus-host disease (GI-GVHD) is one of the complications that can easily occur after hematopoietic stem cell transplantation (HSCT). Timely diagnosis and treatment are pivotal factors that greatly influence the prognosis of patients. However, the current diagnostic method lacks adequate non-invasive diagnostic tools.

METHODS

A total of 190 patients who suspected GI-GVHD were retrospectively included and divided into training set (n = 114) and testing set (n = 76) according to their discharge time. Least absolute shrinkage and selection operator (LASSO) regression was used to screen for clinically independent predictors. Based on the logistic regression results, both computed tomography (CT) signs and clinically independent predictors were integrated in order to build the nomogram, while the testing set was verified independently. The receiver operating characteristic (ROC), area under the curve (AUC), decision curve, and clinical impact curve were used to measure the accuracy of prediction, clinical net benefit, and consistency of diagnostic factors.

RESULTS

Four key factors, including II-IV acute graft-versus-host disease (aGVHD), the circular target sign, multifocal intestinal inflammation, and an increased in total bilirubin, were identified. The combined model, which was constructed from CT signs and clinical factors, showed higher predictive performances. The AUC, sensitivity, and specificity of the training set were 0.867, 0.787, and 0.811, respectively. Decision curve analysis (DCA), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) showed that the developed model exhibited a better prediction accuracy than the others.

CONCLUSIONS

This combined model facilitates timely diagnosis and treatment and subsequently improves survival and overall outcomes in patients with GI-GVHD.

CRITICAL RELEVANCE STATEMENT

GI-GVHD is one of the complications that can easily occur after HSCT. However, the current diagnostic approach lacks adequate non-invasive diagnostic methods. This non-invasive combined model facilitates timely treatment and subsequently improves patients with GI-GVHD survival and overall outcomes.

KEY POINTS

• There is currently lacking of non-invasive diagnostic methods for GI-GVHD. • Four clinical CT signs are the independent predictors for GI-GVHD. • Association between the CT signs with clinical factors may improve the diagnostic performance of GI-GVHD.

PET assessment of acute gastrointestinal graft versus host disease

Acute gastrointestinal graft versus host disease (GI-GVHD) is a common complication following allogeneic haematopoietic cell transplantation (HCT), and is characterised by severe morbidity, frequent treatment-refractoriness, and high mortality. Early, accurate identification of GI-GVHD could allow for therapeutic interventions to ameliorate its severity, improve response rates and survival; however, standard endoscopic biopsy is inadequately informative in terms of diagnostic sensitivity or outcome prediction. In an era where rapid technological and laboratory advances have dramatically expanded our understanding of GI-GVHD biology and potential therapeutic targets, there is substantial scope for novel investigations that can precisely guide GI-GVHD management. In particular, the combination of tissue-based biomarker assessment (plasma cytokines, faecal microbiome) and molecular imaging by positron emission tomography (PET) offers the potential for non-invasive, real-time in vivo assessment of donor:recipient immune activity within the GI tract for GI-GVHD prediction or diagnosis. In this article, we review the evidence regarding GI-GVHD diagnosis, and examine the potential roles and translational opportunities posed by these novel diagnostic tools, with a focus on the evolving role of PET.

Multimodal ultrasound imaging with conventional B-mode, elastography, and parametric analysis of contrast-enhanced ultrasound (CEUS): A novel approach to assess small bowel manifestation in severe COVID-19 disease

