A biomarker panel for acute graft-versus-host disease. Blood. 2009;113:273-278. [PMID: 18832652 DOI: 10.1182/blood-2008-07-167098]

Prediction of absolute risk of acute graft-versus-host disease following hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) is the treatment of choice for a variety of hematologic malignancies and disorders. Unfortunately, acute graft-versus-host disease (GVHD) is a frequent complication of HCT. While substantial research has identified clinical, genetic and proteomic risk factors for acute GVHD, few studies have sought to develop risk prediction tools that quantify absolute risk. Such tools would be useful for: optimizing donor selection; guiding GVHD prophylaxis, post-transplant treatment and monitoring strategies; and, recruitment of patients into clinical trials. Using data on 9,651 patients who underwent first allogeneic HLA-identical sibling or unrelated donor HCT between 01/1999-12/2011 for treatment of a hematologic malignancy, we developed and evaluated a suite of risk prediction tools for: (i) acute GVHD within 100 days post-transplant and (ii) a composite endpoint of acute GVHD or death within 100 days post-transplant. We considered two sets of inputs: (i) clinical factors that are typically readily-available, included as main effects; and, (ii) main effects combined with a selection of a priori specified two-way interactions. To build the prediction tools we used the super learner, a recently developed ensemble learning statistical framework that combines results from multiple other algorithms/methods to construct a single, optimal prediction tool. Across the final super learner prediction tools, the area-under-the curve (AUC) ranged from 0.613–0.640. Improving the performance of risk prediction tools will likely require extension beyond clinical factors to include biological variables such as genetic and proteomic biomarkers, although the measurement of these factors may currently not be practical in standard clinical settings.

Thrombotic microangiopathy with concomitant GI aGVHD after allogeneic hematopoietic stem cell transplantation: Risk factors and outcome

OBJECTIVES

To explore the possible risk factors for the occurrence and mortality of thrombotic microangiopathy (TMA) with concomitant acute graft-vs-host disease (aGVHD) and to investigate outcomes and treatments of this disorder after allo-HSCT.

METHODS

Fifty cases diagnosed with TMA with concomitant aGVHD and 150 controls were identified from a cohort composed of 3992 patients who underwent allo-HSCT from 2008 to 2016.

RESULTS

Grade III-IV aGVHD (P = .000), acute kidney injury (AKI) (P = .033), and hypertension (P = .028) were significant independent risk factors associated with the occurrence of TMA with concomitant aGVHD. A haptoglobin level below normal (P = .013), a maximum volume of diarrhea >2500 mL/d (P = .015), and bloody diarrhea (P = .049) were significant markers for death in both univariate and multivariate analyses. Patients diagnosed with TMA with concomitant aGVHD had a lower overall survival (OS), a higher non-relapse mortality (NRM), but a lower risk of relapse.

CONCLUSIONS

Thrombotic microangiopathy with concomitant aGVHD is a significant complication after allo-HSCT, with a worse outcome, including significantly lower OS and higher NRM. There are specific risk factors associated with occurrence and mortality of this complication.

Systemic Treatment with a miR-146a Mimic Suppresses Endotoxin Sensitivity and Partially Protects Mice from the Progression of Acute Graft-versus-Host Disease

Acute GVHD (aGVHD) is driven by interactions between the allogenic T cell response, inflammation, tissue injury and microbial products that enter the circulation when protective barriers such as the intestinal epithelium become compromised. Mice with aGVHD become hypersensitive to LPS, secreting large quantities of inflammatory mediators that exacerbate tissue injury. We hypothesized that microRNA (miR) modulators could be used in vivo to mitigate LPS hypersensitivity, altering the course of aGVHD. Using the C57BL/6 → (C57BL/6 × DBA/2)F₁ -hybrid model of aGVHD, we measured intestinal permeability over time and used a qPCR array to detect concomitant changes in the expression levels of certain microRNAs (miRs) in the intestine. Large increases in permeability were seen on day 15, when endotoxemia becomes detectable and GVHD-associated histopathological lesions develop. Amongst the miRs with altered expression levels were some that regulate sensitivity to endotoxin. We chose to focus on miR-146a and treated recipient mice systemically with a miR-146a mimic early in the GVH reaction. This led to a reduction in the burst of IFNγ that likely plays a priming role in the mechanism underlying heightened sensitivity to endotoxin. LPS-induced TNFα release and GVHD-associated weight loss were also diminished and survival was prolonged. In summary, systemic treatment with a miR-146a mimic dampens the heightened sensitivity to LPS that occurs concomitantly with increased intestinal permeability and provides partial protection from the progression of acute GVHD.

Liver biopsy findings in patients with hematopoietic cell transplantation

Liver dysfunction is a frequent complication after hematopoietic cell transplantation. Liver biopsy has an important role for confirming the diagnosis of graft-versus-host disease (GVHD) or other liver diseases. The histological features of GVHD are not specific, and GVHD and other coexisting diseases may be present in the same biopsy, which makes the histologic interpretation of the liver biopsy more complex and challenging. The aim of the study is to improve the present diagnostic criteria. Fifty-two liver biopsies were studied. Most biopsies (47, 92%) showed some features of GVHD. Five (9.6%) had no GVHD, 20 (38.5%) had possible GVHD, and 27 (51.9%) had likely GVHD. Histologic features were analyzed semi-quantitatively and scored. Bile duct damage and intraepithelial lymphocytes were significantly more frequent in likely GVHD groups. Bile duct injury score calculated as the sum of bile duct damage and intraepithelial lymphocytes score was 2.3 in no GVHD and possible GVHD groups, and 4.2 in likely GVHD group (P<.001). A bile duct injury score ≥4 correlated well with a diagnosis of GVHD, with sensitivity 74% and specificity 88%. Many cases (36; 70.6%) had a concurrent disease process. Drug-induced liver injury (8, 16%) and sinusoidal obstruction syndrome (6, 12%) are particularly important causes of liver dysfunction. Moderate degree of bile duct injury and intraepithelial lymphocytes were the most helpful histologic findings to confirm the diagnosis of GVHD. In addition, it is important for the pathologist to be aware of the etiologies of liver dysfunction other than GVHD.

