Variation of bronchoalveolar lymphocyte phenotypes with age in the physiologically normal human lung

Role of the Lymphocyte Profile in Mediastinal Lymph Nodes in the Differential Diagnosis of Sarcoidosis and Tuberculous Lymphadenitis Patients Undergoing EBUS-TBNA

BACKGROUND

The value of lymphocyte profiling (LP) in mediastinal lymph nodes for the differential diagnosis of sarcoidosis has not been extensively studied, and existing literature presents mixed results.

METHODS

This was a prospective study of patients with intrathoracic lymphadenopathy who underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). LP in lymph node puncture fluid (LNPF) was evaluated using flow cytometry. The results of LP in sarcoidosis patients were compared with tuberculous lymphadenitis (TBLA) patients. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cut-offs of the statistically significant parameters for screening for sarcoidosis. Based on the optimal cut-offs and the final diagnosis of sarcoidosis and TBLA, the sensitivity, specificity, and accuracy of every statistically significant parameter and different combinations of the above three parameters were calculated for the diagnosis of sarcoidosis.

RESULTS

Forty-five cases of sarcoidosis and 33 cases of TBLA were enrolled in this study. Compared with the LP in TBLA patients, in sarcoidosis patients, the proportion of CD4 T cells and CD4/CD8 ratio increased, and the proportion of CD8 T cells and natural killer (NK) cells decreased. Among all single parameters, the CD4/CD8 ratio had high diagnostic sensitivity (84.4%), specificity (81.8%), and accuracy (83.3%) for sarcoidosis. Among all the combinations of three parameters, the combination of CD4, CD8, and NKT/NK ratio had high diagnostic sensitivity (91.1%), specificity (84.8%), and accuracy (87.2%) for sarcoidosis.

CONCLUSIONS

Assessment of LP in LNPF may improve the differential diagnostic accuracy of sarcoidosis from TBLA and further strengthen the importance of LP in LNPF in the diagnostic workup of sarcoidosis.

A framework for exclusion of alternative diagnoses in sarcoidosis

Sarcoidosis is a multisystem granulomatous syndrome that arises from a persistent immune response to a triggering antigen(s). There is no "gold standard" test or algorithm for the diagnosis of sarcoidosis, making the diagnosis one of exclusion. The presentation of the disease varies substantially between individuals, in both the number of organs involved, and the manifestations seen in individual organs. These qualities dictate that health care providers diagnosing sarcoidosis must consider a wide range of possible alternative diagnoses, from across a range of presentations and medical specialties (infectious, inflammatory, cardiac, neurologic). Current guideline-based diagnosis of sarcoidosis recommends fulfillment of three criteria: 1) compatible clinical presentation and/or imaging 2) demonstration of granulomatous inflammation by biopsy (when possible) and, 3) exclusion of alternative causes, but do not provide guidance on standardized strategies for exclusion of alternative diagnoses. In this review, we provide a summary of the most common differential diagnoses for sarcoidosis involvement of lung, eye, skin, central nervous system, heart, liver, and kidney. We then propose a framework for testing to exclude alternative diagnoses based on pretest probability of sarcoidosis, defined as high (typical findings with sarcoidosis involvement confirmed in another organ), moderate (typical findings in a single organ), or low (atypical/findings suggesting of an alternative diagnosis). This work highlights the need for informed and careful exclusion of alternative diagnoses in sarcoidosis.

Advancements in adoptive CAR immune cell immunotherapy synergistically combined with multimodal approaches for tumor treatment

Adoptive immunotherapy, notably involving chimeric antigen receptor (CAR)-T cells, has obtained Food and Drug Administration (FDA) approval as a treatment for various hematological malignancies, demonstrating promising preclinical efficacy against cancers. However, the intricate and resource-intensive autologous cell processing, encompassing collection, expansion, engineering, isolation, and administration, hamper the efficacy of this therapeutic modality. Furthermore, conventional CAR T therapy is presently confined to addressing solid tumors due to impediments posed by physical barriers, the potential for cytokine release syndrome, and cellular exhaustion induced by the immunosuppressive and heterogeneous tumor microenvironment. Consequently, a strategic integration of adoptive immunotherapy with synergistic multimodal treatments, such as chemotherapy, radiotherapy, and vaccine therapy etc., emerges as a pivotal approach to surmount these inherent challenges. This collaborative strategy holds the key to addressing the limitations delineated above, thereby facilitating the realization of more precise personalized therapies characterized by heightened therapeutic efficacy. Such synergistic strategy not only serves to mitigate the constraints associated with adoptive immunotherapy but also fosters enhanced clinical applicability, thereby advancing the frontiers of therapeutic precision and effectiveness.

Omega-3 long-chain polyunsaturated fatty acids and their bioactive lipids: A strategy to improve resistance to respiratory tract infectious diseases in the elderly?

Age-related changes in organ function, immune dysregulation, and the effects of senescence explain in large part the high prevalence of infections, including respiratory tract infections in older persons. Poor nutritional status in many older persons increases susceptibility to infection and worsens prognosis. Interestingly, there is an association between the amount of saturated fats in the diet and the rate of community-acquired pneumonia. Polyunsaturated fatty acids, particularly omega-3 long chain polyunsaturated fatty acids (ω-3 LC-PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have well-known anti-inflammatory, immunomodulatory, and antimicrobial effects, which may, in theory, be largely induced by PUFAs-derived lipids such as specialized pro-resolving mediators (SPMs). In adults, preliminary results of studies show that ω-3 LC-PUFAs supplementation can lead to SPM generation. SPMs have a crucial role in the resolution of inflammation, a factor relevant to survival from infection independent of the pathogen’s virulence. Moreover, the immune system of older adults appears to be more sensitive to ω-3 PUFAs. This review explores the effects of ω-3 LC-PUFAs, and PUFA bioactive lipid-derived SPMs in respiratory tract infections and the possible relevance of these data to infectious disease outcomes in the older population. The hypothesis that PUFAs have beneficial effects via SPM generation will need to be confirmed by animal experiments and patient-derived data.

Bronchoalveolar lavage fluid analysis in patients with checkpoint inhibitor pneumonitis

BACKGROUND

Checkpoint inhibitor pneumonitis (CIP) is a relatively uncommon but potentially life-threatening immune-related adverse event (irAE). Lung biopsies have not been commonly performed for CIP patients. Bronchoalveolar lavage fluid (BALF) analysis is a useful diagnostic approach for interstitial lung disease. However, BALF features were inconsistent across different studies.

METHODS

We retrospectively reviewed the medical records of 154 patients with pathologically confirmed malignancies and suffering from CIPs between July 2018 and December 2022. Patients who had bronchoalveolar lavage (BAL) data available were enrolled in our study. Patient clinical, laboratory, radiological and follow-up data were reviewed and analyzed.

RESULTS

The BALF differential cell count and lymphocyte subset analysis were performed for 42 CIP patients. There were 32 males (76.2%). The mean age at diagnosis of CIP was 62.0 ± 10.4 (range: 31-78) years. The median time to onset of CIP was 98.5 days after the start of immunotherapy. There were 18 patients (42.9%) with low-grade CIPs and 24 patients (57.1%) with high-grade CIPs. The mean lymphocyte percentage was 36.7 ± 22.5%. There were 34 (81%) CIP patients with a lymphocytic cellular pattern. The median ratio of CD3+CD4+/CD3+CD8+ lymphocytes was 0.5 (0.3, 1.0). The ratio was less than 1.0 for 31 CIP patients (73.8%). However, there was no significant difference in the BALF features between patients with low-grade CIPs and those with high-grade CIPs.

