Rhinitis associated with asthma is distinct from rhinitis alone: The ARIA-MeDALL hypothesis

Asthma, rhinitis and atopic dermatitis (AD) are interrelated clinical phenotypes that partly overlap in the human interactome. The concept of "one-airway-one-disease", coined over 20 years ago, is a simplistic approach of the links between upper- and lower-airway allergic diseases. With new data, it is time to reassess the concept. This article reviews (i) the clinical observations that led to Allergic Rhinitis and its Impact on Asthma (ARIA), (ii) new insights into polysensitisation and multimorbidity, (iii) advances in mHealth for novel phenotype definition, (iv) confirmation in canonical epidemiologic studies, (v) genomic findings, (vi) treatment approaches and (vii) novel concepts on the onset of rhinitis and multimorbidity. One recent concept, bringing together upper- and lower-airway allergic diseases with skin, gut and neuropsychiatric multimorbidities, is the "Epithelial Barrier Hypothesis". This review determined that the "one-airway-one-disease" concept does not always hold true and that several phenotypes of disease can be defined. These phenotypes include an extreme "allergic" (asthma) phenotype combining asthma, rhinitis and conjunctivitis. Rhinitis alone and rhinitis and asthma multimorbidity represent two distinct diseases with the following differences: (i) genomic and transcriptomic background (Toll-Like Receptors and IL-17 for rhinitis alone as a local disease; IL-33 and IL-5 for allergic and non-allergic multimorbidity as a systemic disease), (ii) allergen sensitisation patterns (mono- or pauci-sensitisation versus polysensitisation), (iii) severity of symptoms and (iv) treatment response. In conclusion, rhinitis alone (local disease) and rhinitis with asthma multimorbidity (systemic disease) should be considered as two distinct diseases, possibly modulated by the microbiome, and may be a model for understanding the epidemics of chronic and auto-immune diseases.

Endotypes of difficult-to-control asthma in inner-city African American children

African Americans have higher rates of asthma prevalence, morbidity, and mortality in comparison with other racial groups. We sought to characterize endotypes of childhood asthma severity in African American patients in an inner-city pediatric asthma population. Baseline blood neutrophils, blood eosinophils, and 38 serum cytokine levels were measured in a sample of 235 asthmatic children (6–17 years) enrolled in the NIAID (National Institute of Allergy and Infectious Diseases)-sponsored Asthma Phenotypes in the Inner City (APIC) study (ICAC (Inner City Asthma Consortium)-19). Cytokines were quantified using a MILLIPLEX panel and analyzed on a Luminex analyzer. Patients were classified as Easy-to-Control or Difficult-to-Control based on the required dose of controller medications over one year of prospective management. A multivariate variable selection procedure was used to select cytokines associated with Difficult-to-Control versus Easy-to-Control asthma, adjusting for age, sex, blood eosinophils, and blood neutrophils. In inner-city African American children, 12 cytokines were significant predictors of Difficult-to-Control asthma (n = 235). CXCL-1, IL-5, IL-8, and IL-17A were positively associated with Difficult-to-Control asthma, while IL-4 and IL-13 were positively associated with Easy-to-Control asthma. Using likelihood ratio testing, it was observed that in addition to blood eosinophils and neutrophils, serum cytokines improved the fit of the model. In an inner-city pediatric population, serum cytokines significantly contributed to the definition of Difficult-to-Control asthma endotypes in African American children. Mixed responses characterized by T_H2 (IL-5) and T_H17-associated cytokines were associated with Difficult-to-Control asthma. Collectively, these data may contribute to risk stratification of Difficult-to-Control asthma in the African American population.

Effects of omalizumab on T lymphocyte function in inner-city children with asthma

While omalizumab treatment of inner city children and adolescents with asthma results in improvement in clinical parameters, no change in peripheral blood T cell responses could be demonstrated. Thus, omalizumab appears not to affect T cell function.

Local and systemic effects of cat allergen nasal provocation

Background

Cat allergen is widely distributed in homes and schools; allergic sensitization is common.

Objective

To develop a model of cat allergen nasal challenge to establish dose–response and time–course characteristics and investigate local and systemic biomarkers of allergic inflammation.

Methods

Nineteen cat‐allergic individuals underwent titrated nasal challenge, range 0.243 to 14.6 μg/mL Fel d1, and matched diluent‐only provocation. Clinical response to 8 h was assessed by symptom scores and peak nasal inspiratory flow (PNIF). Nasal fluid was collected using polyurethane sponges and analysed by ImmunoCAP and multiplex assays. Whole blood flow cytometry for basophil surface CD63, CD107a, and CD203c was carried out at baseline and 6 h post‐challenge.

Results

A dose–response to allergen was seen in symptom scores and PNIF, maximal at 10 000 BU/mL (4.87 μg/mL Fel d1), P < 0.0001 vs. diluent. Nasal fluid tryptase was elevated at 5 min after challenge (P < 0.05 vs. diluent); eotaxin, IL‐4, ‐5, ‐9, and ‐13 were increased at 8 h (P < 0.05 to P < 0.0001 vs. diluent); TSLP was undetectable; IL‐10, IL‐17A, and IL‐33 were unchanged compared to diluent challenge. Nasal fluid IL‐5 and IL‐13 correlated inversely with PNIF after challenge (IL‐5, r = −0.79, P < 0.0001; IL‐13, r = −0.60, P = 0.006). Surface expression of CD63 and CD107a was greater at 6 h than at baseline, both in the presence (both P < 0.05) and absence (CD63, P < 0.01; CD107a, P < 0.05) of in vitro allergen stimulation; no changes were seen on diluent challenge day.