The aim was to describe the small bowel morphology with conventional B-mode and elastography and additionally to evaluate dynamic effects of COVID-19 associated small bowel microvascularization using CEUS with color coded perfusion parameters.Thirteen patients with severe COVID-19 acute respiratory distress syndrome (ARDS) were investigated. 13 patients required intensive care treatment with mechanical ventilation. Five patients required extracorporeal membrane oxygenation (ECMO). Contrast-enhanced ultrasound (CEUS) was performed by an experienced investigator as a bolus injection of up to 2.4 ml sulfur hexafluoride microbubbles via a central venous catheter. In the parametric analysis of CEUS, the flare of microbubbles over time is visualized with colors. This is the first work using parametric analysis of CEUS to detect perfusion differences in the small bowel.Parametric analysis of CEUS in the intestinal phase was carried out, using DICOM loops for 20 seconds. In 5 patients, parametric analysis revealed intraindividual differences in contrast agent behavior in the small bowel region. Analogous to the computed tomography (CT) images parametric analysis showed regions of simultaneous hyper- and hypoperfusion of the small intestine in a subgroup of patients. In 5 patients, the parametric image of transmural global contrast enhancement was visualized.Our results using CEUS to investigate small bowel affection in COVID-19 suggest that in severe COVID-19 ARDS systemic inflammation and concomitant micro embolisms may lead to disruption of the epithelial barrier of the small intestine.This is the first study using parametric analysis of CEUS to evaluate the extent of small bowel involvement in severe COVID-19 disease and to detect microemboli. In summary, we show that in COVID-19 the small bowel may also be an important interaction site. This is in line with the fact that enterocytes have been shown to a plenitude of angiotensin converting enzyme (ACE)-2 receptors as entry sites of the virus.

Non-Invasive Diagnosis of Pediatric Intestinal Graft-Versus-Host Disease: A Case Series

Intestinal graft-versus-host disease (I-GvHD) represents a life-threatening complication in allogeneic stem cell transplantation (SCT). Unfortunately, non-invasive validated diagnostic tools to diagnose I-GvHD, evaluate treatment response, and guide the duration of immunosuppression are still lacking. We employed standard ultrasound and power Doppler to diagnose and follow up on pediatric intestinal GvHD. We herein report on three patients, prospectively evaluated among 24 pediatric patients referred to our center for allogeneic SCT. These three patients presented abdominal pain and diarrhea within the first 200 days after transplantation. In the reported cases, we performed small- and large-intestine ultrasound (US) at clinical onset of lower-intestinal symptoms and, when intestinal GvHD was confirmed, at GvHD flares, if any, and at follow-up. US constantly (3/3 patients) revealed increased bowel wall thickening (BWT) with different bowel segments’ involvement from patient to patient. Further, a moderate or strong increased Doppler signaling was seen in 2 out of 3 patients, according to clinical GVHD staging (e.g., the more the increase, the more the staging). Standard sonography corroborated GvHD diagnosis in all patients considered and was able to detect GvHD progression or complete normalization of findings, thus simplifying ensuing clinical decisions. Our report highlights the need to design clinical trials for the validation of non-invasive radiologic tools for diagnosis and follow-up of GvHD, especially in pediatric patients.

Contrast enhanced ultrasonography (CEUS) a novel tool to detect intestinal epithelial barrier dysfunction in severe COVID-19 disease

Ten patients with confirmed COVID-19 disease were studied. Nine patients required intensive care treatment, among them four needed extracorporeal membrane oxygenation (ECMO). Contrast enhanced ultrasonography (CEUS) was performed by one experienced investigator as a bolus injection of up to 2.4 ml of sulphur hexafluoride microbubbles via a central venous catheter. B-Mode evaluation and strain elastography showed mural edema of the small bowel with a thickness of up to 10 mm in all patients. We applied color coded Doppler sonography (CCDS) and power mode with flow-adapted parameters and early, dynamic capillary arterial contrast enhancement of bowel wall structures <10 s to assess perfusion of the small bowel. In all patients, reactive hyperemia was seen in the entire small bowel. In a subgroup of seven patients microbubbles translocated into the intestinal lumen. Thus, high-grade intestinal barrier disruption secondary to SARSCoV-2 infection can be postulated in these patients. This is the first description of perfusion changes and a disruption of the small bowel epithelial barrier in COVID-19 Patients using contrast ultrasonography and elastography.