Associations between acute GVHD-related biomarkers and endothelial cell activation after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) can cause serious transplant-related complications such as graft-versus-host disease (GVHD). Acute GVHD (aGVHD) has been diagnosed by clinical manifestations, laboratory data and pathological effects until now, but recently the discovery of specific biomarkers such as suppression of tumorigenicity 2 (ST2), elafin and regenerating islet-derived 3α (REG3α) is challenging this approach.

METHODS

We investigated the expression of aGVHD-related markers (regulated on activation normal T-cell expressed and secretes: RANTES, elafin, REG3α and ST2) and endothelial cell activation markers (soluble vascular cell adhesion molecule: sVCAM-1 and plasminogen activator inhibitor: PAI-1) in patients undergoing allogeneic HSCT. Additionally, we studied the effects of recombinant soluble thrombomodulin (rTM) on the expression of these markers. Our study cohort included 225 patients who underwent allogeneic HSCT at several institutions in Japan.

RESULTS

RANTES, sVCAM-1, PAI-1, elafin, REG3α and ST2 exhibited significant increases in patients not receiving rTM after HSCT. When we examined patients with confirmed complications, the frequencies of aGVHD and VOD were significantly lower in the rTM-treated group. In addition, aGVHD-related biomarkers such as elafin, REG3α, and ST2 were elevated significantly in patients with aGVHD.

CONCLUSION

Our findings suggest that endothelial cell activation might be linked to aGVHD, and that rTM might act to prevent aGVHD, at least in part, through its effect on endothelial cells.

Circulating Biomarkers to Identify Responders in Cardiac Cell therapy

Bone marrow mononuclear cell (BM-MNC) therapy in ST-elevation acute myocardial infarction (STEMI) has no biological inclusion criteria. Here, we analyzed 63 biomarkers and cytokines in baseline plasma samples from 77 STEMI patients treated with BM-MNCs in the TIME and Late-TIME trials as well as 61 STEMI patients treated with placebo. Response to cell therapy was defined by changes in left ventricular ejection fraction, systolic/diastolic volumes, and wall motion indexes. We investigated the clinical value of circulating proteins in outcome prediction using significance testing, partial least squares discriminant analysis, and receiver operating characteristic (ROC) analysis. Responders had higher biomarker levels (76–94% elevated) than non-responders. Several biomarkers had values that differed significantly (P < 0.05) between responders and non-responders including stem cell factor, platelet-derived growth factor, and interleukin-15. We then used these lead candidates for ROC analysis and found multiple biomarkers with values areas under the curve >0.70 including interleukin 15. These biomarkers were not involved in the placebo-treated subjects suggesting that they may have predictive power. We conclude that plasma profiling after STEMI may help identify patients with a greater likelihood of response to cell-based treatment. Prospective trials are needed to assess the predictive value of the circulating biomarkers.

Endothelial damage is aggravated in acute GvHD and could predict its development

The aim of the present study was to explore whether there is enhanced endothelial dysfunction in patients developing acute GvHD (aGvHD) after allogeneic hematopoietic cell transplantation (allo-HCT) and to identify biomarkers with predictive and/or diagnostic value. In in vitro experiments, endothelial cells (ECs) were exposed to serum from patients with (aGvHD, n=31) and without (NoGvHD, n=13) aGvHD, to evaluate changes in surface adhesion receptors, the reactivity of the extracellular matrix by measuring the presence of Von Willebrand factor (VWF) and platelet adhesion, and the activation of intracellular signaling proteins. Plasma levels of VWF, ADAMTS-13, TNF receptor 1 (TNFR1), soluble vascular cell adhesion molecule 1 and soluble intercellular adhesion molecule 1 were also measured. In vitro results showed a more marked proinflammatory and prothrombotic phenotype in ECs in association with aGvHD. Regarding circulating biomarkers, levels of VWF and TNFR1 above an optimal cutoff score, taken independently or combined, at day 7 after allo-HCT, would be able to positively predict that around 90% of patients will develop aGvHD. Our results demonstrate that endothelial damage is aggravated in those allo-HCT recipients developing aGvHD, and that VWF and TNFR1 are promising predictive aGvHD biomarkers. These findings could contribute to improve the understanding of the pathophysiology of aGvHD.

Combining Flow and Mass Cytometry in the Search for Biomarkers in Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (cGVHD) is a debilitating complication arising in around half of all patients treated with an allogeneic hematopoietic stem cell transplantation. Even though treatment of severe cGVHD has improved during recent years, it remains one of the main causes of morbidity and mortality in affected patients. Biomarkers in blood that could aid in the diagnosis and classification of cGVHD severity are needed for the development of novel treatment strategies that can alleviate symptoms and reduce the need for painful and sometimes complicated tissue biopsies. Methods that comprehensively profile complex biological systems such as the immune system can reveal unanticipated markers when used with the appropriate methods of data analysis. Here, we used mass cytometry, flow cytometry, enzyme-linked immunosorbent assay, and multiplex assays to systematically profile immune cell populations in 68 patients with varying grades of cGVHD. We identified multiple subpopulations across T, B, and NK-cell lineages that distinguished patients with cGVHD from those without cGVHD and which were associated in varying ways with severity of cGVHD. Specifically, initial flow cytometry demonstrated that patients with more severe cGVHD had lower mucosal-associated T cell frequencies, with a concomitant higher level of CD38 expression on T cells. Mass cytometry could identify unique subpopulations specific for cGVHD severity albeit with some seemingly conflicting results. For instance, patients with severe cGVHD had an increased frequency of activated B cells compared to patients with moderate cGVHD while activated B cells were found at a reduced frequency in patients with mild cGVHD compared to patients without cGVHD. Moreover, results indicate it may be possible to validate mass cytometry results with clinically viable, smaller flow cytometry panels. Finally, no differences in levels of blood soluble markers could be identified, with the exception for the semi-soluble combined marker B-cell activating factor/B cell ratio, which was increased in patients with mild cGVHD compared to patients without cGVHD. These findings suggest that interdependencies between such perturbed subpopulations of cells play a role in cGVHD pathogenesis and can serve as future diagnostic and therapeutic targets.