Conclusions

Cat allergen nasal challenge produces local and systemic Th2‐driven inflammatory responses and has potential as a surrogate outcome measure in clinical trials.

Effect of grass pollen immunotherapy on clinical and local immune response to nasal allergen challenge

Rationale

Nasal allergen provocations may be useful in investigating the pathophysiology of allergic rhinitis and effects of treatments.

Objective

To use grass pollen nasal allergen challenge (NAC) to investigate the effects of allergen immunotherapy in a cross‐sectional study.

Methods

We studied nasal and cutaneous responses in untreated subjects with seasonal grass‐pollen allergic rhinitis (n = 14) compared with immunotherapy‐treated allergics (n = 14), plus a nonatopic control group (n = 14). Volunteers underwent a standardized NAC with 2000 biological units of timothy grass allergen (equivalent to 1.3 μg major allergen, Phl p5). Nasal fluid was collected and analysed by ImmunoCAP and multiplex assays. Clinical response was assessed by symptom scores and peak nasal inspiratory flow (PNIF). Cutaneous response was measured by intradermal allergen injection. Retrospective seasonal symptom questionnaires were also completed.

Results

Immunotherapy‐treated patients had lower symptom scores (P = 0.04) and higher PNIF (P = 0.02) after challenge than untreated allergics. They had reduced early (P = 0.0007) and late (P < 0.0001) skin responses, and lower retrospective seasonal symptom scores (P < 0.0001). Compared to untreated allergics, immunotherapy‐treated patients had reduced nasal fluid concentrations of IL‐4, IL‐9 and eotaxin (all P < 0.05, 8 h level and/or area under the curve comparison), and trends for reduced IL‐13 (P = 0.07, area under the curve) and early‐phase tryptase levels (P = 0.06).

Conclusions

Nasal allergen challenge is sensitive in the detection of clinical and biological effects of allergen immunotherapy and may be a useful surrogate marker of treatment efficacy in future studies.

Phenotypes and endotypes of rhinitis and their impact on management: a PRACTALL report

Rhinitis is an umbrella term that encompasses many different subtypes, several of which still elude complete characterization. The concept of phenotyping, being the definition of disease subtypes on the basis of clinical presentation, has been well established in the last decade. Classification of rhinitis entities on the basis of phenotypes has facilitated their characterization and has helped practicing clinicians to efficiently approach rhinitis patients. Recently, the concept of endotypes, that is, the definition of disease subtypes on the basis of underlying pathophysiology, has emerged. Phenotypes/endotypes are dynamic, overlapping, and may evolve into one another, thus rendering clear-cut definitions difficult. Nevertheless, a phenotype-/endotype-based classification approach could lead toward the application of stratified and personalized medicine in the rhinitis field. In this PRACTALL document, rhinitis phenotypes and endotypes are described, and rhinitis diagnosis and management approaches focusing on those phenotypes/endotypes are presented and discussed. We emphasize the concept of control-based management, which transcends all rhinitis subtypes.

Effector cell signature in peripheral blood following nasal allergen challenge in grass pollen allergic individuals

BACKGROUND

Several studies have demonstrated the time course of inflammatory mediators in nasal fluids following nasal allergen challenge (NAC), whereas the effects of NAC on cells in the periphery are unknown. We examined the time course of effector cell markers (for basophils, dendritic cells and T cells) in peripheral blood after nasal grass pollen allergen challenge.

METHODS

Twelve participants with seasonal allergic rhinitis underwent a control (diluent) challenge followed by NAC after an interval of 14 days. Nasal symptoms and peak nasal inspiratory flow (PNIF) were recorded along with peripheral basophil, T-cell and dendritic cell responses (flow cytometry), T-cell proliferative responses (thymidine incorporation), and cytokine expression (FluoroSpot assay).

RESULTS

Robust increases in nasal symptoms and decreases in PNIF were observed during the early (0-1 h) response and modest significant changes during the late (1-24 h) response. Sequential peaks in peripheral blood basophil activation markers were observed (CD107a at 3 h, CD63 at 6 h, and CD203c(bright) at 24 h). T effector/memory cells (CD4(+) CD25(lo) ) were increased at 6 h and accompanied by increases in CD80(+) and CD86(+) plasmacytoid dendritic cells (pDCs). Ex vivo grass antigen-driven T-cell proliferative responses and the frequency of IL-4(+) CD4(+) T cells were significantly increased at 6 h after NAC when compared to the control day.

CONCLUSION

Basophil, T-cell, and dendritic cell activation increased the frequency of allergen-driven IL-4(+) CD4(+) T cells, and T-cell proliferative responses are detectable in the periphery after NAC. These data confirm systemic cellular activation following a local nasal provocation.

