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To describe clinical outcomes in patients with severe asthma (SA) by common sociodemographic determinants of health: sex, race, ethnicity, and age.CHRONICLE is an observational study of subspecialist-treated, United States adults with SA receiving biologic therapy, maintenance systemic corticosteroids, or uncontrolled by high-dosage inhaled corticosteroids with additional controllers. For patients enrolled between February 2018 and February 2020, clinical characteristics and asthma outcomes were assessed by sex, race, ethnicity, age at enrollment, and age at diagnosis. Treating subspecialists reported exacerbations, exacerbation-related emergency department visits, and asthma hospitalizations from 12 months before enrollment through the latest data collection. Patients completed the St. George's Respiratory Questionnaire and the Asthma Control Test at enrollment.Among 1884 enrolled patients, the majority were female (69%), reported White race (75%), non-Hispanic ethnicity (69%), and were diagnosed with asthma as adults (60%). Female, Black, Hispanic, and younger patients experienced higher annualized rates of exacerbations that were statistically significant compared with male, White, non-Hispanic, and older patients, respectively. Black, Hispanic, and younger patients also experienced higher rates of asthma hospitalizations. Female and Black patients exhibited poorer symptom control and poorer health-related quality of life.In this contemporary, real-world cohort of subspecialist-treated adults with SA, female sex, Black race, Hispanic ethnicity, and younger age were important determinants of health, potentially attributable to physiologic and social factors. Knowledge of these disparities in SA disease burden among subspecialist-treated patients may help optimize care for all patients.Supplemental data for this article is available online at at www.tandfonline.com/ijas .

Background Approximately 5-10% of patients with asthma have severe disease. High-quality real-world studies are needed to identify areas for improved management. Objective Aligned with the International Severe Asthma Registry, the CHRONICLE study (ClinicalTrials.gov: NCT03373045) was developed to address this need in the US. Study design Learnings from prior studies were applied to develop a real-world, prospective, noninterventional study of US patients with confirmed severe asthma who are treated by subspecialist physicians and require biologic or maintenance systemic immunosuppressant therapy or who are uncontrolled by high-dosage inhaled corticosteroids and additional controllers. Target enrollment is 4000 patients, with patient observation for ≥3 years. A geographically diverse sample of allergist/immunologist and pulmonologist sites approach all eligible patients under their care and report patient characteristics, treatment, and health outcomes every 6 months. Patients complete online surveys every 1-6 months. Initial results From February 2018 to February 2019, 102 sites screened 1428 eligible patients; 936 patients enrolled. Study sites (40% allergist/immunologist, 42% pulmonologist, 18% both) were similar to other US asthma subspecialist samples. Enrolled patients were 67% female with median ages at enrollment and diagnosis of 55 (range: 18-89) and 26 (0-80) years, respectively. Median body mass index was 31 kg/m2; 3% and 29% were current or former smokers, respectively, and >60% reported ≥1 exacerbation in the prior year and suboptimal symptom control. Conclusion CHRONICLE will provide high-quality provider- and patient-reported data from a large, real-world cohort of US adults with subspecialist-treated severe asthma.

