Chronic inflammation and lung fibrosis: pleotropic syndromes but limited distinct phenotypes

Experimental models of lung fibrosis have been disappointing in predicting therapeutic responses to a wide variety of interventions in clinical fibrosing lung diseases. There are multiple potential reasons, but this fundamentally calls into question the validity of the models and their fidelity to clinical syndromes. We propose that the clinical diseases associated with pulmonary fibrosis, although manifesting a broad array of widely different clinical presentations and features, result in essentially two distinct phenotypes of fibrosis that we will describe. The most common and problematic of these are not effectively modeled experimentally. In this review, we present several clinical entities as examples of the phenotypic distinctions. The first two represent the extremes: postinflammatory fibrosis observed in hypersensitivity pneumonitis (HP) and dysregulated matrix deposition as observed in idiopathic pulmonary fibrosis (IPF). We also present a third clinical entity, that of lung disease associated with rheumatoid arthritis (rheumatoid lung), representing a condition that can manifest as either phenotype, and offering a potential opportunity to explore the mechanisms underlying the pathogenesis of the two distinct fibrotic phenotypes.

Granulomatous bronchiolitis of Crohn's disease successfully treated with inhaled budesonide

A 39-year-old white woman with longstanding Crohn's disease presented with the rare complication of granulomatous bronchiolitis. Rapid resolution after inhaled budesonide is highlighted, as this is the first case described in the literature successfully treated without the need for systemic therapy. This less toxic approach to therapy is warranted in granulomatous bronchiolitis of Crohn's disease to avoid unwanted side effects of steroids and infliximab.

Massive cavitary pulmonary rheumatoid nodules in a patient with HIV

The case of a 52-yr-old female with rheumatoid arthritis and HIV who developed massive, progressive, cavitary pulmonary nodules is described. Multiple diagnostic bronchoscopies and lung biopsies failed to demonstrate the presence of any microorganisms. Pathological analysis showed palisading histiocytes with necrobiosis consistent with rheumatoid nodules. The effect of co-existing HIV infection on the course and prognosis of rheumatoid arthritis is discussed, and it is concluded that the complex relationship between these two disease processes warrants further investigation.

Airway inflammation and remodeling in asthma. Lessons from interleukin 11 and interleukin 13 transgenic mice

Noninflammatory structural alterations, variously referred to as airway remodeling, are well documented in the asthmatic airway. However, the pathogenesis of these alterations, the importance of airway remodeling in generating the asthma phenotype, and the natural history of airway remodeling responses have not been adequately defined. Because exaggerated cytokine production is a characteristic feature of the asthmatic airway, we used constitutive and inducible overexpression transgenic systems to investigate the contributions that interleukin 11 (IL-11) and IL-13 might make to airway remodeling responses. These studies demonstrated that both cytokines produce responses in the murine airway with features similar to those in human asthmatic tissues. IL-11 caused airway fibrosis with the enhanced accumulation of interstitial collagens, myocytes, and myofibroblasts. IL-13 caused mucous metaplasia, enhanced mucin gene expression, enhanced tissue hyaluronic acid accumulation, and subepithelial fibrosis. Importantly, IL-11 was detected most readily in tissues from asthmatic subjects with severe airway remodeling that was similar to that seen in the IL-11 transgenic mice. In addition, IL-11 was shown to inhibit asthma-like inflammation while stimulating airway fibrosis. This suggests that IL-11 elaboration is, in part, an attempt at airway healing. Last, a novel triple transgenic system is described that allows transgene expression to be regulated in a true "on/off" manner. This system may be useful in defining the reversibility of transgene-induced airway remodeling responses.

IL-11: insights in asthma from overexpression transgenic modeling

The evolution of our understanding of IL-11 mirrors, in many ways, the problems that are faced by investigators in the post-genome era and the types of techniques that might need to be used to deal with these issues. IL-11 was discovered as a soluble factor in fibroblast supernatants that stimulated the proliferation of "IL-6-dependent" plasmacytoma cells. It was subsequently demonstrated to be an important stimulator of platelet reconstitution and a pleiotropic regulator of nonrespiratory tissues. In the lung, IL-11 is produced by a variety of structural cells and eosinophils in response to a variety of stimuli, including TGF-beta, major basic proteins, and viruses. IL-11 is also detected in exaggerated quantities at sites of virus infection. Its potential effector functions at these sites were defined with constitutive and inducible overexpression transgenic modeling systems which demonstrated that IL-11 causes nodular mononuclear infiltrates, airway remodeling with subepithelial fibrosis, airways obstruction, and airways hyperresponsiveness and can block alveolar development when expressed during development. In accord with these murine findings, IL-11 is selectively expressed in eosinophils and epithelial cells in patients with moderate and severe asthma where expression correlates directly with disease severity and inversely with FEV(1). Studies using transgenic mice also demonstrated that IL-11 inhibits antigen-induced tissue inflammation. Thus IL-11 might be an important regulator of inflammatory and remodeling responses in the asthmatic airway.

