Idiopathic pneumonia syndrome in mice after allogeneic bone marrow 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.

Immunosuppressive mechanisms of human bone marrow derived mesenchymal stromal cells in BALB/c host graft versus host disease murine models

Background

Mesenchymal stromal cells (MSCs) are proven to have immunosuppressive functions via various mechanisms. These mechanisms were demonstrated by administering bone marrow derived human MSCs (hMSCs) to graft versus host disease (GVHD) murine models.

Methods

BALB/c host mice were irradiated prior to receiving C57BL/6 donor T cell depleted bone marrow (TCDBM) cells (negative control) and donor CD4+ T lymphocyte with (treatment group) or without hMSCs (positive control). The presence of hMSCs in target tissues and lymphoid organs was documented by using in vivo imaging and measuring the expression of EphB2 and ephrin-B2 by RTqPCR. Survival rate and GVHD score were also monitored. Tissue sections were obtained for histopathologic analysis. Flow cytometry was used to document donor T cell alloreactivity and expression of CCR5, CXCR3 and CCR7. ELISA was utilized to determine levels of proinflammatory cytokines, RANTES (CCL5) and phosphorylated STAT 5A/B. RTqPCR was performed to quantify expression of CCL3 and CXCL9. Western blotting was performed to qualitatively measure iNOS expression.

Results

Survival rate and GVHD score improved with hMSC treatment. Pathologic changes of GVHD were abrogated. Documentation of suppression of RANTES, CCL3, CXCL9, CCR5 and CXCR3 with simultaneous decrease of donor T cell alloreactivity was demonstrated 6 days after transplantation, along with reduction of levels of inflammatory cytokines, suppression of STAT 5A/B phosphorylation, increased expression of CCR7 and increased production of nitrous oxide by hMSCs. Documentation of homing of hMSCs to lymphoid organs and target tissues was also performed.

Conclusions

These mechanisms contribute to the current understanding of MSC mechanisms of immunosuppression and forms a comprehensive picture of how they exert immunosuppression in an in vivo model of immune dysregulation.

Electronic supplementary material

The online version of this article (doi:10.1186/s40164-015-0007-0) contains supplementary material, which is available to authorized users.

Preventive azithromycin treatment reduces noninfectious lung injury and acute graft-versus-host disease in a murine model of allogeneic hematopoietic cell transplantation

Noninfectious lung injury and acute graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (allo-HCT) are associated with significant morbidity and mortality. Azithromycin is widely used in allogeneic HCT recipients for pulmonary chronic GVHD, although current data appear controversial. We induced GVHD and noninfectious lung injury in lethally irradiated B6D2F1 mice by transplanting bone marrow and splenic T cells from allogeneic C57BL/6 mice. Experimental groups were treated with oral azithromycin starting on day 14 until the end of week 6 or week 14 after transplantation. Azithromycin treatment resulted in improved survival and decreased lung injury; the latter characterized by improved pulmonary function, reduced peribronchial and perivascular inflammatory cell infiltrates along with diminished collagen deposition, and a decrease in lung cytokine and chemokine expression. Azithromycin also improved intestinal GVHD but did not affect liver GVHD at week 6 early after transplantation. At week 14, azithromycin decreased liver GVHD but had no effect on intestinal GVHD. In vitro, allogeneic antigen-presenting cell (APC)- dependent T cell proliferation and cytokine production were suppressed by azithromycin and inversely correlated with relative regulatory T cell (Treg) expansion, whereas no effect was seen when T cell proliferation occurred APC independently through CD3/CD28-stimulation. Further, azithromycin reduced alloreactive T cell expansion but increased Treg expansion in vivo with corresponding downregulation of MHC II on CD11c(+) dendritic cells. These results demonstrate that preventive administration of azithromycin can reduce the severity of acute GVHD and noninfectious lung injury after allo-HCT, supporting further investigation in clinical trials.

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.

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.

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.

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.

Interferon-gamma regulates idiopathic pneumonia syndrome, a Th17+CD4+ T-cell-mediated graft-versus-host disease

RATIONALE

Pulmonary complications of hematopoietic stem cell transplantation include infections and graft-versus-host diseases, such as idiopathic pneumonia syndrome (IPS). Conflicting data exist regarding the role of the interferon (IFN)-gamma-producing Th1 CD4(+) T-cell subset and IL-17A in IPS.

OBJECTIVES

To determine the role of IFN-gamma and IL-17A in the establishment of pulmonary graft-versus-host disease.