Weily Soong,1 Bradley E Chipps,2 Sean O’Quinn,3 Jennifer Trevor,4 Warner W Carr,5 Laura Belton,6 Frank Trudo,7 Christopher S Ambrose3 1Alabama Allergy & Asthma Center, Birmingham, AL, USA; 2Capital Allergy & Respiratory Disease Center, Sacramento, CA, USA; 3BioPharmaceuticals Medical, AstraZeneca, Gaithersburg, MD, USA; 4University of Alabama at Birmingham, Birmingham, AL, USA; 5Allergy & Asthma Associates of Southern California, Mission Viejo, CA, USA; 6Biostatistics, AstraZeneca, Cambridge, UK; 7BioPharmaceuticals Medical, AstraZeneca, Wilmington, DE, USACorrespondence: Weily SoongAlabama Allergy & Asthma Center, 504 Brookwood Boulevard, Birmingham, AL, 35209, USATel +1 205 871-9661Fax +1 205 870-1621Email wsoong@alabamaallergy.comBackground: Health-related quality of life (HRQoL) and productivity of patients with confirmed severe asthma (SA) have not been well characterized in large, real-world populations.Purpose: To characterize SA impact on HRQoL, work productivity, and activity impairment in a large, real-world cohort in the United States (US).Methods: CHRONICLE is an observational study of specialist-treated adults (≥ 18 years) in the US with SA receiving biologics or maintenance systemic corticosteroids (mSCS), or those persistently uncontrolled by high-dosage inhaled corticosteroids with additional controllers (HD ICS+). At enrollment, patients completed the St. George’s Respiratory Questionnaire (SGRQ) and Work Productivity and Activity Impairment (WPAI) questionnaire. Results were analyzed for those enrolled between February 2018 and February 2020.Results: Among patients who completed enrollment questionnaires (n = 1109), mean age was 54 years and most were women (70%). Among SGRQ respondents (n = 960), mean (SD) total score was 43 (23); 51% reported good/very good health. Among WPAI respondents (n = 1057; 566 employed), mean (SD) overall work impairment was 21% (25). Patients receiving biologics (vs mSCS, HD ICS+ only) had better SGRQ total scores (38 vs 59, 48) and lower work impairment (17% vs 34%, 27%). Patients with better SGRQ activity scores relative to symptom scores had better SGRQ impacts scores, total scores, and reported better overall health.Conclusion: SA significantly affects HRQoL, work productivity, and activity. The SGRQ is a valuable research instrument for evaluating HRQoL in SA. Due to its association with HRQoL and overall health, activity impairment should be a focus when monitoring patients’ disease control.Study Registration: ClinicalTrials.gov Identifier: NCT03373045.Keywords: real-world, St. George’s Respiratory Questionnaire, SGRQ, WPAI, symptoms, activity

Asthma is an inflammatory disease of the airways that may result from exposure to allergens or other environmental irritants, resulting in bronchoconstriction, wheezing, and shortness of breath. The structural changes of the airways associated with asthma, broadly referred to as airway remodeling, is a pathological feature of chronic asthma that contributes to the clinical manifestations of the disease. Airway remodeling in asthma constitutes cellular and extracellular matrix changes in the large and small airways, epithelial cell apoptosis, airway smooth muscle cell proliferation, and fibroblast activation. These pathological changes in the airway are orchestrated by crosstalk of different cell types within the airway wall and submucosa. Environmental exposures to dust, chemicals, and cigarette smoke can initiate the cascade of pro-inflammatory responses that trigger airway remodeling through paracrine signaling and mechanostimulatory cues that drive airway remodeling. In this review, we explore three integrated and dynamic processes in airway remodeling: (1) initiation by epithelial cells; (2) amplification by immune cells; and (3) mesenchymal effector functions. Furthermore, we explore the role of inflammaging in the dysregulated and persistent inflammatory response that perpetuates airway remodeling in elderly asthmatics.

Chronic inflammation involving both innate and adaptive immune cells is implicated in the pathogenesis of asthma. Intercellular communication is essential for driving and resolving inflammatory responses in asthma. Emerging studies suggest that extracellular vesicles (EVs) including exosomes facilitate this process. In this report, we have used a range of approaches to show that EVs contain markers of mitochondria derived from donor cells which are capable of sustaining a membrane potential. Further, we propose that these participate in intercellular communication within the airways of human subjects with asthma. Bronchoalveolar lavage fluid of both healthy volunteers and asthmatics contain EVs with encapsulated mitochondria; however, the % HLA-DR+ EVs containing mitochondria and the levels of mitochondrial DNA within EVs were significantly higher in asthmatics. Furthermore, mitochondria are present in exosomes derived from the pro-inflammatory HLA-DR+ subsets of airway myeloid-derived regulatory cells (MDRCs), which are known regulators of T cell responses in asthma. Exosomes tagged with MitoTracker Green, or derived from MDRCs transduced with CellLight Mitochondrial GFP were found in recipient peripheral T cells using a co-culture system, supporting direct exosome-mediated cell-cell transfer. Importantly, exosomally transferred mitochondria co-localize with the mitochondrial network and generate reactive oxygen species within recipient T cells. These findings support a potential novel mechanism of cell-cell communication involving exosomal transfer of mitochondria and the bioenergetic and/or redox regulation of target cells., Graphical abstract fx1, Highlights • BAL and MDRC-derived exosomes contain mitochondria. • Airway exosomes contain mtDNA. • MDRC-derived exosomes transfer mitochondria to CD4+ T cells. • Exosomal mitochondria co-localize with host cell mitochondria.

