Vascular endothelial growth factor (VEGF) is associated with reduced severity of acute graft-versus-host disease and nonrelapse mortality after allogeneic stem cell transplantation

Unlocking protein-based biomarker potential for graft-versus-host disease following allogenic hematopoietic stem cell transplants

Despite the numerous advantages of allogeneic hematopoietic stem cell transplants (allo-HSCT), there exists a notable association with risks, particularly during the preconditioning period and predominantly post-intervention, exemplified by the occurrence of graft-versus-host disease (GVHD). Risk stratification prior to symptom manifestation, along with precise diagnosis and prognosis, relies heavily on clinical features. A critical imperative is the development of tools capable of early identification and effective management of patients undergoing allo-HSCT. A promising avenue in this pursuit is the utilization of proteomics-based biomarkers obtained from non-invasive biospecimens. This review comprehensively outlines the application of proteomics and proteomics-based biomarkers in GVHD patients. It delves into both single protein markers and protein panels, offering insights into their relevance in acute and chronic GVHD. Furthermore, the review provides a detailed examination of the site-specific involvement of GVHD. In summary, this article explores the potential of proteomics as a tool for timely and accurate intervention in the context of GVHD following allo-HSCT.

Acute graft-versus-host disease increase risk and accuracy in prediction model of transplantation-associated thrombotic microangiopathy in patients with myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation is the only curative therapy for patients with myelodysplastic syndrome. Transplantation-associated thrombotic microangiopathy (TA-TMA) remains a cause of death after transplantation. This study assessed the risk factors of TA-TMA and established a prediction model for this complication. We launched a real-world study from 303 MDS patients after allo-HSCT from Dec 1, 2007, to Jun 1, 2018. Logistic regression was used to analyze risk factors and to establish a nomogram. The accuracy of the model was assessed by C-index and calibration curve. TA-TMA class was associated with an over twofold increase in the risk of death (HR 2.66, 95% CI 1.39-5.09, p = 0.003). Stage III or IV acute graft-versus-host disease (aGVHD) (OR: 6.17, 95% CI: 2.19-17.18, p < 0.001) and occurrence time of aGVHD were the risk factors for TA-TMA. Next, we put these two variants and the other three variants into the prediction model via multivariate Lasso regression. In order to quantify the contribution of each factor, a nomogram was generated and displayed (C index of 0.783). TA-TMA predicts worsened outcomes of overall survival. A cross-validated multivariate score including aGVHD occurrence showed excellent concordance and efficacy of predicting TA-TMA in HSCT patients.

Kidney Disease Following Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (SCT) provides a curative option for the treatment of several malignancies. Its growing use is associated with an increased burden of kidney disease. Acute kidney injury is usually seen within the first 100 days of transplantation and has an incidence ranging between 12 and 73%, with the highest rate in myeloablative allogeneic SCT. A large subset of patients after SCT develop chronic kidney disease. They can be broadly classified into thrombotic microangiopathy, nephrotic syndrome, and calcineurin toxicity. Dialysis requirement after SCT is associated with mortality exceeding 80%. Given the higher morbidity and mortality related to development kidney disease, nephrologists need to be aware of the various causes and best treatment options.

Association of Pre-Transplant Angiopoietin-2 Index with the Risk of Acute Graft versus Host Disease After Hematopoietic Stem Cell Transplantation

Objective:

Angiogenic factors (AFs) released under endothelial stress are reflective of tissue healing, while some may also contribute to tissue damage/inflammation. We investigated whether alterations in the pre-transplant levels of AFs were associated with the risk of acute graft-versus-host disease (aGvHD).

Materials and Methods:

The pre-conditioning plasma levels of angiopoietin-2 (Ang2), endoglin, and follistatin were measured for 37 patients together with inflammatory markers. The index values defined were evaluated to better identify the alterations.

Results:

The patients had higher pre-conditioning levels of Ang2, endoglin, and follistatin compared to controls. The patients with aGvHD had higher Ang2 index and lower albumin index scores in comparison to those without aGvHD. Multivariate analysis revealed that the pre-transplant Ang2 index was an independent risk factor for aGvHD development.

Conclusion:

Pre-transplant evaluation of plasma Ang2 levels along with inflammatory status even before conditioning is associated with endothelial vulnerability. The pre-transplant Ang2 index could be a promising candidate to estimate the risk of aGvHD.

Role of ex vivo Expanded Mesenchymal Stromal Cells in Determining Hematopoietic Stem Cell Transplantation Outcome

Overall, the human organism requires the production of ∼1 trillion new blood cells per day. Such goal is achieved via hematopoiesis occurring within the bone marrow (BM) under the tight regulation of hematopoietic stem and progenitor cell (HSPC) homeostasis made by the BM microenvironment. The BM niche is defined by the close interactions of HSPCs and non-hematopoietic cells of different origin, which control the maintenance of HSPCs and orchestrate hematopoiesis in response to the body’s requirements. The activity of the BM niche is regulated by specific signaling pathways in physiological conditions and in case of stress, including the one induced by the HSPC transplantation (HSCT) procedures. HSCT is the curative option for several hematological and non-hematological diseases, despite being associated with early and late complications, mainly due to a low level of HSPC engraftment, impaired hematopoietic recovery, immune-mediated graft rejection, and graft-versus-host disease (GvHD) in case of allogenic transplant. Mesenchymal stromal cells (MSCs) are key elements of the BM niche, regulating HSPC homeostasis by direct contact and secreting several paracrine factors. In this review, we will explore the several mechanisms through which MSCs impact on the supportive activity of the BM niche and regulate HSPC homeostasis. We will further discuss how the growing understanding of such mechanisms have impacted, under a clinical point of view, on the transplantation field. In more recent years, these results have instructed the design of clinical trials to ameliorate the outcome of HSCT, especially in the allogenic setting, and when low doses of HSPCs were available for transplantation.

