白介素-10在肺移植中的研究进展

肺移植术后的并发症主要包括缺血再灌注损伤、急性排异反应和感染、闭塞性细支气管炎为表现的慢性同种异体移植物功能障碍。白介素-10是一个多效应的细胞因子,可通过抑制炎性免疫反应和T细胞介导的免疫反应,对减轻肺移植术后的并发症有一定的作用。     

Bronchiolitis obliterans syndrome: the final frontier for lung transplantation

Bronchiolitis obliterans syndrome (BOS) is a form of chronic lung allograft dysfunction that affects a majority of lung transplant recipients and is the principal factor limiting long-term transplant survival. BOS is characterized by progressive airflow obstruction unexplained by acute rejection, infection, or other coexistent condition. Although BOS is a proven useful clinical syndrome that identifies patients at increased risk for death, its clinical course and underlying causative factors are now recognized to be increasingly heterogeneous. Regardless of the clinical history, the primary pathologic correlate of BOS is bronchiolitis obliterans, a condition of intraluminal airway fibrosis. This article highlights the body of developing research illustrating the mechanisms by which BOS is mediated, including alloimmune reactivity, the emerging roles of humoral and autoimmunity, activation of innate immune cells, and response to nonimmune-related allograft insults, such as infection and aspiration. In addition, we underscore emerging clinical implications and promising future translational research directions that have the potential to advance our knowledge and improve patient outcomes.     

Chemokine up-regulation in SARS-coronavirus-infected, monocyte-derived human dendritic cells

Lymphopenia and increasing viral load in the first 10 days of severe acute respiratory syndrome (SARS) suggested immune evasion by SARS-coronavirus (CoV). In this study, we focused on dendritic cells (DCs) which play important roles in linking the innate and adaptive immunity. SARS-CoV was shown to infect both immature and mature human monocyte-derived DCs by electron microscopy and immunofluorescence. The detection of negative strands of SARS-CoV RNA in DCs suggested viral replication. However, no increase in viral RNA was observed. Using cytopathic assays, no increase in virus titer was detected in infected DCs and cell-culture supernatant, confirming that virus replication was incomplete. No induction of apoptosis or maturation was detected in SARS-CoV-infected DCs. The SARS-CoV-infected DCs showed low expression of antiviral cytokines (interferon alpha [IFN-alpha], IFN-beta, IFN-gamma, and interleukin 12p40 [IL-12p40]), moderate up-regulation of proinflammatory cytokines (tumor necrosis factor alpha [TNF-alpha] and IL-6) but significant up-regulation of inflammatory chemokines (macrophage inflammatory protein 1alpha [MIP-1alpha], regulated on activation normal T cell expressed and secreted [RANTES]), interferon-inducible protein of 10 kDa [IP-10], and monocyte chemoattractant protein 1 [MCP-1]). The lack of antiviral cytokine response against a background of intense chemokine up-regulation could represent a mechanism of immune evasion by SARS-CoV.     

Primary airway epithelial cell culture from lung transplant recipients.

Long-term survival in lung transplantation is limited by the development of obliterative bronchiolitis, a condition characterised by inflammation, epithelial injury, fibroproliferation and obliteration of bronchioles leading to airflow obstruction. To investigate the role of the bronchial epithelium in the pathogenesis of obliterative bronchiolitis the current study aimed to establish primary bronchial epithelial cell cultures (PBEC) from lung allografts. Four to six bronchial brushings were obtained from sub-segmental bronchi of lung allografts. Cells were seeded onto collagen-coated plates and grown to confluence in bronchial epithelial growth medium. Bronchial brushings (n=33) were obtained from 27 patients. PBECs were grown to confluence from 12 out of 33 (39%) brushings. Failure to reach confluence was due to early innate infection. Bacteria were usually isolated from both bronchoalveolar lavage and culture media, but a separate population was identified in culture media only. Primary culture of bronchial epithelial cells from lung transplant recipients is feasible, despite a high rate of early, patient-derived infection. Latent infection of the allograft, identified only by bronchial brushings, may itself be a persistent stimulus for epithelial injury. This technique facilitates future mechanistic studies of airway epithelial responses in the pathogenesis of obliterative bronchiolitis.     