Background Patients with severe asthma (SA) have a heightened risk of exacerbations including hospitalization. The real-world, specialist-verified incidence and characteristics of exacerbations among patients with SA in the United States have not been described. Objective To describe the real-world incidence, characteristics, and predictors of exacerbations among patients with SA in the United States. Methods The CHRONICLE study is an ongoing observational study of specialist-treated adults with SA in the United States receiving biologic treatment or maintenance systemic corticosteroids or uncontrolled by high-dosage inhaled corticosteroids with additional controllers. For patients enrolled from February 2018 to February 2020, annualized rates and characteristics of exacerbation-related events were summarized by treatment category for 12 months before enrollment and after enrollment through the latest data collection. Results were further analyzed for subgroups of interest. Results Among 1884 enrolled patients, 53.5% and 12.3% experienced an exacerbation and asthma hospitalization, respectively (0.81 and 0.14 per person-year). Of all exacerbations, 36%, 9%, and 15% required an unscheduled health care provider visit, emergency department visit without hospitalization, and hospitalization, respectively. Among patients not receiving biologics or systemic corticosteroids, higher blood eosinophil count, higher fractional exhaled nitric oxide, and lower total immunoglobulin E level were associated with higher exacerbation rates. Exacerbation rates decreased after starting or switching biologics (n = 1299). Multivariate analyses of enrolled patients revealed previous-year exacerbations or hospitalizations, lack of asthma control, and the geographic region also predicted event risk. Conclusion In this real-world cohort of specialist-treated adults with SA in the United States, there was a substantial burden of exacerbations and associated health care resource utilization. Patients receiving biologics had a lower exacerbation burden. Trial Registration ClinicalTrials.gov Identifier: NCT03373045.

Mast cells are present in the airways of patients who have severe asthma despite glucocorticoid treatment; these cells are associated with disease characteristics including poor quality of life and inadequate asthma control. Stem cell factor and its receptor, KIT, are central to mast-cell homeostasis. We conducted a proof-of-principle trial to evaluate the effect of imatinib, a KIT inhibitor, on airway hyperresponsiveness, a physiological marker of severe asthma, as well as on airway mast-cell numbers and activation in patients with severe asthma.We conducted a randomized, double-blind, placebo-controlled, 24-week trial of imatinib in patients with poorly controlled severe asthma who had airway hyperresponsiveness despite receiving maximal medical therapy. The primary end point was the change in airway hyperresponsiveness, measured as the concentration of methacholine required to decrease the forced expiratory volume in 1 second by 20% (PCAmong the 62 patients who underwent randomization, imatinib treatment reduced airway hyperresponsiveness to a greater extent than did placebo. At 6 months, the methacholine PCIn patients with severe asthma, imatinib decreased airway hyperresponsiveness, mast-cell counts, and tryptase release. These results suggest that KIT-dependent processes and mast cells contribute to the pathobiologic basis of severe asthma. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01097694 .).