CONCLUSIONS

The CD3+CD8+ lymphocytosis pattern was the main inflammatory profile in the BALF of CIP patients in this cohort. Targeting CD3+CD8+ lymphocytes might be a treatment option for CIPs.

Liver-directed SERPINA1 gene therapy attenuates progression of spontaneous and tobacco smoke-induced emphysema in α1-antitrypsin null mice

α₁-antitrypsin deficiency is a rare genetic condition that can cause liver and/or lung disease. There is currently no cure for this disorder, although repeated infusions of plasma-purified protein may slow down emphysema progression. Gene therapy in which a single recombinant adeno-associated viral vector (rAAV) administration would lead to sustained protein expression could therefore similarly affect disease progression, and provide the added benefits of reducing treatment burden and thereby improving the patient’s quality of life. The study presented here tests whether treating the Serpina1a-e knockout mouse model of α₁-antitrypsin-deficiency lung disease with gene therapy would have an impact on the disease course, either on spontaneous disease caused by aging or on accelerated disease caused by exposure to cigarette smoke. Liver-directed gene therapy led to dose-dependent levels of biologically active human α₁-antitrypsin protein. Furthermore, decreased lung compliance and increased elastic recoil indicate that treated mice had largely preserved lung tissue elasticity and alveolar wall integrity compared with untreated mice. rAAV-mediated gene augmentation is therefore able to compensate for the loss of function and restore a beneficial lung protease-antiprotease balance. This work constitutes a preclinical study report of a disease-modifying treatment in the Serpina1a-e knockout mouse model using a liver-specific rAAV serotype 8 capsid.

Short palate, lung, and nasal epithelial clone 1 (SPLUNC1) level determines steroid-resistant airway inflammation in aging

Asthma and its heterogeneity change with age. Increased airspace neutrophil numbers contribute to severe steroid-resistant asthma exacerbation in the elderly, which correlates with the changes seen in adults with asthma. However, whether that resembles the same disease mechanism and pathophysiology in aged and adults is poorly understood. Here, we sought to address the underlying molecular mechanism of steroid-resistant airway inflammation development and response to corticosteroid (Dex) therapy in aged mice. To study the changes in inflammatory mechanism, we used a clinically relevant treatment model of house-dust mite (HDM)-induced allergic asthma and investigated lung adaptive immune response in adult (20-22 wk old) and aged (80-82 wk old) mice. Our result indicates an age-dependent increase in airway hyperresponsiveness (AHR), mixed granulomatous airway inflammation comprising eosinophils and neutrophils, and Th1/Th17 immune response with progressive decrease in frequencies and numbers of HDM-bearing dendritic cells (DC) accumulation in the draining lymph node (DLn) of aged mice as compared with adult mice. RNA-Seq experiments of the aged lung revealed short palate, lung, and nasal epithelial clone 1 (SPLUNC1) as one of the steroid-responsive genes, which progressively declined with age and further by HDM-induced inflammation. Moreover, we found increased glycolytic reprogramming, maturation/activation of DCs, the proliferation of OT-II cells, and Th2 cytokine secretion with recombinant SPLUNC1 (rSPLUNC1) treatment. Our results indicate a novel immunomodulatory role of SPLUNC1 regulating metabolic adaptation/maturation of DC. An age-dependent decline in the SPLUNC1 level may be involved in developing steroid-resistant airway inflammation and asthma heterogeneity.

Integrated approach to bronchoalveolar lavage cytology to distinguish interstitial lung diseases

BACKGROUND

Broncho-alveolar lavage (BAL) is a safe diagnostic procedure, useful for differentiating fibrotic lung disorders and for excluding malignancy and infection. A recent multicenter study demonstrated a new, relatively sensitive, and specific index called Bronchoalveolar Cytology Threshold (BCT), useful for distinguishing healthy individuals from patients with lung diseases.

OBJECTIVES

In our study, BCT was applied for the first time to the analysis of interstitial lung diseases (ILDs), investigating its potential for differential diagnosis. Combinations of BAL cells that improve diagnostic accuracy for ILDs were studied and are proposed.

METHODS

A retrospective analysis of BAL samples was performed. We considered more than 1000 BAL samples from patients investigated for ILD, performed at Siena University Hospital. The samples enrolled for the study included 468 patients: 413 with and 55 without ILD. BAL was performed for diagnostic purposes in line with international guidelines. BCT were calculated according to available literature.

RESULTS

Among ILDs, patients with fibrotic hypersensitivity pneumonitis, idiopathic pulmonary fibrosis (IPF) and sarcoidosis showed significantly lower BCTs than unclassified ILD. Asbestosis patients showed significantly lower BCTs than nonspecific interstitial pneumonia (NSIP), cryptogenic organizing pneumonia (COP), connective tissue disease related ILD (CTD-ILD), sarcoidosis and unclassified ILD patients. COP patients showed significantly higher BCT than IPF, f-HP and sarcoidosis. Moreover, COP patients were best distinguished by BCT.

CONCLUSION

The analysis of BAL features is currently included in the diagnostic algorithm of ILDs. BAL cell patterns and BCT index can provide useful information for distinguishing ILDs, reducing the need for invasive procedures. Integrated approaches to BAL analysis can improve the interpretation of results without further cost or loss of time.

The value of bronchoalveolar lavage for discrimination between healthy and diseased individuals

BACKGROUND

Bronchoalveolar lavage (BAL) is standard diagnostic procedure. Procedural recommendations have been made by pneumological societies including normal values for interpretation of BAL cytology. These normal values derive from small studies in healthy volunteers and have never been analysed for their sensitivity and specificity.

OBJECTIVES

This study aims to analyse sensitivity and specificity of these normal values by assessing lavage cell composition in healthy and diseased individuals.

METHODS

More than 6000 BAL were retrospectively analysed for their cellular distribution including BALs of 250 healthy individuals. All BALs were obtained under similar conditions.

RESULTS

Bronchoalveolar lavage cytology of healthy individuals mirrors data from previous studies with smoking being the most important manipulator of BAL cytology. Analyses of proposed normal values demonstrate specificity between 80% and 95%, whereas sensitivity ranges between 35% and 65%. Using different mathematical models, a value summing up the differences to ATS-proposed normal values of the cytological pattern was found to best discriminate between healthy and diseased individuals with a sensitivity of nearly 60% with a predefined specificity of 95%.

CONCLUSION

In summary, our analysis confirmed prior results for healthy volunteers and enlarged these findings by analysing sensitivity and specificity of lavage results in an independent validation cohort of diseased individuals. Thereby, the study may influence the acceptance of BAL in the diagnostic workup of individuals with pulmonary diseases. Additionally, the study proposes a novel value that facilitates lavage interpretation and may therefore be useful in further studies.

