Management of asthma in adults: current therapy and future directions

The Impact of Tezepelumab in Uncontrolled Severe Asthma: A Systematic Review of Randomized Controlled Trials

Asthma, a chronic illness, is characterized by inflammation and airway constriction. Uncontrolled severe asthma is related to poor quality of life and increased utilization of health resources. Conventional treatments are associated with a significant amount of adverse effects. Recent years have seen the identification of various molecular effectors and signaling pathways as interesting targets for the biological therapy of severe asthma that is resistant to current therapies. Because they only target some downstream components of the inflammatory response in asthma, leaving other components unaffected, current biologic treatments only lower the exacerbation rate by 50%. If we focus on the upstream mediators of the inflammatory response in asthma, it might have a greater effect and be more efficient. Tezepelumab is a human monoclonal IgG2 antibody that specifically binds to thymic stromal lymphopoietin (TSLP) at the level of its TSLPR (thymic stromal lymphopoietin receptor) binding site, inhibiting the interaction between human TSLP and TSLPR. It is being used to treat the cytokines on the respiratory epithelial layer known as "alarmins." It is the only biologic drug available for treating severe uncontrolled asthma, despite limitations in biomarker and phenotype. In light of recent developments, the lack of knowledge on tezepelumab prompts us to publish a comprehensive systematic review. We discovered that regardless of blood eosinophil level and fractional exhaled nitric oxide levels, tezepelumab dramatically lowers asthma exacerbation in patients with severe uncontrolled asthma when compared to placebo. Tezepelumab also lessens patients' demand for healthcare resources while improving clinical indicators of lung function, health-related quality of life, and asthma management in patients. Tezepelumab plays a role in enhancing pre-bronchodilator FEV1 and lowering blood eosinophil count and fractional exhaled nitric oxide in patients with or without chronic allergies (FeNO). There have been no reports of fatalities or severe adverse events connected to tezepelumab.

Severe asthma treatment patterns: A multicenter observational study in the Gulf region

Background

Methods

Results

Conclusions

Adverse immunological responses against non-viral nanoparticle (NP) delivery systems in the lung

There is a large, unmet medical need to treat chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis and other respiratory diseases. New modalities are being developed, including gene therapy which treats the disease at the DNA/RNA level. Despite recent innovations in non-viral gene therapy delivery for chronic respiratory diseases, unwanted or adverse interactions with immune cells, particularly macrophages, can limit drug efficacy. This review will examine the relationship between the design and fabrication of non-viral nucleic acid nanoparticle (NP) delivery systems and their ability to trigger unwanted immunogenic responses in lung tissues. NP formulated with peptides, lipids, synthetic and natural polymers provide a robust means of delivering the genetic cargos to the desired cells. However NP, or their components, may trigger local responses such as cell damage, edema, inflammation, and complement activation. These effects may be acute short-term reactions or chronic long-term effects like fibrosis, increased susceptibility to diseases, autoimmune disorders, and even cancer. This review examines the relationship between physicochemical properties, i.e. shape, charge, hydrophobicity, composition and stiffness, and interactions of NP with pulmonary immune cells. Inhalation is the ideal route of administration for direct delivery but inhaled NP encounter innate immune cells, such as alveolar macrophages (AM) and dendritic cells (DC), that perceive them as harmful foreign material, interfere with gene delivery to target cells, and can induce undesirable side effects. Recommendations for fabrication and formulation of gene therapies to avoid adverse immunological responses are given. These include fine tuning physicochemical properties, functionalization of the surface of NP to actively target diseased pulmonary cells and employing biomimetics to increase immunotolerance.

Strategies to conserve salbutamol pressurized metered-dose inhaler stock levels amid COVID-19 drug shortage

Essential inhaler medications for patients with respiratory diseases are backordered due to the coronavirus disease of 2019 (COVID-19). In hospitals, there has been a drastic increase in the use of salbutamol pressurized metered-dose inhalers (pMDIs), as well as salbutamol Diskus, leading to a decline in availability and causing interruptions in the supply chain. Patients with asthma are at higher risk of respiratory complications if they are infected with COVID-19. Salbutamol, a short-acting β-agonist (SABA), could be a life-saving medication during critical conditions. Other short-acting muscarinic antagonists (SAMAs), such as ipratropium pMDI, and combinations of SABA/SAMA, such as Combivent Respimat, are also starting to have supply issues. With the ongoing pandemic, hospitals need to consider conservation strategies to facilitate resource-efficient salbutamol delivery and reduce their waste. In this current opinion, we demonstrate several strategies for avoiding pMDI wastage that can be adopted in both the hospital and community settings. These strategies include reprocessing used or expired pMDIs, using intravenous salbutamol and other short acting inhalers when available, and prescribing maintenance inhalers to prevent over usage of salbutamol pMDIs. We also highlight the important role of physicians and pharmacists in optimizing medication therapies to ensure adequate supplies.