Use of the tetracycline-controlled transcriptional silencer (tTS) to eliminate transgene leak in inducible overexpression transgenic mice

The doxycycline-inducible reverse tetracycline transactivator (rtTA) is frequently used to overexpress transgenes in a temporally regulated fashion in vivo. These systems are, however, often limited by the levels of transgene expression in the absence of dox administration. The tetracycline-controlled transcriptional silencer (tTS), a fusion protein containing the tet repressor and the KRAB-AB domain of the kid-1 transcriptional repressor, is inhibited by doxycycline. We hypothesized that tTS would tighten control of transgene expression in rtTA-based systems. To test this hypothesis we generated mice in which the CC10 promoter targeted tTS to the lung, bred these mice with CC10-rtTA-interleukin 13 (IL-13) mice in which IL-13 was overexpressed in an inducible lung-specific fashion, and compared the IL-13 production and phenotypes of parental mice and the triple transgenic CC10-rtTA/tTS-IL-13 progeny of these crosses. In the CC10-rtTA-IL-13 mice, IL-13, mucus metaplasia, inflammation, alveolar enlargement, and enhanced lung volumes were noted at base line and increased greatly after doxycycline administration. In the triple transgenic tTS animals, IL-13 and the IL-13-induced phenotype could not be appreciated without doxycycline. In contrast, tTS did not alter the induction of IL-13 or the generation of the IL-13 phenotype by doxycycline. Thus, tTS effectively eliminated the baseline leak without altering the inducibility of rtTA-regulated transgenes in vivo. Optimal "off/on" regulation of transgene expression can be accomplished with the combined use of tTS and rtTA.

Inducible targeting of IL-13 to the adult lung causes matrix metalloproteinase- and cathepsin-dependent emphysema

Cigarette smoke exposure is the major cause of chronic obstructive pulmonary disease (COPD). However, only a minority of smokers develop significant COPD, and patients with asthma or asthma-like airway hyperresponsiveness or eosinophilia experience accelerated loss of lung function after cigarette smoke exposure. Pulmonary inflammation is a characteristic feature of lungs from patients with COPD. Surprisingly, the mediators of this inflammation and their contributions to the pathogenesis and varied natural history of COPD are not well defined. Here we show that IL-13, a critical cytokine in asthma, causes emphysema with enhanced lung volumes and compliance, mucus metaplasia, and inflammation, when inducibly overexpressed in the adult murine lung. MMP-2, -9, -12, -13, and -14 and cathepsins B, S, L, H, and K were induced by IL-13 in this setting. In addition, treatment with MMP or cysteine proteinase antagonists significantly decreased the emphysema and inflammation, but not the mucus in these animals. These studies demonstrate that IL-13 is a potent stimulator of MMP and cathepsin-based proteolytic pathways in the lung. They also demonstrate that IL-13 causes emphysema via a MMP- and cathepsin-dependent mechanism(s) and highlight common mechanisms that may underlie COPD and asthma.

Endogenous and exogenous IL-6 inhibit aeroallergen-induced Th2 inflammation

Chronic Th2-dominated inflammation and exaggerated IL-6 production are characteristic features of the asthmatic airway. To understand the processes that are responsible for the chronicity of this response and the role(s) of IL-6 in the regulation of airway Th2 inflammation, we compared the responses induced by OVA in sensitized wild-type mice, IL-6 deficient (-/-) mice, and transgenic mice in which IL-6 was overexpressed in the airway (CC10-IL-6 mice). When compared with wild-type mice, IL-6-/- mice manifest exaggerated inflammation and eosinophilia, increased levels of IL-4, IL-5, and IL-13 protein and mRNA, exaggerated levels of eotaxin, JE/monocyte chemoattractant protein-1, macrophage inflammatory protein-1alpha and -2, and mRNA, increased bronchoalveolar lavage (BAL) TGF-beta1, and exaggerated airway responses to aerosolized methacholine. In contrast, CC10-IL-6 mice, on both C57BL/6 and BALB/c backgrounds, manifest diminished inflammation and eosinophilia, decreased levels of IL-4, IL-5, and IL-13 protein and mRNA, and decreased levels of bronchoalveolar lavage TGF-beta1. IL-6 also decreased the expression of endothelial VCAM-1 and airway responsiveness to methacholine in these animals. These alterations in the IL-6-/- and CC10-IL-6 mice were not associated with significant decreases or increases in the levels of IFN-gamma, respectively. These studies demonstrate that endogenous and exogenous IL-6 inhibit aeroallergen-induced Th2 inflammation and that this inhibition is not mediated by regulatory effects of IFN-gamma. IL-6 may be an important anti-inflammatory, counterregulatory, and healing cytokine in the airway.

