Inhalation challenge with ragweed pollen in ragweed-sensitive asthmatics

We reexamined the ability of inhaled ragweed pollen to induce bronchoconstriction in ragweed-sensitive asthmatic patients using a turbo-inhaler to administer pollen quantitatively. Adult subjects were selected for study on the basis of fall season asthmatic attacks, positive skin test, histamine release, RAST, and bronchial challenge responses to ragweed extract. Not one of 12 such subjects had any bronchial response to oral inhalation of whole pollen grains even when the dose was increased to 7640 pollen grains (more than the estimated maximum daily exposure in season), whereas nasal challenge by the same method produced brisk hay fever responses without bronchospasm. On the other hand, when the pollen was ground to fragments with a size range of 1 to 8 micrometers, oral inhalation produced a 35% fall in airways conductance in six of seven subjects in doses ranging from 59 to 20,000 pollen grain equivalents. Atropine pretreatment did not modify the response to pollen fragments, making an irritant response unlikely. These data, coupled with earlier observations that no more than a few pollen grains penetrate further than the larynx, raise further questions about the role of whole ragweed pollen in fall asthma in allergic patients. In addition, ragweed-allergic asthmatics appear not to have their symptoms at the time of maximum pollen load in the air. We believe that small-particle allergens other than ragweed pollen should be considered in most cases of fall seasonal asthma.     

Effect of vitamin E supplementation on the regular treatment of seasonal allergic rhinitis.

BACKGROUND: Vitamin E supplementation is widely used in clinical practice for the prevention and treatment of different medical conditions. Evidence from basic science studies suggests that vitamin E may reduce immune allergic responses. However, only a few clinical studies of the effect of vitamin E on allergic conditions have been performed in patients with atopic dermatitis and asthma, and none have been performed in patients with allergic rhinitis. OBJECTIVE: To determine the effect of high-dose vitamin E supplementation in combination with the usual ("real-life") treatment on the symptoms of seasonal allergic rhinitis during the pollen season. METHODS: In a double-blind, placebo-controlled, randomized study, 112 patients with documented hay fever received either vitamin E (800 mg/d) or placebo in addition to their regular antiallergic treatment during the pollen season. Patients recorded their daily nasal and eye symptoms and their daily need for other medications to control allergic symptoms. RESULTS: Although no effect was observed on ocular symptoms, nasal symptom scores were lower in patients who received vitamin E supplementation during the hay fever season. However, there was no reduction in the percentage of days with serious symptoms or in the percentage of days that medications were used to control allergic symptoms during the pollen season. CONCLUSIONS: Vitamin E supplementation may be a valuable addition to the treatment of patients with seasonal allergic rhinitis. However, further clinical and basic science studies are needed to determine its real value.     

Natural history of hay fever and pollen sensitization,and doctors' diagnosis of hay fever and pollen asthma in German schoolchildren

BACKGROUND: In order to prevent pollen asthma by immunotherapy it is mandatory to know the best time to initiate it. Children with hay fever complaints are at considerable risk of developing pollen asthma. Population-based data on their natural history is urgently needed. METHODS: A longitudinal cohort study was conducted over four years in six rural towns in Baden-Württemberg, Germany. A questionnaire with questions taken from the International Study of Asthma and Allergies in childhood (ISAAC) was filled in every spring and autumn. Hay fever complaints, asthma defining symptoms and new doctors' diagnosis of hay fever and asthma were recorded. Additionally a skin prick test with pollen allergens was performed every autumn. RESULTS: In 1996, 19.7% of 1101 elementary school children (age: 8.1-9.9 years (5-95%)) were found to be sensitized to pollen and 8.7% had already been diagnosed as having hay fever. In a pooled analysis of 2478 children-summers, children with positive pollen sensitization had a significantly higher risk of developing hay fever symptoms (2.63; 2.17-3.10 odds ratio (OR); 95% confidence interval (CI)) and of being diagnosed as suffering from hay fever (7.88; 4.70-13.20). Furthermore, although their OR for the development of asthma symptoms during the pollen season was 3.88 (2.48-6.07 CI), it was only 0.69 (0.24-2.01 CI) for doctors' diagnosis of pollen asthma. CONCLUSION: Children of elementary school age with pollen sensitization and a history of hay fever are at considerable risk of getting pollen asthma, but they are not quickly diagnosed as such. Specific immunotherapy might be a means of preventing asthma completely in such a situation. Our data helps to estimate the sample size for intervention studies of this kind.     

