Pericapillary hemorrhage as criterion of severe human digestive graft-versus-host disease

Prospective external validation of biomarkers to predict acute graft-versus host disease severity

Biomarker panels at GVHD onset, independently from clinical parameters, were associated with survival and nonrelapse mortality.

Using 3 different biostatistical tools, biomarkers only slightly improved prediction over clinical parameters.

Acute graft-versus-host disease (GVHD) is still the major contributor to comorbidities and mortality after allogeneic hematopoietic stem cell transplantation. The use of plasmatic biomarkers to predict early outcomes has been advocated in the past decade. The purpose of this prospective noninterventional study was to test the ability of panels including 7 biomarkers (Elafin, HGF, IL2RA, IL8, REG3, ST2, and TNFRI), to predict day 28 (D28) complete response to steroid, D180 overall survival, and D180 nonrelapse mortality (NRM). Using previous algorithms developed by the Ann Arbor/MAGIC consortium, 204 patients with acute GVHD were prospectively included and biomarkers were measured at GVHD onset for all of them. Initial GVHD grade and bilirubin level were significantly associated with all those outcomes. After adjustment on clinical variables, biomarkers were associated with survival and NRM. In addition to clinical variables, biomarkers slightly improved the prediction of overall survival and NRM (concordance and net reclassification indexes). The potential benefit of adding biomarkers panel to clinical parameters was also investigated by decision curve analyses. The benefit of adding biomarkers to clinical parameters was however marginal for the D28 nonresponse and mortality endpoints.

Characteristics of late transplant-associated thrombotic microangiopathy in patients who underwent allogeneic hematopoietic stem cell transplantation

Transplant-associated thrombotic microangiopathy (TA-TMA) has a wide range of presentations after hematopoietic stem-cell transplantation (HSCT). We retrospectively studied the risk factors and outcomes of patients with early (≤day 100) and late (>day 100) TA-TMA. Among the 1451 HSCT recipients, early TA-TMA occurred in 45 (3.1%) patients at a median of 27 (3-91) days, and late TA-TMA in 39 (2.7%) patients at a median of 303 (122-2595) days. Patients with early TA-TMA were more likely to have high blood calcineurin-inhibitor levels (P < .001) and acute graph-vs-host disease (GVHD, P < .001), while late TMA patients were more likely to have chronic GVHD (P < .001). The estimated median overall survival after onset of TMA for the entire cohort was 6 months. The estimated median overall survival was not reached in patients with an improvement of TMA vs 2 months in patients with no improvement (P < .001). In the early TMA group, older age (for every 10 years, HR 1.40; 95% CI 1.00-1.94; P = .049) and bacterial infection (HR 2.42; 95% CI 0.98-6.00; P = .056) were positively associated with mortality. Switching to MMF treatment (HR 0.40; 95% CI 0.16-0.99; P = .047) and improvement of TMA (HR 0.08; 95% CI 0.03-0.25; P < .001) were negatively associated with mortality in the multivariate analysis. In the late TMA group, the improvement of TMA was the only independent predictor associated with a lower risk of death (HR 0.05; 95% CI 0.02-0.19; P < .001). Mortality rates in both early and late TMA remain unacceptably high. Future studies are needed for early diagnosis, trigger identifications, and use of targeted treatments.

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.

EASIX in patients with acute graft-versus-host disease: a retrospective cohort analysis

BACKGROUND

Endothelial dysfunction links thrombotic microangiopathy to steroid-refractory graft-versus-host disease (GVHD) after allogeneic stem-cell transplantation. We aimed to assess if the simple formula-lactate dehydrogenase (U/L) × creatinine (mg/dL)/thrombocytes (10⁹ cells per L)-termed the Endothelial Activation and Stress Index (EASIX), might be valuable for the prediction of death in patients with acute GVHD after allogeneic stem-cell transplantation.

METHODS

For this retrospective analysis, we analysed a training cohort (in Germany) and three validation cohorts (in Germany and the USA) of patients with acute GVHD who had received consecutive allogeneic stem-cell transplantation. The primary endpoint was prediction of overall survival when measured at acute GVHD onset (EASIX-GVHD). We validated the prognostic strength of EASIX-GVHD for overall survival and non-relapse mortality in the three independent cohorts by calculating the prediction error (integrated Brier score), and concordance index.

FINDINGS

In the total cohort of patients with acute GVHD (n=311), EASIX-GVHD predicted overall survival in univariable and multivariable models (univariate analysis, hazard ratio [HR] for a one-fold increase 1·16, 95% CI 1·12-1·20, p=0·0004). However, in the subpopulation of patients with myeloablative conditioning (n=72), EASIX-GVHD did not predict overall survival, which is probably attributable to thrombocytopenia at GVHD onset (73 × 10⁹ cells per L [IQR 29·75-180·00] for myeloablative conditioning vs 160 × 10⁹ cells per L [90·0-250·5] for reduced-intensity conditioning; p<0·0001). In patients who received reduced-intensity conditioning (n=239), EASIX-GVHD was a strong predictor of overall survival (HR for a two-fold change of 1·23, 95% CI 1·13-1·34; p<0·0001) and non-relapse mortality (cause-specific HR for a two-fold change of 1·24, 1·12-1·38; p<0·0001). Model validation for prediction of overall survival and non-relapse mortality by EASIX-GVHD was successful in two independent cohorts of adult patients with reduced-intensity conditioning (n=141, n=173) and in a cohort with mainly paediatric patients (n=89).

