Perennial Allergen-Specific Immunoglobulin E Levels Among Inner-City Elderly Asthmatics

Management of Elderly Asthma: Key Questions and Tentative Answers

The aging lung undergoes structural changes, immunosenescence, and inflammation, rendering the elderly more susceptible to developing obstructive airway disease. Thus, asthma in those of chronological age ≥ 65 years is not rare. Elderly asthma (EA) imposes considerable burdens in terms of mortality and morbidity, and expenditure. However, clinicians lack knowledge of EA and thus often prescribe inappropriate management. In this review, we ask 3 key questions frequently encountered during EA diagnosis and treatment: 1) Is EA different?; 2) How can we appropriately diagnose EA?; 3) Are there management strategies specific to EA? Based on recent studies, we provide tentative answers as follows: 1) late-onset EA differs in clinical features and pathogenetic mechanisms from non-EA, and thus further phenotypic and endotypic characterization of EA is needed; 2) both over- and under-diagnosis of asthma in the elderly can be reduced if the objective diagnostic tests are appropriately performed; 3) cautious prescription of ICS to selected EA patients should be encouraged, and a multifaceted approach which involves increasing medical awareness and inhaler use proficiency and adherence, seeking the assistance of caregivers, and correcting micronutrient deficiencies is required to reduce acute exacerbations in EA patients.

Immunosenescence, Inflammaging, and Lung Senescence in Asthma in the Elderly

Prevalence of asthma in older adults is growing along with increasing global life expectancy. Due to poor clinical consequences such as high mortality, advancement in understanding the pathophysiology of asthma in older patients has been sought to provide prompt treatment for them. Age-related alterations of functions in the immune system and lung parenchyma occur throughout life. Alterations with advancing age are promoted by various stimuli, including pathobionts, fungi, viruses, pollutants, and damage-associated molecular patterns derived from impaired cells, abandoned cell debris, and senescent cells. Age-related changes in the innate and adaptive immune response, termed immunosenescence, includes impairment of phagocytosis and antigen presentation, enhancement of proinflammatory mediator generation, and production of senescence-associated secretory phenotype. Immnunosenescence could promote inflammaging (chronic low-grade inflammation) and contribute to late-onset adult asthma and asthma in the elderly, along with age-related pulmonary disease, such as chronic obstructive pulmonary disease and pulmonary fibrosis, due to lung parenchyma senescence. Aged patients with asthma exhibit local and systemic type 2 and non-type 2 inflammation, associated with clinical manifestations. Here, we discuss immunosenescence’s contribution to the immune response and the combination of type 2 inflammation and inflammaging in asthma in the elderly and present an overview of age-related features in the immune system and lung structure.

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.

Associations of atopy and asthma during aging of an adult population over a 20-year follow-up

OBJECTIVE

Atopy is associated with asthma, but cross-sectional studies suggest this association may be weaker in older adults. It remains unclear if atopy predicts asthma later in adult life. We aimed to investigate whether atopy in young adults predicted asthma 20 years later and to quantify the contemporaneous relationship of atopy and asthma as adults age.

METHODS

Participants of the European Community Respiratory Health Survey (ECRHS) in Melbourne aged 20-44 years were followed for 20 years and completed questionnaires, skin prick tests (SPT) and allergen specific immunoglobulin E measurement at a baseline and two subsequent surveys. Using logistic regression and generalized estimating equations, we tested if atopy at baseline predicted current asthma later in life and estimated the association between current atopy measured at each survey and current asthma, while adjusting for potential confounders.

RESULTS

The analysis included 220 participants: 50.9% male. Mean (SD) age at baseline was 35.7 (5.7) years. Asthma and atopy prevalence remained stable over 20 years. Baseline atopy (SPT) was associated with current asthma (OR 9.74, 95%CI 4.22, 22.5) over 20 years, and current atopy (SPT) with concurrent asthma (3.12; 1.70, 5.74).

CONCLUSIONS

Atopy remains strongly associated with current asthma in 40 to 64 year-old adults, both prospectively and contemporaneously, but the prospective association is stronger.

Asthma in the Elderly

The older population has seen the greatest increase in the prevalence of current asthma in recent years. Asthma may begin at any age and when it occurs at an advanced as opposed to a young age, it is often nonatopic, severe, and unremitting. Unfortunately, geriatric-specific guidelines are not available for the diagnosis and treatment of asthma. However, with objective monitoring, avoidance of asthma triggers, appropriate pharmacotherapy, and patient education, the disease can be managed successfully.