Inhaled corticosteroids improve lung function, airway hyper-responsiveness and airway inflammation but not symptom control in patients with mild intermittent asthma: A meta-analysis

It remains controversial whether inhaled corticosteroid (ICS) should be used in patients with intermittent asthma. The present study aimed to assess the effect of ICS compared with placebo or other therapies in patients with intermittent asthma. Medline, Embase and CNKI databases were searched up to June 2016 and a meta-analysis was conducted. The findings demonstrated that in adult patients, when compared with placebo, ICS increased forced expiratory volume in 1 sec FEV1 [standardized mean difference (SMD), 0.51; 95% confidence interval (CI), 0.22-0.80] and alleviated airway hyper-responsiveness, which was indicated as log transformed PC20FEV1 (concentrations of methacholine when there was a fall in FEV1 ≥20%; SMD, 0.87; 95% CI, 0.60 to 1.14). ICS also reduced fractional exhaled nitric oxide (FeNO) levels [weighted mean difference (WMD), -12.57 parts per billion (ppb; a unit of NO concentration in exhaled air); 95% CI -15.88 to -9.25 ppb]. However, symptom scores did not change after ICS treatment (SMD, -0.26; 95% CI, -0.52 to 0). When compared with leukotriene receptor antagonists (LTRA), ICS had no advantage in increasing FEV1 (WMD, 0.04 l; 95% CI, -0.06 to 0.13 l), reducing sputum eosinophil percentage (WMD, -6%; 95% CI, -12.38 to 0.38%) or symptom scores (SMD, 0.44; 95% CI, -0.02 to 0.9). However, in child patients, ICS significantly (P<0.05) increased the possibility of symptom control when compared with placebo [relative risk (RR), 8; 95% CI, 1.04 to 61.52] or LTRA (RR, 2.67; 95% CI, 0.39 to 18.42). In conclusion, ICS improves lung function and alleviates airway hyper-responsiveness and airway inflammation but cannot influence symptom scores, and has no advantage over LTRA in terms of lung function improvement and airway inflammation control in adult patients with mild intermittent asthma. However, in children, the benefit of ICS in symptom control is more significant than with LTRA.

Silencing Nociceptor Neurons Reduces Allergic Airway Inflammation

Lung nociceptors initiate cough and bronchoconstriction. To elucidate if these fibers also contribute to allergic airway inflammation, we stimulated lung nociceptors with capsaicin and observed increased neuropeptide release and immune cell infiltration. In contrast, ablating Nav1.8(+) sensory neurons or silencing them with QX-314, a charged sodium channel inhibitor that enters via large-pore ion channels to specifically block nociceptors, substantially reduced ovalbumin- or house-dust-mite-induced airway inflammation and bronchial hyperresponsiveness. We also discovered that IL-5, a cytokine produced by activated immune cells, acts directly on nociceptors to induce the release of vasoactive intestinal peptide (VIP). VIP then stimulates CD4(+) and resident innate lymphoid type 2 cells, creating an inflammatory signaling loop that promotes allergic inflammation. Our results indicate that nociceptors amplify pathological adaptive immune responses and that silencing these neurons with QX-314 interrupts this neuro-immune interplay, revealing a potential new therapeutic strategy for asthma.

Similarities and differences between asthma health care professional and patient views regarding medication adherence

BACKGROUND

The recent literature has reported disparate views between patients and health care professionals regarding the roles of various factors affecting medication adherence.

OBJECTIVE

To examine the perspectives of asthma patients, physicians and allied health professionals regarding adherence to asthma medication.

METHODOLOGY

A qualitative, multiple, collective case study design with six focus-group interviews including 38 participants (13 asthma patients, 13 pulmonologist physicians and 12 allied health professionals involved in treating asthma patients) was conducted.

