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BACKGROUND: The generation of IgE-mediated food allergy in humans is silent and only diagnosed upon manifestation of clinical symptoms. While experimental models have been used to investigate some mechanisms of allergic sensitization, the generation of humoral immunity and memory remains to be elucidated. Here, we defined the evolution of allergen-specific B-cell responses during epicutaneous sensitization to foods. METHODS: Wild-type and genetic knockout animals, and drug or antibody strategies for cell depletion and immunoglobulin signaling blockade were used to investigate epicutaneous sensitization and disease progression; we analyzed allergen-specific germinal centers and IgG1+ memory B cells by flow cytometry, evaluated humoral responses, and determined clinical reactivity (anaphylaxis). RESULTS: Epicutaneous sensitization caused microscopic skin damage, inflammation, and recruitment of activated dendritic cells to the draining lymph nodes. This process generated allergen-specific IgG1+ germinal center B cells, serum IgG1, and anaphylaxis that was mediated by the alternative pathway. Whether we used peanut and/or ovalbumin from the egg white for sensitization, the allergen-specific IgG1+ memory compartment predominantly exhibited an immature, pro-germinal center phenotype (PDL-2- CD80- CD35+ CD73+ ). Subsequent subclinical exposures to the allergen induced IgE+ germinal center B cells, serum IgE, and likely activated the classical pathway of anaphylaxis. CONCLUSIONS: Our data demonstrate that IgG1+ B-cell immunity against food allergens in epicutaneous sensitization precedes the generation of IgE responses. Therefore, the assessment of allergen-specific cellular and humoral IgG1+ immunity may help to identify individuals at risk of developing IgE-mediated food allergy and hence provide a window for therapeutic interventions.
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Linfócitos B/imunologia , Hipersensibilidade Alimentar/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Anafilaxia/imunologia , Animais , Humanos , Imunidade Humoral , Pele/patologia , Fatores de TempoRESUMO
BACKGROUND: Patients with asthma may be more susceptible to adverse events (AEs) with sublingual immunotherapy tablet (SLIT-tablet) treatment, such as severe systemic reactions and asthma-related events. Using data from eight trials of grass SLIT-tablet in subjects with allergic rhinitis with/without conjunctivitis (AR/C), AE frequencies were determined in adults and children with and without reported asthma. METHODS: Data from randomized, double-blind, placebo-controlled trials of Timothy grass SLIT-tablet MK-7243 (2800 BAU/75 000 SQ-T, Merck/ALK-Abelló) were pooled for post hoc analyses. Subjects with uncontrolled and severe asthma were excluded from the trials. Frequencies for treatment-emergent AEs (TEAEs), local allergic swelling (mouth or throat), systemic allergic reactions, and asthma-related treatment-related AEs (TRAEs) were calculated. RESULTS: Among adults (n = 3314) and children (n = 881), 24% and 31%, respectively, had reported asthma. No serious local allergic swellings or serious systemic allergic reactions occurred in subjects with asthma treated with SLIT-tablet. There was no evidence of increased TEAEs, systemic allergic reactions, or severe local allergic swellings in adults or children with asthma treated with grass SLIT-tablet versus subjects without asthma in or outside of pollen season. There were 6/120 asthma-related TRAEs assessed as severe with grass SLIT-tablet and 2/60 with placebo, without a consistent trend among subjects with and without asthma (5 and 3 events, respectively). CONCLUSIONS: In the AR/C subjects with reported well-controlled mild asthma included in these studies, grass SLIT-tablet did not increase TEAE frequency, severe local allergic swelling, or systemic allergic reactions versus subjects without asthma. There was no indication that treatment led to acute asthma worsening.