METHODS

A semiallogeneic murine model based on C57BL/6 x BALB/c as recipients with transplantation of BALB/c RAG2(-/-) bone marrow and transfer of different genetic knockout T cells (T-bet(-/-), IFN-gamma(-/-), IFN-gammaR(-/-)) on a BALB/c background. Lung tissue was examined for parenchymal changes and infiltrating cells by histology and fluorescence-activated cell sorter analysis.

MEASUREMENTS AND MAIN RESULTS

After transfer of semiallogeneic bone marrow together with donor CD4(+) T cells lacking IFN-gamma or T-bet-a T-box transcription factor controlling Th1 commitment-we found severe inflammation in the lungs, but no enhancement in other organs. In contrast, wild-type donor CD4(+) T cells mediated minimal inflammation only, and donor CD8(+) T cells were not required for IPS development. Mechanistically, the absence of IFN-gamma or IFN-gamma signaling in pulmonary parenchymal cells promoted expansion of IL-17A-producing CD4(+) T cells and local IL-17A release. In vivo depletion of IL-17A reduced disease severity.

CONCLUSIONS

One mechanism of IFN-gamma protection against IPS is negative regulation of the expansion of pathogenic IL-17A-producing CD4(+) T cells through interaction with the IFN-gamma receptor on the pulmonary parenchymal cell population.

Murine models of chronic graft-versus-host disease: insights and unresolved issues

Chronic graft-versus-host-disease (cGVHD) is a major barrier to successful allogeneic hematopoietic stem cell transplantation (allo-HSCT), with highly variable clinical presentations. The pathophysiology of cGVHD remains relatively poorly understood. The utilization of murine models to study cGVHD encompasses experimental challenges distinct from those that have been successfully used to study acute GVHD (aGVHD). Nevertheless, despite these challenges, murine models of cGVHD have contributed to the understanding of cGVHD, and highlight its mechanistic complexity. In this article, insights into the pathophysiology of cGVHD obtained from murine studies are summarized in the context of their relevancy to clinical cGVHD. Despite experimental limitations, current and future models of murine cGVHD will continue to provide insights into the understanding of clinical cGVHD and provide information for new therapeutic interventions.

Acute lung injury after allogeneic stem cell transplantation: from the clinic, to the bench and back again

Allogeneic hematopoietic stem cell transplantation (SCT) is the only curative therapeutic option for a number of malignant and non-malignant conditions, but the success of this treatment strategy is limited by several side effects. Diffuse lung injury is a major complication of SCT that responds poorly to standard treatment and significantly contributes to transplant related morbidity and mortality. Lung injury occurs in both acute and chronic forms and can be either infectious or non-infectious in nature. Acute, non-infectious lung injury following SCT has been defined as idiopathic pneumonia syndrome (IPS). This review will outline the clinical spectrum, risk factors, and pathogeneses of IPS and discuss how current approaches to therapy are being influenced by insights generated using animal models of disease.

Natural history of pulmonary complications in children after bone marrow transplantation

We sought, in children after bone marrow transplantation (BMT), (1) to determine the natural history and incidence of pulmonary complications, (2) to evaluate the diagnostic yield of fiberoptic bronchoscopy and bronchoalveolar lavage (BAL); and (3) to determine the effect of bronchoscopy with lavage on patient outcome. The study design was a retrospective review in a tertiary care university hospital of all children undergoing BMT over a 5-year period. Patients were separated into 2 study groups: children with and without pulmonary complications. Pulmonary complications were defined as new or persistent pulmonary infiltrates on chest radiograph or chest computed tomography scan, respiratory symptoms, hypoxemia, or hemoptysis. Three hundred sixty-three pediatric patients underwent BMT between January 1, 1995, and December 31, 1999. Ninety patients (25%) developed pulmonary complications and were evaluated with bronchoscopy and BAL. Patients with pulmonary complications had a higher mortality (65% versus 44%; P < .01). The median posttransplantation survival for children with pulmonary complications was 258 days, compared with 1572 days in patients without pulmonary complications. The incidence of pulmonary complications was increased in patients with allogeneic BMT (P < .01). The time-dependent onset of severe (grade III to IV) graft-versus-host disease increased the relative risk of pulmonary complications by 2.0 (95% confidence interval, 1.1-3.7; P = .02). Pulmonary complications increased the time-dependent relative risk of mortality by 3.5 (95% confidence interval, 2.5-4.8). The diagnostic yield of bronchoscopy with lavage was 46% in patients undergoing BAL. Diagnostic bronchoscopy did not enhance either 30- or 100-day survival. Pathogen identification did not decrease mortality (P = .45). Pulmonary complications occur in 25% of children undergoing BMT and increase the risk of death in the first year after BMT. Although pathogen identification does not confer a survival advantage, rigorous, prospective screening may allow for earlier identification of pathogens and thereby provide a benefit to this uniquely vulnerable population.

