Competitive TNF Inhibitor (ETANERCEPT) for the Treatment of Idiopathic Pneumonia Syndrome (IPS) Following Allogeneic Stem Cell Transplantation (SCT). A Joint Pediatric Blood and Marrow Transplant Consortium (PBMTC) and Childrens Oncology Group (COG) Study

A call to arms: a critical need for interventions to limit pulmonary toxicity in the stem cell transplantation patient population

Noninfectious pulmonary toxicity after allogeneic hematopoietic stem cell transplantation (allo-HSCT) causes significant morbidity and mortality. Main presentations are idiopathic pneumonia syndrome (IPS) in the acute setting and bronchiolitis obliterans syndrome (BOS) and cryptogenic organizing pneumonia (COP) at later time point. While COP responds well to corticosteroids, IPS and BOS often are treatment refractory. IPS, in most cases, is rapidly fatal, whereas BOS progresses over time, resulting in chronic respiratory failure, impaired quality of life, and eventually, death. Standard second-line treatments are currently lacking, and current approaches, such as augmented T cell-directed immunosuppression, B cell depletion, TNF blockade, extracorporeal photopheresis, and tyroskine kinase inhibitor therapy, are unsatisfactory with responses in only a subset of patients. Better understanding of underlying pathophysiology hopefully results in the identification of future targets for preventive and therapeutic strategies along with an emphasis on currently underutilized rehabilitative and supportive measures.

Pulmonary specific ancillary treatment for pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide an overview of the current literature on pulmonary-specific therapeutic approaches to pediatric acute respiratory distress syndrome to determine recommendations for clinical practice and/or future research.

DATA SOURCES

PubMed, EMBASE, CINAHL, SCOPUS, and the Cochrane Library were searched from inception until January 2013 using the following keywords in various combinations: ARDS, treatment, nitric oxide, heliox, steroids, surfactant, etanercept, prostaglandin therapy, inhaled beta adrenergic receptor agonists, N-acetylcysteine, ipratroprium bromide, dornase, plasminogen activators, fibrinolytics or other anticoagulants, and children. No language restrictions were applied. References from identified articles were searched for additional publications.

STUDY SELECTION

All clinical studies pertaining to pulmonary-specific therapeutic approaches to pediatric acute respiratory distress syndrome were reviewed. If clinical pediatric data were sparse or unavailable, the findings from studies of adult acute respiratory distress syndrome and animal models that might be relevant to pediatric acute respiratory distress syndrome were examined.

DATA EXTRACTION

All relevant studies were reviewed and pertinent data abstracted.

DATA SYNTHESIS

Over the course of three international meetings, the pertinent findings of the literature review were discussed by a panel of 24 experts in the field representing 21 academic institutions and 8 countries. Recommendations developed and the supporting literature were distributed to all panel members without a conflict of interest and were scored by using the Research ANd Development/University of California, Los Angeles Appropriateness method. The modified Delphi approach was used as the methodology to achieve consensus among the panel.

CONCLUSIONS

Overall, the routine use of surfactant, inhaled nitric oxide, glucocorticoids, prone positioning, endotracheal suctioning, and chest physiotherapy cannot be recommended. Inhaled nitric oxide should only be used for patients with documented pulmonary hypertension and/or right ventricular failure. Prone positioning may be considered in patients with severe pediatric acute respiratory distress syndrome. Future studies are definitely warranted to establish the role, if any, of these ancillary treatment modalities in pediatric acute respiratory distress syndrome.

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.