Allergic Rhinitis and its Impact on Asthma (ARIA): achievements in 10 years and future needs

Allergic rhinitis (AR) and asthma represent global health problems for all age groups. Asthma and rhinitis frequently coexist in the same subjects. Allergic Rhinitis and its Impact on Asthma (ARIA) was initiated during a World Health Organization workshop in 1999 (published in 2001). ARIA has reclassified AR as mild/moderate-severe and intermittent/persistent. This classification closely reflects patients' needs and underlines the close relationship between rhinitis and asthma. Patients, clinicians, and other health care professionals are confronted with various treatment choices for the management of AR. This contributes to considerable variation in clinical practice, and worldwide, patients, clinicians, and other health care professionals are faced with uncertainty about the relative merits and downsides of the various treatment options. In its 2010 Revision, ARIA developed clinical practice guidelines for the management of AR and asthma comorbidities based on the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system. ARIA is disseminated and implemented in more than 50 countries of the world. Ten years after the publication of the ARIA World Health Organization workshop report, it is important to make a summary of its achievements and identify the still unmet clinical, research, and implementation needs to strengthen the 2011 European Union Priority on allergy and asthma in children.

Severe chronic allergic (and related) diseases: a uniform approach--a MeDALL--GA2LEN--ARIA position paper

Concepts of disease severity, activity, control and responsiveness to treatment are linked but different. Severity refers to the loss of function of the organs induced by the disease process or to the occurrence of severe acute exacerbations. Severity may vary over time and needs regular follow-up. Control is the degree to which therapy goals are currently met. These concepts have evolved over time for asthma in guidelines, task forces or consensus meetings. The aim of this paper is to generalize the approach of the uniform definition of severe asthma presented to WHO for chronic allergic and associated diseases (rhinitis, chronic rhinosinusitis, chronic urticaria and atopic dermatitis) in order to have a uniform definition of severity, control and risk, usable in most situations. It is based on the appropriate diagnosis, availability and accessibility of treatments, treatment responsiveness and associated factors such as comorbidities and risk factors. This uniform definition will allow a better definition of the phenotypes of severe allergic (and related) diseases for clinical practice, research (including epidemiology), public health purposes, education and the discovery of novel therapies.

Development and implementation of guidelines in allergic rhinitis – an ARIA-GA2LEN paper

The links between asthma and rhinitis are well characterized. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines stress the importance of these links and provide guidance for their prevention and treatment. Despite effective treatments being available, too few patients receive appropriate medical care for both diseases. Most patients with rhinitis and asthma consult primary care physicians and therefore these physicians are encouraged to understand and use ARIA guidelines. Patients should also be informed about these guidelines to raise their awareness of optimal care and increase control of the two related diseases. To apply these guidelines, clinicians and patients need to understand how and why the recommendations were made. The goal of the ARIA guidelines is to provide recommendations about the best management options for most patients in most situations. These recommendations should be based on the best available evidence. Making recommendations requires the assessment of the quality of available evidence, deciding on the balance between benefits and downsides, consideration of patients’ values and preferences, and, if applicable, resource implications. Guidelines must be updated as new management options become available or important new evidence emerges. Transparent reporting of guidelines facilitates understanding and acceptance, but implementation strategies need to be improved.

CD14, a key candidate gene associated with a specific immune response to cockroach

BACKGROUND

Sensitization to cockroach allergen is one of the strongest predictors of asthma morbidity, especially among African Americans.

OBJECTIVE

Our aims were to determine the genomic basis of cockroach sensitization and the specific response to cockroach antigen.

METHODS

We investigated the Th1/Th2 cytokine profile of co-cultured plasmacytoid dendritic cells (pDCs) and CD4+ T cells and the 'transcript signature' of the immune response to cockroach antigen using high-throughput expression profiling of co-cultured cells.

RESULTS

We observed significantly elevated levels of IL-13, IL-10, and TNF-alpha, but undetectable levels of IL-12p70 and IFN-alpha, when cultures were exposed to crude cockroach antigen. A significant difference was observed for IL-13 between cockroach-allergic and non-allergic individuals (P=0.039). Microarray analyses demonstrated a greater response at 48 h compared with 4 h, with 50 genes being uniquely expressed in cockroach antigen-treated cells, including CD14, S100A8, CCL8, and IFI44L. The increased CD14 expression was further observed in purified pDCs, human monocytic THP-1 cells, and the supernatant of co-cultured pDCs and CD4+ T cells on exposure to cockroach extract. Furthermore, the most differential expression of CD14 between cockroach allergy and non-cockroach allergy was only observed among individuals with the CC 'high-risk' genotype of the CD14-260C/T. Ingenuity Pathways Analysis analyses suggested the IFN signalling as the most significant canonical pathway.

CONCLUSION

Our results suggest that these differentially expressed genes, particularly CD14, and genes in the IFN signalling pathway may be important candidates for further investigation of their role in the immune response to cockroach allergen.

Reproducibility of nasal allergen challenge in evaluating the efficacy of intranasal corticosteroid treatment

BACKGROUND

Although nasal challenge with allergen has often been used to evaluate the efficacy of therapeutic modalities used for the treatment of allergic rhinitis, the reproducibility of this model in quantitatively evaluating efficacy has not been rigorously examined.

OBJECTIVE

To examine the reproducibility of the suppressive effects of an intranasal corticosteroid on the clinical and biochemical outcomes of a nasal allergen challenge during two identical treatment periods using the same subjects.