Fecal microbiota transfer for refractory intestinal graft-versus-host disease - Experience from two German tertiary centers

RATIONALE

Steroid refractory graft-vs-host disease (sr-GvHD) represents a challenging complication after allogeneic hematopoietic cell transplantation (allo-HCT). Intestinal microbiota (IM) diversity and dysbiosis were identified as influencing factors for the development of acute GvHD. Fecal microbiota transfer (FMT) is hypothesized to restore IM dysbiosis, but there is limited knowledge about the significance of FMT in the treatment of sr-GvHD.

OBJECTIVES

We studied the effects of FMT on sr-GvHD in allo-HCT patients from two German tertiary clinical centers (n = 11 patients; period: March 2017 until July 2019). To assess safety and clinical efficacy, we analyzed clinical data pre- and post-FMT (day -14 to +30 relative to FMT). Moreover, IM were analyzed in donor samples and in a subset of patients pre- and post-FMT by 16S rRNA sequencing.

RESULTS

Post-FMT, we observed no intervention-associated, systemic inflammatory responses and only minor side effects (5/11 patients: abdominal pain and transformation of peristalsis-each 3/11 and vomiting-1/11). Stool frequencies and volumes were significantly reduced [pre- vs post-FMT (d14): P < .05, respectively] as well as clear attenuation regarding both grading and staging of sr-GvHD was present upon FMT. Moreover, IM analyses revealed an increase of alpha diversity as well as a compositional shifts toward the donor post-FMT.

CONCLUSIONS

In our study, we observed positive effects on sr-GVHD after FMT without the occurrence of major adverse events. Although these findings are in line with published data on beneficial effects of FMT in sr-GvHD, further randomized clinical studies are urgently needed to better define the clinical validity including mode of action.

Parametric Imaging of Contrast-Enhanced Ultrasound (CEUS) for the Evaluation of Acute Gastrointestinal Graft-Versus-Host Disease

In recent years contrast-enhanced ultrasound (CEUS) has been an emerging diagnostic modality for the detection of acute gastrointestinal (GI) graft-versus-host disease (GvHD) in patients after allogeneic stem cell transplantation. However, broad clinical usage has been partially limited by its high dependence on the expertise of an experienced examiner. Thus, the aim of this study was to facilitate detection of acute GI GvHD by implementing false color-coded parametric imaging of CEUS. As such, two inexperienced examiners with basic knowledge in abdominal and vascular ultrasound analyzed parametric images obtained from patients with clinical suspicion for acute GvHD in a blinded fashion. As diagnostic gold standard, histopathological GvHD severity score on intestinal biopsies obtained from lower GI tract endoscopy was performed. The evaluation of parametric images by the two inexperienced ultrasound examiners in patients with histological confirmation of acute GI GvHD was successful in 17 out of 19 patients (89%) as opposed to analysis of combined B-mode ultrasound, strain elastography, and CEUS by an experienced examiner, which was successful in 18 out of 19 of the patients (95%). Therefore, CEUS with parametric imaging of the intestine was technically feasible and has the potential to become a valuable diagnostic tool for rapid and widely accessible detection of acute GvHD in clinical practice.

Fluorodeoxyglucose F 18 for the Assessment of Acute Intestinal Graft-versus-Host Disease and Prediction of Response to Immunosuppressive Therapy

