Tumor necrosis factor-alpha neutralization reduces lung injury after experimental allogeneic bone marrow transplantation

Respiratory Failure Due to Idiopathic Pneumonia Syndrome in a Pediatric Patient After Recipient-derived Allogeneic Chimeric Antigen Receptor T-Cell Therapy

Idiopathic pneumonia syndrome (IPS) is a life-threatening complication of hematopoietic cell transplantation, but it is not clearly described following chimeric antigen receptor (CAR) T-cell therapy. We describe a child who developed IPS after receiving tisagenlecleucel for post-hematopoietic cell transplantation relapsed acute lymphoblastic leukemia and had a remarkable improvement after treatment with corticosteroids and etanercept. We discuss the implications of cytokine signaling in IPS and immunologic considerations of allogeneic CAR T cells. We anticipate that the incidence of IPS and other allogeneic phenomena will be observed more often as allogeneic CAR T cells are employed in more varied settings with more mismatched donors.

Defibrotide modulates pulmonary endothelial cell activation and protects against lung inflammation in pre-clinical models of LPS-induced lung injury and idiopathic pneumonia syndrome

Introduction

A multiple organ dysfunction syndrome (MODS) workshop convened by the National Institute of Child Health and Human Development in 2015 identified acute respiratory distress syndrome (ARDS) and complications of allogeneic blood and marrow transplantation (allo-BMT) as contributors to MODS in pediatric patients. Pulmonary dysfunction also remains a significant complication of allo-BMT. Idiopathic pneumonia syndrome (IPS) defines non-infectious, acute, lung injury that occurs post-transplant. Injury and activation to endothelial cells (ECs) contribute to each form of lung inflammation.

Methods

Two murine models were employed. In an ARDS model, naïve B6 mice receive an intravenous (i.v.) injection of lipopolysaccharide (LPS). In the established model of IPS, naïve B6D2F1 mice receive lethal total body irradiation followed by BMT from either allogeneic (B6) or syngeneic (B6D2F1) donors. Lung inflammation was subsequently assessed in each scenario.

Results

Intravenous injection of LPS to B6 mice resulted in enhanced mRNA expression of TNFα, IL-6, Ang-2, E-, and P-selectin in whole lung homogenates. The expression of Ang-2 in this context is regulated in part by TNFα. Additionally, EC activation was associated with increased total protein and cellularity in broncho-alveolar lavage fluid (BALF). Similar findings were noted during the development of experimental IPS. We hypothesized that interventions maintaining EC integrity would reduce the severity of ARDS and IPS. Defibrotide (DF) is FDA approved for the treatment of BMT patients with sinusoidal obstruction syndrome and renal or pulmonary dysfunction. DF stabilizes activated ECs and protect them from further injury. Intravenous administration of DF before and after LPS injection significantly reduced mRNA expression of TNFα, IL6, Ang-2, E-, and P-selectin compared to controls. BALF showed decreased cellularity, reflecting less EC damage and leak. Allogeneic BMT mice were treated from day -1 through day 14 with DF intraperitoneally, and lungs were harvested at 3 weeks. Compared to controls, DF treatment reduced mRNA expression of TNFα, IL6, Ang-2, E-, and P- selectin, BALF cellularity, and lung histopathology.

Conclusion

The administration of DF modulates EC injury in models of ARDS and IPS. Cytokine inhibition in combination with agents that stabilize EC integrity may be an attractive strategy for patients in each setting.

Noninfectious Pulmonary Complications after Hematopoietic Stem Cell Transplantation

Pulmonary complications after hematopoietic stem cell transplantation (HSCT) are important sources of morbidity and mortality. Improvements in infection-related complications have made noninfectious pulmonary complications an increasingly significant driver of transplantation-related mortality. Broadly, these complications can be characterized as either early or late complications, with idiopathic pneumonia syndrome and bronchiolitis obliterans syndrome the most prevalent early and late complications, respectively. Outcomes with historical treatment consisting mainly of corticosteroids are often poor, highlighting the need for a deeper understanding of these complications' underlying disease biology to guide the adoption of novel therapies that are being increasingly used in the modern era.

Mannan-Binding Lectin Promotes Murine Graft-versus-Host Disease by Amplifying Lipopolysaccharide-Initiated Inflammation

Conditioning regimens used for hematopoietic stem cell transplantation (HCT) can escalate the severity of acute T cell-mediated graft-versus-host disease (GVHD) by disrupting gastrointestinal integrity and initiating lipopolysaccharide (LPS)-dependent innate immune cell activation. Activation of the complement cascade has been associated with murine GVHD, and previous work has shown that alternative pathway complement activation can amplify T cell immunity. Whether and how mannan-binding lectin (MBL), a component of the complement system that binds mannose as well as oligosaccharide components of LPS and lipoteichoic acid, affects GVHD is unknown. In this study, we tested the hypothesis that MBL modulates murine GVHD and examined the mechanisms by which it does so. We adoptively transferred C3.SW bone marrow (BM) cells ± T cells into irradiated wild type (WT) or MBL-deficient C57Bl/6 (B6) recipients with or without inhibiting MBL-initiated complement activation using C1-esterase inhibitor (C1-INH). We analyzed the clinical severity of disease expression and analyzed intestinal gene and cell infiltration. In vitro studies assessed MBL expression on antigen-presenting cells (APCs) and compared LPS-induced responses of WT and MBL-deficient APCs. MBL-deficient recipients of donor BM ± T cells exhibited significantly less weight loss over the first 2 weeks post-transplantation weeks compared with B6 controls (P < .05), with similar donor engraftment in the 2 groups. In recipients of C3.SW BM + T cells, the clinical expression of GVHD was less severe (P < .05) and overall survival was better (P < .05) in MBL-deficient mice compared with WT mice. On day-7 post-transplantation, analyses showed that the MBL-deficient recipients exhibited less intestinal IL1b, IL17, and IL12 p40 gene expression (P < .05 for each) and fewer infiltrating intestinal CD11c+, CD11b+, and F4/80+ cells and TCRβ+, CD4+, CD4+IL17+, and CD8+ T cells (P < .05 for each). Ovalbumin or allogeneic cell immunizations induced equivalent T cell responses in MBL-deficient and WT mice, demonstrating that MBL-deficiency does not directly impact T cell immunity in the absence of irradiation conditioning. Administration of C1-INH did not alter the clinical expression of GVHD in preconditioned WT B6 recipients, suggesting that MBL amplifies clinical expression of GVHD via a complement-independent mechanism. WT, but not MBL-deficient, APCs express MBL on their surfaces. LPS-stimulated APCs from MBL-deficient mice produced less proinflammatory cytokines (P < .05) and induced weaker alloreactive T cell responses (P < .05) compared with WT APCs. Together, our data show that MBL modulates murine GVHD, likely by amplifying complement-independent, LPS-initiated gastrointestinal inflammation. The results suggest that devising strategies to block LPS/MBL ligation on APCs has the potential to reduce the clinical expression of GVHD.

Tolerance of a Vascularized Composite Allograft Achieved in MHC Class-I-mismatch Swine via Mixed Chimerism

Background

Vascularized composite allografts (VCAs) allow reconstruction of devastating injuries and amputations, yet require lifelong immunosuppression that is associated with significant morbidity. Induction of immune tolerance of VCAs would permit widespread use of these procedures. VCAs are acquired from deceased donors most likely to be fully-MHC-mismatched (in contrast to living-related renal transplant donor-recipient pairs matched at one MHC haplotype). After achieving VCA tolerance in a swine model equivalent to clinical living-related renal transplants (single-haplotype MHC mismatches: e.g., “mother-daughter”/haploidentical), we tested our protocol in MHC class I, class II, and fully-MHC-mismatched pairs. Although class II mismatched swine demonstrated similar results as the haploidentical scenario (stable mixed chimerism and tolerance), our protocol failed to prevent rejection of class I and full mismatch VCAs. Here, we describe a new adapted conditioning protocol that successfully achieved tolerance across MHC class-I-mismatch barriers in swine.