Rhinitis in the Elderly

By 2050, the US aging population will nearly double. It will be increasingly important for health care providers to diagnose and manage rhinitis. Nasal symptoms of rhinorrhea, congestion, sneezing, nasal/ocular pruritus, and postnasal drainage affect up to 32% of older adults, and can impact quality of life. Several underlying factors associated with aging may contribute to the pathogenesis of rhinitis in older adults. Although treatment options for rhinitis exist, special considerations need to be made because comorbidities, limited income, memory loss, and side effects of medications are common in older adults and may impact outcomes.

Influenza A infection enhances antigen-induced airway inflammation and hyperresponsiveness in young but not aged mice

BACKGROUND

Although morbidity and mortality rates from asthma are highest in patients > 65 years of age, the effect of older age on airway inflammation in asthma is not well established.

OBJECTIVE

To investigate age-related differences in the promotion of allergic inflammation after influenza A viral respiratory infection on antigen-specific IgE production, antigen-induced airway inflammation and airway hyperresponsiveness in mice.

METHODS

To accomplish this objective, the following model system was used. Young (6 week) and aged (18 months) BALB/c mice were first infected with a non-lethal dose of influenza virus A (H/HKx31). Mice were then ovalbumin (OVA)-sensitized during the acute infection (3-days post inoculation) and then chronically underwent challenge to the airways with OVA. Forty-eight hours after the final OVA challenge, airway hyperresponsiveness (AHR), bronchoalveolar fluid (BALF) cellular and cytokine profile, antigen-specific IgE and IgG1, and lung tissue inflammation were measured.

RESULTS

Age-specific differences were noted on the effect of a viral infection, allergic sensitization, airway inflammation and airway hyperresponsiveness. Serum OVA-specific IgE was significantly increased in only the aged mice infected with influenza virus. Despite greater morbidity (e.g. weight loss and sickness scores) during the acute infection in the 18-month old mice that were OVA-sensitized, there was little effect on the AHR and BALF cellular differential. In contrast, BALF neutrophils and AHR increased, but eosinophils decreased in 6-week mice that were OVA-sensitized during an acute influenza infection.

CONCLUSION

With increased age in a mouse model, viral infection prior to antigen sensitization affects the airway and systemic allergic response differently. These differences may reflect distinct phenotypic features of allergic inflammation in older patients with asthma.

Dendritic cells from aged subjects display enhanced inflammatory responses to Chlamydophila pneumoniae

Chlamydophila pneumoniae (CPn) is a common respiratory pathogen that causes a chronic and persistent airway infection. The elderly display an increased susceptibility and severity to this infection. However, the underlying mechanisms are not well understood. Dendritic cells (DCs) are the initiators and regulators of immune responses. Therefore, we investigated the role of DCs in the age-associated increased CPn infection in vitro in humans. Though the expression of activation markers was comparable between the two age groups, DCs from aged subjects secreted enhanced levels of proinflammatory mediators such as TNF-α and CXCL-10 in response to CPn. In contrast, the secretion of IL-10 and innate interferons, IFN-α and IFN-λ, was severely impaired in DCs from aged donors. The increased activation of DCs from aged subjects to CPn also resulted in enhanced proliferation of CD4 and CD8 T cells in a DC-T coculture. Furthermore, T cells primed with CPn-stimulated DCs from aged subjects secreted increased levels of IFN-γ and reduced levels of IL-10 compared to DCs obtained from young subjects. In summary, DCs from the elderly displayed enhanced inflammatory response to CPn which may result in airway remodeling and increase the susceptibility of the elderly to respiratory diseases such as asthma.

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.

Self-management behaviors in older adults with asthma: associations with health literacy

OBJECTIVES

To examine self-management behaviors, including medication adherence and inhaler technique, in older adults with asthma and their association with health literacy.

DESIGN

Observational cohort study.

SETTING

Primary care and pulmonary specialty practices in two tertiary academic medical centers and three federally qualified health centers in New York, New York, and Chicago, Illinois.

PARTICIPANTS

Adults with moderate or severe persistent asthma aged 60 and older (N = 433).

MEASUREMENTS

Outcomes were adherence to asthma controller medications, metered dose inhaler (MDI) and dry powder inhaler (DPI) techniques, having a usual asthma physician, and avoidance of four common triggers. Health literacy was assessed using the Short Test of Functional Health Literacy in Adults.