Month of birth and allergic disease at the age of 10.

The relationship between month of birth and asthma, hay fever and skin sensitization to mixed grass pollen was analysed in a population-based cross-sectional study in Munich and Bavaria 1989-1990 of 6535 10-year-old children. The relative risk of developing atopic disease is calculated by comparing the prevalence in a single month with the prevalence of all other months. A slightly increased risk of developing allergic skin sensitization for grass pollen (n = 1128) was found for February (odds ratio, 1.3, 95% confidence interval 1.0-1.6), May (1.4, 1.1-1.8) and June (1.3, 1.0-1.6). For hay fever (n = 379) an increase was found for May (1.5, 1.0-2.1) and for allergic asthma (n = 277) for August (1.4, 1.0-2.1). A protective effect was observed for certain months of birth; September for allergic sensitization (0.8, 0.6-1.0), October for and November for hay fever (0.6, 0.3-0.9). The occurrence of hay fever and positive prick test is explained by the seasonal variation of atmospheric grass pollen and the peak in August of asthmatic patients by house dust. Date of birth appears therefore to slightly influence the risk of developing an allergic sensitization and allergic diseases.     

Exercise-Induced Bronchoconstriction

Standardized exercise challenge tests, symptom scores and whole-blood eosinophil and basophil counts were made before and during the pollen season in 32 children suffering from hay fever (n = 16) or hay fever and asthma (n = 16). All participants developed rhinitis symptoms during the season. The hay fever group showed in addition a significant seasonal increase in cough score (but in no other asthma symptom) and in circulating eosinophils (P less than 0.01); mean exercise-induced bronchoconstriction (EIB) did not change despite a slight increase in a few subjects. The asthma group showed seasonal increases in EIB (P less than 0.001), asthma symptom score (P less than 0.002), and total eosinophil count (P less than 0.001). The increase in the latter was significantly higher (P less than 0.05) than that in the hay fever group. The relative basophil count remained unchanged in both groups. In conclusion, the hay fever group and the asthma group could be clearly distinguished with respect to EIB during natural pollen exposure. The significantly higher increases in EIB and circulating eosinophils observed in the asthma group might possibly be due to greater pollen antigen sensitivity in the asthmatics.     

The importance of the pecan tree pollen in allergic manifestations

Background Pecan tree pollen is considered to be highly allergenic. However, no specific scienlific data about its role in causing allergic diseases are avaliable. Ohjective To study the role of pecan tree pollen in the development of allergy. Methods The presence of pecan tree pollen was determined by weekly and monthly counting of airborne grains. The incidence of pecan tree pollen atopy and clinical manifeslations were studied in 395 participants, aged 4–70 years, who comprised 78.2% of the whole eligible population of a rural community. The participants were skin tested for different extracts of allergens, completed detailed questionnaires, and their medical files were evaluated. Results During May. pecan tree pollen grains comprised 70% of the total airborne gruins. A positive skin-prick test (SPT) to pecan was shown by 46(11.6%) participants, constituting 25.4% of the atopic population. Of those who were found atopic to one or more allergens 50.3% had symptoms, whereas the parallel figure for those atopic to pecan pollen was 76.1% (P< 0.0()5); 58.7% of the pecan atopic participants had hay fever, 43.5% had asthma, and 31.5% had both hay fever and asthma. Among peean atopic participants the incidence of hay fever increased with age (P- 0.05) while the incidence of bronchial asthma, as a sole manifestation of allergy, decreased in the > 17-year-old age group (P<0.0I). Of the pecan atopies 65.2% had clinical symptoms coinciding only wilh the pecan pollen season and an additional 10.9% had perennial symptoms. Conclusion Pecan tree releases highly allergenie pollen grains, which are correlated to the incidence of hay fever in the exposed population. The contribution of pecan tree pollen to the symptoms was highly significant after discounting olive and cypress trees thai also pollinate in the spring. In children, the pecan tree constitutes a possible etiologic agent for the development of asthma.     

Quantitative inhalation bronchial challenge in ragweed hay fevery patients: a comparison with ragweed-allergic asthmatics.