METHODS

In a single-blind study, 25 seasonal allergic subjects with positive skin tests to grass or ragweed were studied outside of their pollen season. Subjects underwent a baseline, three-dose allergen challenge. Beginning 1 week later, subjects received two 7-day courses of intranasal beclomethasone (168 microg b.i.d.) separated by a 1-month washout period. Nasal challenges with allergen were performed after each treatment period. The nasal allergic response was evaluated by counting sneezes, recording symptom scores and measuring levels of albumin (an index of vascular permeability), lysozyme (an index of serous glandular secretion) and kinins (proinflammatory peptides) in recovered nasal lavages.

RESULTS

Compared with the baseline challenge, each course of beclomethasone significantly reduced sneezing, symptom scores, albumin and kinins, but not lysozyme. Reproducibility analysis of the net changes from diluent challenge in the two beclomethasone treatment periods, showed the following intraclass correlation coefficients: sneezing (0.92), lysozyme (0.82), symptom scores (0.72), albumin (0.64) and kinins (0.28).

CONCLUSION

We conclude that the nasal challenge model is a reproducible method to evaluate the efficacy of anti-allergic medications. For nasal corticosteroid trials, sneezing, symptom scores and albumin levels are recommended as the most reproducibly suppressive outcome measures.

Cysteinyl leukotrienes: multi-functional mediators in allergic rhinitis

Cysteinyl leukotrienes (CysLTs) are a family of inflammatory lipid mediators synthesized from arachidonic acid by a variety of cells, including mast cells, eosinophils, basophils, and macrophages. This article reviews the data for the role of CysLTs as multi-functional mediators in allergic rhinitis (AR). We review the evidence that: (1) CysLTs are released from inflammatory cells that participate in AR, (2) receptors for CysLTs are located in nasal tissue, (3) CysLTs are increased in patients with AR and are released following allergen exposure, (4) administration of CysLTs reproduces the symptoms of AR, (5) CysLTs play roles in the maturation, as well as tissue recruitment, of inflammatory cells, and (6) a complex inter-regulation between CysLTs and a variety of other inflammatory mediators exists.

Stronger nasal responsiveness to cold air in individuals with rhinitis and asthma, compared with rhinitis alone

BACKGROUND

We have previously proposed that, compared with rhinitis alone, the constellation of upper and lower airway allergic disease is a manifestation of a more severe form of a syndrome affecting the entire airway. If this is correct, not only the lower, but also the upper airways of patients with asthma and rhinitis should demonstrate more abnormalities compared with patients with rhinitis alone, including higher sensitivity to irritant factors. Objective To test the hypothesis that, a previously well-studied natural nasal stimulus, cold, dry air (CDA), produces a stronger response in subjects with allergic rhinitis (AR) and asthma compared with subjects with AR alone.

METHODS

We performed nasal provocation with CDA on 24 individuals with asthma and rhinitis and 17 with rhinitis alone. Prior to and after the challenge, nasal symptoms were recorded using visual analogue scales and nasal lavages were performed to determine histamine and lysozyme levels.

RESULTS

The two groups reacted differently to CDA: after the challenge, patients with rhinitis and asthma reported significantly higher scores for nasal congestion, rhinorrhea and lacrimation. Also in this group, significant increases in histamine and in lysozyme levels in nasal lavage fluids were induced by CDA. In subjects with rhinitis alone, CDA failed to increase histamine or lysozyme levels above baseline. The CDA-induced change from baseline in histamine was significantly higher in the patients with rhinitis and asthma, compared with the rhinitis-only group.

CONCLUSION

Patients with AR and asthma have stronger nasal responsiveness to CDA compared with patients with rhinitis alone. This observation is consistent with the notion that compared with rhinitis alone, the presence of asthma and rhinitis signifies a higher degree of functional abnormality of the entire airway.

Genome scan for loci linked to mite sensitivity: the Collaborative Study on the Genetics of Asthma (CSGA)

Mite sensitivity has been reported to be a major risk factor for asthma. As part of the Collaborative Study on the Genetics of Asthma (CSGA), a genome scan using mite reactivity (Dermatophagoides Pteronyssinus (Der p) and Dermatophagoides farinae (Der f)) as the phenotype was conducted. In 287 CSGA families, 122 were informative for linkage. Evidence supporting linkage was observed for regions on chromosome 19 (D19S591, lod=2.43, P=0.0008; D19S1037, lod=1.57, P=0.007) and chromosome 20 (D20S473/D20S604, lod=1.41, P=0.01). All three ethnic groups appeared to contribute to the evidence for linkage on chromosome 20. African-American families gave strongest support for linkage on chromosomes 3 (D3S2409, lod=1.33, P=0.01), 12 (D12S373, lod=1.51, P=0.008) and 18 (ATA82B02, lod=1.32, P=0.01). Caucasian families showed strong evidence for linkage on chromosome 19 (D19S591, lod=3.51, P=0.00006). Hispanic families supported linkage on chromosomes 11 (D11S1984, lod=1.56, P=0.007), 13 (D13S787, lod=1.30, P=0.01) and 20 (D20S470, lod=1.71, P=0.005). These results suggest that multiple genes may be involved in controlling skin reactivity to Dermatophoigoies.