Diarrhea after allogeneic stem cell transplantation: beyond graft-versus-host disease

Diarrhea constitutes a frequent and often debilitating complication of allogeneic hematopoietic cell transplantation (alloHCT). Especially when accompanied by jaundice, skin rash, and symptoms of the upper gastrointestinal tract, diarrhea strongly suggests emergence of acute graft-versus-host disease (GvHD), which is a serious immune complication of the procedure, with possible fatal consequences. However, especially when diarrhea occurs as an isolated symptom, the other causes must be excluded before initiation of GvHD treatment with immune-suppressive drugs. In this article, a broad overview of the literature of different causes of diarrhea in the setting of alloHCT is provided, revealing causes and presentations different from those observed in the general population. We discuss gastrointestinal GvHD with a special focus on biomarkers, but also uncover underlying infectious: viral, bacterial, and parasitic as well as toxic causes of diarrhea. Finally, we suggest a practical algorithm of approach to patients with diarrhea after alloHCT, which may help to establish a proper diagnosis and initiate a causative treatment.

Composite biomarker panel for prediction of severity and diagnosis of acute GVHD with T-cell-depleted allogeneic stem cell transplants-single centre pilot study

AIMS

Acute graft-versus-host disease (aGVHD) is a leading cause of morbidity and mortality following allogeneic haematopoietic stem cell transplantation (HSCT). The aim of this study was to evaluate the clinical utility of a composite biomarker panel to help identify individuals at risk of developing aGVHD, and to help predict and differentiate between severity of aGVHD following T-cell-depleted allogeneic HSCT.

METHODS

We retrospectively analysed our cohort of biopsy confirmed patients with aGVHD, who underwent T-cell-depleted HSCT and matched them with negative controls without any evidence of aGVHD. Post-transplant serum samples on days 0 and 7 and at onset of aGVHD were analysed for elafin, regenerating islet-derived 3-α, soluble tumour necrosis factor receptor-1, soluble interleukin-2 receptor-α and hepatocyte growth factor. Biomarker data were combined as composite panels A-F (table 2) using logistic regression analysis. Receiver operating characteristic analysis was performed to study sensitivity and specificity of the composite panels.

RESULTS

Our composite biomarker panels significantly differentiated between aGVHD and no GVHD patients at time of onset (panel E) and reliably predicted severity of GVHD grades at days 0 and 7 post-transplant (panels B and D). The area under the curve for the composite panel at time of onset was 0.65 with specificity, sensitivity, positive and negative predictive values of 100%, 55.6%, 100% and 78.9%, respectively (p=0.03).

CONCLUSIONS

This pilot data support the usefulness of these composite biomarker panels in the prediction of severity and diagnosis of aGVHD in patients undergoing T-cell-depleted reduced intensity allogeneic HSCT.

Prediction of graft-versus-host disease: a biomarker panel based on lymphocytes and cytokines

Graft-versus-host disease (GvHD) still belongs to the major challenges after allogeneic hematopoietic stem cell transplantation (HSCT). Immune-suppressive therapy against GvHD is a double-edged sword due to risk of infections and relapse. The ability to adapt prophylactic treatment according to the probability of severe GvHD would be an essential advantage for the patients. We analyzed different biomarkers for their potential to predict the development of GvHD in 28 patients who underwent allogeneic HSCT. Blood was taken once directly after hematopoietic engraftment. In this study, patients were monitored for 12 months after HSCT for the occurrence of acute GvHD or acute/chronic GvHD overlap syndrome. Soluble IL-2 receptor and CD4/CD8 T cell ratio were independently associated with the occurrence of GvHD in the observation period. However, the largest area under the receiver operating characteristic curve with 0.90 was observed when a 5-parameter biomarker score based on CD4⁺ T cells, CD8⁺ T cells, CD19^- CD21⁺ precursor B cells, CD4/CD8 T cell ratio, and soluble IL-2 receptor was used to predict GvHD. In addition, CD8⁺ T cell levels above 2.3% of all mononuclear cells after engraftment may predict relapse-free survival at least for 12 months. In summary, we found a new biomarker panel for prediction of GvHD which is featured by established laboratory assays and high statistical significance. In order to introduce the biomarker panel into routine clinical protocols, we suggest performing a larger multi-center study.

Association of Plasma CD163 Concentration with De Novo-Onset Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (GVHD) is the leading cause of long-term morbidity and mortality after allogeneic hematopoietic cell transplantation. To identify prognostic plasma proteins associated with de novo- or quiescent-onset chronic GVHD (cGVHD), we performed a discovery and validation proteomic study. The total study cohort included 167 consecutive patients who had no clinical evidence of GVHD under minimum glucocorticoid administration and had available plasma samples obtained at 80 ± 14 days after transplantation. We first used high-throughput mass spectrometry to screen pooled plasma using 20 cases with subsequent cGVHD and 20 controls without it, and we identified 20 candidate proteins. We then measured 12 of the 20 candidate proteins by ELISA on the same individual samples and identified 4 proteins for further verification (LGALS3BP, CD5L, CD163, and TXN for de novo onset, and LGALS3BP and CD5L for quiescent onset). The verification cohort included 127 remaining patients. The cumulative incidence of de novo-onset cGVHD was higher in patients with higher plasma soluble CD163 concentrations at day 80 than those with lower concentrations (75% versus 40%, P = .018). The cumulative incidence of de novo- or quiescent-onset cGVHD did not differ statistically according to concentrations of the 3 other proteins at day 80. CD163 is a macrophage scavenger receptor and is elevated in oxidative conditions. These results suggest that monocyte or macrophage activation or increased oxidative stress may contribute to the pathogenesis of cGVHD.

Intravenous mesenchymal stromal cell therapy for inflammatory bowel disease: Lessons from the acute graft versus host disease experience

Bone marrow-derived mesenchymal stromal cells (BMSCs) are primitive, supportive cells of the bone marrow with tri-lineage potential to differentiate into bone, cartilage, fat and muscle. These cells possess both in vitro and in vivo immunomodulatory and wound-healing properties. Several studies have demonstrated efficacy of intravenously administered BMSCs in treating acute graft-versus-host disease (GvHD). Use of intravenous (IV) BMSCs in inflammatory bowel diseases (IBD) in humans has been limited to small studies in adults, but results have been promising. There remain many unanswered questions regarding safety, tolerability, effectiveness and optimal use of BMSCs to treat IBD, particularly in immunocompromised patients. This article reviews the evidence for using BMSCs to treat acute GvHD and how this experience may inform the potential use of BMSCs as a treatment for IBD.