IL-13 stimulates vascular endothelial cell growth factor and protects against hyperoxic acute lung injury

Hyperoxia is an important cause of acute lung injury. To determine whether IL-13 is protective in hyperoxia, we compared the survival in 100% O(2) of transgenic mice that overexpress IL-13 in the lung and of nontransgenic littermate controls. IL-13 enhanced survival in 100% O(2). One hundred percent of nontransgenic mice died in 4-5 days, whereas 100% of IL-13-overexpressing mice lived for more than 7 days, and many lived 10-14 days. IL-13 also stimulated VEGF accumulation in mice breathing room air, and it interacted with 100% (2) to increase VEGF accumulation further. The 164-amino acid isoform was the major VEGF moiety in bronchoalveolar lavage from transgenic mice in room air, whereas the 120- and 188-amino acid isoforms accumulated in these mice during hyperoxia. In addition, antibody neutralization of VEGF decreased the survival of IL-13-overexpressing mice in 100% (2). These studies demonstrate that IL-13 has protective effects in hyperoxic acute lung injury. They also demonstrate that IL-13, alone and in combination with 100% (2), stimulates pulmonary VEGF accumulation, that this stimulation is isoform-specific, and that the protective effects of IL-13 are mediated, in part, by VEGF.

IL-11 selectively inhibits aeroallergen-induced pulmonary eosinophilia and Th2 cytokine production

IL-11 is a pleiotropic cytokine that induces tissue remodeling with subepithelial fibrosis when expressed in the airway. Its effects on the Th2-dominated airway inflammation that is characteristic of asthma, however, are poorly understood. To characterize the effects of IL-11 on Th2 tissue inflammation, we compared the inflammatory responses elicited by OVA in sensitized mice in which IL-11 is overexpressed in a lung-specific fashion (CC10-IL-11) with that in transgene- wild-type littermate controls. Transgene- and CC10-IL-11 transgene+ mice had comparable levels of circulating Ag-specific IgE after sensitization. OVA challenge of sensitized transgene- mice caused airway and parenchymal eosinophilic inflammation, Th2 cell accumulation, and mucus hypersecretion with mucus metaplasia. Exaggerated levels of immunoreactive endothelial cell VCAM-1, mucin (Muc) 5ac gene expression and bronchoalveolar lavage and lung IL-4, IL-5, and IL-13 protein and mRNA were also noted. In contrast, OVA challenge in CC10-IL-11 animals elicited impressively lower levels of tissue and bronchoalveolar lavage inflammation, eosinophilia, and Th2 cell accumulation, and significantly lower levels of VCAM-1 and IL-4, IL-5, and IL-13 mRNA and protein. IL-11 did not cause a comparable decrease in mucus hypersecretion, Muc 5ac gene expression, or the level of expression of RANTES, monocyte chemoattractant protein-2, or monocyte chemoattractant protein-3. In addition, IL-11 did not augment IFN-gamma production demonstrating that the inhibitory effects of IL-11 were not due to a shift toward Th1 inflammation. These studies demonstrate that IL-11 selectively inhibits Ag-induced eosinophilia, Th2 inflammation, and VCAM-1 gene expression in pulmonary tissues.

Clinicians are from Mars and pathologists are from Venus

CONTEXT

Text reports convey critical medical information from pathologists, radiologists, and subspecialty consultants. These reports must be clear and comprehensible to avoid medical errors. Pathologists have paid much attention to report completeness but have ignored the corresponding issue of report comprehension. This situation presents an increasingly serious potential problem. As laboratories are consolidated and as reports are disseminated in new ways (eg, via the World Wide Web), the target audience becomes more diverse and less likely to have any contact with pathologists beyond the written reports themselves.

OBJECTIVE

To compare clinician comprehension with pathologist intent in written pathology reports.

METHODS

Typical surgical pathology reports relevant to surgeons and covering a range of specimen complexity were taken from our hospital files. Questionnaires based on these cases were administered open-book-examination style to surgical attending physicians and trainees during surgical conferences at an academic medical center.

MAIN OUTCOME MEASURES

Scores from questionnaires.

RESULTS

Surgeons misunderstood pathologists' reports 30% of the time. Surgical experience reduced but did not eliminate the problem. Streamlined report formatting exacerbated the problem.

CONCLUSIONS

A communication gap exists between pathologists and surgeons. Familiarity with report format and clinical experience help reduce this gap. Paradoxically, stylistic improvements to report formatting can interfere with comprehension and increase the number of misunderstandings. Further investigation is required to reduce the number of misunderstandings and, thus, medical errors.