Fourteen ragweed hay fever nonasthmatic patients comparably sensitive to a group of ragweed-allergic asthmatics by skin test and leukocyte histamine release were tested by quantitative inhalation bronchial challenge with ragweed extract. The provocation dose of ragweed extract producing 35% decrease in airway conductance was determined and designated PD35. PD35 values in the hay fever patients were not significantly different from PD35 values in the asthmatic group. These data suggest that carefully performed skin tests may be as diagnostically useful as bronchial challenge in routinely confirming the allergic etiology of seasonal asthma.     

Grass pollen immunotherapy for seasonal rhinitis and asthma: a randomized, controlled trial

BACKGROUND: Grass pollen immunotherapy significantly reduces hay fever symptoms and medication requirements. Effects on seasonal asthma are less clear, and concerns over safety persist. OBJECTIVE: The goal of this study was to assess the effects of grass pollen immunotherapy on symptoms, bronchial hyperresponsiveness, and quality of life in seasonal rhinitis and asthma. METHODS: Forty-four patients with severe summer hay fever (of whom 36 reported seasonal chest symptoms and 28 had seasonal bronchial hyperresponsiveness) participated in a randomized, double-blind, placebo-controlled, parallel group study. After symptom monitoring for one summer, participants received injections of a depot grass pollen vaccine (n = 22) or matched placebo injections (n = 22) in a rapid updosing cluster regimen for 4 weeks, followed by monthly injections for 2 years. Outcome measures included hay fever symptoms and medication use, health-related quality of life, and measurements of nonspecific bronchial responsiveness. RESULTS: Significant reductions were observed in the immunotherapy group compared with the placebo group in hay fever symptoms (49%, 15%; P =.01), medication scores (80%, 18%; P =.007), and seasonal chest symptoms (90%, 11%; P <.05). Impairment of overall quality of life (mean score of 7 domains) during the pollen season was less in the immunotherapy group than in the placebo group (median difference [95% CI], 0.8 [0.18-1.5]; P =.02). During the pollen season there was no change in airway methacholine PC(20) (provocation concentration producing a 20% fall in FEV(1)) in the immunotherapy-treated group (P =.5), compared with an almost 3 doubling-dose decrease in the placebo-treated group (P =.01, between-group difference). There were no significant local or systemic side effects during the study. CONCLUSION: Grass pollen immunotherapy improves quality of life in seasonal allergic rhinitis and reduces seasonal asthma symptoms and bronchial hyperresponsiveness.     

Sublingual-swallow immunotherapy with standardized 3-grass pollen extract: a double-blind, placebo-controlled study.

BACKGROUND: Sublingual immunotherapy (SLIT) is accepted as a safe and effective route for the treatment of grass pollen allergy, but clarification of its clinical and biological efficacy requires more study. OBJECTIVE: To evaluate the efficacy, safety, and compliance of SLIT with a standardized 3-grass pollen extract in patients with grass pollen seasonal allergic rhinoconjunctivitis, with or without mild asthma. METHODS: This multicenter, randomized, double-blind study included 127 patients (aged 12-41 years; mean age, 24.9 years) with grass pollen seasonal allergic rhinoconjunctivitis, with or without mild asthma. They received either SLIT with a high-dose, standardized, 3-grass pollen extract or placebo for 10 months before and during the grass pollen season. The efficacy evaluation compared weekly clinical scores (defined as the sum of the symptom score and rescue medication score) to measure rhinoconjunctivitis and asthma for the first 8 weeks of the pollen season. We also evaluated safety and compliance and measured changes in anti-Dactylis specific IgG4 antibody levels. RESULTS: There was a trend in favor of the study group in the mean adjusted clinical score. The groups were not comparable on inclusion (P = .02): the SLIT group included more subjects with asthma and had a higher mean IgG4 serum level. Additional exploration according to subgroups with and without asthma found that among the patients without asthma, the SLIT group had a significantly better clinical score (P = .045). Anti-Dactylis specific IgG4 levels increased significantly in the SLIT group. CONCLUSION: SLIT with a standardized, high-dose, 3-grass pollen extract is safe and significantly improves the clinical score in patients with hay fever and without asthma during the pollen season.     