Increase of interleukin-18 serum levels after engraftment correlates with acute graft-versus-host disease in allogeneic peripheral blood stem cell transplantation

PURPOSE

Acute graft-versus-host disease (GvHD) is a constant and severe complication after allogeneic stem cell transplantation regularly involving skin, liver, gut, and lungs. The cytokine interleukin-18 (IL-18) has been shown to increase in patients who develop acute GvHD after bone marrow tranplantation (BMT).

MATERIALS AND METHODS

Here, we measured IL-18 serum levels after peripheral blood stem cell transplantation (PBSCT) at several characteristic time points in 24 patients (median age 46 years). Patients received a median of 7.3 x 10(6)/kg bodyweight CD34-positive blood stem cells from HLA-matched family donors (n = 5), matched unrelated donors (n = 18), and one mismatched unrelated donor. GvHD prophylaxis consisted of cyclosporin A alone or combined with methotrexate and/or mycophenolate mofetil.

RESULTS

In 14 patients we observed no GvHD or only GvHD grade I whereas ten patients developed GvHD grade II-IV post transplant. Low, intermediate, and high levels of serum IL-18 were found in patients after allogeneic PBSCT independently of GvHD after transplantation. In contrast to GvHD arising after BMT, there was no clear correlation between absolute IL-18 serum levels and GvHD grade after PBSCT. However, the individual time course of IL-18 serum level after engraftment correlates with acute GvHD after PBSCT. In detail, an increase of serum IL-18 of at least 1.6-fold after engraftment is associated with acute GvHD II or higher with a sensitivity of three out of four. Using the 1.6 "cut-off" for IL-18 increase after engraftment, a specificity of up to 100% can be achieved.

CONCLUSION

The time course of IL-18 serum levels might be used for GvHD prediction after PBSCT comparable to absolute serum levels after BMT.

Acute lung injury after allogeneic stem cell transplantation: is the lung a target of acute graft-versus-host disease?

Allogeneic hematopoietic stem cell transplantation (SCT) is an important therapeutic option for a number of malignant and nonmalignant conditions but the broader application of this treatment strategy is limited by several side effects. In particular, diffuse lung injury is a major complication of SCT that responds poorly to standard therapeutic approaches and significantly contributes to transplant-related morbidity and mortality. Historically, approximately 50% of all pneumonias seen after SCT have been secondary to infection, but the judicious use of broad-spectrum antimicrobial prophylaxis in recent years has tipped the balance of pulmonary complications from infectious to noninfectious causes. This mini review will discuss the definition, risk factors and pathogeneses of noninfectious lung injury that occurs early after allogeneic SCT.

Endogenous Nitric Oxide Protects against T Cell-Dependent Lethality during Graft-versus-Host Disease and Idiopathic Pneumonia Syndrome

The pathogenesis of idiopathic pneumonia syndrome (IPS), a noninfectious pulmonary complication of allogeneic bone marrow transplantation (BMT), has not been fully elucidated. However, several contributing factors have been proposed, including lung injury caused by reactive oxygen and nitrogen intermediates during preconditioning and development of graft-vs-host disease (GVHD). Studies on the role of reactive oxygen and nitrogen intermediates in IPS have yielded conflicting results. We have described a murine model of IPS, in which the onset of lung inflammation was delayed by several weeks relative to GVHD. This study evaluated whether the delay in onset of IPS was due to slow turnover of NO-producing, immunosuppressive alveolar macrophages (AM) following BMT. The results indicated that AM were immunosuppressive due to synthesis of NO. However, NO production and immunosuppressive activity by AM did not decline after BMT, but rather remained elevated throughout the 12-wk development of GVHD and IPS. In a 14-day model of IPS, continuous inhibition of NO with aminoguanidine (AG) reduced signs of IPS/GVHD, but also led to higher mortality. When AG treatment was initiated after onset of IPS/GVHD, rapid mortality occurred that depended on the severity of IPS/GVHD. AG-enhanced mortality was not due to inhibition of marrow engraftment, elevated serum TNF-alpha, liver injury, or hypertensive responses. In contrast, T cells were involved, because depletion of CD4(+) lymphocytes 24 h before AG treatment prevented mortality. Thus, NO production following allogeneic BMT affords a protective effect that helps down-regulate injury caused by T cells during GVHD and IPS.