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Alérgenos/imunologia , Asma/complicações , Conjuntivite/complicações , Phleum/efeitos adversos , Rinite Alérgica/complicações , Rinite Alérgica/terapia , Imunoterapia Sublingual , Adolescente , Adulto , Idoso , Alérgenos/administração & dosagem , Alérgenos/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados Aleatórios como Assunto , Testes de Função Respiratória , Rinite Alérgica/fisiopatologia , Imunoterapia Sublingual/efeitos adversos , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Food allergy, in particular peanut allergy, is a growing concern in Western countries. The prevalence of allergy to peanut, which currently stands at 1.4%, nearly tripled between 1997 and 2008. Allergic sensitization is a particularly difficult process to study as it is clinically silent. We sought to identify key pathways and mediators critically involved in the induction of allergic sensitization to peanut. METHODS: Comprehensive metabolomics analysis with liquid chromatography-mass spectrometry was used to detect metabolite changes in mice (C57BL/6) undergoing sensitization. Loss-of-function and gain-of-function studies were performed in mice subjected to two models of peanut sensitization and anaphylaxis that involved either oral or epicutaneous sensitization. Flow cytometric analyses on dendritic cells (DCs) in vitro and in vivo were used to investigate the mechanisms of immune activation. RESULTS: Elevated levels of uric acid (UA) were detected in mice undergoing sensitization as well as in peanut-allergic children who were not challenged with peanut. In mice, the depletion of UA during sensitization prevented the development of peanut-specific immunoglobulins IgE and IgG1 as well as anaphylaxis while exogenous delivery of UA crystals (monosodium urate, MSU) restored the allergic phenotype. Monosodium urate enhanced CD86 and OX40L expression on DCs, independent of Toll-like receptors 2 and 4, the NLRP3 inflammasome, and IL-1ß, via a PI3K signaling pathway. CONCLUSION: Overproduction of the UA alarmin in the local microenvironment plays a critical role in the induction of peanut-allergic sensitization, likely due to its ability to activate DCs. These finding suggest that cellular damage or tissue injury may be an essential requisite for the development of allergic sensitization to foods.
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Alarminas/imunologia , Hipersensibilidade a Amendoim/imunologia , Ácido Úrico/imunologia , Alarminas/metabolismo , Animais , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Metabolômica , Camundongos , Camundongos Endogâmicos C57BL , Hipersensibilidade a Amendoim/metabolismo , Ácido Úrico/metabolismoRESUMO
BACKGROUND: In Canada, severe asthma affects an estimated 5-10% of people with asthma and is associated with frequent exacerbations, poor symptom control and significant morbidity from the disease itself, as well as the high dose inhaled, and systemic steroids used to treat it. Significant heterogeneity exists in service structure and patient access to severe asthma care, including access to biologic treatments. There appears to be over-reliance on short-acting beta agonists and frequent oral corticosteroid use, two indicators of uncontrolled asthma which can indicate undiagnosed or suboptimally treated severe asthma. The objective of this modified Delphi consensus project was to define standards of care for severe asthma in Canada, in areas where the evidence is lacking through patient and healthcare professional consensus, to complement forthcoming guidelines. METHODS: The steering group of asthma experts identified 43 statements formed from eight key themes. An online 4-point Likert scale questionnaire was sent to healthcare professionals working in asthma across Canada to assess agreement (consensus) with these statements. Consensus was defined as high if ≥ 75% and very high if ≥ 90% of respondents agreed with a statement. RESULTS: A total of 150 responses were received from HCPs including certified respiratory educators, respirologists, allergists, general practitioners/family physicians, nurses, pharmacists, and respiratory therapists. Consensus amongst respondents was very high in 37 (86%) statements, high in 4 (9%) statements and was not achieved in 2 (5%) statements. Based on the consensus scores, ten key recommendations were proposed. These focus on referrals from primary and secondary care, accessing specialist asthma services, homecare provision for severe asthma patients and outcome measures. CONCLUSIONS: Implementation of these recommendations across the severe asthma care pathway in Canada has the potential to improve outcomes for patients through earlier detection of undiagnosed severe asthma, reduction in time to severe asthma diagnosis, and initiation of advanced phenotype specific therapies.
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BACKGROUND: School personnel in contact with students with life-threatening allergies often lack necessary supports, creating a potentially dangerous situation. Sabrina's Law, the first legislation in the world designed to protect such children, requires all Ontario public schools to have a plan to protect children at risk. Although it has captured international attention, the differences a legislative approach makes have not been identified. Our study compared the approaches to anaphylaxis prevention and management in schools with and without legislation. METHODS: Legislated (Ontario) and nonlegislated (Alberta, British Columbia, Newfoundland and Labrador, and Quebec) environments were compared. School board anaphylaxis policies were assessed for consistency with Canadian anaphylaxis guidelines. Parents of at-risk children and school personnel were surveyed to determine their perspectives on school practices. School personnel's EpiPen5 technique was assessed. RESULTS: Consistency of school board policies with anaphylaxis guidelines was significantly better in a legislated environment (P=0.009). Parents in a legislated environment reported more comprehensive anaphylaxis emergency forms (P<0.001), while school personnel in nonlegislated environments reported more comprehensive forms (P=0.004). Despite school personnel in both environments receiving EpiPen5 training (>80%), suboptimal technique was commonly observed. However, school personnel in the legislated environment had better technique (P<0.001). CONCLUSION: Our results suggest that school boards in legislated environments have made greater efforts to support students at risk for anaphylaxis compared to nonlegislated environments. However, significant gaps exist in both environments, especially with respect to EpiPen5 administration, content, and distribution of anaphylaxis emergency forms, and awareness of school procedures by school personnel and parents.
