Longitudinal stability of asthma characteristics and biomarkers from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study

Background

Asthma is a biologically heterogeneous disease and development of novel therapeutics requires understanding of pathophysiologic phenotypes. There is uncertainty regarding the stability of clinical characteristics and biomarkers in asthma over time. This report presents the longitudinal stability over 12 months of clinical characteristics and clinically accessible biomarkers from ADEPT.

Methods

Mild, moderate, and severe asthma subjects were assessed at 5 visits over 12 months. Assessments included patient questionnaires, spirometry, bronchodilator reversibility, fractional exhaled nitric oxide (FENO), and biomarkers measured in induced sputum.

Results

Mild (n = 52), moderate (n = 55), and severe (n = 51) asthma cohorts were enrolled from North America and Western Europe. For all clinical characteristics and biomarkers, group mean data showed no significant change from visit to visit. However, individual data showed considerable variability. FEV1/FVC ratio showed excellent reproducibility while pre-bronchodilator FEV1 and FVC were only moderately reproducible. Of note bronchodilator FEV1 reversibility showed low reproducibility, with the nonreversible phenotype much more reproducible than the reversible phenotype. The 7-item asthma control questionnaire (ACQ7) demonstrated moderate reproducibility for the combined asthma cohorts, but the uncontrolled asthma phenotype (ACQ7 > 1.5) was inconstant in mild and moderate asthma but stable in severe asthma. FENO demonstrated good reproducibility, with the FENO-low phenotype (FENO < 35 ppb) more stable than the FENO-high phenotype (FENO ≥ 35 ppb). Induced sputum inflammatory phenotypes showed marked variability across the 3 sputum samples taken over 6 months.

Conclusions

The ADEPT cohort showed group stability, individual stability in some parameters e.g. low FEV1/FVC ratio, and low FENO, but marked individual variability in other clinical characteristics and biomarkers e.g. type-2 biomarkers over 12 months. This variability is possibly related to seasonal variations in climate and allergen exposure, medication changes and acute exacerbations. The implications for patient selection strategies based on clinical biomarkers may be considerable.

Asthma characteristics and biomarkers from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) longitudinal profiling study

BACKGROUND

Asthma is a heterogeneous disease and development of novel therapeutics requires an understanding of pathophysiologic phenotypes. The purpose of the ADEPT study was to correlate clinical features and biomarkers with molecular characteristics, by profiling asthma (NCT01274507). This report presents for the first time the study design, and characteristics of the recruited subjects.

METHODS

Patients with a range of asthma severity and healthy non-atopic controls were enrolled. The asthmatic subjects were followed for 12 months. Assessments included history, patient questionnaires, spirometry, airway hyper-responsiveness to methacholine, fractional exhaled nitric oxide (FENO), and biomarkers measured in induced sputum, blood, and bronchoscopy samples. All subjects underwent sputum induction and 30 subjects/cohort had bronchoscopy.

RESULTS

Mild (n = 52), moderate (n = 55), severe (n = 51) asthma cohorts and 30 healthy controls were enrolled from North America and Western Europe. Airflow obstruction, bronchodilator response and airways hyperresponsiveness increased with asthma severity, and severe asthma subjects had reduced forced vital capacity. Asthma control questionnaire-7 (ACQ7) scores worsened with asthma severity. In the asthmatics, mean values for all clinical and biomarker characteristics were stable over 12 months although individual variability was evident. FENO and blood eosinophils did not differ by asthma severity. Induced sputum eosinophils but not neutrophils were lower in mild compared to the moderate and severe asthma cohorts.

CONCLUSIONS

The ADEPT study successfully enrolled asthmatics across a spectrum of severity and non-atopic controls. Clinical characteristics were related to asthma severity and in general asthma characteristics e.g. lung function, were stable over 12 months. Use of the ADEPT data should prove useful in defining biological phenotypes to facilitate personalized therapeutic approaches.