Pathophysiology of GvHD and Other HSCT-Related Major Complications

For over 60 years, hematopoietic stem cell transplantation has been the major curative therapy for several hematological and genetic disorders, but its efficacy is limited by the secondary disease called graft versus host disease (GvHD). Huge advances have been made in successful transplantation in order to improve patient quality of life, and yet, complete success is hard to achieve. This review assimilates recent updates on pathophysiology of GvHD, prophylaxis and treatment of GvHD-related complications, and advances in the potential treatment of GvHD.

Citrulline and Monocyte-Derived Macrophage Reactivity before Conditioning Predict Acute Graft-versus-Host Disease

During conditioning, intestinal damage induces microbial translocation which primes macrophage reactivity and leads to donor-derived T cell stimulation. Little is known about the role of intestinal health and macrophage reactivity before conditioning in the development of acute graft-versus-host disease (aGVHD) in patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT). We assessed (1) citrulline, a surrogate marker of functional enterocyte mass and (2) circulating monocyte-derived macrophage reactivity, before allo-HCT. Forty-seven consecutive patients were prospectively included. Citrulline levels from blood samples withdrawn 30 days before transplantation were assessed using liquid chromatography combined with mass spectrometry. Monocyte-derived macrophages were isolated and incubated with 5 pathogen-associated molecular patterns: lipopolysaccharide, PamCSK4, flagellin, muramyl dipeptide, and curdlan. Multiplex fluorescent immunoassay on culture supernatant assessed levels of TNF-α, IL-1β, IL-6, and IL-10 in each condition. Citrulline and cytokine levels were analyzed relatively to aGVHD onset within 100 days after transplantation. Citrulline levels were lower in the aGVHD group (n = 20) than in the no-aGVHD group (n = 27) (P = .005). Conversely, IL-6 and IL-10 were greater in aGVHD group, especially after curdlan stimulation (P = .005 and P = .012). Citrulline levels ≤20 µmol/L, IL-6 ≥ 332 pg/mL, and IL-10 ≥ 90 pg/mL were associated with aGVHD development (log-rank test, P = .002, P = .041, and P < .0001, respectively). In multivariate analysis, IL-10 ≥ 90 pg/mL, myeloablative conditioning, and citrulline ≤20 µmol/L remained independent factors of aGVHD development (hazard ratio [HR],  8.18, P = .0003; HR, 4.28, P = .006; and HR, 4.43, P = .01, respectively). Preconditioning citrulline and monocyte-derived macrophage reactivity are objective surrogate markers suitable to identify patients at risk of developing aGVHD. This work highlights the influence of preconditioning status in aGVHD development.

Specific Etiologies Associated With the Multiple Organ Dysfunction Syndrome in Children: Part 1

OBJECTIVE

To describe a number of the conditions associated with multiple organ dysfunction syndrome presented as part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development multiple organ dysfunction syndrome workshop (March 26-27, 2015).

DATA SOURCES

Literature review, research data, and expert opinion.

STUDY SELECTION

Not applicable.

DATA EXTRACTION

Moderated by an expert from the field, issues relevant to the association of multiple organ dysfunction syndrome with a variety of conditions were presented, discussed, and debated with a focus on identifying knowledge gaps and research priorities.

DATA SYNTHESIS

Summary of presentations and discussion supported and supplemented by the relevant literature.

CONCLUSIONS

There is a wide range of medical conditions associated with multiple organ dysfunction syndrome in children. Traditionally, sepsis and trauma are the two conditions most commonly associated with multiple organ dysfunction syndrome both in children and adults. However, there are a number of other pathophysiologic processes that may result in multiple organ dysfunction syndrome. In this article, we discuss conditions such as cancer, congenital heart disease, and acute respiratory distress syndrome. In addition, the relationship between multiple organ dysfunction syndrome and clinical therapies such as hematopoietic stem cell transplantation and cardiopulmonary bypass is also considered. The purpose of this article is to describe the association of multiple organ dysfunction syndrome with a variety of conditions in an attempt to identify similarities, differences, and opportunities for therapeutic intervention.

An early-biomarker algorithm predicts lethal graft-versus-host disease and survival

BACKGROUND. No laboratory test can predict the risk of nonrelapse mortality (NRM) or severe graft-versus-host disease (GVHD) after hematopoietic cellular transplantation (HCT) prior to the onset of GVHD symptoms. METHODS. Patient blood samples on day 7 after HCT were obtained from a multicenter set of 1,287 patients, and 620 samples were assigned to a training set. We measured the concentrations of 4 GVHD biomarkers (ST2, REG3α, TNFR1, and IL-2Rα) and used them to model 6-month NRM using rigorous cross-validation strategies to identify the best algorithm that defined 2 distinct risk groups. We then applied the final algorithm in an independent test set (n = 309) and validation set (n = 358). RESULTS. A 2-biomarker model using ST2 and REG3α concentrations identified patients with a cumulative incidence of 6-month NRM of 28% in the high-risk group and 7% in the low-risk group (P < 0.001). The algorithm performed equally well in the test set (33% vs. 7%, P < 0.001) and the multicenter validation set (26% vs. 10%, P < 0.001). Sixteen percent, 17%, and 20% of patients were at high risk in the training, test, and validation sets, respectively. GVHD-related mortality was greater in high-risk patients (18% vs. 4%, P < 0.001), as was severe gastrointestinal GVHD (17% vs. 8%, P < 0.001). The same algorithm can be successfully adapted to define 3 distinct risk groups at GVHD onset. CONCLUSION. A biomarker algorithm based on a blood sample taken 7 days after HCT can consistently identify a group of patients at high risk for lethal GVHD and NRM. FUNDING. The National Cancer Institute, American Cancer Society, and the Doris Duke Charitable Foundation.