INTERPRETATION

In patients with reduced-intensity conditioning, EASIX-GVHD is a powerful predictor of survival after GVHD. EASIX-GVHD could be the future basis for development of risk-adapted GVHD treatment strategies.

FUNDING

There was no external funding source for this study.

Peripheral tolerance can be modified by altering KLF2-regulated Treg migration

Tregs are essential for maintaining peripheral tolerance, and thus targeting these cells may aid in the treatment of autoimmunity and cancer by enhancing or reducing suppressive functions, respectively. Before these cells can be harnessed for therapeutic purposes, it is necessary to understand how they maintain tolerance under physiologically relevant conditions. We now report that transcription factor Kruppel-like factor 2 (KLF2) controls naive Treg migration patterns via regulation of homeostatic and inflammatory homing receptors, and that in its absence KLF2-deficient Tregs are unable to migrate efficiently to secondary lymphoid organs (SLOs). Diminished Treg trafficking to SLOs is sufficient to initiate autoimmunity, indicating that SLOs are a primary site for maintaining peripheral tolerance under homeostatic conditions. Disease severity correlates with impaired Treg recruitment to SLOs and, conversely, promotion of Tregs into these tissues can ameliorate autoimmunity. Moreover, stabilizing KLF2 expression within the Treg compartment enhances peripheral tolerance by diverting these suppressive cells from tertiary tissues into SLOs. Taken together, these results demonstrate that peripheral tolerance is enhanced or diminished through modulation of Treg trafficking to SLOs, a process that can be controlled by adjusting KLF2 protein levels.

Does defibrotide prophylaxis decrease the risk of acute graft versus host disease following allogeneic hematopoietic cell transplantation?

There is some preliminary evidence, that veno-occlusive disease prophylaxis with defibrotide (DF) may also have a role in decreasing risk of acute graft-versus-host disease (aGvHD) by preventing tissue damage. In this study, we aimed to investigate the role of DF prophylaxis on the development of aGvHD at D+180. One hundred ninety-five consecutive adult patients receiving allogeneic HCT were retrospectively evaluated in 3 groups: no DF, DF/post-HCT (DF D+1 to D+14) and DF/pre-HCT (DF for 14 days concurrently with conditioning). The total (p: 0.057) and grades III/IV (p: 0.051) aGvHD rates at D+180 were 46.5%, 40%, 25.5% and 15.5%, 11.2%, 0% in patients on no DF, DF/post-HCT and DF/pre-HCT. DF may have a role in decreasing incidence and severity of aGvHD, especially if used concurrently with conditioning regimen.

How I treat acute graft-versus-host disease of the gastrointestinal tract and the liver

Treatment of acute graft-versus-host disease (GVHD) has evolved from a one-size-fits-all approach to a more nuanced strategy based on predicted outcomes. Lower and time-limited doses of immune suppression for patients predicted to have low-risk GVHD are safe and effective. In more severe GVHD, prolonged exposure to immunosuppressive therapies, failure to achieve tolerance, and inadequate clinical responses are the proximate causes of GVHD-related deaths. This article presents acute GVHD-related scenarios representing, respectively, certainty of diagnosis, multiple causes of symptoms, jaundice, an initial therapy algorithm, secondary therapy, and defining futility of treatment.

Angiogenic factors and inflammation in steroid-refractory acute graft-vs-host disease

Steroid-refractory acute graft-vs-host disease (aGVHD) remains a frequent and often fatal complication of allogeneic hematopoietic cell transplantation. Recent evidence suggests that angiogenic factors-growth factors that contribute to blood vessel development-may be involved in tissue healing and restitution after inflammatory insults such as aGVHD. However, some angiogenic factors may also be involved in inflammation and worsen clinical outcomes. In this review, we summarize the data relevant to angiogenic factors that may contribute to healing after aGVHD (epidermal growth factor and vascular endothelial growth factor A) and angiogenic factors that may promote inflammation after aGVHD (placental growth factor and follistatin). It is currently unknown whether changes in these factors are a cause or a consequence of aGVHD. Mechanistic studies in the coming years will clarify their roles and identify new pathways for improving outcomes in steroid-refractory aGVHD.

Intra-Arterial Platelet Infusion for Intractable Hemorrhage and Refractory Thrombocytopenia in Children With Gastrointestinal Graft-Versus-Host Disease

Acute gastrointestinal graft-versus-host disease (GVHD) refractory to first-line treatment with systemic corticosteroids results in increased morbidity and potential mortality. We retrospectively assessed the feasibility and efficacy of catheter-directed intra-arterial platelet infusion (IAPI) in two pediatric patients with steroid and transfusion refractory gastrointestinal GVHD causing intractable lower gastrointestinal hemorrhage and refractory thrombocytopenia, that were referred for salvage therapy. Immediate angiographic response was noted with a resolution of hemorrhage and decreased blood requirements. We reviewed the literature regarding this treatment modality and compared it to the available minimally invasive transcatheter techniques to control gastrointestinal hemorrhage.