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Anafilaxia/prevenção & controle , Serviços de Saúde Escolar/legislação & jurisprudência , Instituições Acadêmicas/legislação & jurisprudência , Broncodilatadores/administração & dosagem , Criança , Epinefrina/administração & dosagem , Guias como Assunto , Humanos , Ontário , Pais , EstudantesRESUMO
INTRODUCTION: Budesonide orodispersible tablets (BOT) have been approved in Europe and Canada for the treatment of eosinophilic esophagitis (EoE), a rare and chronic disease. The objective of this study was to assess the economic impact of BOT on both the induction and maintenance of clinico-pathological remission of EoE by performing a cost-utility analysis (CUA). METHODS: For both the induction and maintenance settings, BOT was compared to no treatment in a target population of adult patients with EoE non-responsive to proton pump inhibitor (PPI) treatment. Markov models were developed for the induction and maintenance settings over 52-week and life-time horizons, respectively. Analyses were performed from both a Canadian Ministry of Health (MoH) and societal perspective. The resulting incremental cost-utility ratios (ICURs) were compared to a willingness-to-pay (WTP) threshold of $50,000 Canadian dollars/quality-adjusted life-year (QALY). Sensitivity and scenario analyses were conducted to assess the robustness of the base-case results. RESULTS: In the base-case probabilistic analysis, BOT compared to no treatment resulted in an ICUR of $1073/QALY and $30,555/QALY from a MoH perspective in the induction and maintenance settings, respectively. BOT was a cost-effective option for both induction and maintenance in > 99% of Monte Carlo simulations. In the scenario analyses, the deterministic ICUR of BOT compared to no treatment varied from $682/QALY to $8510/QALY in the induction setting and $21,005/QALY to $55,157/QALY in the maintenance setting. CONCLUSION: BOT was cost-effective compared to no treatment for both the induction and maintenance of clinico-pathological remission of EoE in patients non-responsive to PPIs.
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Budesonida , Esofagite Eosinofílica , Adulto , Canadá , Análise Custo-Benefício , Esofagite Eosinofílica/tratamento farmacológico , Humanos , Anos de Vida Ajustados por Qualidade de Vida , ComprimidosRESUMO
Diagnosis and management of anaphylaxis can be a challenge because reactions are often unexpected and progress quickly. The focus of anaphylaxis management has mostly been on the acute episode, with little attention given to the long-term management of patients at risk. This is compounded by conflicting information in current guidelines and a general lack of agreement among clinicians about which management strategies are the most appropriate. We systematically reviewed the literature to identify and summarize studies that investigated gaps in anaphylaxis management. Our search included MEDLINE, EMBASE, CINAHL, and Evidence-Based Medicine Reviews. Studies were included if they addressed an outcome describing gaps in anaphylaxis knowledge, education, anaphylaxis management, and quality of life (QOL). Populations of interest were health care professionals involved in the care of patients at risk for anaphylaxis, and patients of any age, their parents, caregivers, and teachers in primary care, hospital or community settings. Of 5014 citations that were identified, the final 59 studies (selected from 75 full-text articles) met the inclusion criteria. Two hundred and two gaps were identified and classified according to major themes: gaps in knowledge and anaphylaxis management (physicians and patients); gaps in follow-up care (physicians); and QOL of patients and caregivers. Findings from this systematic review revealed gaps in anaphylaxis management at the level of physicians, patients, and the community. Findings will be used to provide a basis for developing interventional strategies to help address these deficiencies.