Methods

Swine were treated with non-myeloablative total body and thymic irradiation two days prior to infusion of bone marrow cells from an MHC class I-mismatched donor. They also received a short-term treatment with CTLA4-Ig (Belatacept^®) and anti-IL6R mAb (Tociluzimab^®) and were transplanted with an osteomyocutaneous VCA from the same donor.

Results

Stable mixed chimerism and tolerance of MHC class-I-mismatched VCAs was achieved in 3 recipients. Allograft tolerance was associated with a sustained lack of anti-donor T cell response and a concomitant expansion of double negative CD4^-CD8^- T cells producing IL-10.

Conclusions

This study demonstrates the first successful mixed chimerism-induced VCA tolerance in a large animal model across a MHC class-I-mismatch. Future studies aimed at fully-mismatched donor-recipient pairs are under investigation with this protocol.

Pulmonary Complications of Pediatric Hematopoietic Cell Transplantation. A National Institutes of Health Workshop Summary

Approximately 2,500 pediatric hematopoietic cell transplants (HCTs), most of which are allogeneic, are performed annually in the United States for life-threatening malignant and nonmalignant conditions. Although HCT is undertaken with curative intent, post-HCT complications limit successful outcomes, with pulmonary dysfunction representing the leading cause of nonrelapse mortality. To better understand, predict, prevent, and/or treat pulmonary complications after HCT, a multidisciplinary group of 33 experts met in a 2-day National Institutes of Health Workshop to identify knowledge gaps and research strategies most likely to improve outcomes. This summary of Workshop deliberations outlines the consensus focus areas for future research.

Allogeneic reactivity-mediated endothelial cell complications after HSCT: a plea for consensual definitions

Endothelial cell (EC) activation has been suspected of triggering a group of rare and dismal complications that can occur after allogeneic hematopoietic stem cell transplantation (HSCT). Capillary leak syndrome, engraftment syndrome, transplant-associated microangiopathy, diffuse alveolar hemorrhage, and idiopathic pneumonia syndrome are the main nosological entities. Post-HSCT endotheliitis can be triggered by chemotherapy, infections, and calcineurin inhibitors, but allogeneic reactivity is claimed to be the common denominator. Endothelial damages are thought to activate several deleterious pathways (proapoptotic, procoagulant, proinflammatory) and can lead to multiorgan failure; however, clinical manifestations of each syndrome overlap, and their relationship with graft-versus-host disease could be minimal. The lack of well-defined diagnostic criteria does not allow for a clear-cut comparison in the current literature. Therapeutic efforts have been made to intercept the pathogenic mechanisms leading to EC dysfunction, but remission rates and survival remain mostly unsatisfactory. In this article, we have reviewed the incidence, clinical features, and treatment approaches of EC activation syndromes, and we plead for the development of internationally accepted standard definitions.

Late Noninfectious Pulmonary Complications in Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic modality for a number of malignant and nonmalignant conditions. Pulmonary complications following HSCT are associated with increased mortality and morbidity. These complications may be classified into infectious versus noninfectious, and early versus late based on the time of occurrence post-transplant. Thus, exclusion of infectious etiologies is the first step in the diagnoses of pulmonary complications. Late onset noninfectious pulmonary complications typically occur 3 months post-transplant. Bronchiolitis obliterans is the major contributor to late-onset pulmonary complications, and its clinical presentation, pathogenesis, and current therapeutic approaches are discussed. Idiopathic pneumonia syndrome is another important complication which usually occurs early, although its onset may be delayed. Organizing pneumonia is important to recognize due to its responsiveness to corticosteroids. Other late onset noninfectious pulmonary complications discussed here include pulmonary venoocclusive disease, pulmonary cytolytic thrombi, pleuroparenchymal fibroelastosis, thoracic air leak syndrome, and posttransplant lymphoproliferative disorders.

Current Approach to Non-Infectious Pulmonary Complications of Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is an established treatment for patients with a wide range of malignant and nonmalignant conditions. Noninfectious pulmonary complications still remain a leading cause of morbidity and mortality in these patients. Treating hematopoietic stem cell transplantation recipients with noninfectious pulmonary complications is still challenging, and the current treatment armamentarium and strategies are not adequate for patients receiving hematopoietic stem cell transplantation. Further trials are needed for a better description of the pathogenesis and the complete diagnostic criteria as well as for the development of effective therapeutic approaches for the management of noninfectious pulmonary complications of the hematopoietic stem cell transplantation. This review outlines the incidence, risk factors, pathogenesis, and clinical spectrum and discusses the current approaches to the management of noninfectious pulmonary complications of Hematopoietic stem cell transplantation.

Etanercept and Corticosteroid Therapy for the Treatment of Late-Onset Idiopathic Pneumonia Syndrome

Idiopathic pneumonia syndrome (IPS) is a complication of allogeneic hematopoietic stem cell transplantation (HSCT) that typically occurs within the first 100 days after transplantation. Tumor necrosis factor α (TNF-α) has been shown to be a key mediator of IPS, and the TNF-α binding protein etanercept appeared to improve IPS outcomes in small retrospective and prospective studies. IPS also has been observed to occur later (>100 days) after HSCT; however, little is known about the disease course and whether a TNF-α-based therapeutic strategy is efficacious in these patients. To address this question, we performed a retrospective analysis of 23 patients who underwent HSCT between 2004 and 2016 at our institution who developed late-onset IPS and received treatment with etanercept and high-dose corticosteroids (CS). Ten of the 23 patients (43%) attained a complete clinical response to etanercept and CS. Responses were significantly more likely to occur in patients who did not require positive pressure ventilation at the time of diagnosis. Those who responded experienced a durable survival benefit, with a 2-year overall survival of 67%. In the 13 patients (57%) who did not respond to etanercept and CS, the median overall survival was only 13 days (range, 1 to 60 days). The difference in 2-year overall survival between responders and nonresponders was statistically significant (67% versus 0%; P < .001). These results indicate that late-onset IPS carries high mortality, but that treatment with etanercept and CS has activity and can result in long-term survival in some patients. Prompt diagnosis and early institution of therapy before the need for advanced respiratory support is critical for maximizing responses.

Pilot experience with opebacan/rBPI 21 in myeloablative hematopoietic cell transplantation

Bacterial infection and inflammation contribute significantly to the morbidity and mortality of myeloablative allogeneic hematopoietic cell transplantation (HCT). Endotoxin, a component of the outer membrane of Gram-negative bacteria, is a potent inflammatory stimulus in humans. Bactericidal/permeability increasing protein (BPI), a constituent of human neutrophil granules, binds endotoxin thereby precluding endotoxin-induced inflammation and also has direct anti-infective properties against bacteria. As a consequence of myeloablative therapy used in preparation for hematopoietic cell infusion, patients experience gastrointestinal leak of bacteria and bacterial toxins into the systemic circulation and a period of inflammatory cytokine elevation associated with subsequent regimen-related toxicities.  Patients frequently become endotoxemic and febrile as well as BPI-deficient due to sustained neutropenia. To examine whether enhancing endotoxin-neutralizing and anti-infective activity by exogenous administration of a recombinant N-terminal fragment of BPI (rBPI ₂₁, generic name opebacan) might ameliorate regimen-related toxicities including infection, we recruited patients scheduled to undergo myeloablative HCT to participate in a proof-of-concept prospective phase I/II trial. After the HCT preparative regimen was completed, opebacan was initiated 18-36 hours prior to administration of allogeneic hematopoietic stem cells (defined as Day 0) and continued for 72 hours. The trial was to have included escalation of rBPI ₂₁ dose and duration but was stopped prematurely due to lack of further drug availability.  Therefore, to better understand the clinical course of opebacan-treated patients (n=6), we compared their outcomes with a comparable cohort meeting the same eligibility criteria and enrolled in a non-interventional myeloablative HCT observational study (n = 35).  Opebacan-treated participants had earlier platelet engraftment (p=0.005), mirroring beneficial effects of rBPI ₂₁ previously observed in irradiated mice, fewer documented infections (p=0.03) and appeared less likely to experience significant regimen-related toxicities (p=0.05). This small pilot experience supports the potential utility of rBPI ₂₁ in ameliorating HCT-related morbidity and merits further exploration.

