Maintenance of Remission in Crohn???s Disease

Assessing Progression of Biologic Therapies Based on Smoking Status in Patients With Crohn's Disease

BACKGROUND

Active smoking is a well-established risk factor for developing Crohn's disease (CD) and negatively impacts overall disease progression. Patients who start or continue smoking after CD diagnosis are at risk for poor outcomes, higher therapeutic requirements, and have higher rates of relapse. However, it remains unclear if the exposure to smoking leads to increased sequencing through treatment therapies, especially biologics.

METHODS

The Study of Prospective Adult Research Cohort with IBD (SPARC IBD) registry has been collecting patient-reported outcomes data in real-time, as well as laboratory, endoscopic, and pathologic samples from 17 tertiary referral centers since 2016. In this study, we conducted a retrospective review of the SPARC clinical registry collected between December 2016 and January 2021 from 1 participating site, the University of Maryland School of Medicine's Inflammatory Bowel Disease Program. A total of 619 patients were enrolled in the SPARC IBD database. Four hundred twenty-five patients with CD were included for initial review of completeness of data; of these, 144 patients were excluded due to missing data on smoking status and/or biologic treatment, resulting in a final cohort of 281 patients. We collected and analyzed baseline demographic and clinical characteristics. The final cohort was categorized into 3 exposure groups: current, former, and never smokers. Our outcome of interest was number biologics used, categorized into 3 groups: 0, 1, or ≥2 biologics.

RESULTS

One hundred seventy-two never smokers, 70 former smokers, and 39 current smokers were identified. Current, former, and never smokers had no statistically significant differences in number of biologics used (ie, biologic sequencing). However, statistically significant independent risk factors for increased sequencing of biologics were identified. These risk factors included female sex, ileocolonic disease location, younger age at diagnosis, and prolonged disease duration; none of these factors remained significant in adjusted analyses.

CONCLUSION

To date, this is the first study assessing the association of smoking and sequencing of biologics. Although current or former smokers were not found to sequence through more biologics when compared with never smokers, smoking is a well-established risk factor for poor health outcomes, and efforts should be made to counsel patients to quit. Further, additional research must be done to stratify risk to patients based on amount of tobacco exposure.

The microbiome landscape in pediatric Crohn's disease and therapeutic implications

Dysbiosis of the gut microbiome and a pathological immune response in intestinal tissues form the basis of Crohn's disease (CD), which is a debilitating disease with relevant morbidity and mortality. It is increasing in childhood and adolescents, due to western life-style and nutrition and a large set of predisposing genetic factors. Crohn's disease-associated genetic mutations play an essential role in killing pathogens, altering mucosal barrier function, and protecting the host microbiome, suggesting an important pathogenic link. The intestinal microbiome is highly variable and can be influenced by environmental factors. Changes in microbial composition and a reduction in species diversity have been shown to be central features of disease progression and are therefore the target of therapeutic approaches. In this review, we summarize the current literature on the role of the gut microbiome in childhood, adolescent, and adult CD, current therapeutic options, and their impact on the microbiome.

Machine Learning Modeling from Omics Data as Prospective Tool for Improvement of Inflammatory Bowel Disease Diagnosis and Clinical Classifications

Research of inflammatory bowel disease (IBD) has identified numerous molecular players involved in the disease development. Even so, the understanding of IBD is incomplete, while disease treatment is still far from the precision medicine. Reliable diagnostic and prognostic biomarkers in IBD are limited which may reduce efficient therapeutic outcomes. High-throughput technologies and artificial intelligence emerged as powerful tools in search of unrevealed molecular patterns that could give important insights into IBD pathogenesis and help to address unmet clinical needs. Machine learning, a subtype of artificial intelligence, uses complex mathematical algorithms to learn from existing data in order to predict future outcomes. The scientific community has been increasingly employing machine learning for the prediction of IBD outcomes from comprehensive patient data-clinical records, genomic, transcriptomic, proteomic, metagenomic, and other IBD relevant omics data. This review aims to present fundamental principles behind machine learning modeling and its current application in IBD research with the focus on studies that explored genomic and transcriptomic data. We described different strategies used for dealing with omics data and outlined the best-performing methods. Before being translated into clinical settings, the developed machine learning models should be tested in independent prospective studies as well as randomized controlled trials.