Exploration of the volumetric composition of human lung cancer nodules in correlated histopathology and computed tomography

Gaining a complete and comprehensive understanding of lung cancer nodule histological compositions and how these tissues are represented in radiological data is important not only for expanding the current knowledge base of cancer growth and development but also has potential implications for classification standards, radiological diagnosis methods and for the evaluation of treatment response. In this study we generate large scale histological segmentations of the cancerous and non-cancerous tissues within resected lung nodules. We have implemented a processing pipeline which allows for the direct correlation between histological data and spatially corresponding computed tomography data. Utilizing these correlated datasets we evaluated the statistical separation between Hounsfield Unit (HU) histogram values for each tissue type. The findings of this study revealed that lung cancer nodules contain a complex intermixing of cellular tissue types and that trends exist in the relationship between these tissue types. It was found that the mean Hounsfield Unit values for isolated lung cancer nodules imaged with computed tomography, had statistically significantly different values for non-solid bronchoalveolar carcinoma, solid cancerous tumor, blood, and inactive fibrotic stromal tissue.

Early-life co-administration of cockroach allergen and endotoxin augments pulmonary and systemic responses

BACKGROUND

Environmental exposures to cockroach allergen and endotoxin are recognized epidemiological risk factors for the early development of allergies and asthma in children. Because of this, it is important to examine the role of early-life concurrent inhalation exposures to cockroach allergen and endotoxin in the pathogenesis of allergic airways disease.

OBJECTIVE

We examined the effects of repeated concomitant endotoxin and cockroach allergen inhalation on the pulmonary and systemic immune responses of newborn and juvenile mice.

METHODS

C3H/HeBFeJ mice were exposed to inhaled endotoxin and cockroach allergen via intranasal instillation from day 2 to 21 after birth, and systemic and pulmonary responses were examined in serum, bronchoalveolar lavage fluid, and lung tissue.

RESULTS

Cockroach allergen exposures induced pulmonary eosinophilic inflammation, total and allergen-specific IgE, IgG(1), and IgG(2a) production, and alveolar remodelling. Co-exposures with endotoxin and cockroach allergen significantly increased serum IgE and IgG(1), lung inflammation, and alveolar wall thickness, and decreased airspace volume density. Importantly, compared with exposures with individual substances, the responses to co-exposures were more than additive.

CONCLUSIONS

Repeated inhalation exposures of neonatal and juvenile mice to endotoxin and cockroach allergen increased the pulmonary inflammatory and systemic immune responses in a synergistic manner and enhanced alveolar remodelling in the developing lung. These data underscore the importance of evaluating the effect of multiple, concurrent environmental exposures, and of using an experimental model that incorporates clinically relevant timing and route of exposures.

Oral administration of CpG-ODNs suppresses antigen-induced asthma in mice

Oligodeoxynucleotides containing CpG motifs (CpG-ODNs) can protect against eosinophilic airway inflammation in asthma. Previously we have found that parenteral or mucosal administration of CpG-ODNs is effective in preventing (as well as reversing established) disease. In this study, we examined the effect of oral CpG-ODNs on the development of immune tolerance. Using an ovalbumin (OVA)-induced murine model of asthma, we found that CpG-ODNs, administered orally around the time of sensitization, prevented eosinophilic airway inflammation in a dose-dependent manner. Although oral co-administration of CpG-ODNs with OVA (known to induce tolerance) did not significantly change the inhibition of OVA-induced airway eosinophilia, it did modulate OVA-specific immunoglobulin responses: oral administration of OVA alone suppressed OVA-specific IgG1 production, but only mice that received CpG-ODNs demonstrated enhanced levels of OVA-specific IgG2c. Finally, we examined whether oral administration of CpG-ODNs, alone or with OVA, could reverse established eosinophilic airway inflammation. Again, neither OVA nor CpG-ODNs alone modulated established eosinophilic airway inflammation, but a combination of the OVA and CpG-ODNs successfully desensitized the mice. This desensitization was associated with suppression of OVA-specific IgE and enhancement of OVA-specific IgG2c production. These findings provide the first indication that oral administration of CpG-ODNs is effective in preventing and reversing antigen-induced eosinophilic airway inflammation. CpG-ODNs may be useful as a component of oral immunotherapy to promote tolerance in established asthma.