Fecal calprotectin and α1-antitrypsin dynamics in gastrointestinal GvHD

In a previous study, the fecal biomarkers calprotectin and α1-antitrypsin (α1-AT) at symptom onset were reported to be significantly associated with the response to steroids in gastrointestinal GvHD (GI-GvHD). The purpose of this trial was to evaluate the dynamics of the fecal biomarkers calprotectin and α1-AT throughout the course of GvHD. Patients who were refractory to steroids had initially higher biomarker levels and in the course of GvHD demonstrated a continuous increase in fecal biomarkers. In contrast, the dynamics of calprotectin and α1-AT demonstrated low and decreasing levels in cortico-sensitive GvHD. In steroid-refractory patients who received a second line of treatment, the biomarker levels at the beginning of second-line treatment did not predict the subsequent response. Nevertheless, calprotectin levels progressively decreased in subsequent responders, whereas non-responders demonstrated continuously high levels of calprotectin. α1-AT values correlated to a lesser extent with the response to second-line treatment and remained elevated in both non-responders and responders. In conclusion, calprotectin monitoring can be of use in the management of immunosuppressive treatment in GI-GvHD.

Gastrointestinal pathology in transplant patients

The assessment of gastrointestinal (GI) specimens from transplant patients is complicated by the wide range of potentially rare pathologies that may be found in this clinical setting. Acute GI graft-versus-host disease (GvHD) is characterized by epithelial cell apoptosis, although there is increasing recognition that acute and/or chronic inflammation may also be present. By contrast, thus far there are no histological features known to be specific to chronic GI GvHD. Mycophenolate mofetil colitis may mimic both GvHD and inflammatory bowel disease, whereas both cytomegalovirus (CMV) and adenovirus infections can cause gland apoptosis. Post-transplant lymphoproliferative disorder should be considered if a Crohn's-like histological picture is seen, and granulomas in biopsies from umbilical cord blood recipients should raise a suspicion of cord colitis syndrome. Finally, the GI tract may be involved directly or indirectly by the disease that originally required haematopoietic stem cell or liver transplantation.

Superselective arterial embolization of the superior mesenteric artery for the treatment of gastrointestinal hemorrhage following allogeneic hematopoietic stem cell transplantation

Superselective arterial embolization is a common therapeutic procedure for cases of visceral hemorrhage. However, until now, it has not been applied in the treatment of gastrointestinal (GI) hemorrhage caused by acute graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. We describe a case presenting with persistent GI bleeding associated with acute GVHD successfully treated by superselective arterial embolization of the superior mesenteric artery with gelatin sponge after noneffective conventional management. This case will help guide hematologists to deal with a similar situation in the future.

Gastrointestinal acute graft-versus-host disease in children: histology for diagnosis, mesenchymal stromal cells for treatment, and biomarkers for prediction of response

Steroid-nonresponsive acute graft-versus-host disease (aGVHD) after hematopoietic stem cell transplantation carries a poor prognosis. Various groups have reported beneficial effects of mesenchymal stromal cell (MSC) infusion as salvage treatment. Response to treatment is typically evaluated using the diagnostic clinical criteria for aGVHD. In this study, we evaluated the usefulness of additional gastrointestinal biopsy specimens paired with serum biomarkers. In a cohort of 22 pediatric patients, persistent or recurrent diarrhea was seen in 18 children treated with MSC infusion for steroid-refractory aGVHD. To exclude other causes of gastrointestinal pathology, patients were biopsied for histological analysis. Eight of 12 patients exhibited residual tissue damage and villous atrophy, but no active aGVHD. Serum biomarkers have been identified as an alternative tool for monitoring the response to aGVHD treatment. The value of biomarkers for inflammation, tissue, and endothelial cell damage was evaluated in our cohort. Although predictive of response to treatment and survival, these markers lack the necessary specificity and sensitivity to predict response to MSC therapy. Objective endpoints for clinical trials on the treatment of steroid-refractory aGVHD remain to be defined. Thus, we recommend including biopsies and biomarkers to discriminate between ongoing aGVHD and postinflammatory malabsorption.

Prospective qualitative and quantitative non-invasive evaluation of intestinal acute GVHD by contrast-enhanced ultrasound sonography

Intestinal acute GVHD (I-aGVHD) is a life-threatening complication after allografting. Non-invasive bed-side procedures to evaluate extension and treatment response are still lacking. We hypothesized that, during I-aGVHD, contrast-enhanced ultrasound sonography (CEUS) could detect microcirculation changes (MVC) of the bowel wall (BW) and help to monitor treatment response. We prospectively employed CEUS in 83 consecutive patients. Of these, 14 patients with biopsy-proven intestinal GVHD (I-GVHD) were defined as the study group, whereas 16 patients with biopsy-proven stomach GVHD (U-GVHD) without intestinal symptoms, 6 normal volunteers and 4 patients with neutropenic enterocolitis were defined as the control group. All patients were evaluated with both standard ultrasonography (US) and CEUS at the onset of intestinal symptoms, during clinical follow-up and at flare of symptoms. Standard US revealed BW thickening of multiple intestinal segments, useful to determine the extension of GVHD. CEUS showed MVC, which correlated with GVHD activity, treatment response, and predicted flare of intestinal symptoms. US and CEUS findings were superimposable at diagnosis and in remission. CEUS was, however, more sensitive and specific to identify subclinical activity in patients with clinical relevant improvement. These findings were not observed in the control groups. CEUS is a non-invasive, easily reproducible bed-side tool useful to monitor I-aGVHD.