The Impact of Oxidative Stress in Human Pathology: Focus on Gastrointestinal Disorders

Accumulating evidence shows that oxidative stress plays an essential role in the pathogenesis and progression of many diseases. The imbalance between the production of reactive oxygen species (ROS) and the antioxidant systems has been extensively studied in pulmonary, neurodegenerative cardiovascular disorders; however, its contribution is still debated in gastrointestinal disorders. Evidence suggests that oxidative stress affects gastrointestinal motility in obesity, and post-infectious disorders by favoring the smooth muscle phenotypic switch toward a synthetic phenotype. The aim of this review is to gain insight into the role played by oxidative stress in gastrointestinal pathologies (GIT), and the involvement of ROS in the signaling underlying the muscular alterations of the gastrointestinal tract (GIT). In addition, potential therapeutic strategies based on the use of antioxidants for the treatment of inflammatory gastrointestinal diseases are reviewed and discussed. Although substantial progress has been made in identifying new techniques capable of assessing the presence of oxidative stress in humans, the biochemical-molecular mechanisms underlying GIT mucosal disorders are not yet well defined. Therefore, further studies are needed to clarify the mechanisms through which oxidative stress-related signaling can contribute to the alteration of the GIT mucosa in order to devise effective preventive and curative therapeutic strategies.

Smoking May Reduce the Effectiveness of Anti-TNF Therapies to Induce Clinical Response and Remission in Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Cigarette smoking worsens prognosis of Crohn's disease [CD]. We conducted a systematic review and meta-analysis to examine the association between smoking and induction of clinical response or remission with anti-tumour necrosis factor [TNF] therapy.

METHODS

MEDLINE, EMBASE, PubMed, and Cochrane CENTRAL [June 2019] were searched for studies reporting the effect of smoking on short-term clinical response and remission to anti-TNF therapy [≤16 weeks following the first treatment] in patients with CD. Risk ratios [RR] with 95% confidence intervals [CI] were calculated using random-effects models.

RESULTS

Eighteen observational studies and three randomised controlled trials [RCT] were included. Current smokers and non-smokers [never or former] had similar rates of clinical response [observational studies RR: 0.96; 95% CI: 0.88, 1.05; RCTs RR: 1.09; 95% CI: 0.84, 1.41]. When restricted to studies clearly defining the smoking exposure, smokers treated with anti-TNF were less likely to achieve clinical response than non-smokers [smokers defined as having ≥5 cigarettes/day for ≥6 months RR: 0.63; 95% CI: 0.48, 0.83; lifetime never smokers vs ever smokers excluding former smokers RR: 0.81; 95% CI: 0.71, 0.93]. Current smokers were also less likely to achieve clinical remission in observational studies [RR: 0.75; 95% CI: 0.57, 0.98], though this association was not seen in RCTs [RR: 1.04; 95% CI: 0.89, 1.21].

CONCLUSIONS

Smoking is significantly associated with a reduction in the ability of infliximab or adalimumab to induce short-term clinical response and remission when pooling studies where smoking status was clearly defined. When patients with CD are treated with highly effective therapy, including anti-TNF agents, concurrent smoking cessation may improve clinical outcomes.

A rare case of refractory asthma managed with azathioprine

Introduction: Azathioprine is an immune-modulating agent used in the management of autoimmune diseases and in preventing graft rejection. Its role in the management of refractory asthma is not very well-established.Case study: A 47-year-old female with an underlying severe refractory asthma, managed with high dose steroids, was seen as an outpatient. Her course was complicated by frequent asthma exacerbation and severe adverse effects of chronic steroid use. Her symptoms did not respond to standard asthma management per Guidelines for the Diagnosis and Management of Asthma 1. She was tried on other management which included methotrexate and omalizumab injections without success. Azathioprine was started as a steroid-sparing agent following which her symptoms showed dramatic improvement with fewer exacerbations, higher peak flow measurements, and she was able to wean down her daily prednisone dose from 60 mg/day to 5 mg/day.Conclusion: Azathioprine is still an investigational agent for the management of asthma and more research needs to be done to evaluate its role. To our knowledge, this is the second case report which details the therapeutic role of Azathioprine in the management of asthma.