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Anafilaxia/diagnóstico , Anafilaxia/terapia , Conhecimentos, Atitudes e Prática em Saúde , Serviços de Saúde Comunitária , Medicina Baseada em Evidências , Pessoal de Saúde/estatística & dados numéricos , Humanos , Pacientes/estatística & dados numéricos , Médicos/estatística & dados numéricos , Guias de Prática Clínica como Assunto , Qualidade de Vida , Estados UnidosRESUMO
BACKGROUND: Anaphylaxis is often managed inadequately. We used findings from a systematic review of gaps in anaphylaxis management to develop evidence-based recommendations for gaps rated as clinically important by a panel of Canadian allergy experts. METHODS: The nominal group technique (NGT) consensus methodology was used to develop evidence-based recommendations for the management of anaphylaxis in primary care. Physician-specific gaps from our systematic review were prioritized by consensus meeting participants in two rounds, which involved the rating, discussion, and re-rating of gaps. Using current anaphylaxis guidelines, recommendations were then developed for each category of gaps that were identified by the panel as clinically important. RESULTS: Thirty unique physician gaps from the systematic review were categorized according to gaps of knowledge and anaphylaxis practice behaviors. The panel rated diagnosis of anaphylaxis, and when and how to use epinephrine auto-injectors as clinically important knowledge gaps; and rated infrequent or delayed epinephrine administration, low rate of auto-injector prescription, and infrequent or no referrals to allergy specialists after a reaction as important practice behavior gaps. Evidence from four guidelines was used to support the consensus recommendation statements for three resulting categories of gap themes: anaphylaxis management, epinephrine use, and follow-up care. CONCLUSION: We used an NGT consensus methodology to develop an educational resource for primary care physicians and allergists to better understand how to manage patients with anaphylaxis. Next steps include testing our findings against observed data in primary care settings and to develop other strategies or tools to overcome gaps in anaphylaxis management.
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Anafilaxia/terapia , Consenso , Medicina Baseada em Evidências , Guias de Prática Clínica como Assunto , Atenção Primária à Saúde/métodos , Anafilaxia/diagnóstico , Canadá , Humanos , Médicos de Atenção Primária/educaçãoRESUMO
Recent evidence supports a role for T lymphocytes in allergic airway responses. We hypothesized that reducing blood T suppressor cells (Ts) might increase the late airway response (LR). Sprague-Dawley (SD) rats were sensitized with ovalbumin (OA). On days 8, 10, and 12, post-sensitization test SD (n = 14) received monoclonal antibody intravenously (OX-8; 1 mg) specific to rat Ts. Controls received saline (n = 7) or mouse ascites IgG (n = 7). On day 14, animals were challenged with OA aerosol (5% wt/vol) for 5 min, lung resistance was recorded for 8 h (n = 18) and bronchoalveolar lavage was performed. The LR was determined from the area under the lung resistance vs time curve from 75 to 480 min after challenge. In the remaining 10 rats, airway lymphocyte subsets were measured 8 h after OA aerosol challenge in minced and digested lungs. A decrease in percentage of blood and airway Ts, respectively, in test animals was observed vs controls (blood: 6.27 +/- 0.84 vs 32.95 +/- 1.94, P < 0.001); (airway: 5.05 +/- 0.66 vs 24.5 +/- 3.05, P < 0.02). Blood and airway helper T lymphocytes did not differ between test and control animals. The LR was significantly increased in test (22.89 +/- 3.92) vs controls (4.22 +/- 2.18, P < 0.001). Bronchoalveolar lavage macrophages, neutrophils and lymphocytes, and serum OA-specific IgE were also significantly elevated (P < 0.05) in test animals. We conclude that Ts play an important role in attenuating the LR in SD rats.
Assuntos
Espasmo Brônquico/imunologia , Hipersensibilidade/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Aerossóis , Animais , Testes de Provocação Brônquica , Líquido da Lavagem Broncoalveolar/patologia , Imunoglobulina E/imunologia , Depleção Linfocítica , Masculino , Ovalbumina/imunologia , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
An unusual case of Mycobacterium avium complex infection occurred in a young adult with no preexisting disease and no evidence of immunodeficiency. There was diffuse interstitial involvement of the lungs which suggested an active alveolitis. Diagnosis required open-lung biopsy. Restriction fragment length polymorphism analysis and multilocus enzyme electrophoresis indicated that the source of the infection was a hot tub. The infection proved to be exceptionally responsive to treatment, and there was complete resolution with a four-drug regimen.