Have we made progress in the treatment of GVHD?

One reason for the lack of progress in the treatment of acute graft versus host disease (GVHD) is the lack of reliable biomarkers. GVHD of the gastrointestinal (GI) tract is closely associated with non-relapse mortality (NRM) following hematopoietic cell transplantation (HCT). Using an unbiased, large-scale, quantitative proteomic discovery approach, we identified candidate biomarkers that were increased in plasma from HCT patients with GI GVHD. We then validated the lead candidate, REG3α, by ELISA in samples from more than 1000 HCT patients from three transplant centers. Plasma REG3α concentrations were 3-fold higher in patients at GI GVHD onset than in all other patients. REG3α concentrations correlated most closely with lower GI GVHD at GVHD onset and predicted response to therapy at 4 weeks, 1-year NRM, and 1-year survival (P ≤ 0.001). Multivariate analysis showed that advanced clinical stage, severe histologic damage, and high REG3α concentrations at the diagnosis of GVHD independently predicted 1-year NRM, which progressively increased with higher numbers of onset risk factors present. We conclude that REG3α is a plasma biomarker of GI GVHD that can be combined with clinical stage and histologic grade to improve risk stratification of patients, perhaps providing a platform for advances in the treatment of high-risk GVHD.

Endothelial vulnerability and endothelial damage are associated with risk of graft-versus-host disease and response to steroid treatment

There is accumulating evidence indicating that endothelial factors are involved in the pathogenesis of GVHD. We have recently shown that steroid-refractory, but not sensitive, GVHD is characterized by higher pretransplantation serum levels of angiopoetin-2 (ANG2), a hormone mediating endothelial vulnerability. To evaluate whether endothelial vulnerability is a risk factor for GVHD per se or becomes important only when noticeable GVHD is established, we measured ANG2 along with additional serum markers of endothelial stress, including soluble thrombomodulin (sTM), IL-8 (CXCL8), and hepatocyte growth factor (HGF), in patients with no, low-grade, or severe GVHD. Patients with refractory GVHD exhibited elevated serum levels of ANG2, sTM, HGF, and IL-8 posttransplantation compared with patients with sensitive GVHD and patients without GVHD. Pretransplantation ANG2 was the only growth factor correlated with the risk of refractoriness and mortality, and then only within the subset of patients who developed grade III-IV GVHD. In contrast, ANG2 was not predictive of GVHD or nonrelapse mortality (NRM) in patients with no GVHD or low-grade GVHD. These findings provide evidence that endothelial function plays an important role in the pathogenesis of steroid refractoriness in ongoing GVHD; however, endothelial vulnerability does not predict incidence of GVHD.

Loss of endothelial thrombomodulin predicts response to steroid therapy and survival in acute intestinal graft-versus-host disease

Steroid-refractory graft-versus-host disease causes significant morbidity and mortality after allogeneic stem cell transplantation. The pathomechanism of steroid resistance is currently not understood, but it has been suggested that endothelial cell dysfunction plays a role. Endothelial thrombomodulin was quantified along with histological markers of epithelial damage and cytotoxic T cells in colon biopsies from 51 allografted patients, and retrospectively correlated with response to steroids and survival. Loss of endothelial thrombomodulin was the strongest predictor of response to steroids (P=0.02) and nonrelapse mortality (P=0.01) in multivariate analyses adjusting for T-cell infiltrates, histological grading, vessel density, disease status, donor type, and conditioning therapy. Our data provide evidence that at disease onset, loss of endothelial thrombomodulin expression rather than excessive T-cell infiltration associates with steroid-refractory graft-versus-host disease and mortality. Prospective histological investigations are now warranted to improve diagnosis and prognostication of this core complication of stem cell transplantation.

Fecal calprotectin and alpha-1 antitrypsin predict severity and response to corticosteroids in gastrointestinal graft-versus-host disease

Diagnosis of gastrointestinal GVHD (GI-GVHD) is based on clinical symptoms and histologic findings. No biomarkers predicting responses to treatment are routinely available even though 30% to 50% of patients will not respond to corticosteroids. In this study, we aimed to evaluate fecal calprotectin, α-1-antitrypsin (α(1)-AT), and elastase at the time of first symptoms as diagnostic and prognostic tools for GI-GVHD in 72 consecutive patients, of whom 51 developed GI-GVHD. The prognostic value of markers was evaluated by their association with complete response (CR) and steroid-resistant (SR) GVHD. Calprotectin and α(1)-AT concentrations increased with GI-GVHD initial stages but patients with initial stage 1 GI-GVHD had similar marker levels to patients without GI-GVHD, so sensitivity to diagnose GI-GVHD was weak. In contrast, calprotectin and α(1)-AT were predictors for SR-GVHD and CR. Multiple regression modeling identified calprotectin and α(1)-AT concentration as independently predicting SR-GVHD together with initial stage > 2 GI-GVHD. Our results showed that fecal calprotectin and α(1)-AT levels at the time of diagnosis are predictive for responses to treatment but are not diagnostic markers for initial stage 1 to 3 GI-GVHD.