Cytokine levels following allogeneic hematopoietic cell transplantation: a match-pair analysis of home care versus hospital care

Following allogeneic hematopoietic cell transplantation (HCT), patients living near the hospital were treated at home instead of in isolation in the hospital. We analyzed cytokines using Luminex assays for the first 3 weeks after HCT and compared patients treated at home (n = 42) with matched patients isolated in the hospital (n = 37). In the multivariate analysis, patients treated at home had decreased GM-CSF, IFN-γ (p < 0.01), IL-13, IL-5 (p < 0.05), and IL-2 (p < 0.07). Bloodstream infections, anti-thymocyte globulin, G-CSF treatment, immunosuppression, reduced-intensity conditioning (RIC), related vs. unrelated donors, and graft source affected various cytokine levels. When patients with RIC were analyzed separately, home care patients had reduced G-CSF (p = 0.04) and increased vascular endothelial growth factor (VEGF, p = 0.001) at 3 weeks compared with hospital care patients. Patients with low GM-CSF (p < 0.036) and low IFNγ (p = 0.07) had improved survival. Acute GVHD grades III-IV was seen in 7% and 16% of home care and hospital care patients, respectively. One-year transplantation-related mortality was 7% and 16% and survival at 5 years was 69% and 57% in the two groups, respectively. To conclude, patients treated in the hospital showed varying increased levels of GM-CSF, IFN-γ, IL-13, G-CSF, IL-5, and IL-2 and decreased VEGF, which may contribute to acute GVHD.

Follistatin and Soluble Endoglin Predict 1-Year Nonrelapse Mortality after Allogeneic Hematopoietic Cell Transplantation

Damage-associated angiogenic factors (AFs), including follistatin (FS) and soluble endoglin (sEng), are elevated in circulation at the onset of acute graft-versus-host disease (GVHD). We hypothesized that regimen-related tissue injury also might be associated with aberrant AF levels and sought to determine the relevance of these AF on nonrelapse mortality (NRM) in patients with acute GVHD and those without acute GVHD. To test our hypothesis, we analyzed circulating levels of FS, sEng, angiopoietin-2 (Ang2), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) A and B, placental growth factor (PlGF), and soluble VEGF receptor (sVEGFR)-1 and -2, in plasma samples from patients enrolled on Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 0402 (n = 221), which tested GVHD prophylaxis after myeloablative hematopoietic stem cell transplantation (HCT). We found that the interaction between FS and sEng had an additive effect in their association with 1-year NRM. In multivariate analysis, patients with the highest levels of day +28 FS and sEng had a 14.9-fold greater hazard ratio (HR) of NRM (95% confidence interval, 3.2 to 69.4; P < .01) when compared with low levels of FS and sEng. We validated these findings using an external cohort of patients (n = 106). Pre-HCT measurements of FS and sEng were not associated with NRM, suggesting that elevations in these factors early post-HCT may be consequences of early regimen-related toxicity. Determining the mechanisms responsible for patient-specific vulnerability to treatment toxicities and endothelial damage associated with specific AF elevation may guide interventions to reduce NRM post-HCT.

Bilateral Multiple Serous Retinal Detachments Following Bone Marrow Transplantation

Purpose:

To describe a case of bilateral multiple serous retinal detachments (SRD) following bone marrow transplantation (BMT), which showed bilateral response to a single unilateral intravitreal bevacizumab injection.

Case Report:

A 37-year-old man with acute myelogenous leukemia who had received bone marrow transplantation four months prior was referred to our clinic with the chief complaint of gradually decreasing vision in both eyes for three months. During the funduscopic examination, multiple serous retinal detachments (SRD) were observed bilaterally, and he was diagnosed with multiple foci of central serous chorioretinopathy (CSCR). He was advised to discontinue the steroid dosage, which did not make significant improvement, and he was treated with intravitreal bevacizumab injection in the more severely affected eye. One month later, significant improvement was noticed in both eyes.

Conclusion:

Serous retinal detachment is a rare complication following BMT. Significant bilateral improvement after single unilateral intravitreal bevacizumab injection shows not only the possible role of increased level of vascular endothelial growth factor (VEGF) in this case, but also the systemic diffusion of the drug and effect on the contralateral eye following unilateral injection.

Emerging Concepts in Hematopoietic Stem Cell Transplantation-Associated Renal Thrombotic Microangiopathy and Prospects for New Treatments

Thrombotic microangiopathy associated with hematopoietic stem cell transplantation (HSCT-TMA) is a well-recognized complication of HSCT that has a high risk for death. Even in patients who survive, HSCT-TMA is associated with long-term morbidity and chronic organ injury. HSCT-TMA is a multisystem disease that often affects the kidneys. Renal manifestations of HSCT-TMA include reduced glomerular filtration rate, proteinuria, and hypertension. Understanding of the pathophysiology of HSCT-TMA has expanded in the last decade. Endothelial injury plays a major role. Recent studies also suggest involvement of complement activation. HSCT-TMA has also been considered by some to be an endothelial variant of graft-versus-host disease. Understanding the pathophysiology of HSCT-TMA and its association with activation of the complement system may aid in developing novel therapeutic options. In this review, we summarize current knowledge focusing on epidemiology and prognosis, evidence of complement activation, and endothelial injury; the possible link to graft-versus-host disease; and treatment options for HSCT-TMA.

Bone marrow VEGFC expression is associated with multilineage dysplasia and several prognostic markers in adult acute myeloid leukemia, but not with survival

Vascular endothelial growth factor C (VEGFC) stimulates leukemia cell proliferation and survival, and promotes angiogenesis. We studied VEGFC expression in bone marrow samples from 353 adult acute myeloid leukemia (AML) patients and its relationship with several clinical, cytogenetic, and molecular variables. We also studied the expression of 84 genes involved in VEGF signaling in 24 patients. We found that VEGFC expression was higher in AML patients with myelodysplasia-related changes (AML-MRC) than in patients with non-AML-MRC. We also found an association between VEGFC expression and the patient cytogenetic risk group, with those with a worse prognosis having higher VEGFC expression levels. No correlation was observed between VEGFC expression and survival or complete remission. VEGFC expression strongly correlated with expression of the VEGF receptors FLT1, KDR, and NRP1. Thus, in this series, VEGFC expression was increased in AML-MRC and in subgroups with a poorer prognosis, but has no impact on survival.