Safety and Tolerability of Comprehensive Research Bronchoscopy in Chronic Obstructive Pulmonary Disease. Results from the SPIROMICS Bronchoscopy Substudy

RATIONALE

There is an unmet need to investigate the lower airways in chronic obstructive pulmonary disease (COPD) to define pathogenesis and to identify potential markers to accelerate therapeutic development. Although bronchoscopy is well established to sample airways in various conditions, a comprehensive COPD research protocol has yet to be published.

OBJECTIVES

To evaluate the safety and tolerability of a comprehensive research bronchoscopy procedure suitable for multicenter trials and to identify factors associated with adverse events.

METHODS

We report the detailed methodology used to conduct the bronchoscopy used in SPIROMICS (the Subpopulations and Intermediate Outcome Measures in COPD Study). The protocol entailed collection of tongue scrapings and oral rinses as well as bronchoscopy with airway inspection, bronchoalveolar lavage (BAL), protected brushings, and endobronchial biopsies. Visual airway characteristics were graded on a scale of 0 (normal appearance) to 3 (severe abnormality) in four domains: erythema, edema, secretions, and friability. Adverse events were defined as events requiring intervention. Logistic regression modeling assessed associations between adverse event occurrence and key variables.

RESULTS

We enrolled 215 participants. They were 61 ± 9 years old, 71% were white, 53% were male, and post-bronchodilator forced expiratory volume in 1 second was 89 ± 19% predicted. Self-reported asthma was present in 22% of bronchoscopy participants. Oral samples were obtained in greater than or equal to 99% of participants. Airway characteristics were recorded in 99% and were most often characterized as free of edema (61.9%). Less than 50% reported secretions, friability, or erythema. BAL yielded 111 ± 57 ml (50%) of the 223 ± 65 ml of infusate, brushes were completed in 98%, and endobronchial biopsies were performed in 82% of procedures. Adverse events requiring intervention occurred in 14 (6.7%) of 208 bronchoscopies. In logistic regression models, female sex (risk ratio [RR], 1.10; 95% confidence interval [CI], 1.02-1.19), self-reported asthma (RR, 1.17; 95% CI, 1.02-1.34), bronchodilator reversibility (RR, 1.17; 95% CI, 1.04-1.32), COPD (RR, 1.10; 95% CI, 1.02-1.20), forced expiratory volume in 1 second (RR, 0.97; 95% CI, 0.95-0.99), and secretions (RR, 1.85; 1.08-3.16) or friability (RR, 1.64; 95% CI, 1.04-2.57) observed during bronchoscopy were associated with adverse events.

CONCLUSIONS

A research bronchoscopy procedure that includes oral sampling, BAL, endobronchial biopsy, and brushing can be safely performed. Airway characteristics during bronchoscopy, demographics, asthma or COPD, and lung function may convey increased risk for procedure-related events necessitating intervention.

Bronchoalveolar lavage fluid lymphocytosis in 104 dogs (2006-2016)

BACKGROUND

Bronchoalveolar lavage (BAL) fluid cytology and culture are used to characterize respiratory diseases in dogs. Little is known about disorders associated with increased numbers of lymphocytes in BAL fluid.

OBJECTIVE

To evaluate duration of clinical signs and detection of specific respiratory diagnoses in dogs with BAL lymphocytosis.

ANIMALS

One-hundred four client-owned dogs evaluated for respiratory signs.

METHODS

Medical records of dogs that had >300 cells/μL and >20% lymphocytes on a differential cell count of BAL fluid between January 1, 2006, and January 1, 2016, were reviewed retrospectively. Cases were evaluated for the duration of clinical signs and respiratory diagnoses, including aspiration injury, infectious or inflammatory respiratory disease, and airway collapse.

RESULTS

Dogs ranged in age from 0.5 to 16 years (median, 7.9 years) and had a median body weight of 11.4 kg (range, 2.0-42.7 kg). Eosinophilic lung disease was documented in 13 of 104 dogs (Group 1) and airway neutrophilia associated with infectious or inflammatory disease was found in 59 of 104 dogs (Group 2). Lymphocytosis alone in BAL fluid was described in 32 dogs (Group 3). Duration of cough did not differ among groups, but airway collapse was significantly more common in dogs with solitary lymphocytosis than in those with other types of inflammation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Lymphocytosis in BAL fluid is common in dogs and, in many cases, likely represents a common response to airway injury, independent of the type or duration of insult. It is unknown whether airway collapse leads to lymphocytosis or if the inflammatory process causes airway collapse.

Asthma over the Adult Life Course: Gender and Hormonal Influences

Asthma is a common disorder that affects genders differently across the life span. Earlier in life, it is more common in boys. At puberty, asthma becomes more common and often more severe in girls and women. The effect of sex hormones on asthma incidence and its severity is difficult to differentiate from other asthma severity risk factors, such as racial background, socioeconomic factors, obesity, atopy, environmental exposure, and, in particular, lung aging. Recognizing gender-associated and age-associated differences is important to understanding the pathobiology of asthma and to providing effective education and personalized care for patients with asthma across the life course.

Age-related changes in the levels and kinetics of pulmonary cytokine and chemokine responses to Streptococcuspneumoniae in mouse pneumonia models

Streptococcuspneumoniae is a major human pathogen at the extremes of age. The elderly are particularly vulnerable to S.pneumoniae, the most common causative agent of bacterial pneumonia in this population. Despite the availability of vaccines and antibiotics, mortality rates associated with pneumococcal pneumonia in this age group remain high. In light of globally increasing life-expectancy, a better understanding of the patho-mechanisms of elderly pneumococcal pneumonia, including alterations in innate immune responses, is needed to develop improved therapies. In this study we aimed at investigating how increased susceptibility to pneumococcal infection relates to inflammation kinetics in the aged mouse pneumonia model by determining pulmonary cytokine and chemokine levels and comparing these parameters to those measured in young adult mice. Firstly, we detected overall higher pulmonary cytokine and chemokine levels in aged mice. However, upon induction of pneumococcal pneumonia in aged mice, delayed production of certain analytes, such as IFN-γ, MIG (CXCL9), IP-10 (CXCL10), MCP-1 (CCL2), TARC (CCL17) and MDC (CCL22) became apparent. In addition, aged mice were unable to control excess inflammatory responses: while young mice showed peak inflammatory responses at 20 h and subsequent resolution by 48 h post intranasal challenge, in aged mice increasing cytokine and chemokine levels were measured. These findings highlight the importance of considering multiple time points when delineating inflammatory responses to S.pneumoniae in an age-related context. Finally, correlation between pulmonary bacterial burden and cytokine or chemokine levels in young mice suggested that appropriately controlled inflammatory responses support the host to fight pneumococcal infection.

Age-Associated Changes in the Respiratory Epithelial Response to Influenza Infection

Older adults suffer a disproportionate burden of influenza-related morbidity and mortality typically attributed to defects in the aging immune system collectively known as immunosenescence. While the age-related decline in the adaptive immune system has been well characterized, little is known about how aging affects the principal site of influenza infection-the nasal epithelium. In human nasal epithelial cell cultures (hNECs) from older adults, we found similar or increased levels of cytokines during influenza infection compared with hNECs from younger individuals. However, hNECs from older individuals demonstrated decreased mRNA expression for several key proteins that affect clearance of infected cells, including MHC-I and transporter associated with antigen presentation (TAP). These findings were confirmed at the level of protein expression. In vivo studies corroborated the in vitro differences in MHC-I and TAP gene expression and also revealed important decreases in the expression of key influenza-specific antiviral mediators MX1 and IFITM1. Furthermore, epithelial cell-cytotoxic T lymphocyte co-cultures demonstrate that CTL cytotoxic activity is dose-dependent on MHC-I antigen presentation. Taken together, these results indicate that aging is associated with important changes in the nasal epithelium, including antigen presentation and antiviral pathways, which may contribute to increased severity of disease in older adults through impaired clearance of infected cells.