Consequences of long-term inflammation. Airway remodeling

Airway inflammation may not account for all the clinical manifestations of asthma. Airway remodeling, which is thought to be a result of airway chronic inflammation, may help fill this void. Remodeling is described for fatal and nonfatal asthmatics including changes in smooth muscle, collagen deposition, noncollagenous matrix, and mucus glands. This article also reviews the correlation of airway remodeling with clinical, physiologic and biologic data, experimental models of airways remodeling, and effect of therapy on airway remodeling. Throughout, it is emphasized that the concept of airway remodeling is a dynamic process that is active and potentially progressive in asthmatic patients but that may be prevented by appropriate therapy.

Interleukin-6-induced protection in hyperoxic acute lung injury

Hyperoxic lung injury is commonly encountered in patients who require treatment with high concentrations of inspired oxygen. To determine whether interleukin (IL)-6 is protective in oxygen toxicity, we compared the effects of 100% O(2) in transgenic mice that overexpress IL-6 in the lung and transgene (-) controls. IL-6 markedly enhanced survival, with 100% of transgene (-) animals dying within 72 to 96 h, 100% of transgene (+) animals living for more than 8 d and more than 90% of transgene (+) animals living longer than 12 d. This protection was associated with markedly diminished alveolar-capillary protein leak, endothelial and epithelial membrane injury, and lung lipid peroxidation. Hyperoxia also caused cell death with DNA fragmentation in the lungs of transgene (-) animals and IL-6 markedly diminished this cytopathic response. The protective effects of IL-6 were not associated with significant alterations in the activities of copper/ zinc superoxide dismutase (SOD) or manganese SOD. They were, however, associated with the enhanced accumulation of the cell-death inhibitor Bcl-2, but not the cell-death stimulator BAX, and with the heightened accumulation of the cell-death regulator tissue inhibitor of metalloproteinase-1 (TIMP-1). These studies demonstrate that IL-6 markedly diminishes hyperoxic lung injury and that this protection is associated with a marked diminution in hyperoxia-induced cell death and DNA fragmentation. They also demonstrate that this protection is not associated with significant alterations in SOD activity, but is associated with the induction of Bcl-2 and TIMP-1.

Airway hyperresponsiveness and airway obstruction in transgenic mice. Morphologic correlates in mice overexpressing interleukin (IL)-11 and IL-6 in the lung

Understanding the sources of variation in airway reactivity and airflow is important for unraveling the pathophysiology of asthma, obstructive lung disease, and other pulmonary disorders. Transgenic expression of two closely related cytokines in the mouse lung produced opposite effects on these parameters. Interleukin (IL)-6 did not alter basal airways resistance and decreased methacholine responsiveness, whereas IL-11 caused airways obstruction and increased airway responses to methacholine. To clarify these differences we examined histologic sections and used morphometry to compare bronchiolar and parenchymal dimensions in 1- to 2-mo-old transgenic mice expressing IL-6 or IL-11 and littermate control mice. Both transgenic strains showed similar emphysema-like airspace enlargement, nodular peribronchiolar collections of mononuclear cells, thickening of airway walls, and subepithelial airway fibrosis. When compared with littermate control mice, the IL-6 mice showed an approximately 50% increase in the caliber of their bronchioles and an increase in airway wall thickness that was in proportion to the increase in the size of their airways. In contrast, the remodeling response was more robust in the IL-11 transgenic mice. It was also seen in airways with normal external and luminal diameters and thus was out of proportion to the caliber of their airways. These results support the hypothesis that structural alterations and resulting caliber changes of respiratory airways can have important effects on airway physiology and reactivity.

T helper 1 cells and interferon gamma regulate allergic airway inflammation and mucus production

CD4 T helper (Th) type 1 and Th2 cells have been identified in the airways of asthmatic patients. Th2 cells are believed to contribute to pathogenesis of the disease, but the role of Th1 cells is not well defined. In a mouse model, we previously reported that transferred T cell receptor-transgenic Th2 cells activated in the respiratory tract led to airway inflammation with many of the pathologic features of asthma, including airway eosinophilia and mucus production. Th1 cells caused inflammation with none of the pathology associated with asthma. In this report, we investigate the role of Th1 cells in regulating airway inflammation. When Th1 and Th2 cells are transferred together into recipient mice, there is a marked reduction in airway eosinophilia and mucus staining. To address the precise role of Th1 cells, we asked (i), Are Th2-induced responses inhibited by interferon (IFN)-gamma? and (ii) Can Th1 cells induce eosinophilia and mucus in the absence of IFN-gamma? In IFN-gamma receptor(-/-) recipient mice exposed to inhaled antigen, the inhibitory effects of Th1 cells on both airway eosinophilia and mucus production were abolished. In the absence of IFN-gamma receptor signaling, Th1 cells induced mucus but not eosinophilia. Thus, we have identified new regulatory pathways for mucus production; mucus can be induced by Th2 and non-Th2 inflammatory responses in the lung, both of which are inhibited by IFN-gamma. The blockade of eosinophilia and mucus production by IFN-gamma likely occurs through different inhibitory pathways that are activated downstream of Th2 cytokine secretion and require IFN-gamma signaling in tissue of recipient mice.