Airways hyper-responsiveness to bradykinin and methacholine: effects of inhaled fluticasone

BACKGROUND

Although inhaled corticosteroids are the most effective anti-inflammatory agents available for the treatment of asthma, they have, at best, only modest effects on airways responsiveness to methacholine. Thus, hyper-responsiveness to methacholine is a relatively insensitive monitor of the effectiveness of glucocorticoids in asthmatic subjects.

OBJECTIVE

The study aimed to determine if airways hyper-responsiveness to bradykinin provides a more sensitive index of glucocorticoid responsiveness in asthmatic subjects than does hyper-responsiveness to methacholine.

METHODS

A double-blind, placebo-controlled, parallel group study comparing the effects of inhaled fluticasone (220 micro g twice daily) on responsiveness to the two stimuli in asthmatic subjects who had never previously received corticosteroid therapy. Drug (n = 13) or placebo (n = 12) were administered for 16 weeks. Responsiveness to bradykinin and methacholine was determined at baseline and at 4 week intervals.

RESULTS

Placebo did not alter responsiveness to either stimulus compared to baseline. Fluticasone treatment significantly reduced responsiveness to bradykinin (P < 0.001 by Friedman anova) and methacholine (P = 0.02), but changes in responsiveness to bradykinin were significantly greater than those in methacholine responsiveness (P = 0.002). Bradykinin responsiveness was decreased at all treatment times compared to baseline, while methacholine responsiveness was not decreased until 8 weeks of therapy. When data were analyzed as changes from baseline (DeltaLog PD20), DeltaLog PD20 for methacholine was not different at any time-point between the two treatment groups. By contrast, DeltaLog PD20 for bradykinin was significantly greater in patients receiving fluticasone compared to those on placebo at all but the 16-week treatment time. Ten of 13 subjects receiving fluticasone failed, on at least one post-treatment visit, to show a 20% fall in forced expiratory volume (FEV1), even at the highest dose of bradykinin.

CONCLUSIONS

Airways responsiveness to bradykinin is more profoundly, and more rapidly, reduced by inhaled glucocorticoids than is responsiveness to methacholine. Airways hyper-responsiveness to bradykinin provides a convenient and sensitive monitor of glucocorticoid responsiveness in asthma.

Ethnic differences in asthma and associated phenotypes: collaborative study on the genetics of asthma

BACKGROUND

In the Collaborative Study on the Genetics of Asthma, 314 families with 2584 subjects were characterized for asthma and allergy.

OBJECTIVE

The purpose of this investigation was to examine clinical heterogeneity observed in asthma and allergic characteristics among 3 ethnic groups (African American, white, and Hispanic family members).

METHODS

Pulmonary function parameters and asthma associated phenotypes were compared among the ethnic groups.

RESULTS

In comparison with the other groups, African American sibling pairs had a significantly lower baseline FEV(1) percent of predicted (P =.0001) and a higher rate of skin test reactivity to cockroach allergen (P =.0001); Hispanic sibling pairs had significantly more skin reactivity overall (P =.001); and white sibling pairs had significantly lower total serum IgE (P <.05). In addition, there were significantly more relatives with asthma among the African American families than among the white and the Hispanic families (P =.001).

CONCLUSION

Although different environmental backgrounds should be considered, these clinical differences could be due to differences in genetic susceptibility among the ethnic groups, such as those suggested by our previous genome screen.

Nerve growth factor or IL-3 induces more IL-13 production from basophils of allergic subjects than from basophils of nonallergic subjects

BACKGROUND

Studies show that nerve growth factor (NGF) exhibits immunomodulatory activity. This neurotrophin is found at high levels in the serum of asthmatic individuals, is released during allergic reactions, and is reported to augment in vitro histamine and leukotriene C4 release by human basophils.

OBJECTIVE

Because basophils represent a substantial source of IL-4 and IL-13, we tested the effects of NGF on the secretion of these cytokines by cells prepared from allergic subjects and cells prepared from nonallergic subjects.

METHODS

Cytokine and histamine were measured in culture supernatants by ELISA and fluorimetry, respectively. Both real-time RT-PCR and conventional RT-PCR were used to measure IL-13 mRNA expression. NGF receptor expression was determined by 2-color flow cytometry.

RESULTS

Basophil suspensions from allergic subjects secreted some 2.5-fold greater levels of IL-13 when cultured with NGF than did cells prepared from normal control subjects. Flow cytometry revealed no significant differences in TrkA receptors on basophils to explain these findings. The levels of IL-13 secreted by the 2 groups of donors also differed when cells were activated with IL-3 but not when they were activated with anti-IgE antibody. Both NGF and IL-3 failed to induce IL-13 in cell cultures depleted of basophils, suggesting that the measurable IL-13 was indeed basophil-derived. Real-time RT-PCR showed an average induction of IL-13 message above medium control that was 4.3 (+/- 1.7)-fold with NGF and 8.9 (+/- 3.7)-fold with IL-3. Finally, NGF priming resulted in a remarkable enhancement of IL-13 induced by anti-IgE. This was significantly greater than the priming observed for either the IL-4 or histamine when this stimulus was used.