Increased Exhaled Nitric Oxide Following Autologous Peripheral Hematopoietic Stem-Cell Transplantation

BACKGROUND

Increased production of nitric oxide (NO) and oxidative stress following bone marrow transplantation may play a role in the pathogenesis of idiopathic pneumonia syndrome (IPS). We hypothesize that patients who received high-dose chemotherapy followed by autologous peripheral hematopoietic stem-cell transplantation (APHSCT) have increased exhaled NO.

METHOD

We measured exhaled lower respiratory tract NO concentration with a chemiluminescent NO analyzer during a slow vital capacity maneuver against a positive pressure of 16 cm H(2)O at an expiratory flow rate of 50 mL/s in 20 female patients who received high-dose chemotherapy (cyclophosphamide, carmustine, and cisplatin) followed by APHSCT for the treatment of stage III or IV breast carcinoma. Pulmonary function tests were performed, and exhaled NO measurements and clinical and laboratory data were obtained before transplantation and at every 6-week visit after transplantation for 24 weeks.

RESULTS

All study patients had evidence of IPS with dyspnea and reduction in diffusion capacity of the lung for carbon monoxide (DLCO). Lower respiratory tract exhaled NO was significantly higher after APHSCT and during the 6 months of follow-up. Mean (+/- SD) exhaled NO increased from (mean +/- SD) 12.54 +/- 1.32 parts per billion (ppb) before APHSCT to 21.26 +/- 1.94 ppb at 6 weeks (p = 0.099), 21.26 +/- 1.94 ppb (p = 0.006) at 12 weeks, 24.62 +/- 2.55 ppb (p = 0.012) at 18 weeks, and 25.28 +/- 3.31 ppb (p = 0.013) at 24 weeks (all p values were compared to baseline). There was a strong negative correlation between DLCO and exhaled NO (regression coefficient - 0.60, p = 0.01).

CONCLUSION

Lower respiratory tract concentration of exhaled NO is significantly increased following APHSCT and correlates with reduction in DLCO. Increase in lower respiratory tract concentration of NO is a potential marker of IPS.

Late-onset noninfectious pulmonary complications after allogeneic stem cell transplantation are significantly associated with chronic graft-versus-host disease and with the graft-versus-leukemia effect

Late-onset noninfectious pulmonary complications (LONIPCs) occurring beyond 3 months after allogeneic stem cell transplantation (allo-SCT) have become recognized as life-threatening complications, and they reduce the recipient's quality of life. However, the pathogenesis and optimal treatment for LONIPCs are still unclear. In this study, we retrospectively analyzed the incidence and outcome of LONIPCs among allo-SCT recipients. Between October 1993 and September 2001, 96 patients underwent allo-SCT and 76 patients who survived and were free of disease for more than 3 months after SCT were enrolled. Among the 76 patients, 18 patients (23.7%) developed LONIPCs at a median interval of 227 days after allo-SCT (range, 91-1105 days). The patients with LONIPCs were subclassified into those with bronchiolitis obliterans (BO) (6 patients), with interstitial pneumonia (IP) (11 patients), or with both BO and IP (1 patient). The presence of extensive chronic graft-versus-host disease (GVHD) was significantly associated with the development of LONIPCs (P =.0008). Liver or skin involvement in chronic GVHD was not associated, but sicca syndrome was significantly associated with the development of LONIPCs (P <.0001). Most of the IP patients (58.3%) responded well to immunosuppressive treatment, while BO patients did not respond to the therapy. Eight of the 18 patients with LONIPCs died. The major cause of death was respiratory failure (62.5%). The relapse rate of primary malignant disease in the LONIPC patients was significantly lower than that of non-LONIPC patients (1 of 17 [5.9%] versus 16 of 52 [30.8%]; P =.0387). These results indicate that the development of LONIPCs was strongly associated with chronic GVHD and especially with sicca syndrome and the graft-versus-leukemia (GVL) effect.

A critical role for CCR2/MCP-1 interactions in the development of idiopathic pneumonia syndrome after allogeneic bone marrow transplantation