Role of tissue factor in metastasis: functions of the cytoplasmic and extracellular domains of the molecule

Tissue factor (TF) is a transmembrane glycoprotein that complexes with factor VIIa to initiate blood coagulation. It was reported in an earlier study that expression of high levels of TF in a human melanoma cell line promotes metastasis, and that the cytoplasmic domain of TF is required for this metastatic effect. To analyze the functions of the cytoplasmic and extracellular domains of TF in metastasis, two TF mutants were constructed; in one mutant alanine was substituted for each of the three serine residues in the cytoplasmic domain, preventing phosphorylation; in the other mutant alanine was substituted for four key residues in the extracellular domain, preventing binding of factor VIIa and consequently eliminating the initiation of blood coagulation by the TF-VIIa complex. Melanoma lines expressing high levels of either mutant form of TF were weakly metastatic in SCID mice, indicating that phosphorylation of the cytoplasmic domain and formation of a complex with VIIa by the extracellular domain are required for the full metastatic effect of TF. It was also found that increasing TF expression in human melanoma cells does not increase expression of vascular endothelial growth factor or promote growth and vascularization of tumors derived from the melanoma cells, suggesting that TF acts by a mechanism other than angiogenesis to promote metastasis.

Th2-induced airway mucus production is dependent on IL-4Ralpha, but not on eosinophils

Mucus hyperproduction in asthma results from airway inflammation and contributes to clinical symptoms, airway obstruction, and mortality. In human asthmatics and in animal models, excess mucus production correlates with airway eosinophilia. We previously described a system in which TCR transgenic CD4 Th2 cells generated in vitro were transferred into recipient mice and activated in the respiratory tract with inhaled Ag. Th2 cells stimulated airway eosinophilia and a marked increase in mucus production, while mice that received Th1 cells exhibited airway inflammation without eosinophilia or mucus. Mucus could be induced by IL-4-/- Th2 cells at comparable levels to mucus induced by IL-4+/+ Th2 cells. In the current studies we dissect further the mechanisms of Th2-induced mucus production. When IL-4-/- Th2 cells are transferred into IL-4Ralpha-/- mice, mucus is not induced, and BAL eosinophilia is absent. These data suggest that in the absence of IL-4, IL-13 may be critical for Th2-induced mucus production and eosinophilia. To determine whether eosinophils are important in mucus production, IL-5-/- Th2 cells were transferred into IL-5-/- recipients. Eosinophilia was abolished, yet mucus staining in the epithelium persisted. These studies show definitively that IL-5, eosinophils, or mast cells are not essential, but signaling through IL-4Ralpha is critically important in Th2 cell stimulation of mucus production.

Pulmonary expression of interleukin-13 causes inflammation, mucus hypersecretion, subepithelial fibrosis, physiologic abnormalities, and eotaxin production

Interleukin (IL)-13 is a pleiotropic cytokine produced in large quantities by activated CD4(+) Th2 lymphocytes. To define further its potential in vivo effector functions, the Clara cell 10-kDa protein promoter was used to express IL-13 selectively in the lung, and the phenotype of the resulting transgenic mice was characterized. In contrast to transgene-negative littermates, the lungs of transgene-positive mice contained an inflammatory response around small and large airways and in the surrounding parenchyma. It was mononuclear in nature and contained significant numbers of eosinophils and enlarged and occasionally multinucleated macrophages. Airway epithelial cell hypertrophy, mucus cell metaplasia, the hyperproduction of neutral and acidic mucus, the deposition of Charcot-Leyden-like crystals, and subepithelial airway fibrosis were also prominently noted. Eotaxin protein and mRNA were also present in large quantities in the lungs of the transgene-positive, but not the transgene-negative, mice. IL-4, IL-5, granulocyte-macrophage colony-stimulating factor, and monocyte chemoattractant protein-5 were not similarly detected. Physiological evaluations revealed significant increases in baseline airways resistance and airways hyperresponsiveness (AHR) to methacholine in transgene-positive animals. Thus, the targeted pulmonary expression of IL-13 causes a mononuclear and eosinophilic inflammatory response, mucus cell metaplasia, the deposition of Charcot-Leyden-like crystals, airway fibrosis, eotaxin production, airways obstruction, and nonspecific AHR. IL-13 may play an important role in the pathogenesis of similar responses in asthma or other Th2-polarized tissue responses.