CONCLUSION

NGF (like IL-3) can both directly stimulate IL-13 secretion and modulate IgE-mediated responses in basophils. Its enhanced effect on cells from allergic individuals raises the importance of this cytokine in the pathogenesis of allergic disease.

Allergen-induced changes in airway responsiveness are not related to indices of airway edema

BACKGROUND

The mechanisms behind airway hyperresponsiveness in asthma are unknown. Airway wall edema has been proposed as one possible culprit of this phenomenon.

OBJECTIVE

To test the hypothesis that airway edema may be the cause of allergen-induced increases in airway responsiveness in asthma, this trial aimed at determining the relationship between allergen-induced changes in airway responsiveness to inhaled methacholine and indirect indices of edema, namely peripheral airway resistance and the levels of the plasma protein fibrinogen in bronchoalveolar lavage (BAL) fluids.

METHODS

Twenty-six atopic individuals with mild asthma were subjected to bronchoscopy at baseline and 28 hours after allergen inhalation. Before each bronchoscopy, methacholine bronchoprovocation was performed. During bronchoscopy, peripheral airway resistance measurements were obtained by wedged bronchoscopy. BAL fluids were analyzed for fibrinogen, as well as for eosinophilic cationic protein. Cytology was performed, and cytokine gene expression was assessed with competitive reverse transcriptase PCR from cell pellets.

RESULTS

A significant increase in airway responsiveness to methacholine was recorded after allergen, but this did not correlate with changes in peripheral airway resistance (which was not affected) or with BAL fibrinogen (which decreased after allergen). Other BAL outcomes confirmed that airway inflammation was produced and was characterized by a T(H)2 cytokine pattern.

CONCLUSIONS

Airway responsiveness in asthma increases after exposure to allergen in the absence of increased indirect indices of edema. The role of edema in this phenomenon should therefore be tested more vigorously.

Genome-wide linkage analyses of total serum IgE using variance components analysis in asthmatic families

Variance components models were used to analyze total IgE levels in families ascertained though the Collaborative Study of the Genetics of Asthma (CSGA) using a genome-wide array of polymorphic markers. While IgE levels are known to be associated with clinical asthma and recognized to be under strong genetic control (here the heritability was estimated at 44-60% in the three racial groups), specific genes influencing this trait are still largely unknown. Multipoint analysis of 323 markers yielded little indication of specific regions containing a trait locus controlling total serum IgE levels (adjusted for age and gender). Although a number of regions showed LOD statistics above 1.5 in Caucasian families (chromosome 4) and in African-American families (chromosomes 2 and 4), none yielded consistent evidence in all three racial groups. Analysis of total IgE adjusted for gender, age and Allergy Index (a quantitative score of skin test sensitivity to 14 common aeroallergens) was conducted on these data. In this analysis, a much stronger signal for a trait locus controlling adjusted log[total IgE] was seen on the telomeric end of chromosome 18, but only in Caucasian families. This region accounted for most of the genetic variation in log[total IgE], and may represent a quantitative trait locus for IgE levels independent of atopic response. Oligogenic analysis accounting simultaneously for the contribution of this locus on chromosome 18 and other chromosomal regions showing some evidence of linkage in these Caucasian families (on chromosomes 2, 4 and 20) failed to yield significant evidence for interaction.

High-resolution computed tomographic evaluation of airway distensibility and the effects of lung inflation on airway caliber in healthy subjects and individuals with asthma

The effects of a deep inspiration (DI) in individuals with asthma differ from those observed in healthy subjects. It has been postulated that the beneficial effect of lung inflation is mediated by airway stretch. One hypothesis to explain the defects in the function of lung inflation in asthma is that a DI may be unable to stretch the airways. This may result from attenuation of the tethering forces between the airways and the surrounding parenchyma. In the current study, we used high-resolution computed tomography (HRCT) to examine the ability of a DI to distend the airways of subjects with asthma (n = 10) compared with healthy subjects (n = 9) at baseline and after increasing airway tone with methacholine (MCh). We found that both at baseline and after the induction of smooth muscle tone with MCh, a DI distended the airways of healthy and asthmatic subjects to a similar extent, indicating that abnormal interdependence between the lung parenchyma and the airways is unlikely to play a major role in the loss or attenuation of the beneficial effect of lung inflation that characterizes asthma. Furthermore, we observed that after constriction had already been induced by MCh, following a DI, bronchodilation occurred in the healthy subjects but further bronchoconstriction occurred in the subjects with asthma. Our findings suggest that an abnormal excitation contraction mechanism in the airway smooth muscle of subjects with mild asthma counteracts the bronchodilatory effect of a DI. Therefore, the mechanism for reduced bronchodilation after DIs in subjects with mild asthma could be intrinsic to the airway smooth muscle.