CpG DNA and immunotherapy of allergic airway diseases

Atopic asthma is a highly prevalent and serious health problem for which no therapy currently offers the hope of a cure. Preindustrialized and rural populations appear relatively protected from the asthma epidemic; the hygiene hypothesis ascribes this protection to the effects of microbes and microbial products. An important immunostimulant component of microbes is DNA; bacterial DNA contains sequence motifs centred on the CpG dinucleotide, which are suppressed in mammalian DNA. Oligonucleotides containing these motifs (CpG ODN), like bacterial DNA, promote Th1 and regulatory-type immune responses. Using CpG ODN, we and others have demonstrated in murine studies that CpG ODN are effective in preventing the development of atopic airways disease. Moreover, when administered in conjunction with experimental allergen, they promote the reversal of established eosinophilic inflammation. These data suggest that CpG ODN may be a novel therapeutic tool for the treatment of atopic asthma.

CpG oligodeoxynucleotides in asthma

Asthma is a major health problem, of which the prevalence and severity are increasing, particularly in industrialized nations. One hypothesis for this is that diminished exposure to childhood infections in modern society has led to decreased Th1-type inflammation. Reduced Th1 responses may lead to enhanced Th2-type inflammation, important in promoting asthma and allergic disease. The most common current treatment for asthma is corticosteroids; while these agents inhibit the function of inflammatory cells, they are ineffective in altering the initial Th2-type response to allergen in a sensitized individual. A novel therapeutic approach, recently reported in the preclinical setting, is the use of oligodeoxynucleotides (ODNs), which contain unmethylated motifs centered on CG dinucleotides. These CpG ODNs potently induce Th1 cytokines and suppress Th2 cytokines, and can prevent manifestations of asthma in animal models. These agents have the potential to reverse Th2-type responses to allergens and thus restore balance to the immune system. Clinical trials are ongoing.

Endotoxin responsiveness and subchronic grain dust-induced airway disease

Endotoxin is one of the principal components of grain dust that causes acute reversible airflow obstruction and airway inflammation. To determine whether endotoxin responsiveness influences the development of chronic grain dust-induced airway disease, physiological and airway inflammation remodeling parameters were evaluated after an 8-wk exposure to corn dust extract (CDE) and again after a 4-wk recovery period in a strain of mice sensitive to (C3H/HeBFeJ) and one resistant to (C3H/HeJ) endotoxin. After the CDE exposure, both strains of mice had equal airway hyperreactivity to a methacholine challenge; however, airway hyperreactivity persisted only in the C3H/HeBFeJ mice after the recovery period. Only the C3H/HeBFeJ mice showed significant inflammation of the lower airway after the 8-wk exposure to CDE. After the recovery period, this inflammatory response completely resolved. Lung stereological measurements indicate that an 8-wk exposure to CDE resulted in persistent expansion of the airway submucosal cross-sectional area only in the C3H/HeBFeJ mice. Collagen type III and an influx of cells into the subepithelial area participated in the expansion of the submucosa. Our findings demonstrate that subchronic inhalation of grain dust extract results in the development of chronic airway disease only in mice sensitive to endotoxin but not in mice that are genetically hyporesponsive to endotoxin, suggesting that endotoxin is important in the development of chronic airway disease.

Bronchial hyperreactivity is associated with enhanced grain dust-induced airflow obstruction

Bronchial hyperreactivity (BHR) is associated with the presence of airway inflammation in asthma and is seen in individuals occupationally exposed to grain dust. To better understand the relationship between BHR and pulmonary inflammation after grain dust exposure, we carried out an inhalation challenge to corn dust extract (CDE) on seven subjects with BHR [a 20% or greater decrease in forced expiratory volume in 1 s (FEV(1)) compared with diluent FEV(1) with a cumulative dose of histamine </=47.3 breath units] and compared their physiological and inflammatory responses with those of seven matched control subjects. BHR subjects were exposed to nebulized CDE (target dose of 0.16 microg/kg endotoxin) as tolerated; matched controls received equal amounts of CDE. Subjects with BHR complained of chest tightness and dyspnea within the 2 h after inhalation of CDE significantly more frequently than controls. Similarly, subjects with BHR developed significantly greater percent declines in FEV(1) at time points up to 4 h after exposure to CDE. Significant increases in total cells, neutrophils, tumor necrosis factor-alpha, interleukin-6, and interleukin-8 were detected in bronchoalveolar lavage fluid 4 h after inhalation of CDE in all subjects, but no differences were detected between the control and BHR groups. These results suggest that, although subjects with BHR develop a more precipitous decline in FEV(1) after exposure to CDE, the inflammatory response to CDE is similar in subjects with and without BHR.