RESULTS

The mean age was 67, and 36% of participants had marginal or low health literacy. Adherence was low (38%) overall and worse in individuals with low health literacy (22%) than in those with adequate literacy (47%, P < .001) and after adjusting for demographic factors and health status (odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.31-0.73). Similarly, inhaler technique was poor; only 38% and 54% had good MDI and DPI technique, respectively. Technique was worse in those with low health literacy (MDI technique: OR = 0.57, 95% CI = 0.38-0.85; DPI technique: OR = 0.42, 95% CI = 0.25-0.71). Asthma self-monitoring and avoidance of triggers occurred infrequently but were less consistently associated with low health literacy.

CONCLUSION

Adherence to medications and inhaler technique are poor in older adults with asthma and worse in those with low health literacy. Clinicians should routinely assess controller medication adherence and inhaler technique and use low-literacy communication strategies to support self-management in older adults with asthma.

Characteristics of allergic sensitization among asthmatic adults older than 55 years: results from the National Health and Nutrition Examination Survey, 2005-2006

BACKGROUND

Approximately 60% to 80% of children and young adults with asthma are sensitized to at least one allergen. In contrast, previous studies from specific subpopulations of older patients with asthma suggest that allergic sensitization is significantly lower in this age group. The prevalence and patterns of IgE-mediated sensitization have not been compared among a broad population of younger and older patients with asthma.

OBJECTIVE

To determine the prevalence and patterns of IgE-mediated sensitization among a broad population of younger and older patients with asthma.

METHODS

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 2005-2006 to compare IgE-mediated sensitization rates between younger (20-40 years) and older (≥55 years) patients with current asthma. Atopy was defined as a detectable serum IgE to at least 1 allergen in a panel of 19 allergens. The associations among sensitization, current asthma, and asthma control measures (health care use and symptoms) were examined by logistic regression.

RESULTS

In a group of 2,573 patients, either 20 to 40 years of age or 55 years or older, 108 (6.7%) and 43 (4.5%) patients with current asthma were identified, respectively. Allergic sensitization rates among the adults with asthma differed only moderately and not statistically significantly between the age groups; 75.4% of the younger and 65.2% of the older asthmatic patients were sensitized to at least 1 allergen. The association between sensitization and markers of asthma control did not appear to differ among the age groups.

CONCLUSION

Allergic sensitization in older patients with asthma may be more common than previously reported.

The effect of oral tolerance on the allergic airway response in younger and aged mice

BACKGROUND

The effect of increased age on the induction of oral tolerance by low-dose antigen feeding and its effect on the response to antigen airway challenge in aged mice have not been well characterized.

OBJECTIVE

To determine whether oral tolerance can be induced in aged mice and its impact on the development of allergic airway inflammation.

METHODS

Younger (6 weeks old) and aged (18 months old) mice were fed ovalbumin (OVA) prior to sensitization to induce antigen tolerance. Serum antigen-specific immunoglobulins (Igs), bronchoalveolar lavage fluid (BALF), lung histology, enumeration of CD4 + Foxp3+ Treg cells, and airway hyperresponsiveness (AHR) were determined after the final antigen challenge.

RESULTS

Feeding antigen to aged mice prior to sensitization induced oral tolerance as determined by a decrease in antigen-specific IgE and IgG(1); however, the effect was greater in younger mice. Induction of oral tolerance was associated with a greater increase in airway Treg cells in the younger mice. Despite these differences, oral tolerance significantly suppressed features of asthma in aged mice, including BALF total cell and eosinophil numbers, cytokine production, and AHR.

CONCLUSIONS

Aged mice developed oral tolerance to antigen, which suppressed several features of allergic airway inflammation.

Does allergen avoidance work?

Allergic rhinitis affects a large portion of the population. Patients are frequently sensitized to indoor allergens. The most important contributors are house dust mites, pets, and fungi. In very controlled environments where allergen exposure is significantly reduced, individuals have been shown to have clinical improvement in allergic rhinitis and/or asthma symptoms. Achieving sufficient exposure reduction in the home has proven difficult. Nonetheless, evidence exists that demonstrates exposure avoidance can be useful as an adjunct to other therapies, such as pharmacotherapy and immunotherapy, for the treatment of allergic rhinitis.

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.