Idiopathic pneumonia syndrome (IPS) is a major complication after allogeneic bone marrow transplantation (allo-BMT) and involves the infiltration of donor leukocytes and the secretion of inflammatory cytokines. We hypothesized that leukocyte recruitment during IPS is dependent in part upon interactions between chemokine receptor 2 (CCR2) and its primary ligand monocyte chemoattractant protein-1 (MCP-1). To test this hypothesis, IPS was induced in a lethally irradiated parent --> F1 mouse BMT model. Compared with syngeneic controls, pulmonary expression of MCP-1 and CCR2 mRNA was significantly increased after allo-BMT. Transplantation of CCR2-deficient (CCR2-/-) donor cells resulted in a significant reduction in IPS severity compared with transplantation of wild-type (CCR2+/+) cells and in reduced bronchoalveolar lavage (BAL) fluid cellularity and BAL fluid levels of tumor necrosis factor-alpha (TNF-alpha) and soluble p55 TNF receptor (sTNFRI). In addition, neutralization of MCP-1 resulted in significantly decreased lung injury compared with control-treated allogeneic recipients. Experimental data correlated with preliminary clinical findings; patients with IPS have elevated levels of MCP-1 in the BAL fluid at the time of diagnosis. Collectively, these data demonstrate that CCR2/MCP-1 interactions significantly contribute to the development of experimental IPS and suggest that interventions blocking these receptor-ligand interactions may represent novel strategies to prevent or treat this lethal complication after allo-BMT.

Idiopathic pneumonia syndrome after syngeneic bone marrow transplant in mice

Idiopathic pneumonia syndrome is characterized by noninfectious diffuse lung injury after myeloablative chemotherapy and bone marrow transplant. Because little is known about its pathogenesis after autologous-based regimens, we have developed a murine model that closely mimics the human lung disease process. Using an autologous regimen similar to that used for patients with metastatic breast cancer, mice developed pulmonary injury as early as 1 day posttransplant. This lung injury was most dramatically characterized by decreased lung compliance that was associated with an intense monocytic cellular infiltrate of activated macrophages. This influx was preceded by an acute elevation in monocyte chemotactic protein-1 and macrophage inflammatory protein-1alpha. The conditioning regimen caused substantial oxidative stress as manifest by elevations in lung lipid peroxidation and oxidized glutathione. To test the hypothesis that oxidation is directly responsible for the lung toxicity, we administered the antioxidant, n-acetylcysteine. These mice showed substantially less lung injury, thus providing direct evidence that oxidative stress plays a distinct role in the development of lung injury in the early periautologous bone marrow transplant period. Attenuation of lung oxidative stress and/or inflammation in patients undergoing autologous bone marrow transplant may reduce the subsequent development of idiopathic pneumonia syndrome.

TNFalpha, interleukin-10 and interleukin-18 expression in cells of the bronchoalveolar lavage in patients with pulmonary complications following bone marrow or peripheral stem cell transplantation: a preliminary study

Pulmonary complications pose a major clinical problem after bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT). The underlying pathophysiological mechanisms are under investigation. Twenty patients with infectious or non-infectious pulmonary complications after BMT or PBSCT underwent bronchoalveolar lavage (BAL) and tumor necrosis factor-alpha (TNFalpha), interleukin-10 (IL-10) and interleukin-18 (IL-18) mRNA expression was determined in BAL cells in comparison to 11 healthy volunteers. Patients were divided into two groups (infectious pneumonia, n = 14 or idiopathic pneumonia syndrome (IPS)/bronchiolitis obliterans (BO), n = 6). TNFalpha expression was significantly increased in both patient groups compared to the control (0.40 +/- 0.07 and 0.39 +/- 0.09 vs 0.15 +/- 0.05; P < 0.05; semiquantitative PCR analysis; mean +/- s.e.m.). IL-10 expression was significantly elevated the group of patients with infectious pneumonia in comparison to normal controls (0.15 +/- 0.06 vs 0.01 +/- 0.01; P < 0.05) but not in patients with IPS/BO (0.05 +/- 0.04; P > 0.05). However, IL-10 was not expressed in BAL cells of all patients and control individuals. IL-18 expression was significantly decreased in the both patient groups (1.47 +/- 0.24 and 1.79 +/- 0.63) in comparison to the control group (4.29 +/- 0.77; P < 0.05). Survival analysis showed a significant association between elevation of TNFalpha and poor prognosis (P < 0.05). These results highlight the immunoregulatory disturbances in the lungs after BMT/PBSCT.

Oxidative stress and inflammation contribute to lung toxicity after a common breast cancer chemotherapy regimen

Delayed pulmonary toxicity syndrome after high-dose chemotherapy (HDC) and autologous hematopoietic support occurs in up to 64% of women with advanced-stage breast cancer. Using a similar, but nonmyeloablative, HDC treatment regimen in mice, we found both immediate and persistent lung injury, coincident with marked decreases in lung tissue glutathione reductase activity and accompanied by increases in lung oxidized glutathione, bronchoalveolar lavage (BAL) lipid peroxidation, and BAL total cell counts. Most interestingly, at 6 wk, BAL total cell counts had increased fourfold, with lymphocyte cell counts increasing >11-fold. A single supplemental dose of glutathione prevented early lung injury at 48 h but showed no lung-protective effects at 6 wk, whereas single doses of other thiol-sparing agents (Ethyol and glutathione monoethyl ester) showed no benefit. These data suggest that this HDC regimen results in acute and persistent lung toxicity, induced in part by oxidative stress, that culminates with an acute lung cellular inflammatory response. Continuous glutathione supplementation and/or attenuation of the delayed pulmonary inflammatory response may prove beneficial in preventing lung toxicity after the use of these chemotherapeutic agents.