The association between platelet transfusion and idiopathic pneumonia syndrome is unaffected by platelet product type

BACKGROUND

Methods used to produce platelet (PLT) components, pooling of PLT-rich plasma (PRP-PLT) and apheresis (AP-PLT), may variably contribute to the pathogenesis and severity of idiopathic pneumonia syndrome (IPS).

STUDY DESIGN AND METHODS

We performed a retrospective cohort study of 906 allogeneic hematopoietic cell transplant recipients to examine associations between PLT product type and risks of developing IPS and dying after IPS onset. Proportional hazards models included separate terms for the sum of all PLT transfusions and the sum of PRP-PLT units received in the 3 or 7 days before IPS onset. Similarly constructed models analyzed the outcome of time to death after IPS onset. All analyses were adjusted for known IPS risk factors.

RESULTS

Patients received a median of three PRP-PLT transfusions (interquartile range [IQR], 0-6) and five AP-PLT transfusions (IQR, 1-13) while at risk for IPS. Seventy-five patients (8%) developed IPS by Posttransplant Day 120. The proportion of PRP-PLT transfusions was not associated with risk of developing IPS (3-day hazard ratio [HR] 0.98, 95% CI 0.74-1.29, p = 0.86; 7-day HR 1.00, 95% CI 0.86-1.15, p = 0.95) or dying after IPS onset (3-day HR 0.99, 95% CI 0.75-1.31, p = 0.97; 7-day HR 0.98, 95% CI 0.78-1.12, p = 0.47).

CONCLUSION

The association between PLT transfusions and risk of developing IPS or dying after IPS onset does not differ according to PLT product type. Further research is required to identify potentially modifiable steps in PLT component production that contribute to IPS.

A Critical Care and Transplantation-Based Approach to Acute Respiratory Failure after Hematopoietic Stem Cell Transplantation in Children

Acute respiratory failure contributes significantly to nonrelapse mortality after allogeneic hematopoietic stem cell transplantation. Although there is a trend of improved survival over time, mortality remains unacceptably high. An understanding of the pathophysiology of early respiratory failure, opportunities for targeted therapy, assessment of the patient at risk, optimal use of noninvasive positive pressure ventilation, strategies to improve alveolar recruitment, appropriate fluid management, care of the patient with chronic lung disease, and importantly, a team approach between critical care and transplantation services may improve outcomes.

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Outcomes from acute respiratory failure after hematopoietic stem cell transplantation remain unacceptably high.

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The review focuses on strategies to improve these outcomes.

Intestinal barrier loss as a critical pathogenic link between inflammatory bowel disease and graft-versus-host disease

Compromised intestinal barrier function is a prominent feature of inflammatory bowel disease (IBD). However, links between intestinal barrier loss and disease extend much further, including documented associations with celiac disease, type I diabetes, rheumatoid arthritis, and multiple sclerosis. Intestinal barrier loss has also been proposed to have a critical role in the pathogenesis of graft-versus-host disease (GVHD), a serious, potentially fatal consequence of hematopoietic stem cell transplantation. Experimental evidence has begun to support this view, as barrier loss and its role in initiating and establishing a pathogenic inflammatory cycle in GVHD is emerging. Here we discuss similarities between IBD and GVHD, mechanisms of intestinal barrier loss in these diseases, and the crosstalk between barrier loss and the immune system, with a special focus on natural killer (NK) cells. Unanswered questions and future research directions on the topic are discussed along with implications for treatment.

The primacy of IL-6 in IPS?

In this issue of Blood, Varelias and colleagues demonstrate a central role of interleukin (IL)-6 in idiopathic pneumonia syndrome (IPS) after allogeneic stem cell transplantation (SCT) in both mice and humans.

Flow cytometric analysis of the graft-versus-Leukemia-effect after hematopoietic stem cell transplantation in mice

Acute Graft-versus-Host-Disease (aGvHD) is one of the major complications following allogeneic hematopoietic stem cell transplantation (HSCT). Although rather helpful, the use of conventional immunosuppressive drugs leads to general immunosuppression and is toxic. The effects of CD4(+) T-cells, in respect to the development of aGvHD, can be altered by administration of antihuman CD4 monoclonal antibodies, here MAX.16H5 IgG1 . This approach must be tested for possible interference with the Graft-versus-Leukemia-Effect (GvL). Thus, in vitro experiments were conducted, exposing P815 leukemic cells to bone marrow and splenocytes from cd4(-/-) -C57Bl/6 mice transgenic for human CD4 and HLA-DR3 (triple transgenic mice, [TTG]) as well as previously irradiated splenocytes from Balb/c(wt) mice. Using flow cytometry, the vitality of the various malignant and graft cells was analyzed over the course of 4 days. The survival rate of P815 cells did not change significantly when exposed to MAX.16H5 IgG1 , neither did the viability of the graft cells. This provides evidence that MAX.16H5 IgG1 does not impair the GvL effect in vitro. Additionally, P815-Balb/c(wt) leukemic mice were transplanted with P815(GFP) cells, bone marrow, and splenocytes from TTG mice with and without MAX.16H5 IgG1 . Without transplantation, P815(GFP) leukemic cells could be detected by flow cytometry in the liver, the bone marrow, and the spleen of recipients. The antibodies prevented aGvHD while leaving the GvL effect intact. These findings indicate no negative effect of MAX.16H5 IgG1 on the GvL effect in vitro and in vivo after HSCT in a murine model.

Lung parenchyma-derived IL-6 promotes IL-17A-dependent acute lung injury after allogeneic stem cell transplantation

Idiopathic pneumonia syndrome (IPS) is a relatively common, frequently fatal clinical entity, characterized by noninfectious acute lung inflammation following allogeneic stem cell transplantation (SCT), the mechanisms of which are unclear. In this study, we demonstrate that immune suppression with cyclosporin after SCT limits T-helper cell (Th) 1 differentiation and interferon-γ secretion by donor T cells, which is critical for inhibiting interleukin (IL)-6 generation from lung parenchyma during an alloimmune response. Thereafter, local IL-6 secretion induces donor alloantigen-specific Th17 cells to preferentially expand within the lung, and blockade of IL-17A or transplantation of grafts lacking the IL-17 receptor prevents disease. Studies using IL-6(-/-) recipients or IL-6 blockade demonstrate that IL-6 is the critical driver of donor Th17 differentiation within the lung. Importantly, IL-6 is also dysregulated in patients undergoing clinical SCT and is present at very high levels in the plasma of patients with IPS compared with SCT recipients without complications. Furthermore, at the time of diagnosis, plasma IL-6 levels were higher in a subset of IPS patients who were nonresponsive to steroids and anti-tumor necrosis factor therapy. In sum, pulmonary-derived IL-6 promotes IPS via the induction of Th17 differentiation, and strategies that target these cytokines represent logical therapeutic approaches for IPS.