RESULTS

Patients, physicians and allied health professionals understood adherence to be an active process. In addition, all participants believed they had a role in treatment adherence, and agreed that the cost of medication was high and that access to the health care system was restricted. Major disagreements regarding patient-related barriers to medication adherence were identified among the groups. For example, all groups referred to side effects; however, while patients expressed their legitimate concerns, health care professionals believed that patients' opinions of medication side effects were based on inadequate perceptions.

CONCLUSION

Differences regarding medication adherence and barriers to adherence among the groups examined in the present study will provide insight into how disagreements may be translated to overcome barriers to optimal asthma adherence. Furthermore, when designing an intervention to enhance medication adherence, it is important to acknowledge that perceptual gaps exist and must be addressed.

Inflammation and corticosteroid responsiveness in ex-, current- and never-smoking asthmatics

BACKGROUND

It has been suggested that smoking asthmatics benefit less from corticosteroid treatment than never-smoking asthmatics. We investigated differences in blood and sputum inflammatory profiles between ex-, current-, and never-smokers and assessed their ICS treatment response after 2-week and 1-year treatment.

METHODS

We analyzed FEV1, PC20 methacholine and PC20 AMP, (differential) cell counts in sputum and blood in ex-, current- and never-smokers at baseline (n=114), after 2-week treatment with fluticasone 500 or 2000 μg/day (n=76) and after 1-year treatment with fluticasone 500 μg/day or a variable dose of fluticasone based on a self-management plan (n=64).

RESULTS

A total of 114 patients were included (29 ex-, 30 current- and 55 never-smokers. At baseline, ex- and current-smokers had less eosinophils in sputum and blood than never-smokers. Blood neutrophil counts were higher in current- than in never-smokers. A higher number of cigarettes smoked daily was associated with lower blood and sputum eosinophils. After 2-week ICS treatment, FEV1 %predicted improved less in current-smokers than never-smokers (2.4% versus 8.1%, p=0.010) and ex-smokers tended to improve less than never-smokers (4.1%, p=0.067). In contrast, no differences in ICS treatment response in lung function or inflammatory cells were found between the three groups after 1 year.

CONCLUSIONS

Ex- and current-smokers have less eosinophils and more neutrophils in their sputum and blood than never-smokers. Although ex- and current-smokers have a reduced short-term corticosteroid treatment response, we did not find a difference in their long-term treatment response.

Efficacy of interventions to improve adherence to inhaled corticosteroids in adult asthmatics: impact of using components of the chronic care model

BACKGROUND

Adherence to inhaled corticosteroids (ICS) remains poor among asthmatics, yet little is known about the efficacy of interventions to improve adherence. Implementing the Chronic Care Model (CCM) components among patients with respiratory disorders has been associated with an improvement in outcomes, yet little is known about its effects on ICS adherence in asthmatics.

OBJECTIVE

We conducted a systematic review to assess the efficacy of interventions to improve ICS adherence among adult-asthmatics, and whether the use of CCM components (i.e., teaching self-management skills, providing decision support, delivery system design, and clinical information systems) resulted in greater ICS adherence.

METHODS

All English language articles testing the efficacy of an intervention including ICS medication on outcome from MEDLINE and PsychINFO databases through Aug-2010 were reviewed. Interventions were categorized based on the inclusion of CCM components. We standardized treatment effects to obtain effect-size's (ES's) and we combined the ES's of studies according to the number of CCM components included in their interventions.

RESULTS

Eighteen studies met inclusion criteria. Inclusion of a greater number of CCM components within interventions was associated with stronger effects on ICS adherence outcomes, with interventions featuring one, two, and four CCM components having medium (ES = 0.29; 95%CI, 0.16-0.42), large (0.53; 0.40-0.66), and very-large (0.83; 0.69-0.98) effects respectively.

CONCLUSIONS

Findings provide support for using the CCM as a framework for the design and implementation of interventions to improve adherence among adult-asthmatics.