The lack of the bronchoprotective and not the bronchodilatory ability of deep inspiration is associated with airway hyperresponsiveness

In healthy subjects, deep inspiration (DI) acts both as a bronchodilator and a bronchoprotector. The latter is impaired in asthmatics. We have now evaluated whether the lack of bronchoprotection is related to bronchial hyperresponsiveness (BHR), and whether the bronchodilatory effect is also lost in asthmatics. Ten healthy subjects (PC20 > 75 mg/ml), 12 asthmatics with moderate to severe BHR (PC20 < 1 mg/ml), 14 asthmatics with mild to borderline BHR (1 < PC20 < 25 mg/ml), and 10 rhinitics with mild to borderline BHR (1 < PC20 < 25 mg/ml) underwent single-dose methacholine provocations inducing at least 20% reduction in FEV1 after 20 min of DI inhibition. To measure the bronchodilatory effect, DIs were taken immediately after the postmethacholine spirometry, and lung function was again tested. To measure the bronchoprotective effect, DIs were taken before the administration of spasmogen. All four groups achieved the same reductions in FEV1 and FVC, in the absence of deep breaths (analysis of variance [ANOVA], p = 0.49). Only healthy subjects showed bronchoprotection (percent bronchoprotection, mean +/- SEM; healthy: 79 +/- 4.0; asthmatics with moderate to severe BHR: 12 +/- 14.5; asthmatics with mild to borderline BHR: -7 +/- 19.7; rhinitics with mild to borderline BHR: 2 +/- 14.0). In contrast, DIs were able to partially reverse bronchial obstruction in all four groups, albeit percent bronchodilation in healthy subjects was somewhat stronger. The dissociation between bronchoprotection and bronchodilation suggests that the two effects involve different mechanisms.

Absence of nasal mucosal atrophy with fluticasone aqueous nasal spray

OBJECTIVE

To evaluate whether 1 year of continuous treatment with intranasal fluticasone propionate would lead to atrophy in the nasal mucosa compared with an active control, oral terfenadine.

DESIGN

Prospective, randomized, multicenter, open-label, parallel-group study.

SETTING

Two tertiary care academic institutions.

PATIENTS

Seventy-five subjects older than 18 years with perennial allergic rhinitis.

INTERVENTIONS

Patients received either fluticasone propionate aqueous nasal spray, 200 microg once daily, or terfenadine, 60 mg twice daily, for 1 year. Nasal biopsy specimens were obtained before and after 1 year of treatment and were evaluated for evidence of atrophy.

MAIN OUTCOME MEASURES

Epithelial and collagen layer thickness of the nasal mucosa as assessed by light microscopy and the presence and degree of edema, and regularity of collagen fibrils as assessed by electron microscopy. Analyses were performed without knowledge of subject identity or treatment assignment.

RESULTS

Neither fluticasone nor terfenadine treatment led to atrophy in the nasal mucosa by clinical or histologic observation. No significant changes from baseline were observed for any assessment of atrophy. In contrast to what would have been expected if atrophy were to occur, mean epithelial layer thickness in the fluticasone group significantly increased compared with terfenadine treatment (P = .03).

CONCLUSIONS

Treatment with intranasal fluticasone for 1 year increases the thickness of the nasal epithelium as compared with a year's treatment with terfenadine and does not lead to atrophy in the nasal mucosa. The increased thickness in the fluticasone treatment may represent repair from epithelial damage caused by chronic allergic inflammation.

Antigen-specific IgE and IgA antibodies in bronchoalveolar lavage fluid are associated with stronger antigen-induced late phase reactions

The mechanism(s) leading to the development of late phase allergic reactions is (are) unknown. Previous studies have indicated that a relationship between serum IgE and the late phase exists. To explore the relationships between allergen-specific immunoglobulins in bronchoalveolar lavage (BAL) fluids and the magnitude of airflow limitation during the late phase response to inhaled allergen. Ragweed-specific IgE, IgA, secretory IgA (sIgA) and IgG were measured in BAL fluid and in the serum 1-5 weeks before whole lung antigen challenge with ragweed extract, in 16 ragweed allergic asthmatics. In addition, BAL and serum eosinophil cationic protein (ECP) and BAL fibrinogen levels were determined and BAL cells counted and differentiated. The latter procedures were repeated in a second BAL performed 24 h after the end of the ragweed challenge. After the challenge, lung function was monitored hourly for 8 h, to record the magnitude of airflow limitation. Ragweed-specific immunoglobulins were detected in 25% to 37.5% of BAL samples. Compared to the subjects with undetectable BAL fluid ragweed-specific IgE levels at baseline, those with detectable antibodies had stronger late phase reactions as determined by the nadir of FEV1 between hours 4 and 8 after the ragweed inhalation challenge (P = 0.0007). Allergen-induced changes in BAL ECP and fibrinogen levels were also higher in those subjects with detectable ragweed-specific IgE in baseline fluids (P = 0.03 and P = 0.005, respectively). Significant relationships between BAL antigen-specific IgA, serum ragweed-specific IgE and IgA and the late phase reaction were also found. The results of this study point towards the possibility that allergen-specific IgE and IgA may be independently involved in the pathogenesis of the late phase reaction. This notion merits further exploration.

Airways hyperresponsiveness and the effects of lung inflation

Lung inflation has a beneficial effect on the airways of healthy subjects. It acts as a bronchoprotector, that is to prevent bronchoconstriction, and as a bronchodilator, in that it reverses bronchial obstruction. The bronchoprotective effect of deep inspiration is more potent than the bronchodilatory one, and the two phenomena appear to advocate different mechanisms. Asthmatics and rhinitics with airways hyperresponsiveness show an impairment in bronchoprotection induced by deep breaths, whereas the bronchodilatory effect, although reduced, is still effective. The lack of the bronchoprotective effect of deep inspiration may contribute to the development of airways hyperresponsiveness. The mechanisms through which lung inflation exerts its beneficial role in healthy subjects, and the factors impairing such an effect in those with airways hyperresponsiveness, are currently under investigation.