Allergic sensitization to cat in childhood as major predictor of incident respiratory allergy in young adults

BACKGROUND: Little is known on the predictive value of sensitization to specific aeroallergens in children with respect to asthma and hay fever incidence in young adulthood. We followed the incidence of asthma and hay fever in children (mean age 11 years) over 9 years, and analyzed the predictive value of sensitization to five common aeroallergens. METHODS: Three consecutive surveys were conducted in East German school children. Specific IgE antibodies to birch and timothy grass pollen, house dust mite, cat, and cladosporium were measured. In 1207 out of the 2453 children, the 9-year incidence of asthma and hay fever was assessed by reported doctors' diagnoses. For sensitization, diagnostic parameters were determined and logistic regression analyses controlled for relevant confounders. RESULTS: A total of 176/78 incident hay fever/asthma cases occurred equaling a cumulative incidence of 1.93/0.86% per year. Incident asthma was associated with previous sensitization to cat [risk ratio (RR) 3.49, 1.57-7.74] and grass pollen (RR 1.79, 1.01-3.19), whereas incident hay fever was associated with each allergen, with grass pollen (RR 6.00, 4.04-8.90) and cat (RR 5.36, 2.87-9.99) exhibiting the strongest associations. When mutually adjusting for all allergens, sensitization to cat remained significantly associated with asthma and hay fever. The latter was also associated with sensitization to grass pollen. The highest positive predictive values for asthma and hay fever were obtained for cat sensitization (10/49 = 20.4% and 23/49 = 46.9%). CONCLUSIONS: Childhood sensitization to cat and grass pollen predicts the incidence of asthma and hay fever in young adulthood. The predictive capacity differs by allergen and manifestation of atopy.     

Capsaicin cough sensitivity in allergic asthmatic patients increases during the birch pollen season.

BACKGROUND: A change in neural responsiveness may occur as the result of allergic inflammation in the lower airways as well as in the upper airways. In the lower airways, capsaicin cough sensitivity is known to reflect sensory neural reactivity. OBJECTIVE: The aim of this study was to establish whether allergic inflammation changes airway neural sensory reactivity during prolonged allergen exposure. METHODS: Ten nonsmoking patients with birch pollen-allergic asthma performed a capsaicin inhalation challenge twice, once in the off-pollen season and once during the pollen season. The number of coughs and symptoms induced by capsaicin were recorded and compared with those of healthy control subjects. RESULTS: The response to capsaicin, expressed as number of coughs, increased in a dose-dependent manner during both tests. Before the season, the response was similar to that of healthy control subjects, but during the pollen season, the reactivity was significantly increased. Variations in forced expiratory volume in 1 second were not significant before and after each challenge, and values did not change during the pollen season as compared with the winter season. CONCLUSIONS: Sensory reactivity in allergic asthmatic patients may be increased during prolonged allergen exposure as during the pollen season. This finding suggests that allergic inflammation in the lower and/or upper airways may trigger neurogenic mechanisms of significant clinical importance.     

Comparison of responses to pollen extract in subjects with allergic asthma and nonasthmatic subjects with allergic rhinitis

We compared pulmonary responses with inhaled pollen-antigen extract in eight subjects with allergic asthma and eight nonasthmatic subjects with allergic rhinitis. Lower respiratory tract sensitivity to antigen was determined from dose-response curves using SGaw and FEV₁ measurements to quantitate responses. We found no difference in antigen sensitivity in terms of SGaw between the two groups (p > 0.05). Hay fever subjects required almost eight times more antigen to produce a 20% fall in FEV₁, although there was considerable overlap between the two groups. After antigen challenge there were significant increases in lung volumes in asthmatic subjects (RV, +78.6%; FRC, +33.6%; TLC, +12.6%) which were not significantly different from rhinitis subjects (RV, +98.3%; FRC, +39.1%; TLC, +10.3%). Six rhinitis and five asthmatic subjects were rechallenged after pretreatment with atropine (2.5 mg aerosol). Atropine caused an initial increase in SGaw and FEV₁ but failed to alter sensitivity or volume responses in both groups. The effects of a maximum inspiration on physiologic responses to antigen were different in the two groups. Deep inspiration transiently improved SGaw and FRC toward prechallenge values in rhinitis subjects but the same maneuver had little effect in asthma subjects. Although only asthma subjects experience lower respiratory tract symptoms during periods of environmental pollen exposure, these two groups of subjects were indistinguishable on the basis of their immediate responses to inhaled antigen. This suggests that asthmatic symptoms during the pollen season are unrelated to the immediate effects of allergic reactions to pollen. This also suggests that these bronchial challenge responses represent a localized anaphylactic reaction, whereas naturally occurring asthma during the pollen season may represent a syndrome of increased airways reactivity which is perhaps related to antigen exposure.     