Antioxidant Supplements and Gastrointestinal Diseases: A Critical Appraisal

The gastrointestinal tract digests and absorbs dietary nutrients, protects the body against physical and chemical damage from contents in its lumen, provides immunity against external antigens, and keeps an optimum environment for the gut microbiota. These functions cannot be performed normally in several diseases of which the following are discussed here: irritable bowel syndrome and inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. Because these diseases are associated with oxidative stress, a host of antioxidant supplements are used for maintenance and recovery of the gut functions. However, the benefits of these supplements have not been established. The available 80 human trials were rated for levels of confidence and for benefits of the antioxidant supplements. For Crohn's disease, the supplements for which clear benefits occurred in at least 2 studies were allopurinol, Boswellia serrata (frankincense or shallaki), Artemesia species (wormwood), Tripterygium wilfordii (léi gōng téng), and omega-3 fatty acids. Similar beneficial supplements for ulcerative colitis were allopurinol, Matricaria chamomilla (chamomile), Curcuma longa (curcumin in turmeric), and omega-3 fatty acids. There was also a clear benefit for ulcerative colitis in 2 studies where a multiherbal Chinese medicine preparation and an Ayurvedic medicine preparation were used. For irritable bowel syndrome, there was only a marginal benefit of some of the antioxidant supplements. Thus, some antioxidant supplements may be beneficial at certain stages of specific diseases. This is consistent with the current concept that antioxidants act by inhibiting oxidative stress pathways in a tissue- and environment-specific manner and not by simply acting as scavengers.

Immunotherapeutic Biologic Agents in Autoimmune and Autoinflammatory Diseases

In recent decades, innovative strategies to treat patients with inflammatory, immunologically based diseases have advanced in concert with our increased understanding of molecular immunology. Recognition of the spectrum and pathophysiology of autoimmune and autoinflammatory disorders has allowed for the development of cutting-edge therapies for such patients. In this review, key immunotherapeutic approaches for treating inflammatory autoimmune disorders, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), as well as genetic autoinflammatory diseases, such as cryopyrin associated periodic syndromes, are addressed. Indications, risks and additional considerations in the use of these agents are reviewed.

Chronic inflammation up-regulates P-gp in peripheral mononuclear blood cells via the STAT3/Nf-κb pathway in 2,4,6-trinitrobenzene sulfonic acid-induced colitis mice

Patients with inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis, often suffer drug intolerance. This resistance can be divided into intrinsic resistance and acquired resistance. Although there is agreement on acquired resistance, studies regarding intrinsic resistance have demonstrated inconsistencies, especially for Crohn’s disease. For this reason, an animal model of Crohn’s disease was induced with 2,4,6-trinitrobenzene sulfonic acid solution (TNBS), and intrinsic resistance was analyzed by measuring the function and expression of P-glycoprotein (P-gp) in peripheral mononuclear blood cells (PMBC), followed by mechanistic studies. The results revealed reduced retention of cyclosporine A in PMBC over-expressing P-gp in a TNBS-treated group and enhanced secretion of the cytokines IL-1β, IL-6, IL-17, and TNF-α as well as LPS in plasma. These cytokines and LPS can induce P-gp expression through the STAT3/Nf-κb pathway, contributing to a decrease of cyclosporine A retention, which can be reversed by the application of a P-gp inhibitor. Our results demonstrated that the sustained chronic inflammation could induce the intrinsic resistance presented as P-gp over-expression in PBMC in Crohn’s disease through STAT3/Nf-κb pathway and this resistance might be reversed by combinational usage of P-gp inhibitors.

Classical versus alternative macrophage activation: the Ying and the Yang in host defense against pulmonary fungal infections

Macrophages are innate immune cells that possess unique abilities to polarize toward different phenotypes. Classically activated macrophages are known to have major roles in host defense against various microbial pathogens, including fungi, while alternatively activated macrophages are instrumental in immune-regulation and wound healing. Macrophages in the lungs are often the first responders to pulmonary fungal pathogens, and the macrophage polarization state has the potential to be a deciding factor in disease progression or resolution. This review discusses the distinct macrophage polarization states and their roles during pulmonary fungal infection. We focus primarily on Cryptococcus neoformans and Pneumocystis model systems as disease resolution of these two opportunistic fungal pathogens is linked to classically or alternatively activated macrophages, respectively. Further research considering macrophage polarization states that result in anti-fungal activity has the potential to provide a novel approach for the treatment of fungal infections.