VEGF, ANGPT1, ANGPT2, and MMP-9 expression in the autologous hematopoietic stem cell transplantation and its impact on the time to engraftment

As a site of complicated interactions among cytokines, bone marrow niche has been the subject of many scientific studies, mainly in the context of the proteins influencing damage or recovery of endothelium after allogeneic hematopoietic stem cell transplantation (HSCT). In this study, we aimed at exploring mutual correlations of bone marrow niche cytokines involved in the homing and mobilization of hematopoietic stem cells, as well as in angiogenesis. The aim of our study was to evaluate levels of cytokines: VEGF, angiopoietin-1 (ANGPT1), angiopoietin-2 (ANGPT2), and matrix metalloproteinase 9 (MMP-9) during autologous HSCT and to examine their influence on hematological recovery. Forty-three patients with hematological malignancies (33 multiple myeloma, 10 lymphoma) were enrolled in the study. Plasma samples were taken at five time points: before conditioning treatment (BC), on transplantation day (0) and 7 (+7), 14 (+14), and 21 (+21) days after HSCT. The cytokine levels were evaluated by ELISA method. Our study revealed decreased levels of VEGF, ANGPT1, and MMP-9 in the early post-transplant period as compared to the baseline (BC). ANGPT2 was decreased after conditioning treatment, but tended to increase from day +7. On day +7, positive correlations between ANGPT1 level as well as MMP-9 and the time to engraftment were observed. As opposite to ANGPT1, negative correlation between ANGPT2 level on day +7 after HSCT and the time to hematological recovery was noticed. Our study suggests that investigated cytokines are an important part of bone marrow environment and significantly influence the time to engraftment after HSCT.

Initiation of acute graft-versus-host disease by angiogenesis

The inhibition of inflammation-associated angiogenesis ameliorates inflammatory diseases by reducing the recruitment of tissue-infiltrating leukocytes. However, it is not known if angiogenesis has an active role during the initiation of inflammation or if it is merely a secondary effect occurring in response to stimuli by tissue-infiltrating leukocytes. Here, we show that angiogenesis precedes leukocyte infiltration in experimental models of inflammatory bowel disease and acute graft-versus-host disease (GVHD). We found that angiogenesis occurred as early as day+2 after allogeneic transplantation mainly in GVHD typical target organs skin, liver, and intestines, whereas no angiogenic changes appeared due to conditioning or syngeneic transplantation. The initiation phase of angiogenesis was not associated with classical endothelial cell (EC) activation signs, such as Vegfa/VEGFR1+2 upregulation or increased adhesion molecule expression. During early GVHD at day+2, we found significant metabolic and cytoskeleton changes in target organ ECs in gene array and proteomic analyses. These modifications have significant functional consequences as indicated by profoundly higher deformation in real-time deformability cytometry. Our results demonstrate that metabolic changes trigger alterations in cell mechanics, leading to enhanced migratory and proliferative potential of ECs during the initiation of inflammation. Our study adds evidence to the hypothesis that angiogenesis is involved in the initiation of tissue inflammation during GVHD.

Angiogenic Factors Correlate with T Cell Immune Reconstitution and Clinical Outcomes after Double-Unit Umbilical Cord Blood Transplantation in Adults

Umbilical cord blood (UCB) is a valuable graft source for allogeneic hematopoietic stem cell transplantation (HSCT) in patients who lack adult donors. UCB transplantation (UCBT) in adults results in delayed immune reconstitution, leading to high infection-related morbidity and mortality. Angiogenic factors and markers of endothelial dysfunction have biologic and prognostic significance in conventional HSCT, but their role in UCBT has not been investigated. Furthermore, the interplay between angiogenesis and immune reconstitution has not been studied. Here we examined whether angiogenic cytokines, angiopoietin-1 (ANG-1) and vascular endothelial growth factor (VEGF), or markers of endothelial injury, thrombomodulin (TM) and angiopoietin-2 (ANG-2), associate with thymic regeneration as determined by T cell receptor excision circle (TREC) values and recovery of T cell subsets, as well as clinical outcomes in adult recipients of UCBT. We found that plasma levels of ANG-1 significantly correlated with the reconstitution of naive CD4+CD45RA+ and CD8+CD45RA+ T cell subsets, whereas plasma levels of VEGF displayed a positive correlation with CD4+CD45RO+ T cells and regulatory T cells and a weak correlation with TRECs. Assessment of TM and ANG-2 revealed a strong inverse correlation of both factors with naive T cells and TRECs. The angiogenic capacity of each patient's plasma, as determined by an in vitro angiogenesis assay, positively correlated with VEGF levels and with reconstitution of CD4+ T cell subsets. Higher VEGF levels were associated with worse progression-free survival and higher risk of relapse, whereas higher levels of TM were associated with chronic graft-versus-host disease and nonrelapse mortality. Thus, angiogenic factors may serve as valuable markers associated with T cell reconstitution and clinical outcomes after UCBT.

Acute Kidney Injury in Hematopoietic Stem Cell Transplantation: A Review

Hematopoietic stem cell transplantation (HSCT) is a highly effective treatment strategy for lymphoproliferative disorders and bone marrow failure states including aplastic anemia and thalassemia. However, its use has been limited by the increased treatment related complications, including acute kidney injury (AKI) with an incidence ranging from 20% to 73%. AKI after HSCT has been associated with an increased risk of mortality. The incidence of AKI reported in recipients of myeloablative allogeneic transplant is considerably higher in comparison to other subclasses mainly due to use of cyclosporine and development of graft-versus-host disease (GVHD) in allogeneic groups. Acute GVHD is by itself a major independent risk factor for the development of AKI in HSCT recipients. The other major risk factors are sepsis, nephrotoxic medications (amphotericin B, acyclovir, aminoglycosides, and cyclosporine), hepatic sinusoidal obstruction syndrome (SOS), thrombotic microangiopathy (TMA), marrow infusion toxicity, and tumor lysis syndrome. The mainstay of management of AKI in these patients is avoidance of risk factors contributing to AKI, including use of reduced intensity-conditioning regimen, close monitoring of nephrotoxic medications, and use of alternative antifungals for prophylaxis against infection. Also, early identification and effective management of sepsis, tumor lysis syndrome, marrow infusion toxicity, and hepatic SOS help in reducing the incidence of AKI in HSCT recipients.

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.