Coseasonal sublingual immunotherapy reduces the development of asthma in children with allergic rhinoconjunctivitis

BACKGROUND: We wondered whether short-term coseasonal sublingual immunotherapy (SLIT) can reduce the development of asthma in children with hay fever in an open randomized study. OBJECTIVE: We sought to determine whether SLIT is as effective as subcutaneous immunotherapy in reducing hay fever symptoms and the development of asthma in children with hay fever. METHODS: One hundred thirteen children aged 5 to 14 years (mean age, 7.7 years) with hay fever limited to grass pollen and no other clinically important allergies were randomized in an open study involving 6 Italian pediatric allergy centers to receive specific SLIT for 3 years or standard symptomatic therapy. All of the subjects had hay fever symptoms, but at the time of study entry, none reported seasonal asthma with more than 3 episodes per season. Symptomatic treatment was limited to cetirizine, loratadine, nasal budesonide, and salbutamol on demand. The hay fever and asthma symptoms were quantified clinically. RESULTS: The actively treated children used less medication in the second and third years of therapy, and their symptom scores tended to be lower. From the second year of immunotherapy, subjective evaluation of overall allergy symptoms was favorable in the actively treated children. Development of asthma after 3 years was 3.8 times more frequent (95% confidence limits, 1.5-10.0) in the control subjects. CONCLUSIONS: Three years of coseasonal SLIT improves seasonal allergic rhinitis symptoms and reduces the development of seasonal asthma in children with hay fever.     

Seasonal allergic symptoms and their relation to pollen exposure in south-east France

In order to evaluate the relationship between pollen exposure and prevalence of allergic respiratory symptoms, we performed a cross-sectional epidemiological study in 2 areas with contrasted exposure to cypress and grass pollens. The study population consisted of 5427 subjects 18 to 65-years-old representative of the general population. All answered an abridged version of the 1978 ATS questionnaire and a sample had a skin test evaluation including grass and cypress pollens. Prevalence of hay fever symptoms was equal to 31.5% and 14.1%, respectively, in exposed and less exposed community (P < 0.001). Prevalence of hay fever symptoms together with a positive skin test to pollen was also significantly higher in the exposed (13.6%) vs less exposed community (5.5%, P<0.001). In contrast, overall prevalence of asthma was equal to 4.5% and 3.4%, respectively. Prevalence of asthma with positive skin tests was also not statistically significant, equal to 2.5% and 1.9%, respectively. Thus, high exposure to pollen is a risk factor for developing hay fever but not asthma.     

Concentrations of major grass group 5 allergens in pollen grains and atmospheric particles: implications for hay fever and allergic asthma sufferers sensitized to grass pollen allergens