Immune Modulation as Adjunctive Therapy for Pneumocystis pneumonia

Pneumocystis is an opportunistic fungal respiratory pathogen that causes life-threatening pneumonia (Pcp) in patients suffering from defects in cell-mediated immunity, including those with acquired immunodeficiency syndrome (AIDS) and immunosuppression secondary to chemotherapy or organ transplantation. Despite major advances in health care, the mortality associated with Pcp has changed little over the past 25  years. Pcp remains a leading cause of death among HIV infected patients, with mortality rates of 50% or higher for patients developing severe Pcp. In addition, as more potent immunosuppressive therapies are developed for chronic inflammatory diseases, more cases of Pcp are occurring in non-HIV patients and in previously unreported clinical settings. These features highlight the importance of developing a better understanding of the pathogenesis of this disease, and the need to search for new therapeutic strategies to improve the outcome of Pcp patients. Immune-mediated inflammatory responses play an important role in the pathogenesis of Pcp, and may be even more significant in determining the outcome of Pcp than direct damage due to the organism itself. In this review we will summarize the immunopathogenic mechanisms that contribute to Pcp-associated lung injury, and discuss the potential to target these pathways for adjunctive immune modulation therapy for Pcp.

The effect of pentoxifylline and its metabolite-1 on inflammation and fibrosis in the TNBS model of colitis

TNBS-induced colitis has characteristics resembling human Crohn's disease including transmural inflammation, ulceration, and fibrosis. Current treatments target acute symptoms but do not necessarily prevent fibrotic complications of the disease. The aim of this study was to determine the effect of pentoxifylline and its primary metabolite (M-1) on fibrosis in the TNBS-induced colitis model. Myeloperoxidase activity and interleukin-18 are indicators of inflammation and were elevated in the TNBS model. The morphology damage score assesses colon damage and was also elevated in the TNBS model. Collagen as the indicator of fibrosis was quantified and visualized by the Sirius Red/Fast Green staining technique and collagen type I was assessed by Western analysis. Collagen was elevated in the TNBS-induced model. Pentoxifylline and M-1 treatment significantly attenuated colon damage and inflammation in TNBS-colitis (P<0.05). M-1 treatment significantly reduced the TNBS-induced increase in colon weight, colon thickness and total collagen content (P<0.05). Results suggest that pentoxifylline and M-1 inhibit intestinal fibrosis in this experimental model and may prove beneficial in the treatment of intestinal fibrosis associated with human Crohn's disease with the added benefit of inhibiting inflammation and ulceration. This is the first study to examine the effects of racemic M-1 in vivo and one of the few studies to examine the effect of drugs on both inflammation and fibrosis in an experimental model of colitis.

Complications of tumor necrosis factor-α blockade in chronic granulomatous disease-related colitis

BACKGROUND

Chronic granulomatous disease (CGD) is a genetic disorder of the phagocyte NADPH oxidase, which predisposes patients to infections and inflammatory complications, including severe colitis. Management of CGD colitis is a challenge because standard immunosuppressive therapy increases the risk of infection in already immunocompromised hosts.

METHODS

We report the use of infliximab in 5 patients with CGD.

RESULTS

Infliximab administration predisposed patients to severe infections with typical CGD pathogens but not mycobacteria, as reported with infliximab in other conditions. In addition to infections, infliximab administration led to successful closure of fistulae, sometimes with other untoward consequences. Infliximab-associated complications were associated with 2 deaths.

CONCLUSIONS

Infliximab use in the treatment of CGD inflammatory bowel disease requires aggressive antimicrobial prophylaxis, assiduous surveillance for infection, and vigilance for untoward gastrointestinal complications. This experience suggests that infliximab therapy is effective but has untoward consequences in patients with CGD.