TLR4 mutations are associated with endotoxin hyporesponsiveness in humans

There is much variability between individuals in the response to inhaled toxins, but it is not known why certain people develop disease when challenged with environmental agents and others remain healthy. To address this, we investigated whether TLR4 (encoding the toll-like receptor-4), which has been shown to affect lipopolysaccharide (LPS) responsiveness in mice, underlies the variability in airway responsiveness to inhaled LPS in humans. Here we show that common, co-segregating missense mutations (Asp299Gly and Thr399Ile) affecting the extracellular domain of the TLR4 receptor are associated with a blunted response to inhaled LPS in humans. Transfection of THP-1 cells demonstrates that the Asp299Gly mutation (but not the Thr399Ile mutation) interrupts TLR4-mediated LPS signalling. Moreover, the wild-type allele of TLR4 rescues the LPS hyporesponsive phenotype in either primary airway epithelial cells or alveolar macrophages obtained from individuals with the TLR4 mutations. Our findings provide the first genetic evidence that common mutations in TLR4 are associated with differences in LPS responsiveness in humans, and demonstrate that gene-sequence changes can alter the ability of the host to respond to environmental stress.

Effects of CpG DNA on Th1/Th2 balance in asthma

Thus, in our studies, we demonstrated that CpG ODN are effective in preventing the development of eosinophilic airway inflammation and bronchial hyper-reactivity in a murine model of asthma. Antigen-associated elevation of serum IgE levels is also suppressed. CpG ODN, administered in conjunction with antigen, is also effective in down-regulation of established Th2 responses. This protection is neither murine strain-dependent nor model-dependent. Although these effects of CpG ODN are associated with the induction of the Th1 cytokines IFN-gamma and IL-12, neither cytokine is absolutely required for the protection. These results suggest that CpG ODN may be an effective immunomodulatory agent in the treatment, and possibly prevention, of asthma.

CpG oligodeoxynucleotides do not require TH1 cytokines to prevent eosinophilic airway inflammation in a murine model of asthma

BACKGROUND

Oligodeoxynucleotides (ODNs) containing the dinucleotide CpG in a specific sequence context (CpG-ODNs) have the ability to prevent the development of eosinophilic airway inflammation and bronchial hyperreactivity in a murine model of asthma. We have previously demonstrated that CpG-ODNs stimulate expression of the T(H1)-inducing cytokines IFN-gamma and IL-12 in a murine model of asthma and that this stimulation is associated with the protection against asthmatic inflammation.

OBJECTIVE

The purpose of this study was to examine whether the protection conferred by CpG-ODNs in a schistosome egg-egg antigen murine model of asthma is dependent on the induction of IFN-gamma, IL-12, or both.

METHODS

C57BL/6 mice were sensitized to schistosome eggs in the presence or absence of CpG-ODNs or control ODNs and then stimulated with soluble egg antigen in the airway. The protection offered by CpG-ODNs in these mice was compared with the protection induced by CpG-ODNs in IL-12 and IFN-gamma knockout mice and in mice treated with anticytokine blocking antibodies. Double-knockout mice (IL-12/IFN-gamma) were also generated and used in these studies. Determinations included airway eosinophilic inflammation and bronchial hyperreactivity to inhaled methacholine.

RESULTS

We found that CpG-ODNs confer protection against both airway eosinophilia and bronchial hyperreactivity in the absence of IFN-gamma or IL-12 or in the presence of both cytokines together. However, in the absence of either IL-12 or IFN-gamma, mice require 10 times as much CpG-ODNs to be protected against the induction of airway eosinophilia. The T(H2) cytokines IL-4 and IL-5 were reduced in all of the CpG-treated mice, although less in the absence of IL-12 and IFN-gamma.

CONCLUSION

These data indicate that CpG-ODNs prevent the generation of T(H2)-like immune responses by multiple mechanisms, which involve, but do not require, IL-12 and IFN-gamma. A direct suppressive effect of CpG-ODNs on T(H2) responses is suggested by their reduction in IFN-gamma and IL-12 knockout mice.