BACKGROUND: Grass pollen allergens are the most important cause of hay fever and allergic asthma during summer in cool temperate climates. Pollen counts provide a guide to hay fever sufferers. However, grass pollen, because of its size, has a low probability of entering the lower airways to trigger asthma. Yet, grass pollen allergens are known to be associated with atmospheric respirable particles. OBJECTIVE: We aimed (1) to determine the concentration of group 5 major allergens in (a) pollen grains of clinically important grass species and (b) atmospheric particles (respirable and nonrespirable) and (2) to compare the atmospheric allergen load with clinical data to assess different risk factors for asthma and hay fever. METHODS: We have performed a continuous 24 h sampling of atmospheric particles greater and lower than 7.2 microm in diameter during the grass pollen season of 1996 and 1997 (17 October 1996-16 January 1997) by means of a high volume cascade impactor at a height of about 15 m above ground in Melbourne. Using Western analysis, we assessed the reactivity of major timothy grass allergen Phl p 5 specific monoclonal antibody (MoAb) against selected pollen extracts. A MoAb-based ELISA was then employed to quantify Phl p 5 and cross-reactive allergens in pollen extracts and atmospheric particles larger and smaller than 7.2 microm. RESULTS: Phl p 5-specific MoAb detected group 5 allergens in tested grass pollen extracts, indicating that the ELISA employed here determines total group 5 allergen concentrations. On average, 0.05 ng of group 5 allergens were detectable per grass pollen grain. Atmospheric group 5 allergen concentrations in particles > 7.2 microm were significantly correlated with grass pollen counts (rs = 0.842, P < 0. 001). On dry days, 37% of the total group 5 allergen load, whereas upon rainfall, 57% of the total load was detected in respirable particles. After rainfall, the number of starch granule equivalents increased up to 10-fold; starch granule equivalent is defined as a hypothetical potential number of airborne starch granules based on known pollen count data. This indicates that rainfall tended to wash out large particles and contributed to an increase in respirable particles containing group 5 allergens by bursting of pollen grains. Four day running means of group 5 allergens in respirable particles and of asthma attendances (delayed by 2 days) were shown to be significantly correlated (P < 0.001). CONCLUSION: Here we present, for the first time, an estimation of the total group 5 allergen content in respirable and nonrespirable particles in the atmosphere of Melbourne. These results highlight the different environmental risk factors for hay fever and allergic asthma in patients, as on days of rainfall following high grass pollen count, the risk for asthma sufferers is far greater than on days of high pollen count with no associated rainfall. Moreover, rainfall may also contribute to the release of allergens from fungal spores and, along with the release of free allergen molecules from pollen grains, may be able to interact with other particles such as pollutants (i.e. diesel exhaust carbon particles) to trigger allergic asthma.     

Atopy in childhood. I. Gender and allergen related risks for development of hay fever and asthma

Reasons for the gender differences in prevalence rates for asthma remain unclear. We have examined the relationships between allergen skin-test reactions and diagnoses of hay fever and asthma in New Zealand boys and girls examined at the age of 13 years. Information on current and past wheezing, diagnosed asthma, and hay fever was obtained for 662 subjects (341 boys) of a birth cohort followed longitudinally to the age of 13 years, using a physician-administered questionnaire. Atopic status was determined by skin-prick tests to 11 common allergens. The proportion of 13-year-old boys with current asthma was 1.6 times higher and of ever-diagnosed asthma 1.4 times higher than in girls, but the prevalence of recurrent wheeze (> or = three episodes per year) not diagnosed as asthma, or of hay fever, was not significantly different between the sexes. The prevalence of diagnosed asthma increased with increasing numbers of positive skin tests, but hay fever without asthma was little affected above one positive skin-test. Boys had a greater prevalence of any positive skin-test (50.1% vs 37.1%), two or more positive tests (29.3% vs 21.8%), and responses to house dust mite (34.0% vs 23.1%) and cat (14.7% vs 11.2%). Gender differences for asthma became insignificant when adjusted for skin-test responsiveness to house dust mite and/or cat. The proportion of children with diagnosed asthma increased with increasing size of weals to house dust mite and cat dander. Gender differences in allergen sensitivities partly explain the gender differences in diagnosed asthma in children. In both sexes, risk of asthma was primarily associated with sensitization to indoor allergens (house dust mite and cat), and was related to the magnitude of the skin-test response, while the risk of hay fever was primarily associated with grass pollen sensitivity.     

Pollen immunotherapy reduces the development of asthma in children with seasonal rhinoconjunctivitis (the PAT-study)

BACKGROUND: Children with allergic rhinitis are likely to develop asthma. OBJECTIVE: The purpose of this investigation was to determine whether specific immunotherapy can prevent the development of asthma and reduce bronchial hyperresponsiveness in children with seasonal allergic rhinoconjunctivitis. METHODS: From 6 pediatric allergy centers, 205 children aged 6 to 14 years (mean age, 10.7 years) with grass and/or birch pollen allergy but without any other clinically important allergy were randomized either to receive specific immunotherapy for 3 years or to an open control group. All subjects had moderate to severe hay fever symptoms, but at inclusion none reported asthma with need of daily treatment. Symptomatic treatment was limited to loratadine, levocabastine, sodium cromoglycate, and nasal budesonide. Asthma was evaluated clinically and by peak flow. Methacholine bronchial provocation tests were carried out during the season(s) and during the winter. RESULTS: Before the start of immunotherapy, 20% of the children had mild asthma symptoms during the pollen season(s). Among those without asthma, the actively treated children had significantly fewer asthma symptoms after 3 years as evaluated by clinical diagnosis (odds ratio, 2.52; P <.05). Methacholine bronchial provocation test results improved significant in the active group (P <.05). CONCLUSION: Immunotherapy can reduce the development of asthma in children with seasonal rhinoconjunctivitis.     