Circulating angiogenic factors associated with response and survival in patients with acute graft-versus-host disease: results from Blood and Marrow Transplant Clinical Trials Network 0302 and 0802

Circulating angiogenic factors (AF) reflect tissue healing capacity, although some AF can also contribute to inflammation and are indicative of endothelial dysfunction. The AF milieu in acute graft-versus-host disease (aGVHD) has not been broadly characterized. We hypothesized that patients with abundant AF involved in repair/regeneration versus those mediating damage/inflammation would have improved outcomes. Circulating AF known predominantly for repair/regeneration (epidermal growth factor [EGF], fibroblast growth factor-1 and -2, heparin binding-EGF-like growth factor, and vascular endothelial growth factor-A [VEGF-A], -C, and -D) and for damage/inflammation (angiopoietin-2, endothelin-1, soluble endoglin [sEng], follistatin [FS], leptin, and placental growth factor [PlGF]) were measured in a discovery set of hematopoietic cell recipients with grade III and IV aGVHD and compared with controls, then validated in 2 aGVHD cohorts enrolled in Blood and Marrow Transplant Clinical Trials Network (BMT CTN) trials 0302 (n = 105, serum) and 0802 (n = 158, plasma) versus controls without aGVHD (n = 53, serum). Levels of EGF and VEGF-A were lower than in controls at the onset of aGVHD in both trials and higher with complete response to first-line aGVHD therapy in CTN 0802. FS and PlGF were elevated in aGVHD measured in either serum or plasma. At day 28 after initial aGVHD therapy, elevated FS was an independent negative prognostic factor for survival in both cohorts (hazard ratio, 9.3 in CTN 0302; 2.8 in CTN 0802). These data suggest that circulating AF are associated with clinical outcomes after aGVHD and, thus, may contribute to both pathogenesis and recovery.

Circulating Levels of Adipokines Predict the Occurrence of Acute Graft-versus-host Disease

Currently, detecting biochemical differences before and after allogeneic stem cell transplantation (SCT) for improved prediction of acute graft-versus-host disease (aGVHD) is a major clinical challenge. In this pilot study, we analyzed the kinetics of circulating adipokine levels in patients with or without aGVHD before and after allogeneic SCT. Serum samples were obtained and stored at -80℃ within 3 hours after collection, prior to conditioning and at engraftment after transplantation. A protein array system was used to measure the levels of 7 adipokines of patients with aGVHD (n=20) and without aGVHD (n=20). The resistin level at engraftment was significantly increased (p<0.001) after transplantation, regardless of aGVHD occurrence. In the non-aGVHD group, the concentrations of the hepatocyte growth factor (HGF) (mean values±SD; 206.6±34.3 vs. 432.3±108.9 pg/ml, p=0.040) and angiopoietin-2 (ANG-2) (mean values±SD; 3,197.2±328.3 vs. 4,471.8±568.4 pg/ml, p=0.037) at engraftment were significantly higher than those of the pre-transplant period, whereas in the aGVHD group, the levels of adipokines did not change after transplantation. Our study suggests that changes in serum HGF and ANG-2 levels could be considered helpful markers for the subsequent occurrence of aGVHD.

Tuberculosis before hematopoietic stem cell transplantation in patients with hematologic diseases: report of a single-center experience

Background

Few reports discuss the optimal management of patients diagnosed with tuberculosis (TB) before scheduled stem cell transplantation (SCT), who then proceed with transplantation.

Methods

We found 13 patients with TB before SCT (proven, n = 9; probable, n = 3; possible, n = 1) in the medical records of our institution.

Results

Most of the patients had pulmonary TB (n = 8; disseminated, n = 2; extrapulmonary, n = 3). Eight of 9 patients with proven disease had SCT after at least 100 days of anti-tuberculous medication, ranging from 103 to 450 days. None of those patients suffered TB-related events after SCT. However, 1 patient with proven pulmonary TB who underwent SCT after only 40 days of anti-tuberculous therapy subsequently died of TB meningitis. Patients with possible and probable disease had their transplants after 6–176 days of anti-tuberculous medication, and all were alive at the time of analysis. The entire duration of anti-tuberculous medication was 12 months in most cases. With a follow-up duration ranging from 0.7 to 87.5 months, 4 patients died, but TB was the cause of death in only 1 case.

Conclusion

In conclusion, for proven cases of TB, SCT after >100 days of anti-tuberculous medication is probably feasible and safe, in terms of TB control, in patients with various hematologic diseases.

Non-mitogenic form of acidic fibroblast growth factor protects against graft-versus-host disease without accelerating leukemia

Acid fibroblast growth factor (aFGF) has been shown to prevent epithelial damage under various conditions, suggesting its potential to inhibit GVHD. However, because aFGF receptors are expressed on tumor cells, it may possibly offset the graft-vs.-tumor (GVT) effects of allogeneic bone marrow transplantation (allo-BMT). Here, we addressed these questions in a B6→B6D2F1 allo-BMT model. Although aFGF administration attenuated GVHD in non-leukemic recipients, aFGF treatment markedly accelerated death in mice that received recipient-type tumor (P815) cells along with allo- or syngeneic-BMT. Similar protection against GVHD was achieved by administration of a non-mitogenic form of aFGF (naFGF). Importantly, GVT effects were fully preserved in naFGF-treated recipients. Furthermore, aFGF, but not naFGF, significantly enhanced P815 cell proliferation both in vitro and in vivo. Our data indicate that the tumor-promoting, but not GVHD-protecting, effect of aFGF largely depends on its mitogenic activity, and suggest that naFGF may provide a safer approach to inhibiting GVHD in patients with malignancies.

Dysfunction of bone marrow vascular niche in acute graft-versus-host disease after MHC-haploidentical bone marrow transplantation

Acute graft-versus-host disease (aGvHD) is the most common complication of allogeneic hematopoietic stem cell transplantation (HSCT), which is often accompanied by impaired hematopoietic reconstitution. Sinusoidal endothelial cells (SECs) constitute bone marrow (BM) vascular niche that plays an important role in supporting self-renewal capacity and maintaining the stability of HSC pool. Here we provide evidences that vascular niche is a target of aGvHD in a major histocompatibility complex (MHC)–haploidentical matched murine HSCT model. The results demonstrated that hematopoietic cells derived from GvHD mice had the capacity to reconstitute hematopoiesis in healthy recipient mice. However, hematopoietic cells from healthy donor mice failed to reconstitute hematopoiesis in GvHD recipient mice, indicating that the BM niche was impaired by aGvHD in this model. We further demonstrated that SECs were markedly reduced in the BM of aGvHD mice. High level of Fas and caspase-3 expression and high rate of apoptosis were identified in SECs, indicating that SECs were destroyed by aGvHD in this murine HSCT model. Furthermore, high Fas ligand expression on engrafted donor CD4⁺, but not CD8⁺ T cells, and high level MHC-II but not MHC-I expression on SECs, suggested that SECs apoptosis was mediated by CD4⁺ donor T cells through the Fas/FasL pathway.