Immune mechanisms of lung allograft rejection

Extended survival after lung transplantation is primarily limited by progressive airflow obstruction and fibrotic obliteration of the small airways, termed bronchiolitis obliterans syndrome (BOS) and bronchiolitis obliterans (BO), respectively. BO is thought to represent the pulmonary-specific manifestation of chronic allograft rejection and the end result of a spectrum of different immunological insults to the allograft. Historically, research has focused on the adaptive immune system and its cellular-based rejection as the driving factor in the development of BO. Recent research in animal lung transplant models and human lung transplant recipients has identified that chemokines, humoral immunity, autoimmunity, and innate immunity also contribute to lung allograft rejection and BO. This review explores the complex immunological mechanisms that promote the high rate of pulmonary allograft failure and significantly impair survival after lung transplantation. We also identify areas for further research critical to improving transplant outcomes.     

Post-transplant bronchiolitis obliterans.

Over the last decade, improvements in surgical techniques, lung preservation, immunosuppression, and management of ischaemia/reperfusion injury and infections have made intermediate-term survival after lung transplantation an achievable goal. However, chronic allograft dysfunction in the form of bronchiolitis obliterans remains a major hurdle that threatens both the quality of life and long-term survival of the recipients. It affects up to 50-60% of patients who survive 5 yrs after surgery, and it accounts for >30% of all deaths occurring after the third postoperative year. This article discusses the alloimmune-dependent and -independent risk factors for bronchiolitis obliterans, the current understanding of the pathogenesis of bronchiolitis obliterans based on results of animal and human studies, the clinical staging of the complication, strategies that may contribute to the prevention and/or early detection of bronchiolitis obliterans, and suggestions for future research.     

DNA viruses (CMV, EBV, and the herpesviruses)

The human Herpesviridae family consists of eight members: cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus 1 and 2 (HSV-1, -2), varicella-zoster virus (VZV), and human herpesvirus 6, 7, and 8 (HHV-6, -7, -8). Lifelong latency may develop in the host with reactivation during periods of relative immunosuppression that occurs in transplant recipients. These are pleiotropic viruses: in addition to their direct effects of tissue injury and clinical illness, they exhibit several indirect effects, including immunomodulation and effects on angiogenesis and tumorigenesis, which may result in long-term adverse sequelae in the lung allograft. CMV and HHV-6 and -7 are increasingly recognized as major causes of morbidity and mortality in lung transplant recipients. EBV and HHV-8 have proven oncogenic potential. HSV-1 and -2 and VZV are neurotropic, causing perioral fever blisters, genital ulcerations, and, rarely, encephalitis. This article discusses the individual pathogens, preventive strategies in the era of potent treatment regimens for established viral infection or disease and their potential impact on the indirect effects of these viruses on long-term allograft function, and the incidence, risk factors for, and impact of antiviral resistance.     

Inhibition of neutrophil function by the Kaposi's sarcoma-associated herpesvirus vOX2 protein

Kaposi's sarcoma is multifactorial, involving Kaposi's sarcoma-associated herpesvirus (KSHV) infection and immune dysfunction. A KSHV protein (vOX2), fused with the Fc domain of human immunoglobulin G1 to create vOX2:Fc, suppressed neutrophil oxidative burst and inhibited the production of pro-inflammatory chemokines (IL-8 and monocyte chemoattractant protein 1) by monocyte/macrophage cells. vOX2:Fc suppressed the acute inflammatory response in mice in which neutrophil-mediated inflammation was induced by carrageenan. The data suggest that vOX2 can contribute to immune dysfunction and could have anti-inflammatory therapeutic potential.     

Asthmatic epithelial cell proliferation and stimulation of collagen production: human asthmatic epithelial cells stimulate collagen type III production by human lung myofibroblasts after segmental allergen challenge.

Epithelial injury and subepithelial collagen deposition are characteristic of asthma. We hypothesized that epithelial cell proliferation increases after airway injury in asthmatics, that epithelial cells stimulate lung myofibroblast collagen production, and that both processes are modulated by allergen-recruited inflammatory cells. Epithelial cells obtained at baseline, 1 d, and 1 and 2 wk after endobronchial allergen challenge from asthmatics and nonasthmatics were placed in culture, with and without bronchoalveolar lavage cells obtained from the same segment. Epithelial cell proliferation and collagen synthesis by human lung myofibroblasts stimulated with culture medium from these epithelial cells were determined. Epithelial proliferation increased (108 +/- 50% above baseline, p = 0.01 for d, and p = 0.004 for group x day interaction) 1 wk postchallenge in cells from asthmatics, but not from nonasthmatics, and required bronchoalveolar lavage cell coculture. Culture medium from epithelium harvested from asthmatics, but not from nonasthmatics, at 1 to 2 wk postchallenge stimulated collagen type III production 50% to 70% (p = 0.043 for clinical group, p = 0.012 for day, and p = 0.022 for group x day interaction), but not collagen type I. This effect was independent of an acute eosinophilic response. We conclude that epithelial cells from asthmatics, but not from nonasthmatics, are stimulated to proliferate after allergen challenge, and over 1 to 2 wk postchallenge, stimulate collagen type III synthesis by lung myofibroblasts. Epithelial cell proliferation appears dependent upon infiltrating inflammatory cells, but stimulation of collagen type III does not.     