Plasma-derived proteomic biomarkers in human leukocyte antigen-haploidentical or human leukocyte antigen-matched bone marrow transplantation using post-transplantation cyclophosphamide

Recent studies have suggested that plasma-derived proteins may be potential biomarkers relevant for graft-versus-host disease and/or non-relapse mortality occurring after allogeneic blood or marrow transplantation. However, none of these putative biomarkers have been assessed in patients treated either with human leukocyte antigen-haploidentical blood or marrow transplantation or with post-transplantation cyclophosphamide, which has been repeatedly associated with low rates of severe acute graft-versus-host disease, chronic graft-versus-host disease, and non-relapse mortality. We explored whether seven of these plasma-derived proteins, as measured by enzyme-linked immunosorbent assays, were predictive of clinical outcomes in post-transplantation cyclophosphamide-treated patients using plasma samples collected at serial predetermined timepoints from patients treated on prospective clinical studies of human leukocyte antigen-haploidentical (n=58; clinicaltrials.gov Identifier: 00796562) or human leukocyte antigen-matched-related or -unrelated (n=100; clinicaltrials.gov Identifiers: 00134017 and 00809276) T-cell-replete bone marrow transplantation. Day 30 levels of interleukin-2 receptor α, tumor necrosis factor receptor 1, serum STimulation-2 (IL1RL1 gene product), and regenerating islet-derived 3-α all had high areas under the curve of 0.74–0.97 for predicting non-relapse mortality occurrence by 3 months post-transplant in both the human leukocyte antigen-matched and human leukocyte antigen-haploidentical cohorts. In both cohorts, all four of these proteins were also predictive of subsequent non-relapse mortality occurring by 6, 9, or 12 months post-transplant and were significantly associated with non-relapse mortality in univariable analyses. Furthermore, day 30 elevations of interleukin-2 receptor α were associated with grade II–IV and III–IV acute graft-versus-host disease occurring after day 30 in both cohorts. These data confirm that plasma-derived proteins previously assessed in other transplantation platforms appear to retain prognostic and predictive utility in patients treated with post-transplantation cyclophosphamide.

Protein biomarker druggability profiling

Developing automated and interactive methods for building a model by incorporating mechanistic and potentially causal annotations of ranked biomarkers of a disease or clinical condition followed by a mapping into a contextual framework in disease-linked biochemical pathways can be used for potential drug-target evaluation and for proposing new drug targets. We demonstrate the potential of this approach using ranked protein biomarkers obtained in neonatal sepsis by enrolling 127 infants (39 infants with late onset neonatal sepsis and 88 control infants) and by performing a focused proteomic profile of the sera and by applying the interactive druggability profiling algorithm (DPA) developed by us.

B-Cell-Based and Soluble Biomarkers in Body Liquids for Predicting Acute/Chronic Graft-versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the main curative therapy for hematological malignancy such as leukemias, lymphomas, or multiple myelomas and some other hematological disorders. In this therapy, cure of hematological diseases relies on graft-versus-malignancy effects by allogenic immune cells. However, severe posttransplant treatment-associated complications such as acute graft-versus-host disease (aGvHD) and chronic graft-versus-host disease (cGvHD) limit this approach. Most research into GvHD has concentrated on the aGvHD, while the more complex and multifaceted chronic form has been largely poorly investigated. cGvHD is a multi-organ autoimmune disorder and is the major cause of non-relapse morbidity and mortality following allo-HSCT, occurring in about 50% of patients, or 13,000–15,000 patients per year worldwide. Therefore, there is a high medical need for an early prediction of these therapy-associated toxicities. Biomarkers have gained importance over the last decade in diagnosis, in prognosis, and in prediction of pending diseases or side effects. Biomarkers can be cells, factors isolated from target tissues, or soluble factors that can be detected in body fluids. In this review, we aim to summarize some of the recent developments of biomarkers in the field of allo-HSCT. We will focus on cell-based biomarkers (B-cell subsets) for cGvHD and soluble factors including microRNA (miRNA), which are excreted into serum/plasma and urine. We also discuss the potential role of cytosolic and extracellular 70 kDa heat shock proteins (HSP70) as potential biomarkers for aGvHD and their role in preclinical models. Proteomic biomarkers in the blood have been used as predictors of treatment responses in patients with aGvHD for many years. More recently, miRNAs have been found to serve as a biomarker to diagnose aGvHD in the plasma. Another development relates to urine-based biomarkers that are usually detected by capillary electrophoresis and mass spectrometry. These biomarkers have the potential to predict the development of severe aGvHD (grades III–IV), overall mortality, and the pending development of cGvHD in patients posttransplant.

Ex Vivo CD34+-Selected T Cell-Depleted Peripheral Blood Stem Cell Grafts for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Leukemia and Myelodysplastic Syndrome Is Associated with Low Incidence of Acute and Chronic Graft-versus-Host Disease and High Treatment Response

Ex vivo CD34⁺-selected T cell depletion (TCD) has been developed as a strategy to reduce the incidence of graft-versus-host disease (GVHD) after allogeneic (allo) hematopoietic stem cell transplantation (HSCT). Clinical characteristics, treatment responses, and outcomes of patients developing acute (aGVHD) and chronic GVHD (cGVHD) after TCD allo-HSCT have not been well established. We evaluated 241 consecutive patients (median age, 57 years) with acute leukemia (n = 191, 79%) or myelodysplastic syndrome (MDS) (n = 50, 21%) undergoing CD34⁺-selected TCD allo-HSCT without post-HCST immunosuppression in a single institution. Cumulative incidences of grades II-IV and III-IV aGVHD at 180 days were 16% (95% confidence interval [CI], 12 to 21) and 5% (95% CI, 3 to 9), respectively. The skin was the most frequent organ involved, followed by the gastrointestinal tract. Patients were treated with topical corticosteroids, poorly absorbed corticosteroids (budesonide), and/or systemic corticosteroids. The overall day 28 treatment response was high at 82%. The cumulative incidence of any cGVHD at 3 years was 5% (95% CI, 3 to 9), with a median time of onset of 256 days (range, 95 to 1645). The 3-year transplant-related mortality, relapse, overall survival, and disease-free survival were 24% (95% CI, 18 to 30), 22% (95% CI, 17 to 27), 57% (95% CI, 50 to 64), and 54% (95% CI, 47 to 61), respectively. The 1-year and 3-year probabilities of cGVHD-free/relapse-free survival were 65% (95% CI, 59 to 71) and 52% (95% CI, 45 to 59), respectively. Our findings support the use of ex vivo CD34⁺-selected TCD allograft as a calcineurin inhibitor-free intervention for the prevention of GVHD in patients with acute leukemia and MDS.