Asthma Over the Age of 65: All's Well That Ends Well

Asthma in older adults (often classified as those 65 years or older) is relatively common, underdiagnosed, and suboptimally treated. It is an important health problem, as the population of the United States continues to age. Unfortunately, asthma morbidity and mortality rates are highest in this age group. Alterations in the innate and adaptive immune responses occur with aging, and contribute to pathophysiologic differences and subsequent treatment challenges. The symptoms of asthma may differ from those in younger populations, and often include fatigue. There are unique factors that can complicate asthma management among older adults, including comorbidities, menopause, caregiver roles, and depression. Pharmacologic therapies are often not as effective as in younger populations, and may have greater side effects. Spirometry, peak flow measurements, and asthma education are typically underused, and may contribute to delays in diagnosis as well as worse outcomes. There are specific strategies that health care providers can take to improve the care of older adults with asthma.

Asthma in the elderly and late-onset adult asthma

Elderly asthmatics are at a higher risk for morbidity and mortality from their asthma than younger patients. There are important age-related physiologic and immunologic changes that complicate the presentation, diagnosis, and management of asthma in the aged population. Evidence suggests that elderly asthmatics are more likely to be underdiagnosed and undertreated. Additionally, elderly patients with asthma have highest rates of morbidity and mortality from their disease than younger patients. The underlying airway inflammation of asthma in this age group likely differs from younger patients and is felt to be non-type 2 mediated. While elderly patients are underrepresented in clinical trials, subgroup analysis of large clinical trials suggests they may be less likely to respond to traditional asthma therapies (ie, corticosteroids). As the armamentarium of pharmacologic asthma therapies expands, it will be critical to include elderly asthmatics in large clinical trials so that therapy may be better tailored to this at-risk and growing population.

An Official American Thoracic Society Workshop Report: Evaluation and Management of Asthma in the Elderly

Asthma in the elderly (>65 yr old) is common and associated with higher morbidity and mortality than asthma in younger patients. The poor outcomes in this group are due, in part, to underdiagnosis and undertreatment. There are a variety of factors related to aging itself that affect the presentation of asthma in the elderly and influence diagnosis and management. Structural changes in the aging lung superimposed on structural changes due to asthma itself can worsen the disease and physiologic function. Changes in the aging immune system influence the cellular composition and function in asthmatic airways. These processes and differences from younger individuals with asthma are not well understood. Phenotypes of asthma in the elderly have not been clearly delineated, but it is likely that age of onset and overlap with chronic obstructive pulmonary disease impact disease characteristics. Physiologic tests and biomarkers used to diagnose and follow asthma in the elderly are generally similar to testing in younger individuals; however, whether they should be modified in aging has not been established. Confounding influences, such as comorbidities (increasing the risk of polypharmacy), impaired cognition and motor skills, psychosocial effects of aging, and age-related adverse effects of medications, impact both diagnosis and treatment of asthma in the elderly. Future efforts to understand asthma in the elderly must include geriatric-specific methodology to diagnose, characterize, monitor, and treat their disease.

Age-related variation in the cellular composition of equine bronchoalveolar lavage fluid

BACKGROUND

Previous reports reveal variation in the cellular composition of equine bronchoalveolar lavage fluid (BALF).

OBJECTIVES

The purpose of this study was to compare the profiles of BALF from horses to assess age-related differences. Serial BALF samples were collected from the same individuals over a one-year period to identify changes in individual animals as they aged.

METHODS

Collection of BALF was performed on horses aged one week and one, 2, 6, and 12 months. Total nucleated cell count (TNCC), protein concentration, and cytology were assessed. Longitudinal analysis was performed and compared to healthy adults.

RESULTS

Foals at one week and 6 months of age had significantly higher TNCC than adults (medians: 320/μL, 285/μL, and 90/μL, respectively); no differences in total protein were found. Foals at one month had the highest proportion of macrophages (median: 87.3%), differing significantly from both yearlings and adults (medians: 45.5% and 48.7%, respectively). Foals aged one week and one month had significantly lower proportions of lymphocytes than yearlings and adults (medians: 3.2% and 4.7% vs 43.2% and 45.8%, respectively). Eosinophil percentage was lowest in foals aged one week, one month, and 2 months (median: 0.0%) and highest in foals aged 6 months (median: 2.2%). Mast cell percentages were highest in yearlings and adults (medians: 2.2% and 3.3%, respectively) and neutrophil percentage was highest in foals aged one week (13.7%).

CONCLUSIONS

Cytologic profiles of BALF from foals and adult horses differed considerably. Significant changes in TNCC and percentages of lymphocytes, macrophages, and eosinophils occurred with age.

Effect of aging on sputum inflammation and asthma control

BACKGROUND

Aged asthmatic patients experience increased morbidity and mortality. Knowledge of the aging effect on airway inflammation and asthma control is limited.

OBJECTIVE

We sought to compare airway inflammation and its relationship to asthma control in aged versus younger patients and determine whether differences are asthma specific or caused by "inflamm-aging."

METHODS

We performed a prospective study of aged (>60 years) and younger (21-40 years) inner-city patients with asthma. After a run-in period to control for inhaled corticosteroid use, induced sputum was collected. Age-matched nonasthmatic control subjects were included to measure age-related inflammatory changes.

RESULTS

Aged (mean age, 67.9 ± 5.1 years; n = 35) compared with younger (mean age, 30.8 ± 5.9 years; n = 37) asthmatic patients had significantly worse asthma control and lower FEV₁. Aged asthmatic patients had higher sputum neutrophil (30.5 × 10⁴/mL and 23.1%) and eosinophil (7.0 × 10⁴/mL and 3.8%) numbers and percentages compared with younger patients (neutrophils, 13.0 × 10⁴/mL [P < .01] and 6.9% [P < .01]; eosinophils, 2.0 × 10⁴/mL [P < .01] and 1.2% [P < .01]). Aged asthmatic patients had higher sputum IL-6 (P < .01) and IL-8 (P = .01) levels. No significant inflammatory differences between aged and younger control subjects were observed. In aged asthmatic patients increased sputum IL-6 and macrophage inflammatory protein 3α/CCL20 levels were significantly associated with decreased asthma control and increased sputum neutrophil numbers and IL-1β, IL-6, and macrophage inflammatory protein 3α/CCL20 levels were associated with hospitalization.

CONCLUSIONS

The inflammatory patterns of aged versus younger asthmatic patients are associated with increased sputum neutrophil and eosinophil values and cytokine levels related to neutrophil recruitment. Differences in airway inflammation can contribute to diminished asthma control in the aged. Further understanding of asthma pathophysiology in aged patients is needed to improve management of this vulnerable population.