Variable airway responsiveness to inhaled lipopolysaccharide

Individuals exposed to inhaled endotoxin (lipopolysaccharide [LPS]) can develop airway symptomatology and exacerbations of asthma. Moreover, among those occupationally exposed to organic dusts, the progression of airflow obstruction is related to the endotoxin concentration in the bioaerosol. Not everyone exposed to high concentrations of LPS develops these problems. To determine whether individuals express a differential response to inhaled LPS, we challenged 72 healthy volunteers with increasing doses of LPS. Airflow was assessed after each dose and the protocol was terminated for decline in FEV1 >/= 20%. Marked differences in the response to inhaled LPS were observed: eight "sensitive" subjects had at least 20% decline in their FEV1 after inhaling 6.5 micrograms or less of LPS, whereas 11 "hyporesponsive" subjects maintained an FEV1 >/= 90% of their baseline even after inhaling 41.5 micrograms of LPS. Serial testing demonstrated that the response to inhaled LPS is reproducible. Sensitive subjects were more commonly female and hyporesponsive subjects were more often male (p = 0.016). Peripheral blood monocytes from hyporesponsive subjects, compared with sensitive subjects, released less interleukin (IL)-6 and IL-8. These findings demonstrate that an LPS phenotype can be reproducibly elicited in humans, which creates an opportunity to identify genes involved in this response to inhaled LPS.

Psychiatric disorders and survival after lung transplantation

The 30 patients who underwent lung transplantation between 1990 and 1996 were included in this study, and data were analyzed to find predictors of 1-year survival posttransplantation. All patients were followed throughout the posttransplantation period. Fifteen patients had a pretransplantation diagnosis of an anxiety and/or depressive disorders. Of the 30 patients transplanted, 19 survived 12 months or more, and 11 died less than 12 months posttransplantation. The > 12-month survival group had a mean age of 45.2 years at transplantation, compared with a mean age of 43.0 years in the < 12-month group (NS). The mean Psychosocial Assessment of Candidates for Transplant score and premorbid history of smoking did not differ between the groups. The > 12-month survival group had more psychiatric illness pretransplantation than the < 12-month survival group (56% vs. 27%, P < 0.05). The recipients with a psychiatric history (N = 15) were more likely to survive 1 year posttransplantation than the recipients without a psychiatric history (80% vs. 47%, P < 0.05) and were not significantly different from the recipients without a psychiatric history in terms of episodes of rejection, bronchiolitis obliterans, or noncompliance with treatment. Depression and anxiety are treatable disorders that occur frequently in patients with end-stage lung disease, and a premorbid history of either did not predict a worse outcome posttransplantation in this study of lung transplantation recipients.

Asthma guidelines: an assessment of physician understanding and practice

In 1997 the NHLBI updated guidelines for the diagnosis and management of asthma. We hypothesized that not all components of the updated guidelines are well understood by the physicians who care for asthmatics. To develop appropriate educational interventions that address areas of physician misunderstanding, it is important to identify these components. Based upon NHLBI guidelines, we developed a multiple-choice test of asthma knowledge that was distributed to physicians at the University of Iowa; 108 physicians completed the test, including 20 asthma specialists, 11 asthma specialty fellows, 11 General Medicine faculty, five Family Medicine faculty, 51 Internal Medicine residents, and five Family Medicine residents. The mean correct total score for all physicians was 60 +/- 2% (mean +/- SEM). Asthma specialists scored higher in total score and in pharmacology and prevention. However, no group performed well on estimating disease severity. We further identified deficits in the use of spirometry and anti-inflammatory agents in caring for asthmatic patients. Thus, deficits exist in physician understanding and implementation of the NHLBI guidelines for the diagnosis and management of asthma. By identifying specific areas of misunderstanding, we can design better educational interventions. Clearly, educational programs should emphasize new models for estimating chronic disease severity.

Modulation of airway inflammation by CpG oligodeoxynucleotides in a murine model of asthma

Asthma has been increasing in industrialized countries. Evidence suggests that asthma is caused by a Th2 immune response to inhaled environmental Ags and that childhood infections protect against this. We have shown that bacterial DNA contains motifs, centered on unmethylated CpG dinucleotides, which induce Th1-type responses. We hypothesized that the Th1 effect of these CpG motifs may oppose the Th2 type allergic response and suggest that this may account for the protective effect of childhood infection against asthma. We examined the effects of CpG-motif oligodeoxynucleotides (CpG ODN) in a murine model of asthma. Airway eosinophilia, Th2 cytokine induction, IgE production, and bronchial hyperreactivity were prevented by coadministration of CpG ODN with the Ag. Significantly, in a previously sensitized mouse, CpG ODN can prevent allergen-induced airway inflammation. These studies suggest that exposure to CpG DNA may protect against asthma.