Immune modulation with sulfasalazine attenuates immunopathogenesis but enhances macrophage-mediated fungal clearance during Pneumocystis pneumonia

Although T cells are critical for host defense against respiratory fungal infections, they also contribute to the immunopathogenesis of Pneumocystis pneumonia (PcP). However, the precise downstream effector mechanisms by which T cells mediate these diverse processes are undefined. In the current study the effects of immune modulation with sulfasalazine were evaluated in a mouse model of PcP-related Immune Reconstitution Inflammatory Syndrome (PcP-IRIS). Recovery of T cell-mediated immunity in Pneumocystis-infected immunodeficient mice restored host defense, but also initiated the marked pulmonary inflammation and severe pulmonary function deficits characteristic of IRIS. Sulfasalazine produced a profound attenuation of IRIS, with the unexpected consequence of accelerated fungal clearance. To determine whether macrophage phagocytosis is an effector mechanism of T cell-mediated Pneumocystis clearance and whether sulfasalazine enhances clearance by altering alveolar macrophage phagocytic activity, a novel multispectral imaging flow cytometer-based method was developed to quantify the phagocytosis of Pneumocystis in vivo. Following immune reconstitution, alveolar macrophages from PcP-IRIS mice exhibited a dramatic increase in their ability to actively phagocytose Pneumocystis. Increased phagocytosis correlated temporally with fungal clearance, and required the presence of CD4(+) T cells. Sulfasalazine accelerated the onset of the CD4(+) T cell-dependent alveolar macrophage phagocytic response in PcP-IRIS mice, resulting in enhanced fungal clearance. Furthermore, sulfasalazine promoted a TH2-polarized cytokine environment in the lung, and sulfasalazine-enhanced phagocytosis of Pneumocystis was associated with an alternatively activated alveolar macrophage phenotype. These results provide evidence that macrophage phagocytosis is an important in vivo effector mechanism for T cell-mediated Pneumocystis clearance, and that macrophage phenotype can be altered to enhance phagocytosis without exacerbating inflammation. Immune modulation can diminish pulmonary inflammation while preserving host defense, and has therapeutic potential for the treatment of PcP-related immunopathogenesis.

Does smoking reduce infliximab's effectiveness against Crohn's disease?

Crohn's disease (CD) is an idiopathic inflammatory bowel disease and has no known cure. CD symptoms are treated using an array of medicines, including biological agents such as infliximab. However, infliximab therapy is expensive; therefore, identifying variables that can help predict response to infliximab is worthwhile. The present article reviews the impact of tobacco smoking on the efficacy of infliximab in CD. Earlier studies have speculated that smoking has a negative effect on the response to infliximab in CD, but the current literature is largely unable to identify a significant relationship between the two. Although smoking is known to have a negative effect on the course of CD, as well as other organ systems, presently, a CD patient's smoking status should not influence treatment decisions regarding infliximab therapy.

Gastroenterologists' attitudes and self-reported practices regarding inflammatory bowel disease

BACKGROUND

The purpose was to assess organization-, physician-, and patient-based aspects of inflammatory bowel disease (IBD) practice variation within an integrated care delivery system and the extent to which physicians are interested in adopting a chronic care model and/or nurse assistance to manage IBD patients.

METHODS

As part of an observational cohort study to understand variation in IBD care and outcomes, we conducted semistructured, open-ended interviews with 17 gastroenterologists and 1 gastroenterology registered nurse at 6 clinics in an integrated care delivery system. Interviews were taperecorded and transcribed. We coded and analyzed transcripts using standard qualitative methods.

RESULTS

Physicians reported a range of attitudes and practices regarding IBD. Analysis showed differences in 3 domains and 8 subdomains: 1) patient education and choices, including health education and patient use of complementary and alternative medicine; 2) decisions about diagnosis and treatment, including practice guidelines, conferring with colleagues, using infliximab, and medical hospitalization; and 3) organizational aspects of care, including primary care involvement with IBD and MD attitudes toward ancillary support.

CONCLUSIONS

Standardized algorithms on care for IBD patients do not exist, but opportunities may exist to improve IBD care by: having initial work-ups and management of patients in remission in primary care; creating and maintaining opportunities for gastroenterologists to confer with colleagues and acknowledged local experts; and having nurse coordination for medications and labs and/or some type of specialty IBD clinic for high-need patients. This research highlights the need for more directed comparative efficacy and effectiveness trials that will serve to define preferred treatment strategies.