Superior transplantation outcomes of 8/8-matched unrelated donors as well as matched siblings to autologous transplantation for acute myeloid leukemia with intermediate cytogenetics in first remission

OBJECTIVES

For patients with acute myeloid leukemia in first complete remission (AML CR1) lacking HLA-matched sibling donors (MSD), 8/8-matched unrelated donors (URD) are mostly used in cases with poor-risk features. For AML CR1 with intermediate cytogenetics, however, the benefit of 8/8-matched URD should be compared with non-allogeneic therapies as well as MSD.

METHODS

To address this issue, we assessed the transplantation outcomes of 8/8-matched URD (n = 54) compared with MSD (n = 145) or autologous transplantation (n = 89) for AML CR1 with intermediate cytogenetics.

RESULTS

In multivariate analyses, 8/8-matched URD had comparable 6-yr overall survival (OS, P = 0.997), disease-free survival (DFS, P = 0.951), and relapse (P = 0.672) to MSD, whereas 8/8-matched URD had a higher OS (P = 0.070) and DFS (P = 0.035) with lower relapse (P = 0.009) than autologous transplantation. No difference in non-relapse mortality was observed according to donor type. Notably, these equivalent or superior outcomes of 8/8-matched URD compared with MSD or autologous transplantation, respectively, were particularly evident in patients without poor-risk features (n = 200), such as older age, hyperleukocytosis at diagnosis, and myelodysplasia-related changes, who are not usual candidates for URD transplantation.

CONCLUSIONS

These results indicate that 8/8-matched URD are feasible next option in AML CR1 with intermediate cytogenetics, when lacking MSD, even in patients without poor-risk features.

GVHD after allogeneic haematopoietic SCT for AML: angiogenesis, vascular endothelial growth factor and VEGF receptor expression in the BM

There is increasing evidence suggesting that both angiogenesis and endothelial injury are involved in GVHD. To study the dynamics of angiogenesis, we examined 26 patients with AML who had undergone allogeneic haematopoietic SCT. All were in CR and had either acute GVHD (aGVHD) or chronic GVHD (cGVHD). We performed immunohistochemical studies of BM microvessel density (MVD) using Abs against vascular-endothelial (VE)-cadherin, CD34 and CD105, and expression of vascular endothelial growth factor (VEGF) and its receptors VEGFR-1 and VEGFR-2. At the time of diagnosis, the MVD in AML patients was higher than that in the normal controls, and the MVD decreased after induction chemotherapy. Patients with aGVHD had a significantly higher MVD than patients without aGVHD. Conversely, patients with cGVHD did not have a significantly different MVD. In previous aGVHD, we also found more VEGF+ megakaryocytes. XY FISH in sex-mismatched patients showed that the BM blood vessels consisted mainly of recipient endothelial cells. Taken together, these results suggest that new vessel formation and the VEGF/VEGFR system are involved in aGVHD.

Risk and prognostic factors for acute GVHD based on NIH consensus criteria

To investigate the risk factors for acute GVHD (aGVHD), based on NIH consensus criteria (NCC), we evaluated 775 patients who underwent allogeneic transplantation. Of them, 346 patients developed aGVHD by NCC, in whom we also analyzed factors affecting aGVHD-specific survival. The cumulative incidence of aGVHD was 44.7%, consisting of classic aGVHD (n=320) and late-onset (n=26). Multivariate analyses revealed that younger age (P=0.015), unrelated donors (P=0.004) and acute leukemia compared with other hematologic malignancies (P=0.005) were significant risk factors for aGVHD, whereas PBSCs showed no association (P=0.720). Multivariate analyses, with only aGVHD patients, revealed that late-onset aGVHD had superior aGVHD-specific survival to classic aGVHD (P=0.044), and identified the association of visceral organ involvement (P=0.002), severity of aGVHD at onset (P=0.035) and advanced disease status (P<0.001) with inferior aGVHD-specific survival. In conclusion, this study demonstrates the risk and prognostic factors for aGVHD by NCC with some differences with the previous reports that were based on old criteria. The difference in the risk factors according to different criteria will give insights about the pathophysiology of GVHD. The better prognosis of late-onset aGVHD than of classic aGVHD raises the necessity for prospective trials with a large cohort focusing on the onset time.

VEGF165 attenuates the Th17/Treg imbalance that exists when transplanting allogeneic skeletal myoblasts to treat acute myocardial infarction

OBJECTIVES

To investigate whether Th17/Treg imbalance exists, and whether VEGF(165) attenuates the imbalance in allogeneic skeletal myoblast transplantation (allo-SMT) for acute myocardial infarction (AMI).

METHODS

On days 1, 2, 4, and 7 after allo-SMT, the percentages and ratios of Th17 and Treg cells were analyzed by flow cytometry in three groups-the AMI group, the AMI-S group (allo-SMT) and the AMI-V group (with VEGF(165) treatment). Subsequently, related proinflammatory and regulatory cytokines and key transcription factors, ROR-γt mRNA and Foxp3 mRNA expression, were examined by Bio-plex and real-time polymerase chain reaction, respectively.

RESULTS

On days 1, 2, 4, and 7, the percentage of Tregs, related cytokine concentrations and transcript factor Foxp3 mRNA in the AMI-S group were lower than those in the AMI group, while those in the AMI-V group were higher than those in the AMI group. However, the percentage of Th17 cells, related cytokine concentrations and ROR-γt mRNA in the AMI-S group were higher than those in the AMI group; those in the AMI-V group were lower than those in the AMI group. Compared with the AMI group, the ratios of Th17/Treg cells significantly increased in the AMI-S group and decreased in the AMI-V group.

CONCLUSIONS

Th17/Treg imbalance participated in the formation and development of the inflammatory and immune response after allo-SMT. However, transfected VEGF(165) was able to relieve the severity of the Th17/Treg imbalance.