Defibrotide for prophylaxis of hepatic veno-occlusive disease in paediatric haemopoietic stem-cell transplantation: an open-label, phase 3, randomised controlled trial

BACKGROUND

Hepatic veno-occlusive disease is a leading cause of morbidity and mortality after haemopoietic stem-cell transplantation (HSCT). We aimed to assess whether defibrotide can reduce the incidence of veno-occlusive disease in this setting.

METHODS

In our phase 3 open-label, randomised controlled trial, we enrolled patients at 28 European university hospitals or academic medical centres. Eligible patients were younger than 18 years, had undergone myeloablative conditioning before allogeneic or autologous HSCT, and had one or more risk factor for veno-occlusive disease based on modified Seattle criteria. We centrally assigned eligible participants on the basis of a computer-generated randomisation sequence (1:1), stratified by centre and presence of osteopetrosis, to receive intravenous defibrotide prophylaxis (treatment group) or not (control group). The primary endpoint was incidence of veno-occlusive disease by 30 days after HSCT, adjudicated by a masked, independent review committee, in eligible patients who consented to randomisation (intention-to-treat population), and was assessed with a competing risk approach. Patients in either group who developed veno-occlusive disease received defibrotide for treatment. We assessed adverse events to 180 days after HSCT in all patients who received allocated prophylaxis. This trial is registered with ClinicalTrials.gov, number NCT00272948.

FINDINGS

Between Jan 25, 2006, and Jan 29, 2009, we enrolled 356 eligible patients to the intention-to-treat population. 22 (12%) of 180 patients randomly allocated to the defibrotide group had veno-occlusive disease by 30 days after HSCT compared with 35 (20%) of 176 controls (risk difference -7·7%, 95% CI -15·3 to -0·1; Z test for competing risk analysis p=0·0488; log-rank test p=0·0507). 154 (87%) of 177 patients in the defibrotide group had adverse events by day 180 compared with 155 (88%) of 176 controls.

INTERPRETATION

Defibrotide prophylaxis seems to reduce incidence of veno-occlusive disease and is well tolerated. Thus, such prophylaxis could present a useful clinical option for this serious complication of HSCT.

FUNDING

Gentium SpA, European Group for Blood and Marrow Transplantation.

Regenerating islet-derived 3-alpha is a biomarker of gastrointestinal graft-versus-host disease

There are no plasma biomarkers specific for GVHD of the gastrointestinal (GI) tract, the GVHD target organ most associated with nonrelapse mortality (NRM) following hematopoietic cell transplantation (HCT). Using an unbiased, large-scale, quantitative proteomic discovery approach to identify candidate biomarkers that were increased in plasma from HCT patients with GI GVHD, 74 proteins were increased at least 2-fold; 5 were of GI origin. We validated the lead candidate, REG3α, by ELISA in samples from 1014 HCT patients from 3 transplantation centers. Plasma REG3α concentrations were 3-fold higher in patients at GI GVHD onset than in all other patients and correlated most closely with lower GI GVHD. REG3α concentrations at GVHD onset predicted response to therapy at 4 weeks, 1-year NRM, and 1-year survival (P ≤ .001). In a multivariate analysis, advanced clinical stage, severe histologic damage, and high REG3α concentrations at GVHD diagnosis independently predicted 1-year NRM, which progressively increased with higher numbers of onset risk factors present: 25% for patients with 0 risk factors to 86% with 3 risk factors present (P < .001). REG3α is a plasma biomarker of GI GVHD that can be combined with clinical stage and histologic grade to improve risk stratification of patients.

Increased numbers of circulating ECs are associated with systemic GVHD

INTRODUCTION

Circulating endothelial cells (ECs) are known to reflect endothelial injury, and endothelial injury is associated with graft-versus-host disease (GVHD). We hypothesised that circulating ECs might be associated with systemic acute graft-versus-host disease (aGVHD).

METHODS

BALB/c (H-2k(d) ) mice were treated with total body irradiation and then infused with C57B/6-derived T-cell-depleted bone marrow (TCD-BM) cells or TCD-BM cells and splenocytes. Cyclosporine was used to prevent aGVHD. Circulating ECs and allogeneic lymphocytes were analysed by flow cytometry at multiple time points. The morphology and ultrastructure of the endothelium were examined by light microscopy or transmission electron microscopy.

RESULTS

The results indicated that the number of circulating ECs peaked at day 5 after lethal irradiation in all mice; allogenic transplanted mice (TCD-BM cells and splenocytes) developed typical aGVHD beginning at day 7, exhibiting both histological and clinical symptoms of disease. Circulating ECs peaked a second time at day 9 with aGVHD progression. However, following the administration of CSA, an absence of or a reduction in the amount of subsequent endothelial injury was observed.

CONCLUSION

Circulating ECs might be associated with systemic aGVHD.