Antineutrophil cytoplasmic antibodies as markers for systemic autoimmune disease

Antineutrophil cytoplasmic antibodies (ANCA) have been associated with systemic vasculitis for almost 15 years. Significant advances in our understanding of the ANCA phenomenon have occurred with recognition of broadening the spectrum of diseases associated with ANCA, identification of specific antigens recognized by ANCA, and development of antigen specific assays for clinical use. Nevertheless problems continue for the chest physician in interpretation of this test. Although antigen specific testing improves overall performance of the test, accurate assessment of pretest probability of disease is still important for effective use of ANCA testing.

Duodenal hemangioendothelioma: a case report

Epithelioid hemangioendothelioma is extremely rare. A patient with an epithelioid hemangioendothelioma presenting as an annular mass encircling the second portion of the duodenum is described. We believe this to be the first such lesion in this location reported.

Targeted lung expression of interleukin-11 enhances murine tolerance of 100% oxygen and diminishes hyperoxia-induced DNA fragmentation

Acute lung injury is a frequent and treatment-limiting consequence of therapy with hyperoxic gas mixtures. To determine if IL-11 is protective in oxygen toxicity, we compared the effects of 100% O2 on transgenic mice that overexpress IL-11 in the lung and transgene (-) controls. IL-11 markedly enhanced survival in 100% O2 with 100% of transgene (-) animals dying within 72-96 h and > 90% of transgene (+) animals surviving for more than 10 d. This protection was associated with markedly diminished alveolar-capillary protein leak, endothelial and epithelial membrane injury, lipid peroxidation, and pulmonary neutrophil recruitment. Significant differences in copper zinc superoxide dismutase and catalase activities were not noted and the levels of total, reduced and oxidized glutathione were similar in transgene (+) and (-) animals. Glutathione reductase, glutathione peroxidase, and manganese superoxide dismutase activities were slightly higher in transgene (+) as versus (-) mice after 100% O2 exposure, and IL-11 diminished hyperoxia-induced expression of IL-1 and TNF. Hyperoxia also caused cell death with DNA fragmentation in the lungs of transgene (-) animals and IL-11 markedly diminished this cell death response. These studies demonstrate that IL-11 markedly diminishes hyperoxic lung injury. They also demonstrate this protection is associated with small changes in lung antioxidants, diminished hyperoxia-induced IL-1 and TNF production, and markedly suppressed hyperoxia-induced DNA fragmentation.

Inhibitory effects of phenylbutyrate on the proliferation, morphology, migration and invasiveness of malignant glioma cells

The purpose of this study was to characterize the effects of sodium 4-phenylbutyrate (phenylbutyrate) on the proliferation, morphology, migration and invasiveness of malignant glioma cells in vitro. Phenylbutyrate is a novel differentiating and cytotoxic compound used clinically with low toxicity in the treatment of beta-thalassemia, sickle cell anemia and urea cycle disorders. Preliminary clinical trials testing phenylbutyrate as an anti-cancer agent have included patients with malignant glioma. However, little information is available regarding the effects of phenylbutyrate on glioma cells, particularly with respect to the expression of genes important in the pathogenesis of glial malignancy. In experiments reported here, glioma cell lines and explant cells from a tumor patient were exposed to 2, 4 and 8 mM phenylbutyrate and compared to untreated control cells. The effect on cellular proliferation was assessed using cell counts and DNA flow cytometry. Changes in morphology were evaluated using vimentin staining. Scratch and Matrigel assays were performed to assess changes in cellular migration and invasiveness. Finally, Northern blot analysis was used to study c-myc and urokinase expression. Phenylbutyrate was found to have dose-dependent inhibitory effects on glioma cell proliferation, morphology, migration, invasiveness and c-myc and urokinase expression. Mean growth-inhibitory (IC50) phenylbutyrate concentrations ranged from 0.5 mM for T98G cells to 5.0 mM for explant cells. Phenylbutyrate treatment reduced % S phase cells, increased % G0/G1 cells, and produced morphologic changes consistent with induction of differentiation. 24 hours of treatment with 4 mM phenylbutyrate resulted in a 50% reduction in migration and invasiveness. Northern blots showed a decrease in urokinase and c-myc expression at non-cytotoxic doses. We conclude that phenylbutyrate is a promising candidate compound for treating patients with malignant glioma.