Early onset of acute immune-mediated lung injury in a child undergoing allogeneic peripheral blood transplantation

Animal models have recently clarified the lung injury after allogeneic hematopoietic transplantation. These works have confirmed the role of donor T lymphocytes in immune-mediated inflammatory reactions in the lung. We report here a fatal case of a 3-year-old child who developed acute respiratory failure coinciding with the onset of hyper-acute graft versus host disease (aGVHD) after allogeneic peripheral stem cell transplantation. aGVHD was refractory to treatment and the patient died on day +28. Lung necropsy showed interstitial pneumonia and peribronchial and perivascular infiltration by mononuclear cells, with no viral inclusions. These findings are not specific but have been found by some authors in animal models with acute immune-mediated lung injury related with donor T lymphocytes. Immune-mediated lung injury, as defined by animal models, should be considered in patients with severe signs of systemic aGVHD while excluding other known etiologies of pulmonary disease.

Idiopathic pneumonia syndrome after bone marrow transplantation: the role of pre-transplant radiation conditioning and local cytokine dysregulation in promoting lung inflammation and fibrosis

Pulmonary complications and graft-vs.-host disease (GVHD) remain severe threats to survival after bone marrow transplantation (BMT). Idiopathic pneumonia syndrome (IPS) accounts for nearly 50% of all the cases of interstitial pneumonitis after BMT. IPS is characterized by an early inflammatory phase followed by chronic inflammation and fibrosis of lung tissue; however, the immunopathogenesis of this disease is not yet clearly understood. This biphasic syndrome has been reported to be associated with pre-transplant radiation conditioning in some studies while others have suggested that GVHD or autoimmune phenomena may be responsible for its development. The early post-BMT phase is characterized by the presence of inflammatory cytokines whose net effect is to promote lymphocyte influx into lungs with minimal fibrosis, that leads to an acute form of graft-vs.-host reaction-mediated pulmonary tissue damage. Gradual changes over time in leucocyte influx and activation lead to dysregulated wound repair mechanisms resulting from the shift in the balance of cytokines that promote fibrosis. Using data from new animal models of IPS and information from studies of human IPS, we hypothesize that cytokine-modulated immunological mechanisms which occur during the acute and chronic phases after bone marrow transplantation lead to the development of the progressive, inflammatory, and fibrotic lung disease typical of idiopathic pneumonia syndrome.

Hyporesponsiveness of donor cells to lipopolysaccharide stimulation reduces the severity of experimental idiopathic pneumonia syndrome: potential role for a gut-lung axis of inflammation

Idiopathic pneumonia syndrome (IPS) is a major complication of allogeneic bone marrow transplantation (BMT). We have shown that experimental IPS is associated with increased levels of LPS and TNF-alpha in the bronchoalveolar lavage (BAL) fluid. We hypothesized that the deleterious effects of these inflammatory mediators in the lung may be linked to gut injury that develops after BMT. To test this hypothesis, we used mouse strains that differ in their sensitivity to LPS as donors in an experimental BMT model. Lethally irradiated C3FeB6F(1) hosts received BMT from either LPS-sensitive or LPS-resistant donors. Five weeks after BMT, LPS-resistant BMT recipients had significantly less lung injury compared with recipients of LPS-sensitive BMT. This effect was associated with reductions in TNF-alpha secretion (both in vitro and in vivo), BAL fluid LPS levels, and intestinal injury. The relationship between TNF-alpha, gut toxicity, and lung injury was examined further by direct cytokine blockade in vivo; systemic neutralization of TNF-alpha resulted in a significant reduction in gut histopathology, BAL fluid LPS levels, and pulmonary dysfunction compared with control-treated animals. We conclude that donor resistance to endotoxin reduces IPS in this model by decreasing the translocation of LPS across the intestinal border and systemic and pulmonary TNF-alpha production. These data demonstrate a potential etiologic link between gut and lung damage after BMT and suggest that methods that reduce inflammatory responses to LPS, and specifically, those that protect the integrity of the gut mucosa, may be effective in reducing IPS after BMT.