The importance of neovascularization and its inhibition for allogeneic hematopoietic stem cell transplantation

GVHD and tumor relapse are fundamental problems in allogeneic HSCT. Recent research has linked neovascularization to GVHD, tumor growth, and graft-versus-tumor (GVT) activity. Damage of the endothelium by the conditioning regimen provides the initiation stimulus for recruitment of donor-derived endothelial cells and their progenitors. During the early inflammatory phase of GVHD there is considerable neovascularization facilitating migration of inflammatory cells to target organs. In the course of GVHD, however, the vasculature itself becomes a target of alloreactive donor T cells. As a consequence, later stages of GVHD are characterized by fibrosis and rarefaction of blood vessels. Importantly, the inhibition of tumor-neovascularization by activated donor T cells that release antiangiogenic substances contributes to GVT and may be enhanced by pharmacologic inhibition of neovascularization. Furthermore, the therapeutic inhibition of neovascularization may improve immunotherapy for cancer by enhancing leukocyte infiltration in tumor tissue because of normalization of tumor vessels and stimulation of leukocyte-vessel wall interactions. These insights identify important mechanisms underlining the importance of neovascularization for allogeneic immune responses and move therapeutic approaches targeting neovascularization into the spotlight. This perspective covers current knowledge of the role of neovascularization during GVHD as well as GVT and its implications for HSCT.

Transmural penetration of intravenously applied microbubbles during contrast-enhanced ultrasound as a new diagnostic feature in patients with GVHD of the bowel

GVHD is a common complication in patients after allo-SCT. Early detection is important because early therapy may improve the outcome. We evaluated contrast-enhanced ultrasound (CEUS) in patients with GVHD to assess typical imaging features. CEUS was performed in nine patients with histologically proven GVHD. As a control four healthy volunteers and six patients with Crohn's disease (CD) were examined. We employed a high-resolution multi-frequency transducer (6-9 MHz) with contrast harmonic imaging. After the injection of 2.4 mL SonoVue (Bracco, Milan, Italy) intravenously data were acquired and stored digitally. Regions of interest were manually placed over the surrounding mesenteric fat, bowel wall and bowel lumen. Maximum signal increase of each compartment was calculated. Patients with CD and GVHD showed significant contrast uptake in the bowel wall. In contrast to CD patients and healthy volunteers, patients with GVHD showed transmural penetration of microbubbles into the bowel lumen. We assume that the damaged gut mucosal barrier in GVHD enables the microbubbles to penetrate through the bowel wall into the bowel lumen. The penetration of microbubbles into the bowel lumen may serve as a novel diagnostic feature for GVHD if confirmed in controlled clinical trials.

Effect of beta-blockers, Ca2+ antagonists, and benzodiazepines on bleeding incidence in patients with chemotherapy induced thrombocytopenia

Beta-1-adrenoreceptor antagonists, Ca(2+) antagonists, and benzodiazepines negatively affect platelet aggregation in vitro. Few data exists on whether platelet function in vivo is relevantly influenced by exposure to any these substances. We analysed in three cohorts of 100 patients each treated with allogeneic hematopoietic stem cell transplantation (HSCT), autologous HSCT, and intensive chemotherapy, respectively, whether treatment with these drugs was associated with an increased risk of bleeding. Cumulative incidences of bleeding in the three cohorts were 47 +/- 5% after allogeneic transplants, 30 +/- 5% after autologous transplant, and 46 +/- 5% after chemotherapy (p = 0.008). Exposure to beta-blockers (hazard ratio [HR] 0.71, p = 0.32), Ca(2+) antagonists (HR 0.90, p = 0.73), and benzodiazepines (HR 1.18, p = 0.29) did not significantly increase the risk of bleeding in any cohort. Instead, bleeding risk was determined by platelet count, presence of inflammation, azotemia, presence of graft-versus-host disease and treatment with low-molecular weight heparin. After correcting for these factors, no differences in bleeding risk were seen between the three cohorts. In conclusion, therapy with Beta-1-adrenoreceptor antagonists, Ca(2+) antagonists, and benzodiazepines did not appear to significantly increase the risk for hemorrhagic complications in patients with iatrogenic severe thrombocytopenia.

Proteinase-activated receptor-1 mediates allogeneic CD8(+) T cell-induced apoptosis of vascular endothelial cells

Vascular endothelial-cells injury plays a pivotal role in the pathogenesis of graft-versus-host disease (GVHD) and transplant-associated endothelial injury syndrome. Vascular endothelial cells are an exposed target tissue for immune-mediated injury during GVHD. Early endothelial injury syndromes share common features with acute GVHD. Chronic GVHD leads to a rarefaction of microvessels caused by the infiltration of alloreactive cytotoxic T lymphocytes. In this context, allogeneic reactive cytotoxic T cell may contribute to apoptosis of vascular endothelial cells. The involvement of proteinase-activated receptor (PAR-1) in regulation of apoptosis has been recently recognized in many cell types. We hypothesized that apoptosis of vascular endothelial cells induced by allogeneic cytotoxic T cell are mediated via the PAR-1. Allogeneic CD8(+) T cell, PAR-1 agonist peptide (SFLLRN) induced apoptosis of human umbilical vein endothelial cells (HUVECs) and human dermal microvascular endothelial cells (HDMECs) as assessed by AnnexinV-FITC labeling. To ascertain the mechanism of endothelial apoptosis, we determined that allogeneic CD8(+) T cell, SFLLRN enhanced cleavage of caspase-3 and led to p38MAPK activation as assessed by Western blot. The effects of allogeneic CD8(+) T cell and SFLLRN on apoptosis of vascular endothelial cells were largely prevented by a cleavage-blocking anti-human PAR-1-antibody (ATAP2) and a specific inhibitor of p38MAPK. In concert, these observations provide strong evidence that allogeneic CD8(+) T cell induces apoptosis of human vascular endothelial cells through PAR-1-dependent modulation of intrinsic apoptotic pathway via alterations of p38MAPK and caspase-3.