Group B streptococcal beta-hemolysin/cytolysin promotes invasion of human lung epithelial cells and the release of interleukin-8.

Pneumonia and lung injury are hallmarks of early-onset neonatal group B streptococcal (GBS) infections. Production of a beta-hemolysin/cytolysin (beta-h/c) encoded by the cylE gene is associated with GBS virulence in vivo. To elucidate the contribution of the beta-h/c toxin to lung injury, the interactions of GBS wild-type strains and isogenic cylE mutants with A549 lung epithelial cells were examined. Compared with wild-type GBS strains, cylE mutants did not produce cytolytic injury, even at high inocula, and exhibited decreased cellular invasion. Additionally, cylE mutants induced less A549 cell release of the neutrophil chemoattractant interleukin (IL)-8. GBS invasion and IL-8 induction were significantly reduced in the presence of dipalmotyl phosphatidylcholine, a major constituent of lung surfactant and a known inhibitor of beta-h/c activity. These data indicate that the GBS beta-h/c contributes to invasion and immune activation of lung epithelial cells and may represent a multifunctional virulence factor in the early pulmonary stages of GBS infection.     

Pathologic correlates of bronchiolitis obliterans syndrome in pulmonary retransplant recipients

RATIONALE: The main hindrance to long-term success of lung transplantation is bronchiolitis obliterans syndrome (BOS), generally thought to be a manifestation of chronic allograft rejection. BOS is associated histologically with epithelial injury, bronchocentric mononuclear inflammation, and fibrosis of small airways known as bronchiolitis obliterans (BO). Few studies have directly compared clinical, radiographic, and histologic findings of BOS and BO, particularly in the era of improved immunosuppression and infection prophylaxis. Patients undergoing pulmonary retransplantation for BOS provide a unique opportunity to investigate these relationships. METHODS: All patients who underwent pulmonary retransplantation for BOS from 1992 to 2004 at Duke University Medical Center were reviewed. Pathology findings in explanted lung allografts were compared with clinical, radiographic, and transbronchial biopsy data. RESULTS: Over the 12-year study period, 12 patients underwent pulmonary retransplantation for BOS. The median time to BOS was 517 days (intraquartile range, 396 to 819.8 days). BOS scores prior to retransplantation were 2 in 2 patients and 3 in 10 patients. We developed a semiquantitative scoring system for epithelial, inflammatory, and fibrotic changes in affected airways to permit better comparison between BO and BOS. Somewhat surprisingly, only 50% (6 of 12 patients) had severe fibrotic changes, although all had some degree of epithelial injury, fibrosis, or inflammation centered around the bronchi and bronchioles. Furthermore, pathology findings other than BO were present in most explanted allografts and included cholesterol clefts (n = 4), focal invasive aspergillosis (n = 1), interstitial fibrosis (n = 2), and chronic vascular rejection (n = 1). CONCLUSIONS: In this series of patients with advanced BOS undergoing retransplantation, at least some degree of BO was present in all explanted allografts. However, the degree of epithelial changes, fibrosis, and inflammation present among affected bronchi varied considerably. Furthermore, a wide range of pathologic processes of potential clinical significance were evident in half of the patients. We conclude that significant histologic heterogeneity exists among patients undergoing retransplantation for BOS, potentially contributing to the variability of patient responses to treatment.     

Interleukin-12p70 deficiency increases survival and diminishes pathology in Trypanosoma congolense infection

To determine the immunological role played by interleukin (IL)-12 family members in Trypanosoma congolense infection, IL-12p35(-/-), IL-12p40(-/-), and IL-12p35(-/-)/p40(-/-) mice were used. While the latter 2 strains lack all IL-12 homologues, IL-12p35(-/-) mice still produce IL-12p80 homodimers and IL-23. Compared with wild-type mice, all infected IL-12-deficient mouse strains showed prolonged survival, whereas parasitemia levels were unaltered. Interferon (IFN)-gamma production in IL-12-deficient mice was strikingly reduced during the acute and chronic stages of infection, coinciding with significantly reduced chronic-stage hepatocellular damage, as demonstrated by histological analysis and plasma aspartate transaminase measurements. In contrast, IL-10 production was not affected by the absence of IL-12. Taken together, these results show that, during T. congolense infection, the absence of IL-12, but not the IL-12p80 homodimer or IL-23, leads to a reduction in IFN-gamma production, which reduces hepatic pathology and improves host survival in conjunction with IL-10 without negatively affecting parasitemia control.     