TNF-receptor inhibitor therapy for the treatment of children with idiopathic pneumonia syndrome. A joint Pediatric Blood and Marrow Transplant Consortium and Children's Oncology Group Study (ASCT0521)

Idiopathic pneumonia syndrome (IPS) is an acute, noninfectious lung disorder associated with high morbidity and mortality after hematopoietic cell transplantation. Previous studies have suggested a role for TNFα in the pathogenesis of IPS. We report a multicenter phase II trial investigating a soluble TNF-binding protein, etanercept (Enbrel, Amgen, Thousand Oaks, CA), for the treatment of pediatric patients with IPS. Eligible patients were < 18 years old, within 120 days after transplantation, and with radiographic evidence of a diffuse pneumonitis. All patients underwent a pretherapy broncho-alveolor lavage (BAL) to establish the diagnosis of IPS. Systemic corticosteroids (2.0 mg/kg/day) plus etanercept (.4 mg/kg twice weekly × 8 doses) were administered. Response was defined as survival and discontinuation of supplemental oxygen support by day 28 of study. Thirty-nine patients (median age, 11 years; range, 1 to 17) were enrolled, with 11 of 39 patients nonevaluable because of identification of pathogens from their pretherapy BAL. In the remaining 28 patients, the median fraction of inspired oxygen at study entry was 45%, with 17 of 28 requiring mechanical ventilation. Complete responses were seen in 20 (71%) patients, with a median time to response of 10 days (range, 1 to 24). Response rates were higher for patients not requiring mechanical ventilation at study entry (100% versus 53%, P = .01). Overall survival at 28 days and 1 year after therapy were 89% (95% confidence interval [CI], 70% to 96%) and 63% (95% CI, 42% to 79%), respectively. Plasma levels of proinflammatory cytokines were significantly increased at onset of therapy, subsequently decreasing in responding patients. The addition of etanercept to high-dose corticosteroids was associated with high response rates and survival in children with IPS.

Randomized, double-blind, placebo-controlled trial of soluble tumor necrosis factor receptor: enbrel (etanercept) for the treatment of idiopathic pneumonia syndrome after allogeneic stem cell transplantation: blood and marrow transplant clinical trials network protocol

Idiopathic pneumonia syndrome (IPS) is a diffuse, noninfectious lung injury that occurs acutely after allogeneic hematopoietic cell transplantation (HCT). IPS-related mortality has been historically high (>50%) despite treatment with systemic corticosteroids and supportive care measures. We have now examined the role of tumor necrosis factor inhibition in a randomized, double-blind, placebo-controlled trial of corticosteroids with etanercept or placebo. Thirty-four subjects (≥18 years) with IPS after HCT were randomized to receive methylprednisolone (2 mg/kg/day) plus etanercept (0.4 mg/kg twice weekly × 4 weeks; n = 16) or placebo (n = 18). No active infections and a pathogen-negative bronchoscopy were required at study entry. Response (alive, with complete discontinuation of supplemental oxygen support) and overall survival were examined. This study, originally planned to accrue 120 patients, was terminated prematurely due to slow accrual. In the limited number of patients examined, there were no differences in response rates at day 28 of study. Ten of 16 patients (62.5% [95% confidence interval {CI}, 35.4% to 84.8%]) receiving etanercept and 12 of 18 patients (66.7% [95% CI, 41.0% to 86.7%]) receiving placebo met the day 28 response definition (P = 1.00). The median survival was 170 days (95% CI, 11 to 362) with etanercept versus 64 days (95% CI, 26 to 209) with placebo (P = .51). Among responders, the median time to discontinuation of supplemental oxygen was 9 days (etanercept) versus 7 days (placebo). Therapy was well tolerated, with 1 toxicity-related death from infectious pneumonia in the placebo arm. The treatment of IPS with corticosteroids in adult HCT recipients was associated with high early response rates (>60%) compared with historical reports, with poor overall survival. The addition of etanercept did not lead to further increases in response, although the sample size of this truncated trial preclude a definitive conclusion.

Donor-derived CD4(+)/CCR7(+) T-cell partial selective depletion does not alter acquired anti-infective immunity

In previous studies, we observed that a high proportion of donor-derived CD4(+) T cells expressing the chemokine receptor 7 (CCR7) was a major determinant of acute GVHD, without interfering with the incidence of other post-transplant outcomes, especially relapse and nonrelapse mortality rates. Here, we investigated in vitro the impact of partially selective CD4(+)/CCR7(+) T lymphocytes on acquired anti-infective immune response in 10 donors who underwent G-CSF-primed PBSC collection. Similar quantitative and functional proliferative reactions were observed in lymphocyte cultures in the presence of adenovirus and pp65 Ags with unmanipulated and partially depleted donor samples. No responses were observed in the presence of human T-cell lymphotropic virus type 1 used as a negative control. These results complete the proof of concept needed to build a clinical trial investigating partially selective CD4(+)/CCR7(+) T cell-depleted allo-SCT.

c-Rel is an essential transcription factor for the development of acute graft-versus-host disease in mice

Transcription factors of the Rel/NF-κB family are known to play different roles in immunity and inflammation, although the putative role of c-Rel in transplant tolerance and graft-versus-host disease (GVHD) remains elusive. We report here that T cells deficient for c-Rel have a dramatically reduced ability to cause acute GVHD after allogeneic bone marrow transplantation using major and minor histocompatibility mismatched murine models. In the study to understand the underlying mechanisms, we found that c-Rel(-/-) T cells had a reduced ability to expand in lymphoid organs and to infiltrate in GVHD target organs in allogeneic recipients. c-Rel(-/-) T cells were defective in the differentiation into Th1 cells after encountering alloantigens, but were enhanced in the differentiation toward Foxp3(+) regulatory T (Treg) cells. Furthermore, c-Rel(-/-) T cells had largely preserved activity to mediate graft-versus-leukemia response. Taken together, our findings indicate that c-Rel plays an essential role in T cells in the induction of acute GVHD, and suggest that c-Rel can be a potential target for therapeutic intervention in allogeneic hematopoietic cell transplantation in the clinic.

Advances in critical care of the pediatric hematopoietic stem cell transplant patient

Hematopoietic stem cell transplant (SCT) remains a curative option for a variety of malignant and non-malignant disorders in children. Following transplant a proportion of SCT recipients become critically ill and need intensive care. Critical illness may occur in the setting of transplant complications such as graft versus host disease (GVHD), idiopathic pneumonia syndrome (IPS), veno-occlusive disease (VOD) and transplant associated thrombotic microangiopathy (TA-TMA). Hence, familiarity with recent advances in the transplant process and complications is crucial for the intensivist. This article will highlight common complications encountered in the critically ill SCT recipient.

Endothelial and epithelial barriers in graft-versus-host disease

Endothelial and epithelial cells form selectively permeable barriers that separate tissue compartments. These cells coordinate movement between the lumen and tissue via the transcellular and paracellular pathways. The primary determinant of paracellular permeability is the tight junction, which forms an apical belt-like structure around endothelial and epithelial cells. This chapter discusses endothelial and epithelial barriers in graft-versus-host disease after allogeneic bone marrow transplantation, with a focus on the tight junction and its role in regulating paracellular permeability. Recent studies suggest that in graft-versus-host disease, pathological increases in paracellular permeability, or barrier dysfunction, are initiated by pretransplant conditioning and sustained by alloreactive cells and the proinflammatory milieu. The intestinal epithelium is a significant focus, as it is a target organ of graft-versus-host disease, and the mechanisms of barrier regulation in intestinal epithelium have been well characterized. Finally, we propose a model that incorporates endothelial and epithelial barrier dysfunction in graft-versus-host disease and discuss modulating barrier properties as a therapeutic approach.