Pathology of graft-versus-host disease in the gastrointestinal tract

Graft-versus-host disease (GVHD), a common complication of hematopoietic stem cell transplantation, is a clinical syndrome that requires synthesis of clinical, laboratory, and histopathologic findings for diagnosis. The gastrointestinal (GI) tract is commonly affected, and pathologists must recognize subtle morphologic alterations in GI mucosal biopsies to make the diagnosis and to rule out other causes of GI dysfunction such as cytomegalovirus infection and drug effects. This review summarizes the histopathologic features of GVHD in the GI tract and outlines recent recommendations for reporting of GI biopsies with suspected GVHD.

Clinicopathological manifestations and treatment of intestinal transplant-associated microangiopathy

Intestinal transplant-associated microangiopathy (i-TAM) is an important complication after allogeneic hematopoietic SCT. From 1997 to 2006, 87 of 886 patients with diarrhea after transplantation received colonoscopic biopsy. i-TAM, GVHD and CMV colitis were diagnosed histopathologically. The median duration from transplantation to the onset of diarrhea was 32 days (range: 9-130 days) and that from the onset of diarrhea to biopsy was 12 days (range: 0-74 days). The median maximal amount of diarrhea was 2 l/day (range: 130-5600 ml/day). Histopathological diagnosis included i-TAM (n=80), GVHD (n=26), CMV colitis (n=17) and nonspecific findings (n=2) with overlapping. Among 80 patients with i-TAM, abdominal pain was a major symptom, and only 11 patients fulfilled the proposed criteria for systemic TAM. Non-relapse mortality (NRM) among patients without resolution of diarrhea was 72% and i-TAM comprised 57% of NRM. NRM was 25% among patients without intensified immunosuppression, but was 52, 79 and 100% among those with intensified immunosuppression before diarrhea, after diarrhea, and before and after diarrhea, respectively. In conclusion, i-TAM is a major complication presenting massive refractory diarrhea and abdominal pain, which causes NRM. Avoiding intensified immunosuppression that damages vascular endothelium until the resolution of i-TAM may improve transplant outcome.

Vascular endothelium and graft-versus-host disease

Vascular endothelial cells are an exposed target tissue for immune-mediated injury during graft-versus-host disease (GVHD). However, widespread endothelial death resulting in multi-organ failure similar to that in hyperacute solid-organ transplant rejection is not observed during GVHD. The rather mild endothelial injury seen in histological samples from affected skin biopsies contrasts with severe epithelial injury observed sometimes simultaneously. The elucidation of the mechanisms that influence endothelial susceptibility to immune-mediated injury would explain this paradox and may help to separate GVHD from the beneficial graft-versus-leukaemia effect. Transplant-associated microangiopathy, veno-occlusive disease and accelerated arteriosclerosis are vascular injury syndromes that occur after allogeneic stem-cell transplantation. Biomarkers are needed to identify individuals at risk of developing these complications. Treatments that have been found to be particularly effective for these specific endothelial injury syndromes need to be tested in larger clinical trials.

Evaluation of angiopoietins and cell-derived microparticles after stem cell transplantation

Although stem cell transplantation (SCT) is being used for hematopoietic reconstitution following high-dose chemotherapy for malignancy, it involves certain serious transplant-related complications such as graft-versus-host disease (GVHD). Angiopoietins play important roles in angiogenesis. However, the role of angiopoietins after SCT is poorly understood. In this study, 52 patients underwent SCT; 26 patients received allogeneic SCT, while the remaining 26 received autologous SCT. In 48 of 52 patients, levels of angiopoietins, cytokines, and soluble factors were measured by enzyme-linked immunosorbent assay. Soluble Fas ligand (sFasL) and endothelial cell-derived microparticle (EDMP) exhibited significant elevation in the early phase (2-3 weeks) after SCT. In addition, the elevation of interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and sIL-2 receptor (sIL-2R), which are GVHD markers after allogeneic SCT was observed. The level of angiopoietin (Ang)-2 in allogeneic SCT continued to increase for up to 4 weeks, although the level of Ang-1 did not show significant changes. The patients with high Ang-2 exhibited significant increase of sFasL and EDMP compared with those with low Ang-2. In addition, the patients with high-grade GVHD exhibited a significant increase in Ang-2 compared to patients with low-grade GVHD. In the in vitro experiment using endothelial cells, the suppressive effect of Ang-1 on EDMP generation by TNF-alpha was partially inhibited by the addition of Ang-2. Furthermore, multivariate regression analysis showed that EDMP and sFasL were significant factors in Ang-2 elevation. Our results suggest that Ang-2 generation after allogeneic SCT relates to GVHD.

The pathology of scleroderma vascular disease

Systemic sclerosis is characterized by three distinct pathologic processes: fibrosis, cellular/humoral autoimmunity, and specific vascular changes. Although a mild vasculitis may sometimes be present, the vascular pathology of scleroderma is not necessarily inflammatory and is best characterized as a vasculopathy. In this article, the authors propose that SSc vasculopathy is the result of an early event involving vascular injury that eventuates in a vicious cycle mediated in part by the immune process. The subsequent vascular malformation and rarefaction may be a function of systemic angiogenic dysregulation, with over expression of vascular endothelial growth factor but a lack of proper interactions with smooth muscle cells needed to stabilize and organize blood vessels.