Assuntos
Banhos , Imunocompetência , Infecção por Mycobacterium avium-intracellulare/etiologia , Adulto , Feminino , Granuloma/patologia , Humanos , Pulmão/patologia , Infecção por Mycobacterium avium-intracellulare/diagnóstico , Infecção por Mycobacterium avium-intracellulare/tratamento farmacológicoRESUMO
The purpose of the study was to investigate the relationships between upper airways responses and pulmonary responses of two strains of highly inbred rats to inhaled antigen. To do this we measured the upper and lower airways resistance for 60 min after challenge of Brown-Norway rats (BN; n = 13) and an inbred rat strain (MF; n = 11), derived from Sprague-Dawley, with aerosolized ovalbumin (OA). Rats were actively sensitized with OA (1 mg sc) using Bordetella pertussis as an adjuvant. Two weeks later the animals were anesthetized and challenged. Tracheal pressure, esophageal pressure, and airflow were measured, from which total pulmonary resistance was partitioned into upper airway and lower pulmonary resistance (RL). The peak upper airway response to inhaled OA was similar in BN (1.89 +/- 0.66 cmH2O.ml-1.s; n = 7) and MF (2.85 +/- 0.68 cmH2O.ml-1.s; n = 6). The lower airway response to OA challenge was substantially greater in BN, and RL changed from 0.07 +/- 0.01 to 0.34 +/- 0.13 (n = 6; P < 0.05). The MF did not have any significant increase in RL after challenge; the baseline RL was 0.12 +/- 0.02 and only reached a peak value of 0.15 +/- 0.05 (n = 5; P = NS). Lower airway responsiveness of BN (n = 10) to serotonin, an important mediator early allergic airway responses, was similar to MF (n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)
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Antígenos/imunologia , Hipersensibilidade/fisiopatologia , Fenômenos Fisiológicos Respiratórios , Administração por Inalação , Aerossóis , Resistência das Vias Respiratórias/fisiologia , Animais , Antígenos/administração & dosagem , Hipersensibilidade/imunologia , Imunoglobulina E/imunologia , Masculino , Mastócitos/imunologia , Compostos de Metacolina/farmacologia , Ovalbumina/imunologia , Ratos , Ratos Sprague-Dawley , Sistema Respiratório/imunologia , Serotonina/farmacologiaRESUMO
BACKGROUND: Tumour necrosis factor-alpha (TNF-alpha) is a major proinflammatory cytokine that is thought to be important in the pathogenesis of asthma. However, alterations in systemic regulation of this cytokine in asthma have not been examined in the context of corticosteroid therapy. OBJECTIVES: To examine the ability of peripheral blood mononuclear cells (PBMC) from three different groups of patients with asthma requiring varying amounts of inhaled corticosteroids (ICS) for clinical control, and to examine cells from age- and sex-matched nonasthmatic patients to produce TNF-alpha. DESIGN: All patients with asthma had a positive methacholine challenge test. 'High dose' ICS patients with asthma required ICS greater than or equal to 800 microg/day. 'Medium dose' patients with asthma were on less than or equal to 500 microg/day of ICS, whereas 'no ICS' patients with asthma had received no ICS for at least three months. Each patient with asthma was examined in parallel with an age- and sex-matched, nonasthmatic, nonatopic control subject. Cells were cultured (with or without the addition of potential stimulators phytohemagglutinin, lipopolysaccharide, formyl-methionine-leucine-phenylalanine or antihuman CD3), and TNF-alpha production was assessed by ELISA. MAIN RESULTS: PBMC from both high dose ICS (n=8) and no ICS (n=11) patients with asthma produced more than twice the amount of TNF-alpha than cells from matched nonasthmatic control patients (P<0.01) when cultured alone or in the presence of each stimulus (P<0.05). In contrast, there was no significant difference in TNF-alpha production between medium dose ICS patients with asthma and control patients. A group of asymptomatic atopic patients (n=6) did not have an increased level of TNF-alpha production. CONCLUSIONS: Increases in TNF-a production within the PBMC compartment can be observed in both patients with asthma receiving high dose ICS and in a group of patients with mild asthma receiving no ICS therapy, but not in patients with asthma receiving a medium dose of ICS or atopic patients.