Background Asthma prevalence, morbidity, and mortality disproportionately impact African American/Black (AA/B) and Hispanic/Latinx (H/L) communities. Adherence to daily inhaled corticosteroid (ICS), recommended by asthma guidelines in all but the mildest cases of asthma, is generally poor. As-needed ICS has shown promise as a patient-empowering asthma management strategy, but it has not been rigorously studied in AA/B or H/L patients or in a real-world setting. Design and Aim The PeRson EmPowered Asthma RElief (PREPARE) Study is a randomized, open-label, pragmatic study which aims to assess whether a patient-guided, reliever-triggered ICS strategy called PARTICS (Patient-Activated Reliever-Triggered Inhaled CorticoSteroid) can improve asthma outcomes in AA/B and H/L adult patient populations. In designing and implementing the study, the PREPARE research team has relied heavily on advice from AA/B and H/L Patient Partners and other stakeholders. Methods PREPARE is enrolling 1200 adult participants (600 AA/Bs, 600H/Ls) with asthma. Participants are randomized to PARTICS + Usual Care (intervention) versus Usual Care (control). Following a single in-person enrollment visit, participants complete monthly questionnaires for 15 months. The primary endpoint is annualized asthma exacerbation rate. Secondary endpoints include asthma control; preference-based quality of life; and days lost from work, school, or usual activities. Discussion The PREPARE study features a pragmatic design allowing for the real-world assessment of a patient-centered, reliever-triggered ICS strategy in AA/B and H/L patients. Outcomes of this study have the potential to offer powerful evidence supporting PARTICS as an effective asthma management strategy in patient populations that suffer disproportionately from asthma morbidity and mortality.

Hospitalization for acute exacerbation of chronic obstructive pulmonary disease (COPD) is associated with significant morbidity and health care costs, and hospitals in the United States are now penalized by the Centers for Medicare and Medicaid Services for excessive readmissions. Identifying patients at risk of readmission is important, but modifiable risk factors have not been clearly established, and the potential contributing role of psychological disease has not been examined adequately. We hypothesized that depression and anxiety would increase the risk of both short- and long-term readmissions for acute exacerbation of COPD.To characterize the associations between depression and anxiety and COPD readmission risk.We examined the medical records for all patients with a primary diagnosis of acute exacerbation of COPD by International Classification of Diseases, Ninth Revision codes admitted to the University of Alabama at Birmingham Hospital between November 2010 and October 2012. Those who did not meet the standardized study criteria for acute exacerbation of COPD and those with other respiratory illnesses as the primary diagnosis were excluded. Comorbidities were recorded on the basis of physician documentation of the diagnosis and/or the use of medications in the electronic medical record. Multivariable regression analyses identified factors associated with readmission for acute exacerbation of COPD at 1 year and within 30 and 90 days.Four hundred twenty-two patients were included, with 132 readmitted in 1 year. Mean age was 64.8 ± 11.7 years, and mean percent predicted FEV1 was 48.1 ± 18.7%. On univariate analysis, readmitted patients had lower percent predicted FEV1 (44.9 ± 17.3% vs. 50.2 ± 19.4%; P = 0.05) and a higher frequency of depression (47.7% vs. 23.4%; P 0.001). On multivariable analysis, 1-year readmission was independently associated with depression (adjusted odds ratio [OR], 2.67; 95% confidence interval [CI], 1.59-4.47) and in-hospital tobacco cessation counseling (adjusted OR, 0.34; 95% CI, 0.18-0.66). Depression also predicted readmission at 30 days (adjusted OR, 3.83; 95% CI, 1.84-7.96) and 90 days (adjusted OR, 2.47; 95% CI, 1.34-4.55).Depression is an independent risk factor for both short- and long-term readmissions for acute exacerbation of COPD and may represent a modifiable risk factor. In-hospital tobacco cessation counseling was also associated with reduced 1-year readmission.