CD95 ligand-dependant endothelial cell death initiates oral mucosa damage in a murine model of acute graft versus host disease

Oral mucosa lesions are one of the common pathological consequences of acute graft versus host disease (aGVHD), the major complication of allogeneic bone marrow transplantation caused by mature T lymphocytes of donor origin. Oral mucosa damage in aGVHD is characterized by apoptosis induction in the basal keratinocytes, associated with immune effector T-cell infiltration, but its pathogenesis remains unclear because these lesions might result from the patient conditioning therapy that includes radiation and/or chemotherapy. Here, using a murine model of aGVHD that does not involve any conditioning treatment, we show that the earliest detectable oral mucosa lesion is apoptosis of the endothelial cells from chorion capillaries, which precedes basal keratinocyte apoptosis induction. Neither vascular damage nor epithelial-cell death occurred in recipients of allogeneic lymphocytes from CD95 ligand (CD95L)-defective mice. Our findings indicate that oral mucosa lesions in aGVHD are initiated by endothelial-cell death and require CD95L expression by the allogeneic lymphocytes. This early vascular damage may contribute to the induction of further tissue damage in the oral mucosa, through the induction of hypoxia and vascular leakage of immune cells or soluble proapoptotic mediators.

Donor-derived cells and human graft-versus-host disease of the skin

Graft-versus-host disease (GvHD)–induced apoptosis of the skin targets both epidermal keratinocytes and dermal endothelial cells. We studied the donor-versus-recipient origin of GvHD of these target cells in skin of 18 sex-mismatched hematopoietic stem-cell transplant (HSCT) recipients. Combining XY fluorescence in situ hybridization (FISH) and double immunostaining, and further 3D tissue Z-stack analysis, we found keratinocytes and endothelial cells of donor origin, but only in patients with GvHD. Using terminal dUTP nick-end labeling (TUNEL) assay on sister sections, we found a correlation between the numbers of chimeric and apoptotic epidermal and endothelial cells. Moreover, donor-derived cells were more numerous and preferentially distributed in the areas of severe GvHD damage in biopsies performed early in the course of GvHD, whereas they were less numerous and found in the whole epidermis in late biopsies. Because donor-derived cells were found at the site and at the time of maximum tissue damage, they could contribute to epidermal and microvessel repair.

Intestinal thrombotic microangiopathy following reduced-intensity umbilical cord blood transplantation

Thrombotic microangiopathy (TMA) is a significant complication after hematopoietic stem-cell transplantation (HSCT); however, there is little information on it following reduced-intensity cord blood transplantation (RI-CBT). We reviewed the medical records of 123 adult patients who received RI-CBT at Toranomon Hospital between January 2002 and August 2004. TMA was diagnosed in seven patients based on intestinal biopsy (n = 6) or autopsy results (n = 1). While these patients showed some clinical symptoms such as diarrhea and/or abdominal pain, mental status alterations or neurological disorders were not observed in any of them. Laboratory results were mostly normal at the onset of TMA; >2% fragmented erythrocytes (n = 1), <10 mg/dl haptoglobin (n = 1), and >200 IU/dl lactic dehydrogenase (LD) (n = 4). On endoscopic examination, TMA lesions, consisting of ulcers, erosions, and diffuse exfoliation, were distributed spottily from terminal ileum to rectum. Intestinal graft-versus-host disease (GVHD) and cytomegalovirus (CMV) colitis were confirmed in five and four patients, respectively. With therapeutic measures including supportive care (n = 4), fresh frozen plasma (n = 1), and a reduction of immunosuppressive agents (n = 1), TMA improved in four patients. The present study demonstrates that intestinal TMA is a significant complication after RI-CBT. Since conventional diagnostic criteria can overlook TMA, its diagnosis requires careful examination of the gastrointestinal tract using endoscopy with biopsy.

Vascular Endothelial Cells Have Impaired Capacity to Present Immunodominant, Antigenic Peptides: A Mechanism of Cell Type-Specific Immune Escape

Vascular endothelial cells (EC) are an exposed target tissue in the course of CTL-mediated alloimmune diseases such as graft-vs-host disease (GVHD) or solid organ transplant rejection. The outcome of an interaction between CTL and target cells is determined by the amount of Ag presented and the costimulatory signals delivered by the target cells. We compared human EC with leukocytes and epithelial cells as targets for peptide-specific, MHC class I-restricted CTL clones. EC were poor targets for immunodominant CTL. Both endogenously processed antigenic proteins and exogenously added antigenic peptides are presented at 50- to 5000-fold lower levels on EC compared with any other target cell analyzed. This quantitative difference fully explained the poor CTL-mediated killing of EC. There was no evidence that lack of costimulation would contribute significantly to this cell type-specific difference in CTL activation. An HLA-A2-specific CTL clone that killed a broad selection of HLA A2-positive target cells equally well, killed EC less efficiently. Our data suggest that EC present a different Ag repertoire compared with other cell types. By this mechanism, these cells may escape an attack by effector CTL, which have been educated by professional APCs and are specific for immunodominant antigenic peptides.