Induction of airway mucus production By T helper 2 (Th2) cells: a critical role for interleukin 4 in cell recruitment but not mucus production

Airway inflammation is believed to stimulate mucus production in asthmatic patients. Increased mucus secretion is an important clinical symptom and contributes to airway obstruction in asthma. Activated CD4 Th1 and Th2 cells have both been identified in airway biopsies of asthmatics but their role in mucus production is not clear. Using CD4 T cells from mice transgenic for the OVA-specific TCR, we studied the role of Th1 and Th2 cells in airway inflammation and mucus production. Airway inflammation induced by Th2 cells was comprised of eosinophils and lymphocytes; features found in asthmatic patients. Additionally, there was a marked increase in mucus production in mice that received Th2 cells and inhaled OVA, but not in mice that received Th1 cells. However, OVA-specific Th2 cells from IL-4-deficient mice were not recruited to the lung and did not induce mucus production. When this defect in homing was overcome by administration of TNF-alpha, IL-4 -/- Th2 cells induced mucus as effectively as IL-4 +/+ Th2 cells. These studies establish a role for Th2 cells in mucus production and dissect the effector functions of IL-4 in these processes. These data suggest that IL-4 is crucial for Th2 cell recruitment to the lung and for induction of inflammation, but has no direct role in mucus production.

Eosinophilic pneumonia as a presentation of occult chronic granulomatous disease

We present a case of invasive pulmonary aspergillosis (IPA) in a previously healthy young woman who presented with what initially appeared to be an acute eosinophilic pneumonia. A second lung biopsy taken after treatment with steroids showed invasive Aspergillus with associated necrotizing granulomas, a pattern commonly found in chronic granulomatous disease (CGD). Both siblings, and by extrapolation, the patient, were actually found to have CGD. A review of the literature revealed other cases of presumed immunocompetent patients with IPA with presentations and lung histopathology similar to that of our patient. We conclude that chronic granulomatous disease presenting in the adult may be more common than previously assumed, and that patients previously presumed immunocompetent, but with granulomatous invasive pulmonary aspergillosis, may have chronic granulomatous disease. Furthermore, and most devastatingly in this case, the presentation may simulate a recently described steroid responsive acute lung disease, acute eosinophilic pneumonia.

Airway isocyanate-adducts in asthma induced by exposure to hexamethylene diisocyanate

OBJECTIVES

The clinical features, airway histology, and detection of hexamethylene diisocyanate (HDI) protein adducts in endobronchial biopsies from a patient with HDI asthma are described.

METHODS

Isocyanate asthma was diagnosed by history, methacholine challenge, and workplace HDI challenge. Bronchoscopy was performed 24 h after challenge and immunohistochemical staining was performed.

RESULTS

Airway biopsies obtained at bronchoscopy demonstrated inflammatory changes typical for asthma, including increased airway eosinophils and T cells. Immunohistochemical staining with specific anti-HDI antibodies demonstrated the presence and localization of HDI adducts in human bronchial biopsies.

CONCLUSIONS

These studies confirm epithelial exposure to HDI following workplace challenge and demonstrate the feasibility of detecting and localizing isocyanate adducts in human lung tissue. Identifying and characterizing the airway macromolecules to which isocyanates bind in vivo are probably crucial to the understanding of how isocyanates cause sensitization and asthma. The ability to detect isocyanate adducts may also help characterize isocyanate exposure patterns and exposure-disease relationships.

Targeted expression of IL-11 in the murine airway causes lymphocytic inflammation, bronchial remodeling, and airways obstruction

Interleukin-11 is a pleotropic cytokine produced by lung stromal cells in response to respiratory viruses, cytokines, and histamine. To further define its potential effector functions, the Clara cell 10-kD protein promoter was used to express IL-11 and the airways of the resulting transgene mice were characterized. In contrast to transgene (-) littermates, the airways of IL-11 transgene (+) animals manifest nodular peribronchiolar mononuclear cell infiltrates and impressive airways remodeling with subepithelial fibrosis. The inflammatory foci contained large numbers of B220(+) and MHC Class II(+) cells and lesser numbers of CD3(+), CD4(+), and CD8(+) cells. The fibrotic response contained increased amounts of types III and I collagen, increased numbers of alpha smooth muscle actin and desmin-containing cells and a spectrum of stromal elements including fibroblasts, myofibroblasts, and smooth muscle cells. Physiologic evaluation also demonstrated that 2-mo-old transgene (+) mice had increased airways resistance and non-specific airways hyperresponsiveness to methacholine when compared with their transgene (-) littermates. These studies demonstrate that the targeted expression of IL-11 in the mouse airway causes a B and T cell-predominant inflammatory response, airway remodeling with increased types III and I collagen, the local accumulation of fibroblasts, myofibroblasts, and myocytes, and obstructive physiologic dysregulation. IL-11 may play an important role in the inflammatory and fibrotic responses in viral and/or nonviral human airway disorders.

Diffuse panbronchiolitis in a Hispanic man with travel history to Japan

Diffuse panbronchiolitis is a chronic airflow disorder of obscure origin, which has been reported infrequently outside of Japan and never with any long-term follow-up. We report such a case in a Hispanic man. Furthermore, this patient had an extensive travel history to the Far East, including Japan. This case raises the possibility of a poorly transmissible infectious agent responsible for the disease.