Novel Scoring Criteria for the Evaluation of Ocular Graft-versus-Host Disease in a Preclinical Allogeneic Hematopoietic Stem Cell Transplantation Animal Model

Ocular complications occur after transplantation in 60% to 90% of chronic graft-versus-host disease (GVHD) patients and significantly impair vision-related quality of life. Ocular surface inflammation and dry eye disease are the most common manifestations of ocular GVHD. Ocular GVHD can be viewed as an excellent preclinical model that can be studied to understand the immune pathogenesis of this common and debilitating disease. A limitation of this is that only a few experimental models mimic the ocular complications after hematopoietic stem cell transplantation (HSCT) and have focused on the acute GVHD process. To address this issue, we used a preclinical animal model developed by our group where ocular involvement was preceded by systemic GVHD to gain insight regarding the contributing immune mechanisms. Employing this "matched unrelated donor" model enabled the development of clinical scoring criteria, which readily identified different degrees of ocular pathology at both the ocular surface and adnexa, dependent on the level of conditioning before HSCT. As far as we are aware, we report for the first time that these clinical and immune responses occur not only on the ocular surface, but they also heavily involve the lid margin region. In total, the present study reports a preclinical scoring model that can be applied to animal models as investigators look to further explore GVHD's immunologic effects at the level of the ocular surface and eyelid adnexa compartments. We speculate that future studies will use this clinical scoring index in combination with what is recognized histologically and correlated with serum biomarkers identified in chronic/ocular GVHD.

Three-dimensional structure discrepancy between HLA alleles for effective prediction of aGVHD severity and optimal selection of recipient-donor pairs: a proof-of-concept study

The optimal selection of recipient-donor pair and accurate prediction of acute graft-versus-host disease (aGVHD) severity are always the two most crucial works in allogeneic hematopoietic stem cell transplantation (allo-HSCT), which currently rests mostly with HLA compatibility, the most polymorphic loci in the human genome, in clinic. Thus, there is an urgent need for a rapid and reliable quantitative system for optimal recipient-donor pairs selection and accurate prediction of aGVHD severity prior to allo-HSCT. For these reasons, we have developed a new selection/prediction system for optimal recipient-donor selection and effective prediction of aGVHD severity based on HLA three-dimensional (3D) structure modeling (HLA-TDSM) discrepancy, and applied this system in a pilot randomized clinical allo-HSCT study. The 37 patient-donor pairs in the study were typed at low- and high-resolution levels for HLA-A/-B/-DRB1/-DQB1 loci. HLA-TDSM system covering the 10000 alleles in HLA class I and II consists of the revised local and coordinate root-mean-square deviation (RMSD) values for each locus. Its accuracy and reliability were confirmed using stably transfected Hmy2.CIR–HLA-B cells, TCR Vβ gene scan, and antigen-specific alloreactive cytotoxic lymphocytes. Based on the preliminary results, we theoretically defined all HLA acceptable versus unacceptable mismatched alleles. More importantly, HLA-TDSM enabled a successful retrospective verification and prospective prediction for aGVHD severity in a pilot randomized clinical allo-HSCT study of 32 recipient-donor transplant pairs. There was a strong direct correlation between single/total revised RMSD and aGVHD severity (92% in retrospective group vs 95% in prospective group). These results seem to be closely related to the 3D structure discrepancy of mismatched HLA-alleles, but not the number or loci of mismatched HLA-alleles. Our data first provide the proof-of-concept that HLA-TDSM is essential for optimal selection of recipient-donor pairs and effective prediction of aGVHD severity before allo-HSCT.

Proteomic Characterization Reveals That MMP-3 Correlates With Bronchiolitis Obliterans Syndrome Following Allogeneic Hematopoietic Cell and Lung Transplantation

Improved diagnostic methods are needed for bronchiolitis obliterans syndrome (BOS), a serious complication after allogeneic hematopoietic cell transplantation (HCT) and lung transplantation. For protein candidate discovery, we compared plasma pools from HCT transplantation recipients with BOS at onset (n = 12), pulmonary infection (n = 16), chronic graft-versus-host disease without pulmonary involvement (n = 15) and no chronic complications after HCT (n = 15). Pools were labeled with different tags (isobaric tags for relative and absolute quantification), and two software tools identified differentially expressed proteins (≥1.5-fold change). Candidate proteins were further selected using a six-step computational biology approach. The diagnostic value of the lead candidate, matrix metalloproteinase 3 (MMP3), was evaluated by enzyme-linked immunosorbent assay in plasma of a verification cohort (n = 112) with and without BOS following HCT (n = 76) or lung transplantation (n = 36). MMP3 plasma concentrations differed significantly between patients with and without BOS (area under the receiver operating characteristic curve 0.77). Consequently, MMP3 represents a potential noninvasive blood test for diagnosis of BOS.

Recipient and donor JAK2 46/1 haplotypes are associated with acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation

Several genetic polymorphisms have been implicated to affect the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT). The role of cytokines in acute graft-versus-host disease (aGvHD) is well established and many of the involved cytokines signal through the Janus kinase (JAK) pathways. In this study, we assessed the association of recipient and donor JAK2 46/1 haplotypes and allo-HSCT outcome in a cohort of 124 acute myeloid leukemia patients. Both, recipient and donor 46/1 haplotypes significantly affected aGvHD grades II-IV development (p = 0.006 and p = 0.031, respectively), furthermore the influence of the haplotypes seemed to be additive. In multivariate analyses the recipient haplotype remained independently related (p = 0.012) to aGvHD, while the donor not (p = 0.08). We observed significantly less relapses among haplotype carriers (p = 0.004), but overall survival did not differ (p = 0.732). Our findings suggest that recipient and donor JAK2 46/1 haplotypes might be involved in the regulation of aGvHD.

Soluble DNAM-1, as a Predictive Biomarker for Acute Graft-Versus-Host Disease

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Because diagnosis of aGVHD is exclusively based on clinical symptoms and pathological findings, reliable and noninvasive laboratory tests for accurate diagnosis are required. An activating immunoreceptor, DNAM-1 (CD226), is expressed on T cells and natural killer cells and is involved in the development of aGVHD. Here, we identified a soluble form of DNAM-1 (sDNAM-1) in human sera. In retrospective univariate and multivariate analyses of allo-HSCT patients (n = 71) at a single center, cumulative incidences of all grade (grade I-IV) and sgrade II-IV aGVHD in patients with high maximal serum levels of sDNAM-1 (≥30 pM) in the 7 days before allo-HSCT were significantly higher than those in patients with low maximal serum levels of sDNAM-1 (<30 pM) in the same period. However, sDNAM-1 was not associated with other known allo-HSCT complications. Our data suggest that sDNAM-1 is potentially a unique candidate as a predictive biomarker for the development of aGVHD.