Background Severe asthma (SA) often requires subspecialist management and treatment with biologic therapies or maintenance systemic corticosteroids (mSCS). Objective To describe contemporary, real-world biologic and mSCS use among US subspecialist-treated patients with SA. Methods CHRONICLE is an ongoing, noninterventional study of US adults with SA treated by allergists/immunologists or pulmonologists. Eligible patients are receiving biologics or mSCS or are uncontrolled on high-dosage inhaled corticosteroids with additional controllers. Biologic and mSCS use patterns and patient characteristics were summarized for patients enrolled between February 2018 and February 2019. Results Among protocol-eligible patients, 58% and 12% were receiving biologics and mSCS, respectively, with 7% receiving both. Among 796 enrolled, most were women (67%), non-Hispanic white (71%), of suburban residence (50%), and had elevated body mass index (median: 31). Respiratory and nonrespiratory comorbidities were highly prevalent. With biologics (n = 557), 51% were anti–immunoglobulin E and 48% were anti–interleukin (IL)-5/IL-5Rα; from May 2018, 76% of initiations were anti–IL-5/IL-5Rα. In patients receiving mSCS, median prednisone-equivalent daily dose was 10 mg. Multivariate logistic regression found that patients of hospital clinics, sites with fewer nonphysician staff, and with a recorded concurrent chronic obstructive pulmonary disease diagnosis were less likely to receive biologics and more likely to receive mSCS. Conclusion In this real-world sample of US subspecialist-treated patients with SA not controlled by high-dosage inhaled corticosteroids with additional controllers, mSCS use was infrequent and biologic use was common, with similar prevalence of anti–immunoglobulin E and anti–IL-5/IL-5Rα biologics. Treatment differences associated with patient and site characteristics should be investigated to ensure equitable access to biologics and minimize mSCS use. Trial Registration ClinicalTrials.gov Identifier: NCT03373045 .

Background Inhaled corticosteroids (ICSs) are recommended as first-line controller medications for persistent asthma. However, guidelines on the initial ICS doses, step-up and step-down algorithms, and when to switch to combination therapy vary. Objective To understand the ideal starting doses of ICS therapy based on current evidence and to systematically compare low, moderate, and high starting doses of ICSs as monotherapy and in combination with long-acting β-agonists with respect to efficacy and safety. Methods MEDLINE, Embase, and Cochrane databases were searched for relevant English-language articles published from 1980 to November 17, 2018. Randomized controlled trials with adult, steroid-naive, ICS-free (for ≥4 weeks) patients with asthma and a duration of 4 weeks or longer with an ICS treatment arm (monotherapy or combination therapy) were included. Separate fixed-effects Bayesian network meta-analyses were conducted on the extracted data for peak expiratory flow, forced expiratory volume in 1 second, nighttime rescue medication use, nighttime symptom score, and study withdrawal because of an adverse event. Results A total of 31 randomized controlled trials were analyzed. All starting doses of ICSs were comparable with respect to nighttime rescue medication use, nighttime symptom score, change in forced expiratory volume in 1 second, and study withdrawal because of an adverse event. Significant improvement in morning peak expiratory flow was observed with high-dose ICSs and with low- and moderate-dose ICSs and long-acting β-agonists than with low-dose ICSs. Conclusion Overall, a high starting dose of ICSs had no additional clinical benefit in 3 of the 4 efficacy parameters compared with low or moderate ICS doses for controlling moderate to severe asthma but might have potential safety concerns.

Background Asthma exacerbation risk increases with worsening asthma control. Prevailing numerical control tools evaluate only current symptom impairment despite the importance of also assessing risk based on exacerbation history. An easy-to-use questionnaire addressing impairment and risk domains of control is needed. Objective To validate a composite asthma control tool that includes impairment and risk assessments (Asthma Impairment and Risk Questionnaire [AIRQ]). Methods Four-hundred forty-two patients aged ≥12 years with physician-diagnosed asthma who were followed in specialty practices completed 15 impairment and risk questions with dichotomized yes/no responses. Patients spanned all Global Initiative for Asthma severities and were classified as well-controlled, not well-controlled, or very poorly controlled according to a standard of Asthma Control Test (ACT) score plus prior-year exacerbations. Logistic regression analyses identified questions with the greatest predictive validity to discriminate among patients and determine cut points for these 3 classifications. Results The final AIRQ comprises 10 equally weighted yes/no impairment and risk questions. The final 10-item models yielded receiver operating characteristic curves of 0.94 to identify well-controlled versus not well-/very poorly controlled and 0.93 to identify well-/not well-controlled versus very poorly controlled asthma, as reflected by the ACT plus prior-year exacerbations standard. Cut points of 0-1, 2-4, and 5-10 best represented well-, not well-, and very poorly controlled asthma. Conclusions AIRQ is a rigorously validated composite measure designed to identify adults and adolescents with varying degrees of asthma control. Ongoing investigations will determine test-retest reliability, responsiveness to change, and predictive ability for future exacerbations.