Graft-versus-tumor effect according to type of graft-versus-host disease defined by National Institutes of Health consensus criteria and associated outcomes

The impact of National Institutes of Health consensus criteria (NCC) graft-versus-host disease (GVHD) on survival has rarely been investigated in a large cohort of patients with GVHD presenting before and after day 100 posttransplantation. We retrospectively investigated 775 patients who underwent allogeneic stem cell transplantation and assessed the GVHD effects on survival by the time-dependent covariates in Cox proportional hazards regression models. Using the NCC, the patients were classified into 4 groups: (1) no GVHD (n = 251); (2) acute GVHD (aGVHD) only (n = 199), including 26 patients with late aGVHD; (3) classic chronic GVHD (cGVHD; n = 232); and (4) overlap syndrome (OS; n = 93). Multivariate analyses showed that classic cGVHD (hazard ratio [HR], 0.46; 95% confidence interval [CI], 0.27-0.77) and OS (HR, 0.52; 95% CI, 0.28-0.96) were associated with significantly decreased risk of relapse, whereas aGVHD only was not associated with relapse rate (HR, 1.11; 95% CI, 0.76-1.63). All aGVHD events, including the period of aGVHD in patients who developed cGVHD after aGVHD, also did not affect the risk of relapse (HR, 0.74; 95% CI, 0.49-1.12). All types of GVHD were significantly associated with higher nonrelapse mortality in common. Finally, patients with aGVHD only had significantly lower overall survival and disease-free survival compared with those without GVHD, in contrast to favorable survival outcomes in patients with cGVHD without previous aGVHD. This study demonstrates that NCC GVHD type is associated with different graft-versus-tumor effects. Further studies are needed to investigate risk factors, pathogenesis, and biomarkers for each type of NCC GVHD.

Blockade of Vascular Endothelial Growth Factor (VEGF) Aggravates the Severity of Acute Graft-versus-host Disease (GVHD) after Experimental Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT)

BACKGROUND

Recent clinical observation reported that there was a significant correlation between change in circulating vascular endothelial growth factor (VEGF) levels and the occurrence of severe acute graft-versus-host disease (GVHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT), but the action mechanisms of VEGF in GVHD have not been demonstrated.

METHODS

This study investigated whether or not blockade of VEGF has an effect on acute GVHD in a lethally irradiated murine allo-HSCT model of B6 (H-2(b))→B6D2F1 (H-2(b/d)). Syngeneic or allogeneic recipient mice were injected subcutaneously with anti-VEGF peptides, dRK6 (50 µg/dose) or control diluent every other day for 2 weeks (total 7 doses).

RESULTS

Administration of the dRK6 peptide after allo-HSCT significantly reduced survival with greaterclinical GVHD scores and body weight loss. Allogeneic recipients injected with the dRK6 peptide exhibited significantly increased circulating levels of VEGF and expansion of donor CD3(+) T cells on day +7 compared to control treated animals. The donor CD4(+) and CD8(+) T-cell subsets have differential expansion caused by the dRK6 injection. The circulating VEGF levels were reduced on day +14 regardless of blockade of VEGF.

CONCLUSION

Together these findings demonstrate that the allo-reactive responses after allo-HSCT are exaggerated by the blockade of VEGF. VEGF seems to be consumed during the progression of acute GVHD in this murine allo-HSCT model.

Late effects on haemostasis after haematopoietic stem cell transplantation

Allogeneic and autologous hematopoietic stem cell transplantations are important therapeutic options for patients with hematologic disorders. Hemostatic complications are frequent after hematopoietic stem cell transplantation with a considerable morbidity and mortality. The incidence of bleedings and thrombosis is highest in the first few weeks after transplantation, but may also occur later. However, beyond the first year of transplantation only limited data are available. In long-term survivors the risk for premature atherosclerosis increases over time after allogeneic hematopoietic stem cell transplantation and it is higher than in the age-adjusted general population and in recipients of autologous transplantation.

Survival benefits from reduced-intensity conditioning in allogeneic stem cell transplantation for young lower-risk MDS patients without significant comorbidities

OBJECTIVE

The aim of this study was to determine the optimum conditioning intensity for allogeneic stem cell transplantation (SCT) in young (age ≤50), lower-risk (INT-1 by IPSS) Myelodysplastic syndrome (MDS) patients without significant comorbidities (hematopoietic cell transplantation-comorbidity index score ≤3).

METHODS

Transplant outcomes from 46 consecutive patients were retrospectively analyzed according to the conditioning intensity: reduced-intensity conditioning (RIC; n = 14), intensified RIC by adding low-dose total body irradiation (iRIC; n = 15), and myeloablative conditioning (MAC; n = 17).

RESULTS

After a median follow-up of 73.7 months, RIC had a better 4-yr overall survival (OS) (92.9%) compared with the iRIC (64.2%) or MAC (70.6%). Multivariate analysis showed that RIC was associated with improved OS compared with the MAC [relative risk (RR) of 0.08, P = 0.022] because of a lower transplant-related mortality (TRM) (RR, 0.08, P = 0.035). iRIC failed to show survival benefits over the MAC (RR of 0.77, P = 0.689) because of similarly high TRM (RR of 0.41, P = 0.480). Cumulative incidence of acute and chronic graft-versus-host disease (GVHD) after RIC was higher, but GVHD-specific survival was significantly better (RIC 100% vs. iRIC 45.7% vs. MAC, P = 0.018). Relapse rate was not different among the three groups, but in the RIC group, azacitidine was available and useful for inducing remission in two patients.

CONCLUSION

This study shows that RIC improved OS by directly lowering TRM and indirectly giving an additional chance for relapsed MDS in the era of hypomethylating treatment. RIC-SCT should be considered for relative healthy lower-risk MDS patients.

Small vessels, big trouble in the kidneys and beyond: hematopoietic stem cell transplantation–associated thrombotic microangiopathy

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a challenging diagnosis after hematopoietic stem cell transplantation. Although endothelial injury represents the final common pathway of disease, the exact pathophysiology of TA-TMA remains unclear. Potential causes include infections, chemotherapy, radiation, and calcineurin inhibitors. Recent literature addresses the roles of cytokines, graft-versus-host disease, the coagulation cascade, and complement in the pathogenesis of TA-TMA. Current diagnostic criteria are unsatisfactory, because patients who have received a transplant can have multiple other reasons for the laboratory abnormalities currently used to diagnose TA-TMA. Moreover, our lack of understanding of the exact mechanism of disease limits the development and evaluation of potential treatments. Short- and long-term renal complications contribute to TA-TMA's overall poor prognosis. In light of these challenges, future research must validate novel markers of disease to aid in early diagnosis, guide current and future treatments, prevent long-term morbidity, and improve outcomes. We focus on TA-TMA as a distinct complication of hematopoietic stem cell transplantation, emphasizing the central role of the kidney in this disease.