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Asma/metabolismo , Glucocorticoides/uso terapêutico , Fator de Necrose Tumoral alfa/biossíntese , Administração por Inalação , Adolescente , Adulto , Idoso , Antiasmáticos/administração & dosagem , Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Asma/imunologia , Beclometasona/administração & dosagem , Beclometasona/uso terapêutico , Budesonida/administração & dosagem , Budesonida/uso terapêutico , Estudos de Casos e Controles , Células Cultivadas , Feminino , Glucocorticoides/administração & dosagem , Humanos , Hipersensibilidade Imediata/metabolismo , Leucócitos Mononucleares/metabolismo , Masculino , Compostos de Metacolina/metabolismo , Pessoa de Meia-IdadeRESUMO
Intestinal T helper type 2 (Th2) immunity in food allergy results in IgG1 and IgE production, and antigen re-exposure elicits responses such as anaphylaxis and eosinophilic inflammation. Although interleukin-4 (IL-4) is critically required for allergic sensitization, the source and control of IL-4 during the initiation of Th2 immunity in vivo remains unclear. Non-intestinal and non-food allergy systems have suggested that natural killer-like T (NKT) or γδ T-cell innate lymphocytes can supply the IL-4 required to induce Th2 polarization. Group 2 innate lymphoid cells (ILCs) are a novel IL-4-competent population, but their contribution to initiating adaptive Th2 immunity is unclear. There are also reports of IL-4-independent Th2 responses. Here, we show that IL-4-dependent peanut allergic Th2 responses are completely intact in NKT-deficient, γδ T-deficient or ILC-deficient mice, including antigen-specific IgG1/IgE production, anaphylaxis, and cytokine production. Instead, IL-4 solely from CD4(+) Th cells induces full Th2 immunity. Further, CD4(+) Th cell production of IL-4 in vivo is dependent on OX40L, a costimulatory molecule on dendritic cells (DCs) required for intestinal allergic priming. However, both Th2 cells and ILCs orchestrated IL-13-dependent eosinophilic inflammation. Thus, intestinal Th2 priming is initiated by an autocrine/paracrine acting CD4(+) Th cell-intrinsic IL-4 program that is controlled by DC OX40L, and not by NKT, γδ T, or ILC cells.
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Alérgenos/imunologia , Arachis/química , Interleucina-4/imunologia , Intestinos/imunologia , Glicoproteínas de Membrana/imunologia , Hipersensibilidade a Amendoim/imunologia , Células Th2/imunologia , Fatores de Necrose Tumoral/imunologia , Alérgenos/química , Animais , Eosinófilos/imunologia , Eosinófilos/patologia , Imunidade Inata , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Interleucina-13/genética , Interleucina-13/imunologia , Interleucina-4/genética , Intestinos/patologia , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Knockout , Ligante OX40 , Hipersensibilidade a Amendoim/patologia , Receptores de Antígenos de Linfócitos T gama-delta/genética , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Células Th2/patologia , Fatores de Necrose Tumoral/genéticaRESUMO
BACKGROUND: Seasonal rhinitis is manifested by a series of nasal symptoms in response to exposure to seasonal allergens including ragweed pollen. Understanding its immunological mechanisms may help to better manage the disease. OBJECTIVE: We sought to determine comprehensively ragweed-induced cytokine and chemokine production by peripheral blood mononuclear cells from normal individuals and patients with seasonal rhinitis sensitized to ragweed pollen, and to assess its regulation by exogenous IL-10. METHODS: Cells were cultured in the presence or absence of a purified ragweed pollen extract with or without exogenous IL-10. Cytokines and chemokines were measured in the supernatant. Gene expression was evaluated using real-time quantitative reverse transcription PCR. RESULTS: Ragweed stimulation significantly increased the production of the Th2-associated cytokines IL-5, IL-9 and IL-13, the chemokines CCL17 and CCL22 and the regulatory cytokine IL-10 in allergic patients, whereas transforming growth factor-beta (TGF-beta) production was increased only in normal individuals. No difference was detected between groups in the production of the Th1 cytokine IFN-gamma or the Th1-affiliated chemokines CXCL10 and CXCL11. Exogenous IL-10 significantly suppressed spontaneous and induced production of both Th1- and Th2-associated cytokines and chemokines. CONCLUSION: Our work demonstrated that locally manifested allergic rhinitis is underlined by a systemic Th2 immune response specific to allergens. The molecular pathogenesis of allergic rhinitis may be linked to a compromised allergen-specific immune regulation, e.g., reduced spontaneous and allergen-induced TGF-beta production in patients compared with healthy controls. Our data also show that IL-10 inhibits both the effector and directional mechanisms of allergen-specific immune response, further supporting its potential therapeutic benefit in preventing and treating allergic diseases.