T-lymphocyte production of macrophage inflammatory protein-1α is critical to the recruitment of CD8+ T cells to the liver, lung, and spleen during graft-versus-host disease

To investigate the mechanism by which macrophage inflammatory protein-1α (MIP-1α) affects graft-versus-host disease (GVHD), the expression and function of MIP-1α in 2 murine models of GVHD were evaluated. In irradiated class I and class II disparate recipients, the expression of messenger RNA (mRNA) and protein for MIP-1α was significantly increased in GVHD target organs after transfer of allogeneic lymphocytes compared to syngeneic lymphocytes. When lymphocytes unable to make MIP-1α were transferred, there was a decrease in the production of MIP-1α in the liver, lung, and spleen of bm1 (B6.C-H2bm1/By) and bm12 (B6.C-H2bm12/KhEg) recipients compared to the transfer of wild-type splenocytes. At day 6 there was a 4-fold decrease in the number of transferred CD8+ T cells in the lung and approximately a 2-fold decrease in the number of CD8+ T cells in the liver and spleen in bm1 recipients after transfer of MIP-1α–deficient (MIP-1α−/−) splenocytes compared to wild-type (MIP-1α+/+) splenocytes. These differences persisted for 13 days after splenocyte transfer. In contrast, the number of donor CD4+ T cells found in the liver and lung was significantly increased after the transfer of MIP-1α−/− compared to wild-type splenocytes in bm12 recipients from day 6 through day 10. Thus, the transfer of allogeneic T cells was associated with the enhanced expression of MIP-1α in both a class I and class II mismatch setting. However, the increased expression only led to enhanced recruitment of CD8+, but not CD4+, donor T cells. Production of MIP-1α by donor T cells is important in the occurrence of GVHD and functions in a tissue-dependent fashion.

T-lymphocyte production of macrophage inflammatory protein-1α is critical to the recruitment of CD8+ T cells to the liver, lung, and spleen during graft-versus-host disease

To investigate the mechanism by which macrophage inflammatory protein-1α (MIP-1α) affects graft-versus-host disease (GVHD), the expression and function of MIP-1α in 2 murine models of GVHD were evaluated. In irradiated class I and class II disparate recipients, the expression of messenger RNA (mRNA) and protein for MIP-1α was significantly increased in GVHD target organs after transfer of allogeneic lymphocytes compared to syngeneic lymphocytes. When lymphocytes unable to make MIP-1α were transferred, there was a decrease in the production of MIP-1α in the liver, lung, and spleen of bm1 (B6.C-H2bm1/By) and bm12 (B6.C-H2bm12/KhEg) recipients compared to the transfer of wild-type splenocytes. At day 6 there was a 4-fold decrease in the number of transferred CD8+ T cells in the lung and approximately a 2-fold decrease in the number of CD8+ T cells in the liver and spleen in bm1 recipients after transfer of MIP-1α–deficient (MIP-1α−/−) splenocytes compared to wild-type (MIP-1α+/+) splenocytes. These differences persisted for 13 days after splenocyte transfer. In contrast, the number of donor CD4+ T cells found in the liver and lung was significantly increased after the transfer of MIP-1α−/− compared to wild-type splenocytes in bm12 recipients from day 6 through day 10. Thus, the transfer of allogeneic T cells was associated with the enhanced expression of MIP-1α in both a class I and class II mismatch setting. However, the increased expression only led to enhanced recruitment of CD8+, but not CD4+, donor T cells. Production of MIP-1α by donor T cells is important in the occurrence of GVHD and functions in a tissue-dependent fashion.

Pulmonary cytolytic thrombi: a previously unrecognized complication of bone marrow transplantation

Lung injury is a frequent and severe complication of bone marrow transplantation (BMT). Over the past 5 years we have recognized a new noninfectious pulmonary complication of allogeneic BMT in 12 patients, presenting with fever, pulmonary nodules on chest computed tomography, and distinctive histopathologic appearance descriptively termed "pulmonary cytolytic thrombi" (PCT). All but one patient were children transplanted for malignant (9) and nonmalignant (3) conditions. Ten of the patients had active graft-versus-host disease (GVHD) of skin, bowel, or both at the time of diagnosis of the PCT. In all cases occlusive vascular lesions were present, most of them associated with hemorrhagic infarcts. The endothelial cell layer was discontinuous in all cases stained with antibody to CD31. The thrombi had entrapped recognizable leukocytes and CD45-positive cell fragments embedded in a tenacious basophilic material. The symptoms and radiologic findings resolved in weeks to months. PCT may represent a previously unrecognized form of pulmonary acute GVHD.