Patient-centered care and its effect on outcomes in the treatment of asthma

Patient-centered care may be pivotal in improving health outcomes for patients with asthma. In addition to increased attention in both research and clinical forums, recent legislation also highlights the importance of patient-centered outcomes research in the Patient Protection and Affordable Care Act. However, whether patient-centered care has been shown to improve outcomes for this population is unclear. To answer this question, we performed a systematic review of the literature that aimed to define current patient-focused management issues, characterize important patient-defined outcomes in asthma control, and identify current and emerging treatments related to patient outcomes and perspectives. We used a parallel search strategy via Medline(®), Cochrane Central Register of Controlled Trials, CINAHL(®) (Cumulative Index to Nursing and Allied Health Literature), and PsycINFO(®), complemented with a reference review of key articles that resulted in a total of 133 articles; 58 were interventions that evaluated the effect on patient-centered outcomes, and 75 were descriptive studies. The majority of intervention studies demonstrated improved patient outcomes (44; "positive" results); none showed true harm (0; "negative"); and the remainder were equivocal (14; "neutral"). Key themes emerged relating to patients' desires for asthma knowledge, preferences for tailored management plans, and simplification of treatment regimens. We also found discordance between physicians and patients regarding patients' needs, beliefs, and expectations about asthma. Although some studies show promise regarding the benefits of patient-focused care, these methods require additional study on feasibility and strategies for implementation in real world settings. Further, it is imperative that future studies must be, themselves, patient-centered (eg, pragmatic comparative effectiveness studies) and applicable to a variety of patient populations and settings. Despite the need for further research, enough evidence exists that supports incorporating a patient-centered approach to asthma management, in order to achieve improved outcomes and patient health.

Adipose-derived stromal cells inhibit allergic airway inflammation in mice

Allergic asthma is an inflammatory airway disease caused by T helper type 2 (Th2)-driven immune responses. Recent studies have demonstrated that adipose-derived stromal cells (ASC) have an immunosuppressive effect on T-cell activity. This study was performed to investigate whether ASC can inhibit Th2-dependent allergic airway inflammation in mice. BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injection. To investigate the effect of ASC on the development of asthma phenotypes, 2 × 10⁶ ASC were injected intravenously before OVA challenge. We evaluated the airway hyperresponsiveness (AHR), the proportion of eosinophils and cytokine production in bronchoalveolar lavage fluid (BALF), airway inflammation, and the intracellular cytokine staining of T cells in the BALF and spleen. Airway hyperresponsiveness, airway eosinophilia, and mucus production were markedly reduced after ASC administration before OVA challenge. The increased interleukin (IL)-4, IL-5, and transforming growth factor (TGF)-β1 levels in the BALF after OVA challenge were significantly reduced by the administration of ASC. This inhibition was accompanied by decreased IL-4(+) CD4(+) T cells and increased interferon (IFN)-γ(+) CD4(+) T cells in the BALF and spleen. The results of this study suggest that ASC administration before an allergen challenge inhibits AHR, lung inflammation, and Th2 cytokine production induced by an allergen challenge through inhibition of Th2 cell activity.

The Saudi Initiative for Asthma

The Saudi Initiative for Asthma (SINA) provides up-to-date guidelines for healthcare workers managing patients with asthma. SINA was developed by a panel of Saudi experts with respectable academic backgrounds and long-standing experience in the field. SINA is founded on the latest available evidence, local literature, and knowledge of the current setting in Saudi Arabia. Emphasis is placed on understanding the epidemiology, pathophysiology, medications, and clinical presentation. SINA elaborates on the development of patient-doctor partnership, self-management, and control of precipitating factors. Approaches to asthma treatment in SINA are based on disease control by the utilization of Asthma Control Test for the initiation and adjustment of asthma treatment. This guideline is established for the treatment of asthma in both children and adults, with special attention to children 5 years and younger. It is expected that the implementation of these guidelines for treating asthma will lead to better asthma control and decrease patient utilization of the health care system.