Mutation in the gene responsible for cystic fibrosis and predisposition to chronic rhinosinusitis in the general population

CONTEXT

Chronic rhinosinusitis (CRS) is a common condition in the US general population, yet little is known about its underlying molecular cause. Chronic rhinosinusitis is a consistent feature of the autosomal recessive disorder cystic fibrosis (CF).

OBJECTIVE

To determine whether mutations in the cystic fibrosis transmembrane regulator (CFTR) gene, which is responsible for CF, predispose to CRS.

DESIGN

Case-control study conducted from 1996 to 1999 in which the DNA of CRS patients and controls was typed for 16 mutations that account for 85% of CF alleles in the general population. Chronic rhinosinusitis patients with 1 CF mutation were evaluated for a CF diagnosis by sweat chloride testing, nasal potential difference measurement, and DNA analysis for additional mutations.

SETTING

Otolaryngology-head and neck clinic of a US teaching hospital.

PARTICIPANTS

One hundred forty-seven consecutive adult white patients who met stringent diagnostic criteria for CRS and 123 CRS-free white control volunteers of similar age range, geographic region, and socioeconomic status.

MAIN OUTCOME MEASURES

Presence of CF mutations by DNA analysis among CRS patients vs controls.

RESULTS

Eleven CRS patients were found to have a CF mutation (DeltaF508, n = 9; G542X, n = 1; and N1303K, n = 1). Diagnostic testing excluded CF in 10 of these patients and led to CF diagnosis in 1. Excluding this patient from the analyses, the proportion of CRS patients who were found to have a CF mutation (7%) was significantly higher than in the control group (n = 2 [2%]; P =.04, both having DeltaF508 mutations). Furthermore, 9 of the 10 CF carriers had the polymorphism M470V, and M470V homozygotes were overrepresented in the remaining 136 CRS patients (P =.03).

CONCLUSION

These data indicate that mutations in the gene responsible for CF may be associated with the development of CRS in the general population. JAMA. 2000;284:1814-1819.

Deep inspiration-induced bronchoprotection is stronger than bronchodilation

We have previously shown that in healthy subjects, deep inspiration (DI) has not only a bronchodilatory but also a bronchoprotective effect that is absent in asthmatic subjects. We conducted the study reported here to test the hypothesis that the bronchoprotective effect is stronger than the bronchodilatory effect, and to determine the extent to which these two effects are related. Ten healthy subjects underwent provocations in which single doses of methacholine, previously shown to reduce FEV(1) by 10% to 20% (Dose 1) and by 20% to 40% (Dose 2) were administered after a 20-min period devoid of DI. To measure the bronchodilator effect, DIs were performed immediately after the first spirometry after methacholine, and were followed by another lung function test. To measure their bronchoprotective effect, DIs were performed before administration of a single dose of methacholine, and the FEV(1) after methacholine was compared with that of another single-dose challenge in which DIs were not included. From these outcomes, bronchodilation and bronchoprotection indices were constructed and compared with each other. At Dose 1 (mild obstruction), the ability of DIs to reverse methacholine-induced obstruction was equal to their ability to prevent it (bronchodilation index [BDI] versus bronchoprotection index [BPI]: 1.62 +/- 0.21 versus 2.02 +/- 0.40 [mean +/- SEM], p = 0.26). At Dose 2, the relative potency of both the bronchodilating and bronchoprotective effects of DIs increased, but bronchoprotection was significantly stronger (BDI versus BPI: 3.40 +/- 0.43 versus 6.98 +/- 1.42, p = 0.02). Correlation analysis of the two indices indicated that as the BPI increased, the BDI reached a plateau. We conclude that in healthy humans, the bronchoprotective effect of lung inflation is stronger than the bronchodilatory effect.

Endogenous glucocorticoids and antigen-induced acute and late phase pulmonary responses

BACKGROUND

Several studies suggest that endogenous glucocorticoids can dampen the severity of experimental allergic reactions in animals.

OBJECTIVE

To investigate the influence that endogenous glucocorticoids have on the course of IgE-mediated pulmonary early and late phase reactions.

METHODS

Twenty-one allergic asthmatic and six healthy control subjects underwent inhaled antigen challenge with measurements of plasma cortisol and cortisone by gas chromatography-mass spectrometry.

RESULTS

There were no differences between the asthmatic and control groups in the baseline levels of cortisol or cortisone. However, the asthmatic subjects had significantly higher cortisol levels (67.2 +/- 8.6 vs 35.1 +/- 4.5 ng/mL; P = 0.04) and had higher cortisol/cortisone ratios (4.8 +/- 0. 6 vs 3.0 +/- 0.2; P = 0.01) 8 h after challenge compared to the control subjects. Among the asthmatic subjects, those whose FEV1 recovered rapidly had higher baseline levels of cortisol and those who displayed a late phase reaction had lower levels of cortisol during the late phase period.

CONCLUSION

The results suggest that endogenous glucocorticoids may play a significant role in the modulation of airway responses to antigen challenge, and that antigen challenge may induce cortisol production in allergic subjects.