IFN-γ receptor-deficient donor T cells mediate protection from graft-versus-host disease and preserve graft-versus-tumor responses after allogeneic bone marrow transplantation

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow transplantation. It has been previously reported that lung GVHD severity directly correlates with the expansion of donor Th17 cells in the absence of IFN-γ. However, the consequence of Th17-associated lung GVHD in the presence of IFN-γ has not been well characterized. In the current study, T cells from IFN-γ receptor knockout (IFN-γR(-/-)) mice, capable of producing IFN-γ but unable to signal in response to IFN-γ, have been used to elucidate further the role of IFN-γ in GVHD. We found the transfer of donor T cells from either IFN-γR(-/-) or IFN-γ knockout (IFN-γ(-/-)) mice resulted in significant increases in donor Th17 cells in the lung. Marked increases in IL-4-producing Th2 cells infiltrating the lungs were also observed in the mice of donor IFN-γR(-/-) T cells. Notably, despite the presence of these cells, these mice did not show the severe immune-mediated histopathological lung injury observed in mice receiving donor IFN-γ(-/-) T cells. Increases in lung GVHD did occur in mice with donor IFN-γR(-/-) T cells when treated in vivo with anti-IFN-γ demonstrating that the cytokine has a protective role on host tissues in GVHD. A survival benefit from acute GVHD was also observed using donor cells from IFN-γR(-/-) T cells compared with control donors. Importantly, tumor-bearing mice receiving IFN-γR(-/-) T cells versus wild-type donor T cells displayed similar graft-versus-tumor (GVT) effects. These results demonstrate the critical role of IFN-γ on host tissues and cell effector functions in GVHD/GVT.

Human biomarker discovery and predictive models for disease progression for idiopathic pneumonia syndrome following allogeneic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (SCT) is the only curative therapy for many malignant and nonmalignant conditions. Idiopathic pneumonia syndrome (IPS) is a frequently fatal complication that limits successful outcomes. Preclinical models suggest that IPS represents an immune mediated attack on the lung involving elements of both the adaptive and the innate immune system. However, the etiology of IPS in humans is less well understood. To explore the disease pathway and uncover potential biomarkers of disease, we performed two separate label-free, proteomics experiments defining the plasma protein profiles of allogeneic SCT patients with IPS. Samples obtained from SCT recipients without complications served as controls. The initial discovery study, intended to explore the disease pathway in humans, identified a set of 81 IPS-associated proteins. These data revealed similarities between the known IPS pathways in mice and the condition in humans, in particular in the acute phase response. In addition, pattern recognition pathways were judged to be significant as a function of development of IPS, and from this pathway we chose the lipopolysaccaharide-binding protein (LBP) protein as a candidate molecular diagnostic for IPS, and verified its increase as a function of disease using an ELISA assay. In a separately designed study, we identified protein-based classifiers that could predict, at day 0 of SCT, patients who: 1) progress to IPS and 2) respond to cytokine neutralization therapy. Using cross-validation strategies, we built highly predictive classifier models of both disease progression and therapeutic response. In sum, data generated in this report confirm previous clinical and experimental findings, provide new insights into the pathophysiology of IPS, identify potential molecular classifiers of the condition, and uncover a set of markers potentially of interest for patient stratification as a basis for individualized therapy.

Incidence, clinical features, and risk factors of idiopathic pneumonia syndrome following hematopoietic stem cell transplantation in children

BACKGROUND

Idiopathic pneumonia syndrome (IPS) is a severe complication that can occur after hematopoietic stem cell transplantation (HSCT) and is often associated with a fatal outcome despite intensive supportive care.

PROCEDURE

To assess the incidence and risk factors of IPS, we reviewed 251 consecutive patients (median age, 7.0 years) who received HSCT at the Department of Pediatrics, Nagoya University Hospital, between January 1990 and July 2009.

RESULTS

Twenty of 251 (cumulative incidence of IPS at 2 years after HSCT, 8.0%; 95% confidence interval (CI), 5.1-12.4%) patients developed IPS. The median duration from HSCT to diagnosis of IPS was 67 days (range, 12-486 days). Patients with IPS had significantly higher 5-year transplant-related mortality compared to patients without IPS (52% (95% CI, 19-77%) vs. 13% (95% CI, 5-25%), P < 0.001), and the probability of 5-year overall survival was significantly worse for patients with IPS (42% (95% CI, 25-64%) vs. 68% (95% CI, 59-76%), P = 0.01). By multivariate analysis, high risk in underlying disease (HR, 2.5; 95% CI, 1.0-6.7; P = 0.05) and a busulfan-containing regimen (HR, 3.5; 95% CI, 1.3-9.9; P < 0.01) were identified as the independent risk factors for developing IPS.

CONCLUSION

The prophylactic strategies for IPS in patients with these risk factors were warranted.

High-dose corticosteroids with or without etanercept for the treatment of idiopathic pneumonia syndrome after allo-SCT

Idiopathic Pneumonia Syndrome (IPS) is a common complication after allo-SCT and results in high mortality rates. Conventional treatment for IPS typically includes supportive care and high-dose corticosteroids (CS). Data suggests that TNF-α is important in the pathogenesis of IPS and that the TNF-α inhibitor etanercept may be useful for IPS treatment. We performed a retrospective comparison of consecutive patients treated at our center for IPS with CS only from 1999 to 2003 (group 1, n=22) or CS plus etanercept from 2004 to 2007 (group 2, n=17). In all, 18% of patients in group 1 vs 53% in group 2 were successfully taken off respiratory support and discharged from the hospital (P=0.039). OS was significantly better for recipients of CS plus etanercept (P=0.003). The estimated survival at 28 days and 2 years after IPS was 36.4% (95% CI 17-56%) and 9.1% (95% CI 2-25%) for group 1 and 88.2% (95% CI 61-97%) and 18% (95% CI 4-38%) for group 2, respectively. Our retrospective comparison suggests that the addition of etanercept to CS for IPS improves response rates and OS. However, outcomes remain limited in both groups, highlighting the need for more effective interventions to treat early and late complications of IPS.

Inhibition of IL-32 activation by α-1 antitrypsin suppresses alloreactivity and increases survival in an allogeneic murine marrow transplantation model

Interleukin (IL)-32 was originally identified in natural killer cells and IL-2-activated human T lymphocytes. As T cells are activated in allogeneic transplantation, we determined the role of IL-32 in human mixed lymphocyte cultures (MLCs) and GVHD. In allogeneic MLCs, IL-32 increased two-fold in responding T cells, accompanied by five-fold increases of TNFα, IL-6, and IL-8. After allogeneic hematopoietic cell transplantation, IL-32 mRNA levels in blood leukocytes were statistically significantly higher in patients with acute GVHD (n = 10) than in serial samples from patients who did not develop acute GVHD (n = 5; P = .02). No significant changes in IL-32 levels were present in patients with treated (n = 14) or untreated (n = 8) chronic GVHD, compared with healthy controls (n = 8; P = .5, and P = .74, respectively). As IL-32 is activated by proteinase-3 (PR3), we determined the effect of the serine protease inhibitor α-1 antitrypsin (AAT) on IL-32 levels and showed suppression of IL-32 and T-lymphocyte proliferation in MLCs. In an MHC-minor antigen disparate murine transplant model, preconditioning and postconditioning treatment with AAT resulted in attenuation or prevention of GVHD and superior survival compared with albumin-treated controls (80% vs 44%; P = .04). These findings suggest that AAT modulates immune and inflammatory functions and may represent a novel approach to prevent or treat GVHD.