It is anticipated that bioactive fragments of the extracellular matrix (matrikines) can influence the development and progression of chronic diseases. The enzyme leukotriene A4 hydrolase (LTA4H) mediates opposing proinflammatory and anti-inflammatory activities, through the generation of leukotriene B4 (LTB4) and degradation of proneutrophilic matrikine Pro-Gly-Pro (PGP), respectively. We show that abrogation of LTB4 signaling ameliorated inflammation and airway hyperresponsiveness (AHR) in a murine asthma model, yet global loss of LTA4H exacerbated AHR, despite the absence of LTB4. This exacerbated AHR was attributable to a neutrophil-independent capacity of PGP to promote pathological airway epithelial remodeling. Thus, we demonstrate a disconnect between airway inflammation and AHR and the ability of a matrikine to promote an epithelial remodeling phenotype that negatively affects lung function. Subsequently, we show that substantial quantities of PGP are detectable in the sputum of moderate-severe asthmatics in two distinct cohorts of patients. These studies have implications for our understanding of remodeling phenotypes in asthma and may rationalize the failure of LTA4H inhibitors in the clinic.

Most patients with asthma are managed by primary care providers. Severe asthma is associated with substantial morbidity and health care resource use, and long-term sequelae of severe asthma include airway remodeling and a greater risk of developing chronic obstructive pulmonary disease. These consequences highlight the importance of early identification and improved management of patients with severe asthma. Although treatment guidelines can be confusing and it can be difficult to keep abreast of updates, routine assessments of lung function, frequency and severity of exacerbations, symptom control, and medication adherence in the primary care setting provide the necessary information for identifying severe asthma and determining appropriate management strategies. An increased understanding of asthma pathophysiology and its relationship to disease activity has identified therapeutic targets and associated biomarkers. Biologic therapies directed at these targets offer individualized targeted treatment of severe asthma. We review evidence-based guidelines for identification and management of severe asthma, clarify the relationship of asthma control and asthma severity, and provide an overview of new biologic therapies offering additional treatment options for patients with severe asthma.

Asthma is a chronic inflammatory disease process involving the conductive airways of the human lung. The dysregulated inflammatory response in this disease process may involve multiple cell-cell interactions mediated by signaling molecules, including lipid mediators. Extracellular vesicles (EVs) are lipid membrane particles that are now recognized as critical mediators of cell-cell communication. Here, we compared the lipid composition and presence of specific lipid mediators in airway EVs purified from the bronchoalveolar lavage (BAL) fluid of healthy controls and asthmatic subjects with and without second-hand smoke (SHS) exposure. Airway exosome concentrations were increased in asthmatics, and correlated with blood eosinophilia and serum IgE levels. Frequencies of HLA-DR+ and CD54+ exosomes were also significantly higher in asthmatics. Lipidomics analysis revealed that phosphatidylglycerol, ceramide-phosphates, and ceramides were significantly reduced in exosomes from asthmatics compared to the non-exposed control groups. Sphingomyelin 34:1 was more abundant in exosomes of SHS-exposed asthmatics compared to healthy controls. Our results suggest that chronic airway inflammation may be driven by alterations in the composition of lipid mediators within airway EVs of human subjects with asthma.