Synergistic activation of the human cytomegalovirus major immediate early promoter by prostaglandin E2 and cytokines

Human cytomegalovirus (HCMV) is a common cause of morbidity and mortality in immunosuppressed patients, especially transplant recipients. In this population, infection is frequently due to reactivation of latent virus. The major immediate early promoter of HCMV controls production of immediate early gene products, which are both trans- and cis-active and are responsible for reactivation. Activation of this promoter is therefore a crucial step in regulation of reactivation infection. It is known that there are cAMP-response elements in the HCMV major immediate early promoter. We hypothesized that prostaglandins (PG), like PGE2, which are known to increase cAMP, as well as cytokines known to be released during acute inflammation, may be important in the regulation of this promoter and thus in reactivation of HCMV. To examine this, we transfected pCAT760, a plasmid containing the major immediate early promoter of HCMV upstream of a chloramphenicol acetyltransferase (CAT) gene, into THP-1 cells. These cells were subsequently stimulated with PGE2 and/or one of a variety of cytokines. We found that PGE2, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1 beta each upregulated the HCMV major immediate early promoter. TNF-alpha, IL-1 beta, IL-6, and IL-10 were each synergistic or additive with PGE2 in upregulating the promoter. Since PGE2 and the cytokines are all products of activated macrophages, we suggest that acute inflammation and macrophage activation may predispose to reactivation of latent HCMV.

Alveolar macrophages inhibit retrovirus-mediated gene transfer to airway epithelia

Gene transfer with integrating vectors such as recombinant retrovirus has the potential to correct inherited lung diseases permanently. As a gene therapy target, the pulmonary epithelium presents several challenges to vector delivery in vivo. Many of the host defenses that have evolved to prevent infection from inhaled bacteria or viruses represent potential barriers to gene transfer to the lung. We performed in vitro studies to determine whether two components of the innate immune system of the lung, airway surface fluid and alveolar macrophages, inhibit retroviral gene transfer to airway epithelia. Human alveolar macrophages obtained by bronchoalveolar lavage from normal subjects were left untreated or activated with lipopolysaccharide (LPS) for 3 hr in the presence of subconfluent human bronchial epithelial cells (HBE); than 4 x 10(5) cfu DA-luciferase retrovirus was added. Three days after infection, luciferase activity was measured in cell lysates. When the epithelial cells were co-cultured with LPS-activated macrophages, retroviral gene transfer to HBE cells was reduced by approximately 60%. Nonactivated macrophages decreased the transfection to approximately 55% of control values. In control experiments with either activated or inactivated macrophages but without epithelia, no luciferase activity was detected, suggesting that terminally differentiated alveolar macrophages are not infected by the recombinant retrovirus. Pretreatment of alveolar macrophages with dexamethasone restored gene transfer to approximately 60% of control values. In contrast, incubation of retrovirus with airway surface fluid had no inhibitory effect on gene transfer. These experiments document that AM inhibit retrovirus-mediated gene transfer to airway epithelia in vitro, and may represent a barrier to retroviral gene transfer in vivo. These barriers may be overcome, at least partially, with pharmacological agents.