Boswellic acids extract attenuates pulmonary fibrosis induced by bleomycin and oxidative stress from gamma irradiation in rats

BACKGROUND

Interstitial pulmonary fibrosis is characterized by an altered cellular composition of the alveolar region with excessive deposition of collagen. Lung inflammation is also common in pulmonary fibrosis. This study aims to test the inhibition of 5-lipooxygenase (5-LOX) by boswellic acid (BA) extract in an experimental model of pulmonary fibrosis using bleomycin (BL).

METHODS

Boswellic acid extract (1 g/kg) was force-fed to rats seven days prior to administration of BL or gamma irradiation or both. BL (0.15 U/rat) in 25 μl of 0.9% normal saline (NS) or 0.9% NS alone was administered intratracheally. Rats were exposed to two fractionated doses of gamma irradiation (0.5 Gy/dose/week) with a gamma cell-40 (Cesium-137 irradiation units, Canada) during the last two weeks of the experiment. BA was administered during BL or irradiation treatment or both. After the animals were sacrificed, bronchoalveolar lavage was performed; lungs were weighed and processed separately for biochemical and histological studies.

RESULTS

In rats treated with BL, levels of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) were significantly elevated (P = 0.05 and P = 0.005). Hydroxyproline was highly and extensively expressed. Immunoreactive compounds were abundantly expressed, represented in the levels of macrophages infiltrate, accumulation of eosinophils and neutrophils in the lung as well as the aggregation of fibroblasts in the fibrotic area. The levels of lipoxygenase enzyme activity were significantly increased (P = 0.005). Antioxidant activities measured in BL-treated rats deteriorated, coupled with the elevation of both levels of plasma lipid peroxide (LP) content and bronchoalveolar lavage lactate dehydrogenase activity. BA-treated rats had reduced number of macrophages, (P = 0.01), neutrophils in bronchoalveolar lavage (P = 0.01) and protein (P = 0.0001). Moreover, the hydroxyproline content was significantly lowered in BA-treated rats (P = 0.005). BA extract inhibited the TGF-ß induced fibrosis (P = 0.01) and 5-LOX activity levels (P = 0.005).Histologically, BA reduced the number of infiltrating cells, ameliorated the destruction of lung architecture and attenuated lung fibrosis.

CONCLUSION

BA attenuates the BL-induced injury response in rats, such as collagen accumulation, airway dysfunction and injury. This study suggests that the blocking of 5-LOX may prevent the progression of fibrosis.

Prevention of GVHD while sparing GVL effect by targeting Th1 and Th17 transcription factor T-bet and RORγt in mice

Allogeneic hematopoietic cell transplantation (HCT) is effective therapy for hematologic malignancies through T cell-mediated GVL effects. However, HCT benefits are frequently offset by the destructive GVHD, which is also induced by donor T cells. Naive Th can differentiate into Th1 and Th17 subsets and both can mediate GVHD after adoptive transfer into an allogeneic host. Here we tested the hypothesis that blockade of Th1 and Th17 differentiation is required to prevent GVHD in mice. T cells with combined targeted disruption of T-bet and RORγt have defective differentiation toward Th1 and Th17 and skewed differentiation toward Th2 and regulatory phenotypes, and caused ameliorated GVHD in a major MHC-mismatched model of HCT. GVL effects mediated by granzyme-positive CD8 T cells were largely preserved despite T-bet and RORγt deficiency. These data indicate that GVHD can be prevented by targeting Th1 and Th17 transcription factors without offsetting GVL activity.

An official American Thoracic Society research statement: noninfectious lung injury after hematopoietic stem cell transplantation: idiopathic pneumonia syndrome

RATIONALE

Acute lung dysfunction of noninfectious etiology, known as idiopathic pneumonia syndrome (IPS), is a severe complication following hematopoietic stem cell transplantation (HSCT). Several mouse models have been recently developed to determine the underlying causes of IPS. A cohesive interpretation of experimental data and their relationship to the findings of clinical research studies in humans is needed to better understand the basis for current and future clinical trials for the prevention/treatment of IPS.

OBJECTIVES

Our goal was to perform a comprehensive review of the preclinical (i.e., murine models) and clinical research on IPS.

METHODS

An ATS committee performed PubMed and OVID searches for published, peer-reviewed articles using the keywords "idiopathic pneumonia syndrome" or "lung injury" or "pulmonary complications" AND "bone marrow transplant" or "hematopoietic stem cell transplant." No specific inclusion or exclusion criteria were determined a priori for this review.

MEASUREMENTS AND MAIN RESULTS

Experimental models that reproduce the various patterns of lung injury observed after HSCT have identified that both soluble and cellular inflammatory mediators contribute to the inflammation engendered during the development of IPS. To date, 10 preclinical murine models of the IPS spectrum have been established using various donor and host strain combinations used to study graft-versus-host disease (GVHD). This, as well as the demonstrated T cell dependency of IPS development in these models, supports the concept that the lung is a target of immune-mediated attack after HSCT. The most developed therapeutic strategy for IPS involves blocking TNF signaling with etanercept, which is currently being evaluated in clinical trials.

CONCLUSIONS

IPS remains a frequently fatal complication that limits the broader use of allogeneic HSCT as a successful treatment modality. Faced with the clinical syndrome of IPS, one can categorize the disease entity with the appropriate tools, although cases of unclassifiable IPS will remain. Significant research efforts have resulted in a paradigm shift away from identifying noninfectious lung injury after HSCT solely as an idiopathic clinical syndrome and toward understanding IPS as a process involving aspects of both the adaptive and the innate immune response. Importantly, new laboratory insights are currently being translated to the clinic and will likely prove important to the development of future strategies to prevent or treat this serious disorder.

Translational research efforts in biomarkers and biology of early transplant-related complications

In the time since the first allogeneic hematopoietic stem cell transplantation (HSCT) was performed over 40 years ago, this life-saving procedure has been used increasingly for patients with hematologic, metabolic, and malignant diseases. Despite major advances in our understanding of the immunologic processes (both beneficial and injurious) that are associated with HSCT and improvements in supportive and critical care medicine, successful outcomes are still limited by several serious complications. As such, the establishment of effective therapeutic strategies for these complications will be crucial as increasing numbers of high-risk transplants are performed each year. The development of such approaches is fundamentally dependent upon a basic understanding of pathophysiologic mechanisms of disease and also on our ability to successfully translate these insights back to the bedside. This brief review will highlight breakthroughs in translational research endeavors that have paved the way for the development of novel strategies intended to change the standard of care and optimize outcomes for patients in whom allogeneic HSCT offers the only hope for a cure.

Innovative uses of tumor necrosis factor alpha inhibitors

Tumor necrosis factor alpha (TNF-alpha) is an inflammatory cytokine that is released by a variety of cell types, including immune effector cells and tissue-specific cells. TNF-alpha has been shown to promote inflammation via the activation and induction of cytokines interleukin 1 (IL-1), IL-6, and IL-8 and by the upregulation of adhesion molecules on endothelial cells leading to increased leukocyte extravasation. Theoretically, the blockade of TNF should have widespread potential in the treatment of numerous inflammatory diseases. Currently, 3 TNF-alpha inhibitors available in the United States are approved for psoriasis and psoriatic arthritis: infliximab, etanercept, and adalimumab. Numerous case reports and case series have been published in recent years reporting the off-label uses of these drugs in various inflammatory skin diseases. This review summarizes the most recent reports on 20 such conditions.

Idiopathic pneumonia syndrome in mice after allogeneic bone marrow transplantation: association between idiopathic pneumonia syndrome and acute graft-versus-host disease

OBJECTIVE

To explore the association between idiopathic pneumonia syndrome (IPS) and acute graft-versus-host disease (aGVHD) in allogeneic hematopoietic stem cell transplantation.