Although it is clear that the loss of CD4+ T cells is a predisposing factor for the development of Pneumocystis pneumonia, specific Th mechanisms mediating protection are not well understood. Th1, Th2, and Th17 responses have each been implicated in protective responses during infection. As STAT4 may promote Th1 and Th17 development, yet antagonize Th2 development, we investigated its role in Pneumocystis murina host defense. STAT4 was required for Th1 and, unexpectedly, Th2 responses in the lungs of C57BL/6 (BL/6) and BALB/c mice 14 d postchallenge, but only BALB/c Stat4−/− mice demonstrated susceptibility to P. murina lung infection. BL/6 Stat4−/−, but not BALB/c Stat4−/−, mice maintained an enhanced alternatively activated (M2) macrophage signature in the lungs, which we have previously reported to be associated with enhanced P. murina clearance. In addition, anti-P. murina class-switched Abs were increased in BL/6 Stat4−/− mice, but not BALB/c Stat4−/− mice. Supporting our experimental observations, plasma from HIV-infected individuals colonized with Pneumocystis jirovecii contained significantly lower levels of the Th2 cytokines IL-4, IL-5, and IL-13 compared with HIV-infected individuals who were not colonized. Collectively, our data suggest that robust local and systemic Th2-mediated responses are critical for immunity to Pneumocystis.

We have recently reported that mice deficient in the myeloid Src-family tyrosine kinases Hck, Fgr, and Lyn (Src triple knockout [TKO]) had augmented innate lung clearance of Pneumocystis murina that correlated with a higher ability of alveolar macrophages (AMs) from these mice to kill P. murina. In this article, we show that despite possessing enhanced killing, AMs from naive Src TKO mice did not demonstrate enhanced inflammatory responses to P. murina. We subsequently discovered that both AMs and lungs from P. murina-infected Src TKO mice expressed significantly greater levels of the M2a markers RELM-α and Arg1, and the M2a-associated chemokines CCL17 and CCL22 than did wild-type mice. IL-4 and IL-13, the primary cytokines that promote M2a polarization, were not differentially produced in the lungs between wild-type and Src TKO mice. P. murina infection in Src TKO mice resulted in enhanced lung production of the novel IL-1 family cytokine IL-33. Immunohistochemical analysis of IL-33 in lung tissue revealed localization predominantly in the nucleus of alveolar epithelial cells. We further demonstrate that experimental polarization of naive AMs to M2a resulted in more efficient killing of P. murina compared with untreated AMs, which was further enhanced by the addition of IL-33. Administration of IL-33 to C57BL/6 mice increased lung RELM-α and CCL17 levels, and enhanced clearance of P. murina, despite having no effect on the cellular composition of the lungs. Collectively, these results indicate that M2a AMs are potent effector cells against P. murina. Furthermore, enhancing M2a polarization may be an adjunctive therapy for the treatment of Pneumocystis.

Asthma is a common medical condition affecting 300 million people worldwide. Airway inflammation, smooth muscle bronchoconstriction leading to airflow obstruction, and mucous hypersecretion are clinical hallmarks of asthma. The NHLBI Expert Panel Report 3 recommends inhaled corticosteroids (ICS) for patients with moderate to severe persistent asthma. Inhaled corticosteroids (ICS) target gene transcription through their interactions with the glucocorticoid (GC) receptor (GR) at the glucocorticoid response element (GRE). The GC/GR complex enhances anti-inflammatory but inhibits pro-inflammatory mediator production. Classically, asthma has been described as a Th2-associated eosinophil-predominant disease, but recently alternative models have been described including a Th17-mediated neutrophil-predominant phenotype resulting in patients with more severe disease who may be less responsive to steroids. Additional mechanisms of steroid resistance include increased activity of GR phosphorylating kinases which modify the interactions of GR with transcription factors to inhibit the ability of GR to bind with GRE, leading to an increase in pro-inflammatory gene transcription. Oxidative stress also affects the balance between pro-inflammatory and anti-inflammatory gene transcription through the modification of transcription factors and cofactors (such as PI3K) leading to the inhibition of histone deacetylase 2. Continued investigations into the mechanisms behind glucocorticoid resistance will lead to novel treatments that improve control of severe refractory asthma.