Diesel exhaust particles enhance lung injury related to bacterial endotoxin through expression of proinflammatory cytokines, chemokines, and intercellular adhesion molecule-1

Epidemiologic studies demonstrate acute and serious adverse effects of particulate air pollution on respiratory health, especially in people who are susceptible to bacterial infection. However, the underlying mechanism remains to be elucidated. To provide experimental evidence for the epidemiologic data, we determined the effects of diesel exhaust particles (DEP), major participants in particulate pollutants, on lung injury related to bacterial endotoxin in mice. Intratracheal instillation of DEPs synergistically enhanced lung injury related to endotoxin from gram-negative bacteria, which was characterized by neutrophil sequestration, interstitial edema, and alveolar hemorrhage. In the presence of endotoxin, DEPs further activated the nuclear translocation of p65 subunit of nuclear factor-kappaB (NF-kappaB) in the lung and increased the lung expression of intercellular adhesion molecule-1, interleukin-1beta, macrophage chemoattractant protein-1, keratinocyte chemoattractant (KC), macrophage inflammatory protein-1alpha, and Toll-like receptors. DEPs given alone increased the lung expression of Toll-like receptor 4 and the nuclear localization of p50 subunit of NF-kappaB. The combined exposure to DEPs and endotoxin decreased nuclear localization of CCAAT/enhancer binding protein beta. These results provide the first experimental evidence that DEPs enhance neutrophilic lung inflammation related to bacterial endotoxin. The enhancement is mediated by the induction of proinflammatory molecules, likely through the expression of Toll-like receptors and the activation of p65-containing dimer(s) of NF-kappaB, such as p65/p50.     

Toll-like receptor 7 protects from atherosclerosis by constraining "inflammatory" macrophage activation

Background Toll-like receptors (TLRs) have long been considered to be major culprits in the development of atherosclerosis, contributing both to its progression and clinical complications. However, evidence for most TLRs beyond TLR2 and TLR4 is lacking. Methods and Results We used experimental mouse models, human atheroma cultures, and well-established human biobanks to investigate the role of TLR7 in atherosclerosis. We report the unexpected finding that TLR7, a receptor recognizing self-nucleic acid complexes, is protective in atherosclerosis. In Apoe(-/-) mice, functional inactivation of TLR7 resulted in accelerated lesion development, increased stenosis, and enhanced plaque vulnerability as revealed by Doppler ultrasound and/or histopathology. Mechanistically, TLR7 interfered with macrophage proinflammatory responses to TLR2 and TLR4 ligands, reduced monocyte chemoattractant protein-1 production, and prevented expansion of Ly6C(hi) inflammatory monocytes and accumulation of inflammatory M1 macrophages into developing atherosclerotic lesions. In human carotid endarterectomy specimens TLR7 levels were consistently associated with an M2 anti-inflammatory macrophage signature (interleukin [IL]-10, IL-1RA, CD163, scavenger and C-type lectin receptors) and collagen genes, whereas they were inversely related or unrelated to proinflammatory mediators (IL-12/IL-23, interferon beta, interferon gamma, CD40L) and platelet markers. Moreover, in human atheroma cultures, TLR7 activation selectively suppressed the production of key proatherogenic factors such as monocyte chemoattractant protein-1 and tumor necrosis factor without affecting IL-10. Conclusions These findings provide evidence for a beneficial role of TLR7 in atherosclerosis by constraining inflammatory macrophage activation and cytokine production. This challenges the prevailing concept that all TLRs are pathogenic and supports the exploitation of the TLR7 pathway for therapy.     