METHODS

Established acute GVHD model of C57BL/6-->BALB/c mice. Chest computed tomography (CT) scans were dynamically performed in recipient mice after transplant. Lung histopathology and cytokine levels (including TNF-alpha and IFN-gamma) were examined in three experimental groups: mice receiving simple irradiation, syngeneic transplants, and allogeneic transplants.

RESULTS

All allogeneic transplant mice developed aGVHD. On CT, most aGVHD mice had bilateral diffuse lung infiltrates, while syngeneic transplant mice had normal lungs. On histopathology, aGVHD mice had acute pneumonitis. On immunohistochemistry, the infiltrates were mainly CD4+ T cells during aGVHD onset, but CD8+ T cells predominated during aGVHD progression. Lung TNF-alpha and IFN-gamma levels were higher in the three experimental groups than in normal controls on days +3 and +7 post-transplant. On day +7, TNF-alpha levels were higher in allogeneic than in syngeneic transplant mice; IFN-gamma levels were not different. On days +12 and +16, TNF-alpha levels were higher but IFN-gamma levels were lower in allogeneic mice than in syngeneic transplant mice.

CONCLUSIONS

The underlying cause of IPS is aGVHD. T cells and TNF-alpha may play a role in the pathogenesis of aGVHD-induced IPS. IPS progression may be associated with decreasing lung IFN-gamma levels.

Immunomodulatory effects of vitamin D: implications for GVHD

GVHD remains a major source of morbidity and mortality after allogeneic BMT. GVHD is mediated by alloreactive T cells derived from the hematopoietic graft that target host tissues. Pre-clinical models have shown that presentation of alloantigens by host DCs results in the activation of donor-derived T cells that mediate GVHD. Strategies that interfere with the Ag-presenting capacity of DCs after allogeneic transplantation may decrease the risk of developing GVHD. Vitamin D is a hormone essential for calcium metabolism that shows immunomodulatory properties. We showed that correction of vitamin D deficiency appeared to mitigate manifestations of GVHD. In pre-clinical studies, we have shown that vitamin D inhibits DC maturation, polarizes T-cell populations toward the expression of Th2 as compared with Th1 cytokines, and blunts allogeneic T-cell proliferation in response to DC stimulation. Exposure to vitamin D resulted in increased expression of IDO, an enzyme responsible for tryptophan metabolism that is upregulated in tolerizing DCs. These data suggest that exposure to vitamin D results in immature DC populations that bias toward tolerizing rather than stimulatory T-cell populations. Vitamin D may therefore have a role in the prevention of GVHD.

Association between acute graft versus host disease and lung injury after allogeneic haematopoietic stem cell transplantation

OBJECTIVE

To investigate the characteristics of chest high-resolution computed tomography (HRCT) and pathogenesis of acute graft versus host disease (acute GVHD)-induced lung injury after allogeneic haematopoietic stem cell transplantation (allo-HSCT).

METHODS

A study of 47 patients with acute GVHD of grades II-IV describes the clinical manifestations and characteristics of chest HRCT of acute GVHD-induced lung injury. Detection of serum interferon gamma (IFNgamma) and tumour necrosis factor alpha (TNFalpha) were performed before the treatment for acute GVHD. Transbronchial biopsy was performed in four patients whose chest HRCT did not recover completely after treatment for acute GVHD. Pulmonary function was measured in patients who survived more than 6 months in every 3 months.

RESULTS

Chest HRCT scans were performed in 47 cases and 20 cases showed abnormal in which 17 cases were suspected of acute GVHD-induced lung injury. In 17 patients with acute GVHD-induced lung injury, HRCT revealed diffused interstitial infiltrate in five cases, diffused interstitial and alveolar infiltrate in seven cases, diffused interstitial and segmental lobar alveolar infiltrate in five cases accompanied by bilateral pleural effusion and hydropericardium in nine patients. There was no statistical significance between the levels of serum IFNgamma and TNFalpha in cases with and without lung injury, but the levels of serum IFNgamma and TNFalpha in patients were significantly higher than the healthy group (IFNgamma: p=0.000, TNFalpha: p=0.000). The histopathology of the lung tissue was characterized by disorganization, epithelial cell damage, interstitial fibroplasias and interstitial T lymphocyte or macrophage infiltrate. Forty-seven cases all attained the treatment for acute GVHD, and the total effective rate and the rate of completely remission (CR) were 74.47 and 55.32%, respectively. The total effective rate and the rate of CR in the treatment for acute GVHD-induced lung injury were 94.12 and 58.82%, respectively. The effective rate of treatment for acute GVHD-induced lung injury positively correlated with that for acute GVHD (r=0.771, p=0.001). Three cases in nine cases with lung injury and three cases in 15 cases without lung injury who survived more than 6 months developed late-onset non-infectious lung injury. Eleven patients of 24 patients who survived more than 6 months had abnormal pulmonary function, including seven patients in nine patients with acute GVHD-induced lung injury and four patients in 15 patients without acute GVHD-induced lung injury. There was no difference in the incidence of late-onset non-infectious lung injury, but significance in the incidence of abnormal pulmonary function between cases with and without lung injury (p=0.033, cross-tabs).

CONCLUSIONS

These results suggested that the lung might be one of the target organs of acute GVHD and participation of T lymphocyte, macrophage and cytokines such as IFNgamma and TNFalpha might play a role in the pathogenesis of acute GVHD-induced lung injury. Acute GVHD-induced lung injury may progress to late-onset non-infectious lung injury.

Etanercept clearance during an in vitro model of continuous venovenous hemofiltration

BACKGROUND/AIMS

Etanercept is a tumor necrosis factor-alpha antagonist used in inflammation-mediated conditions. Continuous venovenous hemofiltration (CVVH) has also been used in patients with inflammatory conditions. This study evaluated etanercept clearance using an in vitro CVVH model.

METHODS

Etanercept clearance was assessed in vitro in bovine blood at 1-3 mg/l final serum concentration, and urea control at 750 mg/l. CVVH was performed using polyacrylonitrile, polysulfone, and polymethylmethacrylate filters at 3 l/h ultrafiltrate and 200 ml/min blood flow rates. Transmembrane clearance was estimated using sieving coefficient calculations, and adsorptive removal rate was approximated using a mass balance calculation.

RESULTS

Urea sieving coefficient remained constant (1.04 +/- 0.01). Ultrafiltrate etanercept concentrations were undetectable (sieving coefficient < 0.02) and transmembrane and adsorptive clearances were negligible.

CONCLUSION

Etanercept is not cleared appreciably by transmembrane or adsorptive mechanisms in CVVH using polyacrylonitrile, polysulfone, or polymethylmethacrylate hemofilters.

The cyclin dependent kinase inhibitor (R)-roscovitine prevents alloreactive T cell clonal expansion and protects against acute GvHD

Cell cycle re-entry of quiescent T lymphocytes regulated by cdk2 is required for antigen-specific clonal expansion and generation of productive T cell responses. Recently, we determined that induction of antigen-specific T cell tolerance results in impaired cdk2 activity leading to enhanced Smad3 transactivation, upregulation of p15 and blockade of cell cycle progression. Here we report that pharmacologic inhibition of cdk2 with (R)-roscovitine blocked expansion of alloreactive T cells in vitro and in vivo and protected from lethal acute GvHD. In addition to inhibiting alloreactive T cell responses, (R)-roscovitine prevented TNF-alpha-mediated activation of NF-kappa B pathway, which is involved in the inflammatory process leading to the development of GvHD. The combined anti-proliferative and anti-inflammatory properties of (R)-roscovitine make it an attractive treatment modality toward control of GvHD.