[Study for an allergic inflammation model using human lungs and its pharmacological application]

The complement system, which plays an important role in inmate immunity, is considered to be important in the pathophysiology of allergic asthma. A patient with allergic asthma shows the reversible characteristic system of bronchoconstriction, increased mucus secretion, and complicated airway inflammation. Various cytokines secreted from Th2 cells contribute to the system. Cysteinyl-leukotrienes (CysLTs) are also considered to be one of the important mediators involved in asthmatic pathophysiology. However, the effects of a drug on humans may not be the same as those on animals due to species differences in complement-related molecules. In this series of experiments, we tried to establish a model in which the effects of a drug on the production of CysLTs from human lung preparations were evaluated following an anaphylactic reaction. CysLT production increased when the passively sensitized lung tissues were stimulated with anti-IgE antibody. The coaddition of anaphylatoxin, C5a, with the anti-IgE antibody potentiated CysLT production. The response to C3a was weaker when compared with that to C5a. In addition, increased production of CysLTs by adding serum at a specific ratio was dose dependently inhibited by nonpeptide C5a receptor antagonist, W-54011, or a novel complementary peptide inhibitor of C5a, acetyl peptide A. From these results, it is suggested that C5a potentiates cysLT production from human lung tissues and contributes to allergic inflammation like asthma, and thus acetylated peptide A and W-54011 are useful for suppressing allergic inflammation in the lungs.

Mast cell migration to Th2 stimulated airway smooth muscle from asthmatics

BACKGROUND

Mast cell microlocalisation within the airway smooth muscle (ASM) bundle is an important determinant of the asthmatic phenotype. We hypothesised that mast cells migrate towards ASM in response to ASM derived chemokines.

METHODS

Primary ASM cultures from subjects with and without asthma were stimulated with interleukin (IL)-1beta, IL-4, and IL-13 alone and in combination. Mast cell chemotaxis towards these ASM supernatants was investigated, and the chemotaxins mediating migration by using specific blocking antibodies for stem cell factor (SCF) and the chemokine receptors CCR3, CXCR1, 3 and 4 as well as the Gi inhibitor pertussis toxin and the tyrosine kinase inhibitor genistein were defined. The concentrations of CCL11, CXCL8, CXCL10, TGF-beta, and SCF in the supernatants were measured and the effect of non-asthmatic ASM supernatants on the mast cell chemotactic activity of asthmatic ASM was examined.

RESULTS

Human lung mast cells and HMC-1 cells migrated towards Th2 stimulated ASM from asthmatics but not non-asthmatics. Mast cell migration was mediated through the combined activation of CCR3 and CXCR1. CCL11 and CXCL8 expression by ASM increased markedly after stimulation, but was similar in those with and without asthma. ASM supernatants from non-asthmatics inhibited mast cell migration towards the asthmatic ASM supernatant.

CONCLUSION

Th2 stimulated ASM from asthmatics is chemotactic for mast cells. Non-asthmatic ASM releases a mediator or mediators that inhibit mast cell migration towards stimulated asthmatic ASM. Specifically targeting mast cell migration into the ASM bundle may provide a novel treatment for asthma.

Asthma-like symptoms prevalence in five Turkish urban centers

BACKGROUND

Asthma, which is a chronic inflammatory disorder of the airways characterized by the infiltration of inflammatory cells, is a common cause of morbidity in adults. It is almost the third leading cause of preventable hospitalization in the developed countries and accounts for approximately millions of visits to emergency departments.

METHODS

In this study, we aimed to determine asthma prevalence in five urban centers in Turkey. Three of the cities were located in the middle-west region of the Anatolia one of them as located across the Mediterranean cost and the last one was in the north part of the country. Data of totally 2353 participants was collected by the trained interviewers, who visited the households and administered the questionnaire to the household members at or over the age of 15 years.

RESULTS

The prevalence of asthma was found to be 6.6 % and the difference of asthma prevalence between the urban centers was statistically non-significant (p = 0.059).

Compromised arterial oxygen saturation in elderly asthma sufferers results in selective cognitive impairment

Forty elderly patients with asthma or chronic obstructive pulmonary disorder (COPD) were compared to a comparison group of forty age-matched healthy volunteers on a range of measures of cognitive performance, and levels of arterial haemoglobin oxygen saturation recorded. Members of the patient group were found to have significantly lower oxygen saturation compared to the comparison group, and performed significantly poorer on tests of delayed word recall and serial subtractions, but not on other tasks. Correlational analysis between participants' oxygen saturation levels and test scores across the whole sample indicated significant positive relationships existed for the digit symbol substitution and serial subtractions tasks. The results are discussed in terms of cerebral oxygen delivery, glucose metabolism, age related cognitive decline, and relative task demands.