A review of the equine age-related changes in the immune system: comparisons between human and equine aging, with focus on lung-specific immune-aging

The equine aging process involves many changes to the immune system that may be related to genetics, the level of nutrition, the environment and/or an underlying subclinical disease. Geriatric horses defined as horses above the age of 20, exhibit a decline in body condition, muscle tone and general well-being. It is not known whether these changes contribute to decreased immune function or are the result of declining immune function. Geriatric years are characterized by increased susceptibility to infections and a reduced antibody response to vaccination as a result of changes in the immune system. Humans and horses share many of these age-related changes, with only a few differences. Thus, inflamm-aging and immunosenescence are well-described phenomena in both human and equine research, particularly in relation to the peripheral blood and especially the T-cell compartment. However, the lung is faced with unique challenges because of its constant interaction with the external environment and thus may not share similarities to peripheral blood when considering age-related changes in immune function. Indeed, recent studies have shown discrepancies in cytokine mRNA and protein expression between the peripheral blood and bronchoalveolar lavage immune cells. These results provide important evidence that age-related immune changes or 'dys-functions' are organ-specific.

T cell subsets in human airways prior to and following endobronchial administration of endotoxin

BACKGROUND AND OBJECTIVES

Bronchial instillation of lipopolysaccharide (LPS) provides a reversible model of lung inflammation that may resemble early stages of acute respiratory distress syndrome (ARDS). We investigated the distributions of T-cell subsets in the human airways and sought to determine whether pro- and anti-inflammatory T cells are involved in the local immune response to lung inflammation.

METHODS

Bronchoalveolar lavage (BAL) was performed in 15 healthy volunteers, after which Escherichia coli LPS (4 ng/kg) was administered. BAL was repeated at 2, 4, 6, 8 or 24 h after instillation of LPS.

RESULTS

BALF CD4+ and CD8+ T cells were characterized by expression of activation markers (HLA-DR+CD38+), the proportion of cells expressing naïve markers (CD45RA+CD27+CCR7+) was lower, and that of cells expressing effector memory markers (CD45RA-CD27+CCR7-) was higher, compared with peripheral blood. Bronchial LPS induced a local inflammatory response with recruitment of CD4+ (P=0.014), CD8+ T cells (P=0.034), an increase in the proportion of CD4+CD25+CD127lowFoxp3+ regulatory T cells (Tregs) (P=0.045) and a tendency towards an increase in CD4+CD161+ cells (P=0.071) were observed.

CONCLUSIONS

A unique distribution of T cells with little day-to-day variation was found in human airways. An increase in Tregs after endobronchial LPS suggests a role for Tregs during early stages of pulmonary inflammation.

Clinical usefulness of bronchoalveolar lavage cellular analysis and lymphocyte subsets in diffuse interstitial lung diseases

BACKGROUND

Diffuse interstitial lung diseases (DILDs) form a part of a heterogeneous group of respiratory diseases. Bronchoalveolar lavage (BAL) analysis has been used for differential diagnosis of DILDs, but their clinical usefulness is controversial. The aim of this study was to investigate the clinical usefulness of BAL cellular analysis with lymphocyte subsets for the differential diagnosis of DILDs.

METHODS

A total of 69 patients diagnosed with DILDs were enrolled. Basic demographic data, BAL cellular analysis with lymphocyte subsets, histology, and high resolution computed tomogram (HRCT) findings were analyzed and compared as per disease subgroup.

RESULTS

Significant differences were found between groups in the proportion of neutrophils (P=0.0178), eosinophils (P=0.0003), T cells (P=0.0305), CD4 cells (P=0.0002), CD8 cells (P<0.0001), and CD4/CD8 ratio (P<0.0001). These findings were characteristic features of eosinophilic pneumonia and sarcoidosis. Other parameters were not significantly different between groups. At the cut-off value of 2.16 for sarcoidosis, CD4/CD8 ratio showed sensitivity of 91.7% (95% CI, 61.5-98.6%) and specificity of 84.2% (95% CI, 72.1-92.5%).

CONCLUSIONS

Routine analysis of BAL lymphocyte subset may not provide any additional benefit for differential diagnosis of DILDs, except for conditions where BAL is specifically indicated, such as eosinophilic pneumonia or sarcoidosis.

Asthma in the elderly: what we know and what we have yet to know

In the past, asthma was considered mainly as a childhood disease. However, asthma is an important cause of morbidity and mortality in the elderly nowadays. In addition, the burden of asthma is more significant in the elderly than in their younger counterparts, particularly with regard to mortality, hospitalization, medical costs or health-related quality of life. Nevertheless, asthma in the elderly is still been underdiagnosed and undertreated. Therefore, it is an imperative task to recognize our current challenges and to set future directions. This project aims to review the current literature and identify unmet needs in the fields of research and practice for asthma in the elderly. This will enable us to find new research directions, propose new therapeutic strategies, and ultimately improve outcomes for elderly people with asthma. There are data to suggest that asthma in older adults is phenotypically different from young patients, with potential impact on the diagnosis, assessment and management in this population. The diagnosis of AIE in older populations relies on the same clinical findings and diagnostic tests used in younger populations, but the interpretation of the clinical data is more difficult. The challenge today is to encourage new research in AIE but to use the existing knowledge we have to make the diagnosis of AIE, educate the patient, develop a therapeutic approach to control the disease, and ultimately provide a better quality of life to our elderly patients.

Age effects on blood gas, spirometry, airway reactivity, and bronchoalveolar lavage fluid cytology in clinically healthy horses

Background

Despite the increasing number of geriatric horses attended by veterinarians, there is a lack of understanding of aging‐related changes on the respiratory system of horses.

Objective

To identify aging‐related changes on the respiratory function and bronchoalveolar lavage fluid (BALF) cytology of horses.

Animals

Fifteen healthy young adult (2–11 years) and 16 healthy aged (≥20 years) horses.

Methods

The respiratory system was examined by measurement of arterial blood gases (ABG), use of respiratory inductive plethysmography (RIP) for assessment of breathing pattern and ventilatory parameters, histamine bronchoprovocation, and BALF cytology.

Results

No significant differences were detected with regard to values obtained by ABG or bronchoprovocation of young adult and aged healthy horses. In aged horses, there were significant differences in mean ± SD of the following parameters when compared to young horses: prolonged expiratory time (Te) measured by RIP (3.9 ± 1.5 s versus 3.0 ± 0.6 s), decreased percentage of alveolar macrophages (40.6 ± 11.3% versus 53.5 ± 9.6%), and increased percentage of lymphocytes (53.4 ± 9.5% versus 43.9 ± 11.0%). No correlations between airway reactivity and ventilatory parameters, ABG, or BALF cytology were found in this asymptomatic population.

Conclusions

These results suggest that aging does not cause changes in the results obtained by ABG, most RIP‐derived variables, and bronchoprovocation in the horse. A decreased percentage of macrophage and an increased percentage of lymphocytes in the BALF cytology may be expected in the asymptomatic geriatric horse and may be a result of aging.

Activated CD8(+) T cells and NKT cells in BAL fluid improve diagnostic accuracy in sarcoidosis

PURPOSE

The clinical diagnosis of pulmonary sarcoidosis is based on the presence of noncaseating granulomas in an appropriate clinical setting with either bilateral hilar adenopathy and/or parenchymal infiltrates. Lymphocytosis with an increased CD4/CD8 T cell ratio in bronchoalveolar lavage fluid is supportive. We evaluated the diagnostic accuracy of a predictive binary logistic regression model in sarcoidosis based on sex, age, and bronchoalveolar lavage fluid cell profile with and without the inclusion of HLA-DR(+) CD8(+) T cells and natural killer T-cell fractions.