Regulation of interleukin-1 receptor antagonist by Th1 and Th2 cytokines

Airway inflammation is an important aspect of asthma. Recent studies of airway inflammation in asthma have focused attention on cytokines released by T helper lymphocyte type 1 (Th1)- and Th2-like T cells. Interleukin (IL)-1 is also increased in the airways of asthmatics, and it is most likely derived from airway and alveolar macrophages. The effects of Th1 or Th2 cytokines on the release of IL-1 or its specific antagonist, IL-1ra, have not been well studied. We examined the response of THP-1 cells, a myelomonocytic cell line, to stimulation with various Th1 and Th2 cytokines and found that IL-4, IL-10, and IFN-gamma increased IL-1ra mRNA and protein release. The increase in mRNA was not due to an increase in IL-1ra mRNA stability. IL-4 (10 ng/ml) increased IL-1ra release from 9,641 +/- 322 [from cells stimulated with lipopolysaccharide (LPS) alone] to 50,796 +/- 1,917 pg/ml (from cells stimulated with LPS and IL-4). IL-10 (10 ng/ml) caused a similar upregulation of IL-1ra from LPS-stimulated cells: 87,478 +/- 7,808 compared with 8,004 +/- 1,166 pg/ml released from the cells stimulated with LPS alone. Cells stimulated with IFN-gamma (100 U/ml) and LPS released 27,854 +/- 3,626 pg/ml of IL-1ra, compared with 9,069 +/- 236 pg/ml in the presence of LPS alone. In addition, the Th1 cytokine, IFN-gamma, but not the Th2 cytokines, IL-4 and IL-10, upregulated IL-1 beta mRNA and increased the release of IL-1 beta protein. Similar studies were performed using freshly isolated monocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycobacterium tuberculosis in lung transplant recipients

The diagnosis and treatment of Mycobacterium tuberculosis, although difficult in normal hosts, are even more complex in transplant recipients. As a result of the use of immunosuppressive agents, transplant recipients are not only predisposed to primary tuberculous infections, but they are also uniquely at risk for reactivation of latent infection acquired prior to transplantation or transmitted via the donor organ. The diagnosis of pulmonary tuberculosis can be even more elusive in the setting of lung transplantation where other pulmonary complications can make diagnosis difficult. Here we report a case of a patient who died of disseminated M. tuberculosis 12 wk after lung transplantation, and we review tuberculous infections in lung transplant recipients.

T-lymphocyte dysregulation in asthma

In this paper, we have reviewed the evidence suggesting that T-cell dysregulation is important in the pathogenesis of asthma. The history, clinical presentation, and an overview of the appropriate management of asthma have been briefly reviewed. T cells obtained from the airways of asthmatics display signs of activation; these changes mirror the intramural inflammation found at biopsy. There is debate about the importance of T helper/suppressor ratios in this population of cells, but alterations in these ratios have been noted with experimental allergen exposure, as well as during acute asthma attacks; some of these changes revert toward normal with steroid therapy. The division of T helper lymphocytes into Th1 and Th2 cells, first described in studies of murine immunology, appear to be relevant in humans, particularly in allergic disease. Although IL-4 and IL-5, prototypical Th2 cytokines, have been most clearly implicated in asthma, there is some evidence supporting a role for Th1 cells/cytokines as well.

Regulation of expression of the IL-1 receptor antagonist (IL-1ra) gene by products of the human cytomegalovirus immediate early genes

Human cytomegalovirus (HCMV), which is a major cause of morbidity and mortality in immunosuppressed patients, can itself alter immune function. It has previously been shown that HCMV immediate early (IE) gene products regulate the IL-1 beta promoter. The purpose of these studies was to determine whether HCMV IE gene products regulate expression of the IL-1 receptor antagonist (IL-1ra) gene. THP-1 cells, a myelomonocytic cell line, were transfected with a plasmid containing one or more of the HCMV IE genes downstream of the HCMV major immediate early promoter, or with a control plasmid. IL-1 beta and IL-1ra protein secretion was evaluated by ELISA, and expression of the mRNA for the cytokines was examined by means of Northern blot analysis. The HCMV IE1+2 gene products were found to increase expression of the mRNA for both IL-1 beta and IL-1ra; however, only the IL-1ra protein was released in increased amounts. The individual HCMV IE gene products had different effects on expression of the IL-1ra gene; the HCMV IE1 gene product down-regulated expression of the IL-1ra gene, whereas the IE2 gene product up-regulated expression of the IL-1ra gene. Thus, HCMV IE gene products can either up-regulate or down-regulate expression of the IL-1ra gene, depending on which IE genes are expressed in monocytes-macrophages. This study adds to the understanding of how HCMV can alter immune function during both active and latent infection.