Steroid-refractory GVHD: T-cell attack within a vulnerable endothelial system

Acute graft-versus-host disease (GVHD) is a major complication of allogeneic stem cell transplantation (SCT) and can be readily controlled by systemic high-dose steroids in many patients. However, patients whose GVHD is refractory to this therapy have a poor prognosis. Refractory patients have ongoing end-organ damage despite effective immunosuppression with second-line regimens, suggesting pathomechanisms independent from the initiating T-cell attack. To explore whether endothelial damage might contribute to GVHD refractoriness and to study the role of angiopoietin-2 (ANG2) in this process, we have compared kinetics of T-cell activation markers and markers of endothelial dysfunction in the serum of patients with sensitive (n = 23) and refractory GVHD (n = 25). Longitudinal measurements of soluble FAS ligand along with other immune markers demonstrate that refractory patients are not exposed to an overwhelming or unresponsive T-cell attack. However, in contrast to sensitive GVHD, refractory GVHD was associated with rising thrombomodulin levels and high ANG2/ vascular endothelial-derived growth factor ratios. Patients with refractory GVHD showed significantly increased ANG2 levels already before SCT. These results suggest that endothelial cell vulnerability and dysfunction, rather than refractory T-cell activity, drives treatment refractoriness of GVHD and opens new avenues for prediction and control of this devastating condition.

Reduced-intensity conditioning regimen combined with low-dose total body irradiation in the treatment of myelodysplastic syndrome

Although reduced-intensity conditioning (RIC) has been increasingly used in patients with myelodysplastic syndrome (MDS) to reduce transplant-related mortality, a high relapse rate in RIC remains an unresolved problem. Considering the additive antileukemic effect of low-dose total body irradiation (TBI), we evaluated the feasibility of combining RIC regimens with low-dose TBI in de novo MDS. The RIC regimen combined with low-dose TBI in this study consisted of fludarabine (150 mg/m(2)), intravenous busulfan (6.4 mg/kg), and TBI (400 cGy). Antithymocyte globulin was used to overcome HLA mismatching. A total of 31 subjects were recruited with a median age of 39 years (range 19-63). The patients received transplants from siblings (n = 20) or unrelated donors (n = 11). All patients rapidly achieved full-donor chimerism. At a median follow-up for survivors of 35 months (range 6.0-54.9), the 3-year overall survival, event-free survival, transplantation-related mortality, and relapse rates were 67.6, 63.2, 20.5 and 11.4%, respectively. The 3-year cumulative incidence of acute (grades II-IV) and chronic extensive graft-versus-host disease in patients who survived at least 100 days was 39.2 and 44.6%, respectively. These results suggest that an RIC combined with low-dose TBI may be a feasible therapeutic approach for treating de novo MDS.

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.

Validation of recently proposed consensus criteria for thrombotic microangiopathy after allogeneic hematopoietic stem-cell transplantation

BACKGROUND

The lack of an accepted definition of transplantation-associated thrombotic microangiopathy (TMA) has led the Blood and Marrow Transplants Clinical Trials Network (CTN) and International Working Group (IWG) to propose a definition for TMA with some differences. However, there have been few studies validating and comparing both newly proposed criteria for TMA.

METHODS

To validate recently proposed criteria for TMA by CTN and IWG, we analyzed 672 patients who underwent allogeneic stem-cell transplantation between January 2002 and December 2006.

RESULTS

The cumulative incidences of TMA by CTN and IWG were 6.1% and 2.5%, respectively. The cumulative incidence of overall TMA (O-TMA) including probable-TMA defined as meeting CTN criteria without renal or neurologic dysfunction, as well as TMA by CTN (definite-TMA), was 12.7%. Sixty-six percent of TMA by CTN did not have any degree of schistocytosis by IWG criteria (≥4%), and 18% of TMA by IWG criteria did not have renal or neurologic dysfunction. On multivariate analyses, probable-TMA as well as definite-TMA adversely affected the survival of a cohort including all patients. In patients with O-TMA, the degree of schistocytosis (≥4% or not) failed to show prognostic significance, whereas renal involvement was a significant prognostic factor associated with poor survival.

CONCLUSIONS

Both proposed consensus criteria have major pitfalls in their use as uniformly accepted diagnostic criteria for TMA. The use of O-TMA as a broad definition for TMA and the grading system by the presence of renal involvement may be a counterproposal for future trials.

The Outcome of Unrelated Hematopoietic Stem Cell Transplants with Total Body Irradiation (800 cGy) and Cyclophosphamide (120 mg/kg) in Adult Patients with Acquired Severe Aplastic Anemia

To verify the feasibility of 800 cGy of total body irradiation (TBI) with 120 mg/kg of cyclophosphamide (TBI-800/Cy-120) as a conditioning regimen for unrelated stem cell transplantation (u-SCT) in adult patients with severe aplastic anemia, we analyzed 50 consecutive patients who underwent u-SCT, including 26 patients from our previous pilot study. Seventeen patients received transplants from mismatched donors via high-resolution DNA typing (8 of 8). Thirty-eight patients received bone marrow and 12 peripheral blood stem cells (PBSCs). Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and short-course methotrexate. All patients achieved engraftment, and the median days of neutrophil and platelet recovery were 13 days and 20 days, respectively. The 5-year estimated overall survival was 88.0%. The cumulative incidences of acute grade II-IV GVHD (aGVHD) and chronic GVHD (cGVHD) were 46.0% and 50.3%, respectively. Only an HLA-mismatched donor was associated with the occurrence of aGVHD on multivariate analyses, whereas prior aGVHD and the use of PBSCs were associated with the occurrence of cGVHD on univariate analyses. In conclusion, the excellent outcomes of u-SCT with TBI-800/Cy-120 suggest that u-SCT may be applicable to patients with severe aplastic anemia even without prior treatment with immunosuppressive therapy, which will require testing in prospective trials in the future.