The use of cystathionine gamma-synthase in the production of alpha and chiral beta deuterated amino acids

Chiral exchange at the alpha hydrogen position can be carried out on gram scale in 2H2O for all of the standard amino acids utilizing Escherichia coli cystathionine gamma-synthase. The alpha hydrogen exchange of glycine is highly stereoselective. The amino acids fall into four classes with respect to the selectivity of exchange at the beta position: beta'/beta rate approximately 50 (arginine, glutamine, histidine, homoserine, and lysine), beta'/beta rate approximately 8 (asparagine, glutamate, methionine, ornithine, and S-methyl cysteine), beta'/beta approximately 1 (leucine, aspartate, and alanine), and those seemingly too slow for large-scale exchange (isoleucine, phenylalanine, O-methyl tyrosine, serine, threonine, tryptophan, and valine). The stereochemistry of selective beta exchange is the same for all cases studied.

T cell unresponsiveness correlates with quantitative TCR levels in a transgenic model

Two lines of transgenic mice were developed which differ in their level of expression of V beta 11. To determine the role of TCR density in tolerance induction, these mice were bred with I-E expressing mice and were investigated for tolerance induction. T cells expressing V beta 11 at high density are deleted by negative selection. T cells expressing < 10% of the normal TCR receptor density are not subject to negative selection and were not activated in vitro. There is a correlation in receptor density in both strains of mice with in vitro activation. These findings support the notion that there is a definable quantitative signal threshold which is critical for tolerance induction.

A 19F-NMR study of the membrane-binding region of D-lactate dehydrogenase of Escherichia coli

D-Lactate dehydrogenase (D-LDH) is a membrane-associated respiratory enzyme of Escherichia coli. The protein is composed of 571 amino acid residues with a flavin adenine dinucleotide (FAD) cofactor, has a molecular weight of approximately 65,000, and requires lipids or detergents for full activity. We used NMR spectroscopy to investigate the structure of D-LDH and its interaction with phospholipids. We incorporated 5-fluorotryptophan (5F-Trp) into the native enzyme, which contains five tryptophan residues, and into mutant enzymes, where a sixth tryptophan is substituted into a specific site by oligonucleotide-directed mutagenesis, and studied the 5F-Trp-labeled enzymes using 19F-NMR spectroscopy. In this way, information was obtained about the local environment at each native and substituted tryptophan site. Using a nitroxide spin-labeled fatty acid, which broadens the resonance from any residue within 15 A, we have established that the membrane-binding area of the protein includes the region between Tyr 228 and Phe 369, but is not continuous within this region. This conclusion is strengthened by the results of 19F-NMR spectroscopy of wild-type enzyme labeled with fluorotyrosine or fluorophenylalanine in the presence and absence of a nitroxide spin-labeled fatty acid. These experiments indicate that 9-10 Phe and 3-4 Tyr residues are located near the lipid phase.

Qc-1, a novel Q-region-controlled CTL determinant expressed on B lymphocytes

Using cloned cytotoxic T lymphocytes (CTL), we have identified a Q region controlled determinant with a unique strain and tissue distribution. Several strains that express the classically defined Qa-2 determinant and other Q region controlled determinants do not express the CTL determinant. In addition, strain BALB/cByJ, which does not normally express any Q region controlled cell surface determinant, expresses this new determinant. Cross-reactivity between the Q region controlled CTL determinant and a Kk region controlled class I product (probably H-2Kk) was observed. Finally, among lymphocytes, the CTL determinant is expressed preferentially (if not exclusively) on B cells, thus distinguishing it from all previously described Q region controlled determinants, which are expressed predominantly on T cells. We provisionally designate this novel Q region controlled CTL determinant Qc-1. The possibility that Qc-1 is recognized together with a self antigen is discussed.

Qc-1, a novel Q-region-controlled CTL determinant expressed on B lymphocytes

Using cloned cytotoxic T lymphocytes (CTL), we have identified a Q region controlled determinant with a unique strain and tissue distribution. Several strains that express the classically defined Qa-2 determinant and other Q region controlled determinants do not express the CTL determinant. In addition, strain BALB/cByJ, which does not normally express any Q region controlled cell surface determinant, expresses this new determinant. Cross-reactivity between the Q region controlled CTL determinant and a Kk region controlled class I product (probably H-2Kk) was observed. Finally, among lymphocytes, the CTL determinant is expressed preferentially (if not exclusively) on B cells, thus distinguishing it from all previously described Q region controlled determinants, which are expressed predominantly on T cells. We provisionally designate this novel Q region controlled CTL determinant Qc-1. The possibility that Qc-1 is recognized together with a self antigen is discussed.