METHODS

A retrospective analysis of differential cell counts and lymphocyte phenotypes by flow cytometry in bronchoalveolar lavage was performed in 183 patients investigated for possible diffuse parenchymal lung disease. A logistic regression model with age, sex, lymphocyte fraction, eosinophils, and CD4/CD8 ratio in bronchoalveolar lavage fluid (basic model) was compared with a final model, which also included fractions of HLA-DR(+) CD8(+) T cells and natural killer T cells. Diagnostic accuracy of the two models was assessed by receiver operating characteristic (ROC) curves.

RESULTS

The area under the ROC curve for the basic and final model was 0.898 [95 % confidence interval (CI) 0.852-0.945] and 0.937 (95 % CI 0.902-0.972), respectively, p = 0.008.

CONCLUSIONS

Assessment of HLA-DR(+) CD8(+) T cell and natural killer T-cell fractions may improve diagnostic accuracy and further strengthen the importance of bronchoalveolar lavage in the diagnostic workup of sarcoidosis.

Influences of smoking and aging on allergic airway inflammation in asthma

Asthma is a heterogeneous disease with varying phenotypes and numerous risk factors. This condition results from complex interactions between genetic and environmental factors, and active smoking is one of these risk factors. The effects of aging should also be taken into account in these interactions. From an epidemiological standpoint, smokers and/or elderly patients with asthma are not small part in the total population with asthma. Furthermore, both smoking and aging are important risk factors for severe asthma. This review discusses the potential effects of smoking and aging on healthy subjects and patients with asthma, particularly from the perspective of inflammatory changes. First we show evidence that smokers and the elderly have increased neutrophil counts in their airways, which may have impacts on their clinical characteristics of elderly smokers with asthma. Secondly, on the basis of our recent findings on the interactions between smoking and aging in patients with asthma, we propose that IgE/eosinophilic inflammation should not be underestimated in elderly smokers with asthma, particularly those who are atopic. This review may expand our understanding of the effects of smoking and aging on asthma with a new perspective of an old issue.

Bronchoalveolar lavage results are independent of season, age, gender and collection site

Background

Clinical interpretation of bronchoalveolar lavage fluid results is dependent on the availability of reference values for healthy individuals. Only a few studies have published such reference values and the applicability of results is restricted by small sample sizes and the limited representativeness of the study population. We aim to investigate the influence of age, gender, collection site and season on bronchoalveolar lavage fluid results and to establish reference values for use in clinical practice.

Methodology/Principal Findings

Bronchoalveolar lavage fluid data from 295 healthy never-smoking volunteers, investigated during 1990–2009, were analyzed retrospectively. 47 volunteers had 2–5 repeat lavages during the course of several years. Fluid recovery, total number of cells, cell concentration, and differential cell counts on cytospin prepared slides were recorded. Reference values, as represented by the 5^th to the 95^th percentile, were 72–96% for macrophages, 2–26% for lymphocytes, 0–4% for neutrophils and 0–1% for eosinophils. Basophils and mast cells were rare. When repeat lavages were performed, there was a relatively large intra-individual variability, mainly for macrophages and lymphocytes. An age dependent decrease of lavage fluid return was present, but there was no age dependent correlation with any of the other BALF parameters. The BALF cell parameters were independent of gender, season and site (lingula vs. middle lobe).

Conclusions/Significance

Our data show that bronchoalveolar lavage fluid cell differential count is independent of age, gender, season and collection site (RML or lingua). It therefore seems acceptable to use the same reference values for all never-smoking individuals.

An official American Thoracic Society clinical practice guideline: the clinical utility of bronchoalveolar lavage cellular analysis in interstitial lung disease

BACKGROUND

The clinical utility of bronchoalveolar lavage fluid (BAL) cell analysis for the diagnosis and management of patients with interstitial lung disease (ILD) has been a subject of debate and controversy. The American Thoracic Society (ATS) sponsored a committee of international experts to examine all relevant literature on BAL in ILD and provide recommendations concerning the use of BAL in the diagnosis and management of patients with suspected ILD.

PURPOSE

To provide recommendations for (1) the performance and processing of BAL and (2) the interpretation of BAL nucleated immune cell patterns and other BAL characteristics in patients with suspected ILD.

METHODS

A pragmatic systematic review was performed to identify unique citations related to BAL in patients with ILD that were published between 1970 and 2006. The search was updated during the guideline development process to include published literature through March 2011. This is the evidence upon which the committee's conclusions and recommendations are based.

RESULTS

Recommendations for the performance and processing of BAL, as well as the interpretation of BAL findings, were formulated by the committee.

CONCLUSIONS

When used in conjunction with comprehensive clinical information and adequate thoracic imaging such as high-resolution computed tomography of the thorax, BAL cell patterns and other characteristics frequently provide useful information for the diagnostic evaluation of patients with suspected ILD.

Dysregulation of neutrophil CXCR2 and pulmonary endothelial icam-1 promotes age-related pulmonary inflammation

We have previously demonstrated that aging is associated with prolonged pulmonary inflammation in a murine model of thermal injury. To further investigate these observations, we examined lung congestion, markers of neutrophil chemotaxis and adhesion, and lung endothelia responses in young and aged mice following burn injury. Analysis of lung tissue and bronchoalveolar lavage fluid 24 hours after injury revealed that more neutrophils accumulated in the lungs of aged mice (p<0.05), but did not migrate into the alveoli. We then sought to determine if accumulation of neutrophils in the lungs of aged mice was due to differences in the peripheral neutrophil pool or local changes within the lung. Following burn injury, aged mice developed a pronounced peripheral blood neutrophilia (p<0.05) in comparison to their younger counterparts. In aged animals, there was a reduced frequency and mean fluorescent intensity of neutrophil CXCR2 expression (p<0.05). Interestingly, in uninjured aged mice, peripheral blood neutrophils demonstrated elevated chemokinesis, or hyperchemokinesis, (p<0.05), but showed a minimal chemotatic response to KC. To determine if age impacts neutrophil adhesion molecules, we assessed CD62L and CD11b expression on peripheral blood neutrophils. No age-dependent difference in the frequency or mean fluorescent intensity of CD62L or CD11b was observed post-burn trauma. Examination of pulmonary vasculature adhesion molecules which interact with neutrophil selectins and integrins revealed that intracellular adhesion molecule-1 (ICAM-1) was elevated in aged mice at 24 hours after burn as compared to young mice (p<0.05). Overall, our data suggests that age-associated pulmonary congestion observed following burn injury may be due to differences in lung endothelial adhesion responses that are compounded by elevated numbers of hyperchemokinetic circulating neutrophils in aged mice.