Inhibition of neovascularization to simultaneously ameliorate graft-vs-host disease and decrease tumor growth

BACKGROUND Blood vessels are formed either by sprouting of resident tissue endothelial cells (angiogenesis) or by recruitment of bone marrow (BM)-derived circulating endothelial progenitor cells (EPCs, vasculogenesis). Neovascularization has been implicated in tumor growth and inflammation, but its roles in graft-vs-host disease (GVHD) and in tumors after allogeneic BM transplantation (allo-BMT) were not known. METHODS We analyzed neovascularization, the contribution of endothelial cells and EPCs, and the ability of anti-vascular endothelial-cadherin antibody, E4G10, to inhibit neovascularization in mice with GVHD after allo-BMT using immunofluorescence microscopy and flow cytometry. We examined survival and clinical and histopathologic GVHD in mice (n = 10-25 per group) in which GVHD was treated with the E4G10 antibody using immunohistochemistry, flow cytometry, and cytokine immunoassay. We also assessed survival, the contribution of green fluorescent protein-marked EPCs to the tumor vasculature, and the ability of E4G10 to inhibit tumor growth in tumor-bearing mice (n = 20-33 per group) after allo-BMT using histopathology and bioluminescence imaging. All statistical tests were two-sided. RESULTS We found increased neovascularization mediated by vasculogenesis, as opposed to angiogenesis, in GVHD target tissues, such as liver and intestines. Administration of E4G10 inhibited neovascularization by donor BM-derived cells without affecting host vascularization, inhibited both GVHD and tumor growth, and increased survival (at 60 days post-BMT and tumor challenge with A20 lymphoma, the probability of survival was 0.29 for control antibody-treated allo-BMT recipients vs 0.7 for E4G10-treated allo-BMT recipients, 95% confidence interval = 0.180 to 0.640, P < .001). CONCLUSIONS Therapeutic targeting of neovascularization in allo-BMT recipients is a novel strategy to simultaneously ameliorate GVHD and inhibit posttransplant tumor growth, providing a new approach to improve the overall outcome of allogeneic hematopoietic stem cell transplantation.

HLA-matched sibling transplantation with BM and CD34(+)-purified PBSCs in adult patients with high-risk severe aplastic anemia to overcome graft rejection without an increase in GVHD

The transplantation of a large number of stem cells can overcome graft rejection but with the increased risk of GVHD. In this study, we analyzed the outcome of 32 adult patients with acquired severe aplastic anemia (SAA) who were at a high risk for graft rejection, including multiple transfusions (median 147 units, range 20-680) and long disease duration (median 67 months, range 3-347), and who had received both BM and CD34(+)-purified PBSCs from an HLA-matched sibling donor to reduce graft rejection. T cells in PBSCs were depleted using a magnetic-activated cell sorting method (CliniMACS system). Conditioning regimens consisted largely of CY and antithymocyte globulin (ATG) with fludarabine (FLU) or procarbazine (PCB). With a median follow-up of 89 months, the 8-year probability of survival was 87.5%. Neutrophils and plts promptly recovered, and none of the patients developed graft failure. The cumulative incidences of acute and chronic GVHD were 9.4 and 18.0%, respectively. Sustained engraftment and excellent survival without an apparent increase in the rate of GVHD in high-risk patients using the current approach showed that high-dose SCT with both BM and CD34(+)-purified PBSCs may yield better outcomes in heavily transfused and/or allo-immunized patients with SAA.

The contribution of endothelial activation and injury to end-organ toxicity following allogeneic hematopoietic stem cell transplantation

Over the last 25 years, allogeneic hematopoietic stem cell transplantation (HSCT) has been used increasingly as a curative treatment option for patients with hematologic and neoplastic diseases. Despite major advances in transplant immunology and improvements in supportive and critical care medicine, HSCT is still plagued by several life-threatening complications. As such, the establishment of effective therapeutic options for these complications will be crucial as increasing numbers of high-risk transplants are performed each year. This brief review will discuss the contribution of vascular endothelial cell activation and injury to inflammation and end-organ toxicity that occurs following allogeneic HSCT, and will highlight translational research efforts that have paved the way to the development of novel strategies to treat and prevent disease. Finally, we will discuss in detail the clinical manifestations and challenges encompassed by the syndrome of thrombotic microangiopathy following HSCT.

Renal thrombotic microangiopathy after hematopoietic cell transplant: role of GVHD in pathogenesis

BACKGROUND AND OBJECTIVES

Thrombotic microangiopathy (TMA) is a known complication of hematopoietic cell transplantation (HCT). The etiology and diagnosis of TMA in this patient population is often difficult because thrombocytopenia, microangiopathic hemolytic anemia, and kidney injury occur frequently in HCT recipients, and are the result of a variety of insults.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

The authors reviewed renal pathology and clinical data from HCT patients to determine the prevalence of TMA and to identify correlative factors for developing TMA in the kidney. Kidney tissue was evaluated from 314 consecutive autopsies on patients who died after their first HCT (received between 1992 and 1999). Renal pathology was classified into three groups: (1) no renal thrombus (65%), (2) TMA (20%), and (3) isolated thrombosis (15%). Logistic regression models estimated the associations between each histologic category and clinical parameters: donor and recipient gender, patient age, human leukocyte antigen (HLA) matching of the donor and recipient, total body irradiation (TBI), acute graft versus host disease (GVHD), acute kidney injury, medications, and viral infections.

RESULTS

In a multivariate analysis, TMA correlated with acute GVHD grades II to IV, followed by female recipient/male donor, TBI > 1200 cGy, and adenovirus infection. Grades II to IV acute GVHD and female gender were associated with isolated renal thrombus.

CONCLUSIONS

TMA in HCT recipients is associated with acute GVHD grades II to IV, recipient/donor mismatch, TBI > 1200 cGy, and adenovirus infection.

Feasibility of NIH consensus criteria for chronic graft-versus-host disease

To assess the applicability of the National Institutes of Health (NIH) consensus criteria (NCC) for chronic graft-versus-host disease (cGVHD), 211 patients who developed GVHD more than 100 days after allogeneic transplantation were reclassified using NCC. Classifications were: late acute GVHD (44 patients, 21%), overlap syndrome (64 patients, 30%) and classic cGVHD (103 patients, 49%). Classic cGVHD and overlap syndrome patients (n=167) were graded using both the revised Seattle criteria (RSC) and NIH global scoring (NGS). Twenty-three patients (14%) had mild, 81 (48%) had moderate and 63 (38%) had severe cGVHD. After a median follow-up of 46 months (range 5-71 months), the 4-year GVHD-specific survival was not significantly different among the different subtypes of NCC. Among patients with late acute GVHD, however, the pattern of acute GVHD onset (late, persistent or recurrent) was significantly different with respect to GVHD-specific survival. Among patients with overlap syndrome and classic cGVHD, multivariate analysis showed that NGS as well as RSC were useful in predicting survival and discontinuation of immunosuppressive therapy despite of more detailed grouping. Our study indicates that NCC is applicable. The clinical impact of NIH types and NGS should be verified through prospective studies.