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

BACKGROUND

Idiopathic pneumonia syndrome (IPS) is a frequent and potentially fatal complication of bone marrow transplantation (BMT). We have previously shown that experimental IPS is associated with increased levels of lipopolysaccaride (LPS) and tumor necrosis factor-alpha (TNFalpha) in the bronchoalveolar lavage (BAL) fluid, and that administration of LPS to animals with extensive graft versus host exacerbated underlying lung injury (Blood 1996; 88: 3230).

METHODS

Lethally irradiated CBA mice received BMT from allogeneic (B10.BR) or syngeneic (CBA) donors. The role of TNFalpha in the exacerbation of pulmonary toxicity caused by LPS injection and in the evolution of IPS after allogeneic BMT was examined by neutralizing TNFalpha after BMT using a soluble binding protein (rhTNFR:Fc).

RESULTS

Five weeks after BMT, administration of rhTNFR:Fc dramatically reduced mortality and prevented the exacerbation of lung injury caused by LPS administration. This protective effect was associated with preservation of pulmonary function and with marked reductions of cells, neutrophils, and LPS in the BAL fluid of treated animals. TNFalpha neutralization from week 4 to 6 after allogeneic BMT effectively halted the progression of systemic GVHD and significantly reduced, but did not prevent lung injury that developed during the treatment period.

CONCLUSIONS

We conclude that TNFalpha is central to early LPS induced toxicity in this model and is a significant, but not the exclusive contributor to the development of IPS after allogeneic BMT.

KGF pretreatment decreases B7 and granzyme B expression and hastens repair in lungs of mice after allogeneic BMT

We investigated keratinocyte growth factor (KGF) as a pretreatment therapy for idiopathic pneumonia syndrome (IPS) generated as a result of lung damage and allogeneic T cell-dependent inflammatory events occurring in the early peri-bone marrow (BM) transplant (BMT) period. B10.BR (H2(k)) recipient mice were transplanted with C57BL/6 (H2(b)) BM with spleen cells after lethal irradiation with and without cyclophosphamide conditioning with and without subcutaneous KGF pretreatment. KGF-pretreated mice had fewer injured alveolar type II (ATII) cells at the time of BMT and exhibited ATII cell hyperplasia at day 3 post-BMT. The composition of infiltrating cells on day 7 post-BMT was not altered by KGF pretreatment, but the frequencies of cells expressing the T-cell costimulatory molecules B7.1 and B7.2 and mRNA for the cytolysin granzyme B (usually increased in IPS) were decreased by KGF. Sera from KGF-treated mice had increases in the Th2 cytokines interleukin (IL)-4, IL-6, and IL-13 4 days after cessation of KGF administration (i.e., at the time of BMT). These data suggest that KGF hinders IPS by two modes: 1) stimulation of alveolar epithelialization and 2) attenuation of immune-mediated injury as a consequence of failure to upregulate cytolytic molecules and B7 ligand expression and the induction of anti-inflammatory Th2 cytokines in situ.

Idiopathic pneumonia syndrome after allogeneic bone marrow transplantation in mice. Role of pretransplant radiation conditioning

Idiopathic pneumonia syndrome (IPS) is a significant clinical problem encountered among patients treated with bone marrow transplantation (BMT). IPS is identified as an inflammatory lung disease characterized by diffuse interstitial pneumonitis and alveolitis leading to interstitial fibrosis in the absence of an identifiable infectious agent. In an earlier study we characterized a murine model of IPS following allogeneic BMT that exhibits several features of human IPS. In this report we show that the lung represents a unique target of post-BMT disease in this model. The kinetics of developing lung disease were found to be markedly different from the kinetics of graft-versus-host disease in other tissues such as liver, colon, ear, skin, and tongue. Mice transplanted by our standard protocol with T-cell-depleted semiallogeneic donor bone marrow plus donor spleen cells in the absence of pretransplant radiation conditioning did not develop lung inflammation or fibrosis characteristic of IPS. Pretransplant radiation conditioning in the absence of BMT also failed to cause IPS, demonstrating an important role for radiation conditioning in the development of BMT-related IPS. The occurrence of lung disease post-BMT was found to be dependent on radiation conditioning in a dose-dependent manner. Finally, thoracic irradiation alone was demonstrated to be sufficient in causing IPS in mice transplanted with bone marrow plus spleen cells, albeit with reduced severity. Based on these findings, we conclude that pretransplant radiation conditioning plays an important role in the development of IPS following allogeneic BMT.