Bronchoalveolar lavage cell pattern from healthy human lung

Bronchoalveolar lavage (BAL) is widely accepted as a key diagnostic procedure in interstitial lung diseases (ILD). We performed a study to obtain reference intervals of differential cell patterns in BAL fluid with special attention to the origin of lavage fluid, e.g. bronchial/alveolar, to atopy and smoking status and to age of the healthy people. We performed bronchoalveolar lavage in 55 healthy subjects with known atopy status (age: 18-64 years, non-smokers/smokers: 34/21) and determined differential cell counts and lymphocyte subsets in BAL fluid and blood. Moreover, in a subgroup of non-smoking healthy individuals we measured the expression of the regulatory T cell marker forkhead box protein 3 (FoxP3) on blood and BAL fluid lymphocytes in addition to a comprehensive set of activation markers. Differential cell counts from the alveolar lavage fraction differed significantly from calculated pooled fractions (n = 11). In contrast, marginal differences were found between atopic and non-atopic subjects. Interestingly, the BAL fluid CD4(+) /CD8(+) ratio correlated strongly with age (r(2) = 0·50, P < 0·0001). We consider the bronchial and alveolar fraction to be lavage fluid from fundamentally different compartments and recommend analysis of the alveolar fraction in diagnostic work-up of ILD. In addition, our data suggest that age corrected BAL fluid CD4(+) /CD8(+) ratios should be used in the clinical evaluation of patients with interstitial lung diseases.

Asthma in the elderly: Current understanding and future research needs--a report of a National Institute on Aging (NIA) workshop

Asthma in the elderly is underdiagnosed and undertreated, and there is a paucity of knowledge on the subject. The National Institute on Aging convened this workshop to identify what is known and what gaps in knowledge remain and suggest research directions needed to improve the understanding and care of asthma in the elderly. Asthma presenting at an advanced age often has similar clinical and physiologic consequences as seen with younger patients, but comorbid illnesses and the psychosocial effects of aging might affect the diagnosis, clinical presentation, and care of asthma in this population. At least 2 phenotypes exist among elderly patients with asthma; those with longstanding asthma have more severe airflow limitation and less complete reversibility than those with late-onset asthma. Many challenges exist in the recognition and treatment of asthma in the elderly. Furthermore, the pathophysiologic mechanisms of asthma in the elderly are likely to be different from those seen in young asthmatic patients, and these differences might influence the clinical course and outcomes of asthma in this population.

Age-related changes in immune function: effect on airway inflammation

Immunosenescence is defined as changes in the innate and adaptive immune response associated with increased age. The clinical consequences of immunosenescence include increased susceptibility to infection, malignancy and autoimmunity, decreased response to vaccination, and impaired wound healing. However, there are several immune alterations that might facilitate persistence of asthma into late adulthood or development of asthma after the age of 50 to 60 years. Asthma in older patients is not uncommon, and this is a growing population as the average lifespan increases. Specific innate changes that might affect severity of asthma in older patients or be involved in the development of late-onset asthma include impaired mucociliary clearance and changes in airway neutrophil, eosinophil, and mast cell numbers and function. Additionally, age-related altered antigen presentation and decreased specific antibody responses might increase the risk of respiratory tract infections. Respiratory tract infections exacerbate asthma in older patients and possibly play a role in the pathogenesis of late-onset asthma. Furthermore, cytokine profiles might be modified with aging, with some investigators suggesting a trend toward T(H)2 cytokine expression. This review examines specific innate and adaptive immune responses affected by aging that might affect the inflammatory response in older adults with asthma.

Protease-activated receptor-2 induces myofibroblast differentiation and tissue factor up-regulation during bleomycin-induced lung injury: potential role in pulmonary fibrosis

Idiopathic pulmonary fibrosis constitutes the most devastating form of fibrotic lung disorders and remains refractory to current therapies. The coagulation cascade is frequently activated during pulmonary fibrosis, but this observation has so far resisted a mechanistic explanation. Recent data suggest that protease-activated receptor (PAR)-2, a receptor activated by (among others) coagulation factor (F)Xa, plays a key role in fibrotic disease; consequently, we assessed the role of PAR-2 in the development of pulmonary fibrosis in this study. We show that PAR-2 is up-regulated in the lungs of patients with idiopathic pulmonary fibrosis and that bronchoalveolar lavage fluid from these patients displays increased procoagulant activity that triggers fibroblast survival. Using a bleomycin model of pulmonary fibrosis, we show that bleomycin induces PAR-2 expression, as well as both myofibroblast differentiation and collagen synthesis. In PAR-2-/- mice, both the extent and severity of fibrotic lesions are reduced, whereas myofibroblast differentiation is diminished and collagen expression is decreased. Moreover, fibrin deposition in the lungs of fibrotic PAR-2-/- mice is reduced compared with wild-type mice due to differential tissue factor expression in response to bleomycin. Taken together, these results suggest an important role for PAR-2 in the development of pulmonary fibrosis, and the inhibition of the PAR-2-coagulation axis may provide a novel therapeutic approach to treat this devastating disease.

Allergy and asthma in the elderly

Allergies and asthma are diseases that affect individuals of all ages, and their prevalence is comparable in all age groups. As age demographics in the United States and other countries shift to greater proportions and numbers of patients in the "elderly" categories, it is becoming increasingly important for clinicians to become aware of the impact of aging on a variety of diseases. Allergy and asthma are recognized as inflammatory disorders, and there are data demonstrating that age-related changes in immune function can have a significant impact on these disorders.

Maintained smoking cessation for 6 months equilibrates the percentage of sputum CD8+ lymphocyte cells with that of nonsmokers

Little is known about the longitudinal effects of smoking cessation on sputum inflammatory cells. We aimed to investigate the changes in sputum inflammatory cells and T-lymphocyte subpopulations after 6 and 12 months smoking cessation. Induced sputum was obtained from 68 healthy smokers before and after 6 months (n = 21) and 1 year (n = 14) smoking cessation and from ten healthy never-smokers. Inflammatory cells were identified by morphology and T-lymphocyte subpopulations by flow cytometry. Sputum macrophages were decreased after 12 months of smoking cessation in comparison to baseline, while neutrophils increased. Moreover, CD8+ T-cells were decreased in smokers before smoking cessation compared to never-smokers and increased in smokers after 6 months of smoking cessation in comparison to baseline; result that was maintained after 1 year of smoking cessation. These novel findings indicate that smoking cessation can equilibrate certain inflammatory cells of smokers with those of nonsmokers, within 6 months of smoking cessation.

Age-associated inflammation and toll-like receptor dysfunction prime the lungs for pneumococcal pneumonia

BACKGROUND

Aging is associated with increased inflammation and risk of community-acquired pneumonia. Streptococcus pneumoniae co-opts the nuclear factor kappa B (NFkB)-regulated proteins polymeric immunoglobulin receptor (pIgR) and platelet-activating factor receptor (PAFr) to attach and invade cells. We sought to determine whether aging and chronic inflammation were associated with increased pIgR and PAFr levels in the lungs and increased susceptibility to S. pneumoniae infection.

METHODS

Lung protein and messenger RNA levels were quantitated using Western blot and quantitative polymerase chain reaction. NFkB activation was measured by electrophoretic mobility shift assay. Cytokine levels were measured by cytometric bead analysis. To model chronic inflammation, mice were implanted with osmotic pumps that delivered tumor necrosis factor-alpha.

RESULTS

Aged mice and those infused with tumor necrosis factor-alpha had increased levels of pIgR and PAFr in their lungs and were more susceptible to S. pneumoniae infection. During pneumonia, aged mice had reduced levels of pIgR and PAFr and less NFkB activation, despite greater bacterial burden. We determined that aged mice had decreased amounts of lung Toll-like receptors 1, 2, and 4 and reduced capacity to respond to S. pneumoniae with proinflammatory cytokine production.