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Ambrosia/imunologia , Antígenos de Plantas/imunologia , Citocinas/imunologia , Pólen/imunologia , Rinite Alérgica Sazonal/imunologia , Células Th1/imunologia , Células Th2/imunologia , Adulto , Antígenos de Plantas/farmacologia , Citocinas/farmacologia , Feminino , Humanos , Imunidade Celular/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Rinite Alérgica Sazonal/prevenção & controleRESUMO
The aim of this study was to examine the relationships between allergen-induced early and late airway responses and antigen-specific IgE, IgG, and lymphocyte subsets in blood and bronchoalveolar lavage (BAL). Brown Norway rats were sensitized at 7 weeks of age with ovalbumin (1 mg s.c.) with use of Bordetella pertussis as an adjuvant. Three weeks after sensitization, animals were anesthetized and challenged with an aerosol of ovalbumin (5% wt/vol in saline) for 5 minutes. Each animal was studied for 8 hours with repeated measurements of lung resistance. Blood was obtained at 0, 1, 2, and 3 weeks before ovalbumin challenge. Ovalbumin-specific IgE and IgG were determined by ELISA. No specific antibody was detectable before sensitization. Ovalbumin-specific IgE and IgG rose between 1 to 2 weeks after sensitization and peaked at 3 weeks. The IgE level did not correlate with the magnitude of either the early or the late responses. In a similar manner no correlation existed between the magnitude of specific IgG and the late response. However, a significant inverse correlation (r = -0.73; p < 0.01) occurred between specific IgG and the early response. No correlation occurred between the ratio of helper (W3/25 +) to suppressor (OX-8 +) lymphocytes in blood and BAL and airway responses to allergen. The size of the early and late responses were correlated, suggesting a common stimulus. Despite the blunting of the early response by repeated sensitization the late response was unaffected, suggesting that the factors that determine the physiologic expression of the early and late responses are different.
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Asma/imunologia , Hipersensibilidade Tardia/imunologia , Imunoglobulina E/imunologia , Imunoglobulina G/imunologia , Animais , Líquido da Lavagem Broncoalveolar/citologia , Epitopos , Citometria de Fluxo , Hipersensibilidade Tardia/epidemiologia , Imunização , Subpopulações de Linfócitos/citologia , Prevalência , Ratos , Ratos Endogâmicos BNRESUMO
T lymphocytes are potentially of importance in determining the inflammatory response in the airways after allergen challenge. We hypothesized that the proliferative response of lymphocytes on exposure to allergen in vitro would be associated with the magnitude of the airway response in vivo after inhalational challenge. We studied Brown Norway rats that were actively sensitized with ovalbumin (OA) in aluminum hydroxide gel using Bordetella pertussis as an adjuvant. Two weeks later, blood mononuclear cells were isolated, and their proliferative response to culture with OA was measured with 3H-thymidine incorporation. Subsequently, the animals were anesthetized and challenged with aerosolized OA. Early allergic response (ER) and late (LR) allergic response were determined from the changes in pulmonary resistance (RL). Both significant ER and LR were observed in sensitized and challenged animals. The LR (measured as the area under the curve of RL against time) had a median value of 15.2 and ranged from 0.1 to 81.1 units. Lymphocyte proliferation occurred on exposure to OA (34,336 +/- 7,447 cpm) but less than after the mitogen Concanavalin A (250,685 +/- 76,676 cpm). The stimulation index (OA-stimulated 3H-thymidine incorporation standardized for baseline incorporation) was positively correlated with the magnitude of the late response. Interleukin-2 was significantly increased in the supernatant of cultured mononuclear cells exposed to OA, confirming T-cell activation. We conclude that the capacity of sensitized peripheral blood lymphocytes to respond to allergens may determine the magnitude of late airway responses.
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Broncoconstrição/fisiologia , Hipersensibilidade/fisiopatologia , Ativação Linfocitária , Linfócitos T/fisiologia , Resistência das Vias Respiratórias/fisiologia , Animais , Testes de Provocação Brônquica , Broncoconstrição/imunologia , Células Cultivadas , Ratos , Ratos Endogâmicos BN , Fatores de TempoRESUMO
Increased epithelial permeability is associated with intestinal inflammation, but there is little information on factors that regulate barrier function in the absence of or before inflammation. We examined if interleukin (IL)-4, or serum from atopic individuals, could alter the barrier function of human colonic epithelial (T84) monolayers to antigenic-sized macromolecules. IL-4 and atopic serum significantly decreased T84 monolayer resistance and increased transepithelial horseradish peroxidase (HRP) transport. Bidirectional transport studies demonstrated that IL-4 selectively enhanced apical-to-basal movement of HRP. HRP transport induced by IL-4 was inhibited by cold (4 degrees C) and the tyrosine kinase inhibitor genistein, but not the protein kinase C inhibitor staurosporine. Electron microscopic analysis demonstrated that both transcellular and paracellular pathways were affected. Anti-IL-4 antibodies abolished the increase in HRP transport in response to both IL-4 and serum. We speculate that enhanced production of IL-4 in allergic conditions may be a predisposing factor to inflammation by allowing uptake of luminal antigens that gain access to the mucosal immune system.