Fas-induced pulmonary apoptosis and inflammation during indirect acute lung injury

RATIONALE: Indirect acute lung injury (ALI) is associated with high morbidity and mortality. No specific therapies have been developed, because the underlying pathophysiological processes remain elusive. OBJECTIVES: To investigate the contribution of Fas-induced apoptotic and nonapoptotic/inflammatory signaling to the pathology of indirect ALI. METHODS: A mouse model of indirect ALI, induced by successive exposure to hemorrhagic shock and cecal ligation and puncture, was used. Quantification of active caspase-3 and the short splice variant of FLICE-inhibitory protein, (FLIP)short, was performed by Western blotting and immunohistochemistry, and cytokines/chemokines were assessed by cytometric bead array or ELISA. M30 immunostaining was done to evaluate epithelial cell apoptosis. Lung injury was assessed on the basis of myeloperoxidase activity, bronchoalveolar lavage protein, and lung histology. MEASUREMENTS AND MAIN RESULTS: Twelve hours after insult, lung monocyte chemoattractant protein-1, keratinocyte-derived chemokine, macrophage inflammatory protein-2, IL-6, tumor necrosis factor-alpha, and caspase-3 were increased and FLIP(short) was decreased. Fas- and Fas ligand-deficient mice showed marked protection from lung inflammation and apoptosis and decreased ALI. This was associated with a 10-day survival benefit. Similarly, 4 hours after pulmonary instillation of Fas-activating antibody in vivo, lung chemokines were markedly elevated in background mice and, interestingly, to a similar degree in macrophage-deficient animals. Fas activation on lung epithelial cells in vitro led to chemokine production that was dependent on extracellular signal-regulated kinase. CONCLUSIONS: Activation of apoptotic and nonapoptotic/inflammatory Fas signaling is an early important pathophysiological event in the development of indirect ALI after hemorrhagic shock and sepsis, in which lung epithelial cells appear to play a central role.     

Discordant pulmonary proinflammatory cytokine expression during acute hyperoxia in the newborn rabbit.

Newborn animals are resistant to oxygen toxicity. To investigate this phenomenon, the proinflammatory cytokines interleukin (IL)-1 beta, IL-8, and monocyte chemoattractant protein-1 (MCP-1) were measured during newborn rabbit hyperoxic lung injury. Pups were exposed to > 95% O2 for 8-9 days, followed by 60% O2 until 36 days of age. Lung lavage fluid, RNA, and tissue sections were collected at 0, 2, 4, 6, 8, 10, 12, 14, 22, and 36 days. Acute inflammation occurred by 6-10 days of hyperoxia, and fibrosis by 22 days. Northern hybridization of lung homogenates from hyperoxia-exposed pups showed elevated MCP-1 and IL-8 mRNA expression at 6 and 10 days, respectively, compared to age-matched, air-exposed controls. Lavage fluid IL-8 protein also peaked at 10 days, and was strongly correlated to neutrophil numbers in lavage. In situ hybridization revealed elevated IL-1 beta mRNA in macrophages, alveolar epithelial and interstitial cells at 2-10 days, elevated MCP-1 mRNA in similar cell types at 4-8 days, and elevated IL-8 mRNA in these cells and neutrophils at 4-10 days. IL-1 beta and IL-8 expression peaked during peak inflammation, whereas peak MCP-1 expression preceded macrophage influx. Comparing newborn and adult animals' chemokine response may help explain their differences in hyperoxia susceptibility.     

Intratracheal recombinant surfactant protein d prevents endotoxin shock in the newborn preterm lamb

RATIONALE: The susceptibility of neonates to pulmonary and systemic infection has been associated with the immaturity of both lung structure and the immune system. Surfactant protein (SP) D is a member of the collectin family of innate immune molecules that plays an important role in innate host defense of the lung. OBJECTIVES: We tested whether treatment with recombinant human SP-D influenced the response of the lung and systemic circulation to intratracheally administered Escherichia coli lipopolysaccharides. METHODS: After intratracheal lipopolysaccharide instillation, preterm newborn lambs were treated with surfactant and ventilated for 5 h. Measurement: Survival rate, physiologic lung function, lung and systemic inflammation, and endotoxin level in plasma were evaluated. MAIN RESULTS: In control lambs, intratracheal lipopolysaccharides caused septic shock and death associated with increased endotoxin in plasma. In contrast, all lambs treated with recombinant human SP-D were physiologically stable and survived. Leakage of lipopolysaccharides from the lungs to the systemic circulation was prevented by intratracheal recombinant human SP-D. Recombinant human SP-D prevented systemic inflammation and decreased the expression of IL-1beta, IL-8, and IL-6 in the spleen and liver. Likewise, recombinant human SP-D decreased IL-1beta and IL-6 in the lung and IL-8 in the plasma. Recombinant human SP-D did not alter pulmonary mechanics following endotoxin exposure. Recombinant human SP-D was readily detected in the lung 5 h after intratracheal instillation. CONCLUSIONS: Intratracheal recombinant human SP-D prevented shock caused by endotoxin released from the lung during ventilation in the premature newborn.