Graft-versus-host disease (GVHD) is a common complication that increases morbidity and mortality after allogeneic stem cell transplantation (allo-SCT). Fluorodeoxyglucose F 18 (¹⁸F-FDG)-positron emission tomography (PET) imaging has been demonstrated to be highly informative for evaluating and mapping of intestinal GVHD. To corroborate and extend existing findings and to investigate whether glucose metabolism assessed by ¹⁸F-FDG-PET might be an effective diagnostic tool to predict corticosteroid-refractory acute GVHD and overall survival. In this retrospective analysis, 101 patients with clinically suspected acute intestinal GVHD underwent ¹⁸F-FDG-PET between June 2011 and February 2019. Seventy-four of these patients with clinically and/or histologically proven acute intestinal GVHD as well as positive ¹⁸F-FDG-PET findings were analyzed in detail to assess the predictive value of ¹⁸F-FDG-PET regarding the response to immunosuppressive therapy and survival. Quantitative PET parameters, particularly the maximum standard uptake value (SUVmax), of patients with a fast response (ie, clinical improvement and decreased GVHD activity by at least 1 stage after 1 week of GVHD treatment) or slow/no response (ie, persistent disease activity for more than 1 week or increasing GVHD activity following first-line immunosuppressive therapy) were evaluated. ¹⁸F-FDG-PET detected intestinal GVHD with a sensitivity of 93% (95% confidence interval [CI], 85% to 97%) and specificity of 73% (95% CI, 45% to 91%). Patients with a fast response to immunosuppressive therapy had a mean SUVmax of 13.7 (95% CI, 11.0 to 16.5) compared with 7.6 (95% CI, 7.0 to 8.3; P = .005) observed in patients with prolonged or no response. The median overall survival (OS) was 573.0 days (95% CI, 539.5 to 606.5 days) for patients with fast response versus 255 days (95% CI, 161.0 to 349.0 days; P = .009) for patients with slow or no responses. A SUVmax threshold >8.95 applied to ¹⁸F-FDG-PET performed within 100 days after transplantation identified patients with a median OS of 390 versus 117 days for patients with SUVmax ≤8.95 (P = .036). SUVmax threshold and donor type were independent factors for OS. Our results indicate that ¹⁸F-FDG-PET is highly accurate in identifying patients with acute intestinal GVHD and may predict responses to immunosuppressive therapy as well as survival, particularly when applied within the first 100 days after transplantation. These results provide a strong rationale to integrate PET imaging in future prospective trials evaluating new therapies for acute GVHD.

[Potential of ultrasound in allogeneic stem cell transplantation and transplant-related complications]

Allogeneic hematopoietic stem cell transplantation (HCT) is a complex therapeutic procedure causing significant morbidity and mortality, including the gastrointestinal tract. Early diagnosis and treatment of HCT-associated complications are, therefore, of utmost importance to improve overall HCT outcome. Sonography can be a powerful diagnostic tool and is easily accessible at the bedside of HCT patients. In the hands of a sonography-experienced physician, it allows for instant diagnosis and can also rule out several important transplant-associated complications. Here we review available evidence on the diagnostic and clinical value of ultrasound prior, during and after HCT.

Favourable survival in "Discordant" acute gastrointestinal graft versus host disease (GI-GVHD) is explained by mild clinical course and treatment-responsive disease

We have previously reported that haematopoietic progenitor cell transplantation recipients with biopsy-negative acute Gastrointestinal Graft versus Host Disease (Discordant GVHD) demonstrate superior survival compared to "True Positive" cases. We aimed to elucidate this discrepancy by examining clinical and laboratory predictors of survival among patients treated for True Positive or Discordant GVHD. Data were obtained by retrospective chart review. At diagnosis, the incidence of severe symptoms, hypoalbuminaemia, hyperbilirubinaemia, and poor performance status were recorded. Following treatment, the incidence of non-response to first-line corticosteroids was assessed. Differences between cohorts were compared using Fisher's exact test. 74 patients were identified, comprising 55 (74%) True Positive and 19 (26%) Discordant GVHD cases. True Positive cases were significantly more likely to have baseline severe symptoms (84% vs. 36%; p = 0.0002) and hypoalbuminaemia (94% vs. 75%; p = 0.023). There was no significant difference between cohorts in terms of hyperbilirubinaemia or performance status. Non-response to corticosteroid therapy was observed significantly more frequently in the True Positive cohort (55% vs. 11%; p = 0.001). In summary, the superior survival observed in Discordant GVHD is explained by a less severe GI-GVHD phenotype at diagnosis and a greater likelihood of response to corticosteroids. Further research is warranted to explain biological mechanisms for these findings.