A Novel Diagnostic and Prognostic Biomarker Panel for Endothelial Cell Damage-Related Complications in Allogeneic Transplantation

Noninfectious transplantation-related complications (TRCs), such as graft-versus-host disease or TRC with endothelial cell damage (TRC-EC), remain as the major obstacle for successful allogeneic hematopoietic cell transplantation (allo-HCT). However, the diagnosis and prognosis for the emergence of these complications are difficult to define during the early post allo-HCT period. Here, we tried to generate a novel diagnostic system for TRC-EC by analyzing 188 adult patients who received allo-HCT. Our study found that the peripheral blood levels of angiopoietin 2 (ANG2), C-reactive protein (CRP), D-dimer, and thrombomodulin (TM) at the onset of TRCs were significantly associated with the development of TRC-EC. We next developed a composite biomarker panel incorporating the risk values of ANG2, CRP, D-dimer, and TM at the onset of TRCs, which classified these patients into 3 risk groups: low, intermediate, and high risk. As a result, the panel was useful not only for the diagnosis of TRC-EC with high specificity and sensitivity, but also for the prediction of the patients' long-term outcome. The 5-year overall survival (OS) rates of patients in the low-, intermediate-, and high-risk groups since the occurrence from TRCs were 76.2%, 54.9%, and 26.9%, respectively, and the high-risk score was significantly associated with both poor OS (hazard ratio [HR], 5.60; 95% confidence interval [CI], 2.81 to 11.20; P < .01) and frequent nonrelapse mortality (HR, 19.75; 95% CI, 5.59 to 69.77; P < .01). Thus, the composite panel proposed in this study provides a powerful tool for the diagnosis of TRC-EC and for the prediction of survival for patients with TRC-EC after allo-HCT.

Biomarker Panel for Chronic Graft-Versus-Host Disease

PURPOSE

To identify diagnostic and prognostic markers of chronic graft-versus-host disease (cGVHD), the major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT).

PATIENTS AND METHODS

Using a quantitative proteomics approach, we compared pooled plasma samples obtained at matched time points after HCT (median, 103 days) from 35 patients with cGVHD and 18 without cGVHD (data are available via ProteomeXchange with identifier PXD002762). Of 105 proteins showing at least a 1.25-fold difference in expression, 22 were selected on the basis of involvement in relevant pathways and enzyme-linked immunosorbent assay availability. Chemokine (C-X-C motif) ligand 9 (CXCL9) and suppression of tumorigenicity 2 (ST2) also were measured on the basis of previously determined associations with GVHD. Concentrations of the four lead biomarkers were measured at or after diagnosis in plasma from two independent verification cohorts (n = 391) to determine their association with cGVHD. Their prognostic ability when measured at approximately day +100 after HCT was evaluated in plasma of a second verification cohort (n = 172).

RESULTS

Of 24 proteins measured in the first verification cohort, nine proteins were associated with cGVHD, and only four (ST2, CXCL9, matrix metalloproteinase 3, and osteopontin) were necessary to compose a four-biomarker panel with an area under the receiver operating characteristic curve (AUC) of 0.89 and significant correlation with cGVHD diagnosis, cGVHD severity, and nonrelapse mortality. In a second verification cohort, this panel distinguished patients with cGVHD (AUC, 0.75), and finally, the panel measured at day +100 could predict cGVHD occurring within the next 3 months with an AUC of 0.67 and 0.79 without and with known clinical risk factors, respectively.

CONCLUSION

We conclude that the biomarker panel measured at diagnosis or day +100 after HCT may allow patient stratification according to risk of cGVHD.

The Role of Biomarkers in the Diagnosis and Risk Stratification of Acute Graft-versus-Host Disease: A Systematic Review

Allogeneic hematopoietic cell transplantation (HCT) is an increasingly used curative modality for hematologic malignancies and other benign conditions. Attempts to reduce morbidity and mortality and improve survival in patients undergoing HCT are crucial. The ability to diagnose acute graft-versus-host disease (aGVHD) in a timely manner, or to even predict aGVHD before clinical manifestations, along with the accurate stratification of these patients, are critical steps to improve the treatment and outcomes of these patients. Many novel biomarkers that may help achieve these goals have been studied recently. This overview is intended to assist clinicians and investigators by providing a comprehensive review and analytical interpretation of the current knowledge concerning aGVHD and biomarkers likely to prove useful in diagnosis and risk stratification of this condition, along with the difficulties that hamper this approach.

Proteomics analysis reveals a Th17-prone cell population in presymptomatic graft-versus-host disease

Gastrointestinal graft-versus-host-disease (GI-GVHD) is a life-threatening complication occurring after allogeneic hematopoietic cell transplantation (HCT), and a blood biomarker that permits stratification of HCT patients according to their risk of developing GI-GVHD would greatly aid treatment planning. Through in-depth, large-scale proteomic profiling of presymptomatic samples, we identified a T cell population expressing both CD146, a cell adhesion molecule, and CCR5, a chemokine receptor that is upregulated as early as 14 days after transplantation in patients who develop GI-GVHD. The CD4⁺CD146⁺CCR5⁺ T cell population is Th17 prone and increased by ICOS stimulation. shRNA knockdown of CD146 in T cells reduced their transmigration through endothelial cells, and maraviroc, a CCR5 inhibitor, reduced chemotaxis of the CD4⁺CD146⁺CCR5⁺ T cell population toward CCL14. Mice that received CD146 shRNA-transduced human T cells did not lose weight, showed better survival, and had fewer CD4⁺CD146⁺CCR5⁺ T cells and less pathogenic Th17 infiltration in the intestine, even compared with mice receiving maraviroc with control shRNA- transduced human T cells. Furthermore, the frequency of CD4⁺CD146⁺CCR5⁺ Tregs was increased in GI-GVHD patients, and these cells showed increased plasticity toward Th17 upon ICOS stimulation. Our findings can be applied to early risk stratification, as well as specific preventative therapeutic strategies following HCT.