CONCLUSIONS

Aged mice and, potentially, elderly humans are more susceptible to pneumonia because of a priming effect of chronic inflammation and Toll-like receptor dysfunction.

Changes in immune function in asthma in the elderly

Asthma is an inflammatory disorder of the airway. The airway inflammation of asthma is typically an allergic inflammation characterized by cells and mediators described as a "Th2" inflammatory response. There is a growing body of evidence describing changes in the function of immune cells upon aging, a phenomenon referred to as "immunosenescence". Several studies utilizing animal models and human subjects with asthma have begun to explore age-related effects on the airway inflammation in asthma. This review explores the existing data on the presence and effects of immunosenescence or age-related changes in immune function in asthma.

The influence of age on immunity to infection with Mycobacterium tuberculosis

Changes within the immune system during aging lead to an elderly population that is both highly susceptible to infectious diseases and unresponsive to typical vaccine protocols. Using the murine model of tuberculosis, we have identified key differences in the generation of T-helper 1 cell immunity between old and young mice, and this information may be important for the design of new vaccines or post exposure therapies to protect the elderly against infectious diseases. In response to infection with Mycobacterium tuberculosis, it has been shown that the generation of antigen-specific CD4(+) T-cell immunity is impaired in old mice. In contrast, recent findings document that old mice display a transient enhanced resistance that occurs within the first 3 weeks of infection. Early resistance was associated with the presence of CD8(+) T cells and their ability to produce interferon-gamma (IFN-gamma) well before their young counterparts. Further investigation into the mechanism by which CD8(+) T cells are induced to secrete IFN-gammain vivo could provide an approach to enhance the effector function of these cells and subsequently protect elderly individuals from respiratory pathogens such as M. tuberculosis.

The role of bronchoalveolar lavage in interstitial lung disease

Considerable progress has been made in understanding the similarities and differences among the forms of the interstitial lung diseases (ILDs), particularly the forms of idiopathic interstitial pneumonia, now recognized as distinct clinicopathologic entities. Lung parenchymal evaluation by high-resolution CT scanning of the chest may provide images that are virtually diagnostic of certain forms of ILD, but other testing, including bronchoalveolar lavage (BAL) and lung biopsy, may be required for accurate diagnosis. The differential diagnosis of these disorders rests on the clinician's interpretation of the clinical presentation and physical examination findings, pulmonary function testing, radiographic imaging, and, if required, sampling of lung tissue. This discussion examines the usefulness of BAL in the diagnosis of specific forms of ILD.

Lung infections and aging

Respiratory tract infections are the leading cause of death due to infectious disease in the elderly. Many factors, especially waning immune responses and the onset of age-associated organ dysfunction, likely account for an increase in susceptibility to respiratory tract infection in the elderly, and morbidity and mortality rates are substantially greater for the elderly when outcomes are compared to that of younger individuals. The presence of underlying disease states such as chronic obstructive pulmonary disease (COPD) or other organ system disease further increases the likelihood of developing severe pneumonia in the elderly population, and the frail elderly, particularly when institutionalized in chronic care facilities, are at high risk for developing severe and recurrent pneumonia. This article will discuss various factors associated with advanced age that predispose the elderly to respiratory infections and summarize current approaches to treatment and prevention.

Role of lung inflammatory mediators as a cause of exercise-induced arterial hypoxemia in young athletes

We examined whether lung inflammatory mediators are increased during exercise and whether pharmacological blockade can prevent exercise-induced arterial hypoxemia (EIAH) in young athletes. Seventeen healthy athletes (9 men, 8 women; age 23 +/- 3 yr) with varying degrees of EIAH completed maximal incremental treadmill exercise tests after administration of fexofenadine, zileuton, and nedocromil sodium or placebo in a randomized double-blind crossover study. Lung function, arterial blood gases, and inflammatory metabolites in plasma, urine, and induced sputum were assessed. Drug administration did not improve EIAH or gas exchange during exercise. At maximal exercise, oxygen saturation fell to 91.4 +/- 2.6% (drug trial) and 91.9 +/- 2.1% (placebo trial) and alveolar-arterial oxygen difference widened to 28.1 +/- 6.3 Torr (drug trial) and 29.3 +/- 5.7 Torr (placebo trial). Oxygen consumption, ventilation, and other exercise variables were similarly unaffected by drug treatment. Although plasma histamine increased with exercise, values did not differ between trials, and urinary leukotriene E(4) and 11beta-prostaglandin F(2alpha) levels were unchanged after exercise. Postexercise sputum revealed no significant changes in markers of inflammation. These results demonstrate that EIAH in young athletes is not attenuated with acute administration of drugs targeting histamine and bioactive lipids. We conclude that airway inflammation is of insufficient magnitude to cause impairments in gas exchange and does not appear to be linked to EIAH in healthy young athletes.

Longitudinal profile of bronchoalveolar lavage cell characteristics in patients with a good outcome after lung transplantation

Bronchoalveolar lavage fluid (BALF) analysis is used in patients after lung transplantation (LTX) to obtain more insight into pathological conditions such as acute and chronic allograft rejection. Information on the normal course of BALF cell characteristics in patients with "good outcome" after LTX is limited. Therefore we analyzed 169 BALF samples from 63 well-defined "good outcome" patients after LTX (no acute or chronic transplant dysfunction, bacterial, fungal, or viral infections at the time of BAL). Total cell count decreased from the first months: median (range) 234 x 10(3) (70-610) cells/ml to 103 x 10(3) (10-840) cells/ml during the second year posttransplantation (p < 0.001). Cell differential counts did not change during the 2-yr study period. The CD4/CD8 ratio increased significantly from 0.32 (0.11-0.46) just posttransplantation to 0.62 (0.16-4.27) the second year after LTX. This increasing ratio was mainly due to a sharp decreasing CD8(+) cell count. Thus, characteristics of BAL cellular patterns in patients with good outcomes after LTX show important changes over time. We have defined control values for the BALF cellular profile in patients without pathological airway conditions after LTX. We propose to use these control values as a tool for diagnosing patients with pulmonary complications after LTX and for the follow-up of treatment regimens.

The characterization of bronchoalveolar lavage fluid in very elderly patients with cerebrovascular disease

BACKGROUND

Elderly patients with cerebrovascular disease have a high frequency of pneumonia due to impaired immune function and the occurrence of micro-aspiration.

METHODS

We performed bronchoalveolar lavage in 11 very elderly subjects with cerebrovascular disease and 9 healthy volunteers to investigate whether there were changes of local immunity in the lungs of the elderly subjects. The total cell count, the cell characteristics, and the lymphocyte subsets in bronchoalveolar lavage fluid were compared between the two groups.

RESULTS

A significant increase in the total cell count as well as in the number of neutrophils and CD8(+) T cells was observed in the elderly group. In addition, the mean CD4/CD8 lymphocyte ratio was lower in the elderly patients than in the healthy volunteers.

CONCLUSIONS

These observations suggest that silent micro-aspiration occurs in many elderly individuals with cerebrovascular disease and that pulmonary defenses decrease with age.