Pharmacological targeting of anaphylatoxin receptors during the effector phase of allergic asthma suppresses airway hyperresponsiveness and airway inflammation

Airway hyperresponsiveness and airway inflammation are hallmarks of allergic asthma, the etiology of which is crucially linked to the presence of Th2 cytokines. A role for the complement anaphylatoxins C3a and C5a in allergic asthma was suggested, as deficiencies of the C3a receptor (C3aR) and of complement factor C5 modulate airway hyperresponsiveness, airway inflammation, and Th2 cytokine levels. However, such models do not allow differentiation of effects on the sensitization phase and the effector phase of the allergic response, respectively. In this study, we determined the role of the anaphylatoxins on the effector phase of asthma by pharmacological targeting of the anaphylatoxin receptors. C3aR and C5a receptor (C5aR) signaling was blocked using the nonpeptidic C3aR antagonist SB290157 and the neutralizing C5aR mAb 20/70 in a murine model of Aspergillus fumigatus extract induced pulmonary allergy. Airway hyperresponsiveness was substantially improved after C5aR blockade but not after C3aR blockade. Airway inflammation was significantly reduced in mice treated with the C3aR antagonist or the anti-C5aR mAb, as demonstrated by reduced numbers of neutrophils and eosinophils in bronchoalveolar lavage fluid. Of note, C5aR but not C3aR inhibition reduced lymphocyte numbers in bronchoalveolar lavage fluid. Cytokine levels of IL-5 and IL-13 in bronchoalveolar lavage fluid were not altered by C3aR or C5aR blockade. However, blockade of both anaphylatoxin receptors markedly reduced IL-4 levels. These data suggest an important and exclusive role for C5aR signaling on the development of airway hyperresponsiveness during pulmonary allergen challenge, whereas both anaphylatoxins contribute to airway inflammation and IL-4 production.

Management of paediatric asthma

Paediatric asthma best practice not only includes prescribing the correct therapeutic mix based on consensus guidelines, but also reducing therapy once control has been achieved. Clinicians should also be aware that asthma in young children is a heterogeneous entity, and a beneficial response to bronchodilators and/or inhaled steroids is not inevitable. In general, preschool children and infants should not be prescribed inhaled corticosteroids above 200 microg beclometasone dipropionate equivalent twice a day, or regular oral steroids, or long acting beta2-adrenoceptor agonists. New therapies such as anti-IgE antibodies are on the horizon, but these are unlikely to replace the established drug combinations. More likely is that the delivery of established drugs will become more convenient (for example, once a day inhaled corticosteroids, or season dependent prophylactic therapy).

Efficacy and tolerability of anti-immunoglobulin E therapy with omalizumab in patients with concomitant allergic asthma and persistent allergic rhinitis: SOLAR

BACKGROUND

Anti-IgE therapy could be particularly beneficial for patients with concomitant disease as it targets a common factor in both diseases. The aim of this study was to evaluate the efficacy and safety of omalizumab in patients with concomitant moderate-to-severe asthma and persistent allergic rhinitis.

METHODS

This multicentre, randomized, double-blind, parallel-group, placebo-controlled trial evaluated the safety and efficacy of omalizumab. A total of 405 patients (12-74 years) with a stable treatment (>/= 400 microg budesonide Turbuhaler) and >/= 2 unscheduled medical visits for asthma during the past year or >/= 3 during the past 2 years were enrolled. Patients received omalizumab (>/= 0.016 mg/kg/IgE [IU/ml] per 4 weeks) or placebo for 28 weeks.

RESULTS

Fewer patients treated with omalizumab experienced asthma exacerbations (20.6%) than placebo-treated patients (30.1%), P = 0.02. A clinically significant (>/= 1.0 point) improvement in both Asthma Quality of Life Questionnaire and Rhinitis Quality of Life Questionnaire occurred in 57.7% of omalizumab patients compared with 40.6% of placebo patients (P < 0.001). Omalizumab reduced Wasserfallen symptom scores for asthma (P = 0.023), rhinitis (P < 0.001) and the composite asthma/rhinitis scores (P < 0.001) compared with placebo. Serious adverse events were observed in 1.4% of omalizumab-treated patients and 1.5% of placebo-treated patients.

CONCLUSION

Omalizumab is well tolerated and effective in preventing asthma exacerbations and improving quality of life in patients with concomitant asthma and persistent allergic rhinitis.