Regulation of expression of the IL-1 receptor antagonist (IL-1ra) gene by products of the human cytomegalovirus immediate early genes

Human cytomegalovirus (HCMV), which is a major cause of morbidity and mortality in immunosuppressed patients, can itself alter immune function. It has previously been shown that HCMV immediate early (IE) gene products regulate the IL-1 beta promoter. The purpose of these studies was to determine whether HCMV IE gene products regulate expression of the IL-1 receptor antagonist (IL-1ra) gene. THP-1 cells, a myelomonocytic cell line, were transfected with a plasmid containing one or more of the HCMV IE genes downstream of the HCMV major immediate early promoter, or with a control plasmid. IL-1 beta and IL-1ra protein secretion was evaluated by ELISA, and expression of the mRNA for the cytokines was examined by means of Northern blot analysis. The HCMV IE1+2 gene products were found to increase expression of the mRNA for both IL-1 beta and IL-1ra; however, only the IL-1ra protein was released in increased amounts. The individual HCMV IE gene products had different effects on expression of the IL-1ra gene; the HCMV IE1 gene product down-regulated expression of the IL-1ra gene, whereas the IE2 gene product up-regulated expression of the IL-1ra gene. Thus, HCMV IE gene products can either up-regulate or down-regulate expression of the IL-1ra gene, depending on which IE genes are expressed in monocytes-macrophages. This study adds to the understanding of how HCMV can alter immune function during both active and latent infection.

Relative release of interleukin-1 beta and interleukin-1 receptor antagonist by alveolar macrophages. A study in asbestos-induced lung disease, sarcoidosis, and idiopathic pulmonary fibrosis

We examined the influence of untreated interstitial lung disease (ILD) on the in vitro release of interleukin-1 beta (IL-1 beta) and interleukin-1 receptor antagonist (IL-Ira) from alveolar macrophages (AM); AM were harvested from normal volunteers, ILD patients, and patients with asbestos-related pleural disease but no ILD. AM were cultured for 24 h and assays for IL-1 beta and IL-1ra were done using sensitive and specific enzyme-linked immunosorbent assay. A greater amount of IL-1 beta was detected in AM supernatants from asbestosis, sarcoidosis, and IPF patients than in those from normal subjects. The IL-1 beta:IL-1ra ratio (IL-1 beta activity index [IL-1AI]) was significantly lower in supernatants of normal macrophages compared with macrophage supernatants from individuals with ILD. The IL-1AI correlated with bronchoalveolar lavage cellularity, a marker of disease activity. Current smoking was associated with lower IL-1 beta and IL-1ra release in ILD. The IL-1AI is a convenient method for comparison of IL-1 beta activity between patient populations.

Pulmonary embolization and infarction. An iatrogenic complication of transcatheter embolization of a cerebral arteriovenous malformation with polyvinyl alcohol sponge

Transcatheter embolization therapy of vascular abnormalities is a well-accepted technique. It is particularly useful in the preoperative management of cerebral arteriovenous malformations, in which the risk of significant hemorrhage at surgery would otherwise be unacceptably high. A patient developed symptomatic pulmonary emboli and infarction following an uneventful embolization using polyvinyl alcohol particles. The authors believe this to be the first reported case of this complication of embolic therapy using polyvinyl alcohol.

IL-1 receptor antagonist release is regulated differently in human alveolar macrophages than in monocytes

These studies compared the release of interleukin-1 receptor antagonist (IL-1 RA) from alveolar macrophages and peripheral blood monocytes. The cells were cultured in medium containing various amounts of heat-inactivated fetal calf serum (FCS), granulocyte-macrophage colony-stimulating factor (GM-CSF), lipopolysaccharide (LPS), and immunoglobulin G (IgG). In serum-free medium alone, IL-1 RA release was similar from macrophages and monocytes. Increasing FCS concentration caused a significant upregulation of IL-1 RA release in macrophages but not in monocytes. GM-CSF caused a small increase in both cell types. LPS caused downregulation of IL-1 RA release from monocytes but not from macrophages. IgG did not affect IL-1 RA release in either cell group. These studies demonstrate that regulation of IL-1 RA release is different in monocytes and macrophages.

Pulmonary edema after freebase cocaine smoking--not due to an adulterant

A case of pulmonary edema following smoking freebase cocaine is described. We did not clearly establish the mechanism, but this case is unique since adulterants and contaminants were excluded unlike all previously reported patients.