Efficacy and safety of oral beclomethasone dipropionate for ileal or ileal-right colon Crohn's disease of mild-to-moderate activity or in remission: Retrospective study

Although conventional glucocorticosteroids are the main treatments for active Crohn's disease, several problems are associated with steroid dependence and steroid-related adverse events. To assess the efficacy and safety of oral beclomethasone dipropionate (BDP) coated tablets in adults with mild-to-moderate Crohn's disease. Thirty-four patients (age 18-70years) with a diagnosis of Crohn's disease confirmed by conventional criteria (barium enema, clinical criteria, colonoscopy, histology) were retrospectively evaluated in the study. All subjects received a treatment schedule with BDP 5-10mg/day for 24weeks. BDP significantly (p=0.005) reduced mean Crohn's Disease Activity Index (CDAI) score from 169.6 at baseline to 123.2 after 24weeks. Clinical success was evident at 24weeks in 66.7% of patients with initial active disease, and remission was maintained at week 24 in 93.8% of patients with remission at baseline. Overall, female non-smokers had the best response to treatment. BDP was well tolerated and the only adverse events observed were nausea (n=1), facial erythema (n=1) and one patient with raised fasting blood glucose level. These results clearly suggest that oral BDP coated tablets are effective and safe for treatment of mild-to-moderate Crohn's disease of ileal or ileal-right colonic localisation.

The management of fistulizing oral Crohn's disease with infliximab

A 20-year-old female patient with oral Crohn's disease developed a fistula in her neck from a focus of intra-oral infection. Despite repeated courses of antimicrobial therapy over a period of several months, the fistula failed to resolve. However, following administration of infliximab, a monoclonal antitumour necrosis factor-alpha antibody, the fistula resolved spontaneously without the need for any further treatment.

Immune dysfunction in inflammatory bowel disease

Ulcerative colitis (UC) and Crohn's disease (CD) are idiopathic inflammatory bowel diseases (IBDs) that are characterized by chronic periods of exacerbation and remission. Research into the immunopathogenesis of IBD adds support to the theory that the disease results from a dysfunctional regulation of the immune system that leads to the polarization of intestinal immune cells toward a Th1 (T helper) response. The immunologic factors that mediate alterations in intestinal homeostasis and the development of intestinal mucosal inflammation have been at the forefront of IBD research. Cytokines, which are important regulators of leukocyte trafficking and apoptotic cell death, have emerged as essential immune molecules in the pathogenesis of IBD. In this study, recent advances in the understanding of the dynamism of cytokines and the consequences for mucosal immunity and inflammation in IBD are discussed. Furthermore, this study highlights the potential use of cytokines, anti-cytokine antibodies, and cytokine-related biologic therapies as novel targets for the treatment of IBD.

Pneumocystis carinii activates the NF-kappaB signaling pathway in alveolar epithelial cells

Pneumocystis carinii pneumonia (PcP) is a clinically important infection of immunocompromised patients. Although the interaction of Pneumocystis with the alveolar epithelium has been well documented, very little information regarding the epithelial response to Pneumocystis is currently available. In order to study Pneumocystis-epithelium interactions, a murine cell line derived specifically from an alveolar epithelial cell (AEC) was utilized. The coculture of murine AECs with mouse Pneumocystis induced a dose- and time-dependent release of the CXC chemokine MIP-2. Importantly, the specific removal of Pneumocystis from the preparation, or the pretreatment of AECs with sulfasalazine, a potent and specific inhibitor of NF-kappaB, nearly completely abrogated the chemokine response to Pneumocystis. Since the murine MIP-2 promoter contains consensus kappaB binding sequences, the ability of Pneumocystis to stimulate NF-kappaB signaling in AECs was examined. Pneumocystis stimulation of an AEC line stably transfected with a kappaB-dependent reporter construct triggered the NF-kappaB signaling pathway and reporter production. These data were confirmed in gel shift assays, providing direct evidence that Pneumocystis induced the nuclear translocation of the p50/p65 heterodimeric form of NF-kappaB. Maximal NF-kappaB activation was dependent upon direct contact with viable Pneumocystis organisms. These data demonstrate that Pneumocystis activates NF-kappaB signaling in AECs and establish a reporter cell line for studying NF-kappaB activation in AECs. Given the global regulatory functions of the NF-kappaB family, these findings suggest that Pneumocystis directly alters AEC gene expression in a manner that promotes pulmonary immune and inflammatory responses.