Separating graft-versus-leukemia from graft-versus-host disease in allogeneic hematopoietic stem cell transplantation

Routine methods to maximize the graft-versus-leukemia (GvL) activity of allogeneic hematopoietic stem cell transplantation (HSCT) without the detrimental effects of graft-versus-host disease (GvHD) are lacking. Depletion or inhibition of alloreactive T cells is partially effective in preventing GvHD, but usually leads to decreased GvL activity. The current model for the pathophysiology of acute GvHD describes a series of immune pathways that lead to activation of donor T cells and inflammatory cytokines responsible for tissue damage in acute GvHD. This model does not account for how allotransplant can lead to GvL effects without GvHD, or how the initial activation of donor immune cells may lead to counter-regulatory effects that limit GvHD. In this review, we will summarize new findings that support a more complex model for the initiation of GvHD and GvL activities in allogeneic HSCT, and discuss the potential of novel strategies to enhance GvL activity of the transplant.

Influence of oral beclomethasone dipropionate on early non-infectious pulmonary outcomes after allogeneic hematopoietic cell transplantation: results from two randomized trials

Early non-infectious pulmonary complications represent a significant cause of mortality after hematopoietic cell transplantation (HCT). We tested the hypothesis that oral beclomethasone dipropionate (BDP) is effective for preventing early non-infectious pulmonary complications after allogeneic HCT. We retrospectively reviewed the medical records of 120 patients, 60 in each treatment arm, to identify non-infectious and infectious pulmonary events and pulmonary function test results from all patients who participated in two randomized trials of oral BDP for treatment of acute gastrointestinal GVHD. 17-Beclomethasone monopropionate (17-BMP), the active metabolite of BDP, was evaluated in blood from the right atrium in four patients. Thirty-three of 42 (79%) placebo-treated patients experienced a decrease of the DL(CO) from pretransplant to day 80 after transplant, compared with 27 of 49 (55%) BDP-treated patients (P=0.02). In the first 200 days after randomization, there were no cases of non-infectious pulmonary complications in BDP-treated patients, vs four cases among placebo-treated patients (P=0.04). Levels of 17-BMP were detected in atrial blood at steady state. Delivery of a potent glucocorticoid such as 17-BMP to the pulmonary artery after oral dosing of BDP may be useful in modulating pulmonary inflammation and preventing the development of non-infectious pulmonary complications after allogeneic HCT.

Induction of natural killer T cell-dependent alloreactivity by administration of granulocyte colony-stimulating factor after bone marrow transplantation

Granulocyte colony-stimulating factor (G-CSF) is often used to hasten neutrophil recovery after allogeneic bone marrow transplantation (BMT), but the clinical and immunological consequences evoked remain unclear. We examined the effect of G-CSF administration after transplantation in mouse models and found that exposure to either standard G-CSF or pegylated-G-CSF soon after BMT substantially increased graft-versus-host disease (GVHD). This effect was dependent on total body irradiation (TBI) rendering host dendritic cells (DCs) responsive to G-CSF by upregulating their expression of the G-CSF receptor. Stimulation of host DCs by G-CSF subsequently unleashed a cascade of events characterized by donor natural killer T cell (NKT cell) activation, interferon-gamma secretion and CD40-dependent amplification of donor cytotoxic T lymphocyte function during the effector phase of GVHD. Crucially, the detrimental effects of G-CSF were only present when it was administered after TBI conditioning and at a time when residual host antigen presenting cells were still present, perhaps explaining the conflicting and somewhat controversial clinical studies from the large European and North American BMT registries. These data have major implications for the use of G-CSF in disease states where NKT cell activation may have effects on outcome.

Preventive usage of broad spectrum chemokine inhibitor NR58-3.14.3 reduces the severity of pulmonary and hepatic graft-versus-host disease

Pulmonary graft-versus-host disease (pGVHD) is a major complication after allogeneic bone marrow transplantation (BMT), which involves donor leukocyte migration into the lung along chemokine gradients, leading to pulmonary dysfunction and respiratory insufficiency. As broad spectrum chemokine inhibitor (BSCI) NR58-3.14.3 suppresses leukocyte migration in response to various chemokines, including CCL2, CCL3, CCL5, we investigated the effects of NR58-3.14.3 on the evolution of pGVHD. Lethally irradiated B6D2F1 mice received BMT from syngeneic (B6D2F1) or allogeneic (C57BL/6) donors, and animals were treated with either NR58-3.14.3 or vehicle control from day -1 to day +14. At week 6, in allogeneic recipients that received BSCI, inflammatory cell infiltrates in the lung were decreased, and reduced histopathologic changes translated into improved pulmonary function when compared to allo-controls. Acute GVHD of the liver was also diminished, whereas no differences were seen in the gut. Alloantigen-dependent splenic T cell expansion and systemic TNF-alpha and IFN-gamma levels were comparable in NR58-3.14.3-treated animals and allo-controls. No suppressive effect of NR58-3.14.3 on CTL cytotoxicity was found, and diminished cellular infiltrates in lung and liver were most likely due to decreased migration of mononuclear cells. Therefore, novel approaches involving BSCIs may provide a promising tool in the management of pGVHD.

Acute kidney injury in pediatric stem cell transplant recipients

Because respiratory dysfunction after hematopoietic stem cell transplantation is a manifestation of a continuum of dysfunction temporarily induced by the transplant process, a proactive rather than reactive approach might prevent or attenuate its progression to acute respiratory distress syndrome. Organ dysfunction in this population results from cytokine-driven processes, of which the first manifestation includes fluid accumulation. We describe a multistep protocol that first targets fluid balance control, both through restriction of intake and through augmentation of output using dopamine and furosemide infusions. If these steps fail to stem the tide of water accumulation, we advocate the relatively early use of continuous renal replacement therapy, its use triggered by a continued increase in body weight (>10% above baseline), an increasing c-reactive protein level, and an increasing oxygen need. Renal function parameters do not figure in this protocol. We recommend continuous renal replacement therapy at 35 mL/kg/h (2,000 mL/1.73 m(2)/h), a dose that allows adequate flexibility in fluid management and that may provide effective clearance of proinflammatory (and anti-inflammatory) mediators that drive the evolving dysfunction. Proactive intervention improves the clinical status such that the transition to mechanical ventilation may proceed smoothly or in some cases even may be avoided altogether.

Pulmonary function changes in experimental graft-versus-host disease of the lung

Pulmonary graft-versus-host disease (p-GVHD) is a serious complication after allogeneic stem cell transplantation (allo-SCT) of high morbidity and high mortality. We characterized breathing patterns and pulmonary function changes in correlation to lung histopathology and survival by using a well-established murine model of p-GVHD. Lethally irradiated B6D2F1 mice received SCT from either syngeneic B6D2F1 or allogeneic C57BL/6 animals. Within 6 weeks, severe p-GVHD developed in allogeneic recipients characterized by progressive interstitial, alveolar, peribronchial, and periluminal inflammatory cell infiltration, whereas in syngeneic recipients lung histology remained normal. Allogeneic recipients demonstrated decreased minute ventilation (MV), reduced peak inspiratory and expiratory flow rates as early as 1 week after SCT. In addition, allo-SCT resulted in restrictive pulmonary function changes as early as 7 days after transplantation and in progressive airflow obstruction within 6 weeks. Decreased breathing abilities and pulmonary function changes of allogeneic recipients were associated with increased mortality and the severity of acute graft-versus-host disease (aGVHD). These findings show that p-GVHD can be characterized by changes in pulmonary function and functional respiratory insufficiency. Furthermore, our data strengthen the understanding, that the lung is a critical target organ of aGVHD.