Assuntos
Interleucina-4/fisiologia , Mucosa Intestinal/metabolismo , Adulto , Anticorpos/farmacologia , Transporte Biológico , Linhagem Celular , Permeabilidade da Membrana Celular , Colo/metabolismo , Enterite/metabolismo , Inibidores Enzimáticos/farmacologia , Epitélio/metabolismo , Genisteína/farmacologia , Peroxidase do Rábano Silvestre/metabolismo , Humanos , Hipersensibilidade Imediata/sangue , Hipersensibilidade Imediata/metabolismo , Interleucina-4/antagonistas & inibidores , Interleucina-4/farmacologia , Microscopia Eletrônica , Pessoa de Meia-Idade , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Estaurosporina/farmacologiaRESUMO
To evaluate the hypothesis that lymphocyte stimulation can modify the bronchoconstrictive response to inhalational challenge with an allergen, we administered interleukin-2 (IL-2), an important lymphokine in lymphocyte activation and proliferation, to actively sensitized rats. Brown Norway rats received either human recombinant IL-2 (n = 8) or its vehicle (n = 7) twice a day from the ninth to the fourteenth day after active sensitization to ovalbumin (OA) and were challenged with an aerosol of OA. Lung resistance (RL) during the early response increased to a maximum of 698 +/- 230% and 180 +/- 26% of baseline values in the animals receiving IL-2 and vehicle, respectively (p less than 0.025). The late response was threefold greater in IL-2-treated than in vehicle-treated animals (p = 0.01). IL-2 increased OA-specific IgG levels in the serum, but it did not significantly affect total or specific IgE levels. IL-2 caused an inflammatory infiltrate around the airways with significant increases in eosinophils, lymphocytes, and mast cells prior to antigen challenge. Our results indicate that stimulation of cell-mediated immunity can affect airway responsiveness to antigen.
Assuntos
Antígenos/administração & dosagem , Broncoconstrição/fisiologia , Interleucina-2/fisiologia , Animais , Brônquios/patologia , Testes de Provocação Brônquica , Líquido da Lavagem Broncoalveolar/imunologia , Imunização , Imunoglobulina E/análise , Imunoglobulina G/análise , Interleucina-2/farmacologia , Contagem de Leucócitos , Pulmão/patologia , Linfócitos , Masculino , Mastócitos/patologia , Cloreto de Metacolina , Ovalbumina/imunologia , Ratos , Ratos Endogâmicos BNRESUMO
BACKGROUND: Although there are several reports of the prevalence of latex sensitization among health care workers, the incidence of sensitization is unknown. OBJECTIVE: The objective of this study was to estimate the incidence of sensitization among latex glove users at a hospital in Hamilton, Ontario, Canada. METHODS: Workers with negative results to the skin test at baseline were followed prospectively over 1 year, some wearing powdered gloves and others using powder-free gloves. They were reevaluated in 1995 with a questionnaire and skin prick test (SPT) sensitivity to latex reagents, three common inhalants, and six foods. A conversion was defined as a (new) latex SPT with wheal diameter at least 4 mm greater than saline control. Glove extracts were assayed for antigenic protein, and air samples were obtained to estimate exposure to airborne latex protein. RESULTS: During powdered glove use, personal exposures ranged from 5 to 616 ng/m3, whereas during powder-free glove use, all but two results for air samples were below the limit of detection (about 0.1 ng/m3). During the study period, the protein concentration in the powdered gloves, initially mean 557 microg/gm of sample, declined at a rate of 295 microg/gm per year (p < 0.0001). Of the 1075 SPT-negative participants at baseline, 479 were working in eligible wards, and of these, 435 (91%) participated in follow-up, 227 using powder-free gloves and 208 using powdered gloves. We identified four conversions, two (1.0%) in the powdered glove group and two (0.9%) in the powder-free group. The two participants using powdered gloves were the only converters who were symptomatic. The significance of skin test conversions identified in the powder-free group, both asymptomatic patients, is unclear. The limitations of the study are discussed, including the limited power, the declines in latex protein concentrations, and the possibility of information (observer) bias. CONCLUSION: To our knowledge, this represents the first reported estimate (about 1%) of incidence of sensitization in hospital personnel using latex gloves.