Advances in understanding the pathogenesis of graft-versus-host disease

Allogeneic haematopoietic stem cell transplantation (HCT) is a potent immunotherapy with curative potential for several haematological disorders. Overcoming the immunological barrier of acute graft-versus-host disease (GVHD) remains a fundamental impediment to expanding the efficacy of HCT. GVHD reflects a complex pathological interaction between the innate and adaptive immune systems of the host and donor. Over the past decade there has been a tremendous advancement in our understanding of the cellular and molecular underpinnings of this devastating disease. In this review, we cover several recently appreciated facets of GVHD pathogenesis including novel extracellular mediators of inflammation, immune subsets, intracellular signal transduction, post-translation modifications and epigenetic regulation. We begin to develop general themes regarding the immunological pathways in GVHD pathogenesis, discuss critical outstanding questions, and explore new avenues for GVHD treatment and prevention.

Cytokine Profile of Engraftment Syndrome in Pediatric Hematopoietic Stem Cell Transplant Recipients

The biology of engraftment syndrome is poorly understood, and the degree of overlap with acute graft-versus-host disease (GVHD) is unclear. To understand engraftment syndrome better, plasma cytokine profiles were evaluated in 56 pediatric allogeneic bone marrow transplant recipients before transplant, on the day of stem cell infusion, and weekly until day +100. Patients were divided into 4 groups: those with isolated engraftment syndrome (n = 8), acute GVHD (n = 12), both engraftment syndrome and acute GVHD (n = 4), and neither engraftment syndrome nor acute GVHD (n = 32). Engraftment syndrome was observed a median of 13.5 days (range, 10 to 28) after transplant, whereas acute GVHD was diagnosed a median of 55 days (range, 19 to 95) after transplant. Four patients developed both engraftment syndrome at a median of 10.5 days (range, 10 to 11) and acute GVHD at a median of 35 days (range, 23 to 56) after stem cell infusion. Median plasma levels of IL-1β, IL-6, IL-12, IL-4, and IL-13 were significantly elevated in patients with isolated engraftment syndrome when compared with isolated acute GVHD. A rise of proinflammatory cytokines (IL-1β, IL-6, and IL-12) was followed by surge in anti-inflammatory cytokines (IL-4 and IL-13) in patients with isolated engraftment syndrome. The observation of elevated IL-1β suggests that engraftment syndrome could be an inflammasome mediated phenomenon.

Transcriptome analysis of GVHD reveals aurora kinase A as a targetable pathway for disease prevention

Graft-versus-host disease (GVHD) is the most common complication of hematopoietic stem cell transplant (HCT). However, our understanding of the molecular pathways that cause this disease remains incomplete, leading to inadequate treatment strategies. To address this, we measured the gene expression profile of nonhuman primate (NHP) T cells during acute GVHD. Utilizing microarray technology, we measured the expression profiles of CD3(+) T cells from five cohorts: allogeneic transplant recipients receiving (i) no immunoprophylaxis (No Rx), (ii) sirolimus monotherapy (Siro), (iii) tacrolimus-methotrexate (Tac-Mtx), as well as (iv) autologous transplant recipients (Auto) and (v) healthy controls (HC). This comparison allowed us to identify transcriptomic signatures specific for alloreactive T cells and determine the impact of both mTOR (mechanistic target of rapamycin) and calcineurin inhibition on GVHD. We found that the transcriptional profile of unprophylaxed GVHD was characterized by significant perturbation of pathways regulating T cell proliferation, effector function, and cytokine synthesis. Within these pathways, we discovered potentially druggable targets not previously implicated in GVHD, prominently including aurora kinase A (AURKA). Utilizing a murine GVHD model, we demonstrated that pharmacologic inhibition of AURKA could improve survival. Moreover, we found enrichment of AURKA transcripts both in allo-proliferating T cells and in sorted T cells from patients with clinical GVHD. These data provide a comprehensive elucidation of the T cell transcriptome in primate acute GVHD and suggest that AURKA should be considered a target for preventing GVHD, which, given the many available AURKA inhibitors in clinical development, could be quickly deployed for the prevention of GVHD.

Application of Proteomics in Acute Graft-Versus-Host Disease Management: An Integrative Review and Nursing Implications

BACKGROUND

After allogeneic hematopoietic stem cell transplantation, one of the major barriers to clinical management of acute graft-versus-host disease (aGVHD) is a lack of reliable and validated noninvasive tests for diagnosis and prognosis. Proteomic studies have indicated a strong correlation between the level of certain body fluid proteins and clinical outcomes after aGVHD. Specific proteins have been identified that could be robust biomarkers for overall prognosis or for differential diagnosis of target organs in aGVHD.

OBJECTIVES

The authors aimed to evaluate the literature related to proteomic biomarkers that are indicated in the occurrence, severity, and management of aGVHD.

METHODS

PubMed and CINAHL® databases were searched for articles published from January 2004 to June 2014. Eight articles matching the inclusion criteria were identified, and the findings of these articles were summarized and their clinical implications noted.

FINDINGS

Proteomics appears to be a promising tool to assist oncology nurses and nurse practitioners with patient education, develop personalized plans of care to reduce morbidity, initiate communication regarding end-of-life decisions, and improve overall nursing management of the population of patients with aGVHD.

MicroRNA-181a, a potential diagnosis marker, alleviates acute graft versus host disease by regulating IFN-γ production

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a valuable therapeutic strategy for a wide variety of diseases. Acute graft-versus-host disease (aGVHD) is a major complication in up to 75% of allo-HSCT. The absence of a reliable predicative marker for aGVHD onset prevents preemptive treatment and impedes widespread and successful application of this therapy. In this study we found that after allo-HSCT, the levels of miR-181a were reduced significantly prior to the onset of aGVHD. More importantly, the degree of its reduction correlated with the severity of aGVHD. Mechanistically, miR-181a affects the function of T lymphocytes by down-regulating IFN-γ in a dose-dependent manner. Meanwhile, we confirmed that miR-181a can effectively preserve the anti-leukemic effect in vitro. Using a murine allo-HSCT model, we demonstrated that murine miR-181b, the human miR-181a homolog, served as an effective predictor of aGVHD. Moreover, expression of this microRNA ameliorated the severity of aGVHD. Collectively, these results show that the level of miR-181a may serve as a reliable marker for the diagnosis and prognosis the onset of aGVHD. Am. J. Hematol. 90:998-1007, 2015. © 2015 Wiley Periodicals, Inc.