花粉症患者发作期外周血Ⅱ型固有淋巴样细胞(ILC2)亚群的水平变化及其临床意义

目的初步探讨花粉症患者在花粉季节发作期外周血Ⅱ型固有淋巴样细胞(ILC2)亚群表达水平、功能变化及其胞内STAT6信号通路水平变化。方法纳入10例花粉症患者、10例尘螨致敏哮喘患者以及12例健康儿童,分别在花粉季节发作期和非发作期采用流式细胞术监测其外周血ILC2细胞及其胞内Th2型因子水平变化。分选各组外周血Lin-细胞亚群,体外给予前炎症因子(IL-25和IL-33)刺激培养7 d,酶联免疫吸附法检测细胞培养上清中IL-5和IL-13的水平,Western blot法检测各组细胞总蛋白质中信号传导及转录激活因子6(STAT6)的磷酸化水平。结果在花粉季节发作期内,花粉症患者外周血ILC2细胞表达水平[(23.09±7.86)%]显著高于尘螨过敏哮喘组[(6.84±3.85)%]以及健康对照组[(1.69±0.87)%],差异均有统计学意义(P<0.05)。在非发作期,花粉症患者外周血ILC2细胞水平呈现下降趋势[(11.30±2.45)%],但依旧高于同期的尘螨致敏哮喘组[(3.76±1.96)%]以及健康对照组[(1.32±0.91)%],差异有统计学意义(P<0.05)。此外,在花粉季节发作期内,花粉症患者外周血IL-13+ILC2[(6.94±3.16)%vs(4.17±1.98)%,P<0.05]、尘螨致敏哮喘患者外周血IL-13+ILC2[(1.89±0.70)%vs(1.44±0.55)%,P<0.05]均显著高于非发作期。体外给予IL-25或IL-33刺激,均可以上调花粉症组和尘螨致敏哮喘组培养上清中IL-5和IL-13的水平,且当联合应用IL-25和IL-33可以协同放大此种刺激效应。Western blot证实应用IL-25和IL-33协同刺激可以显著上调花粉症患者组Lin-细胞胞内STAT6磷酸化水平。结论花粉季节发作期内,花粉症患者体内ILC2细胞数目及功能异常可能是导致花粉症患者在短时间内临床症状出现或急性加重的另一诱因。     

Ragweed-specific IgA in nasal lavage fluid of ragweed-sensitive allergic rhinitis patients: increase during the pollen season

Because the secretions of asthma and rhinitis contain toxic eosinophil granule proteins and because secretory IgA is the most potent immunoglobulin stimulus for eosinophil degranulation, we measured eosinophil-derived neurotoxin and ragweed-specific IgA and IgE antibodies in nasal lavage before and during the ragweed pollen season in 44 hay fever patients. We found IgA antibody in nanogram/milliliter concentrations before the season and rising 20-fold by the end of the season. IgE antibody was present in picogram/milliliter concentrations and did not change. Eosinophils and eosinophil-derived neurotoxin also increased. We conclude that IgA is the predominant antibody in allergic nasal secretions and increases with allergen exposure. The hypothesis that secretory IgA antibody-allergen complexes contributes to allergic inflammation by stimulating eosinophil degranulation warrants further study.     

Clinical atopy and associated factors in primary-school pupils

To investigate potential risk factors for clinical atopy in childhood, we obtained cross-sectional data from a cohort of 1376 8-year-old pupils. Parental atopy (hay fever, asthma, eczema), gestational age, maternal smoking habits, and the child's history of asthma, hay fever, and eczema were ascertained by questionnaire. Combining the history and the result of a skin prick test using seven aeroallergens, we defined the child's atopic diseases. Of the population evaluated, 25.4% were categorized as atopic (10.2% allergic asthma, 17.3% eczema, 6.9% hay fever). As compared with the clear nonatopics (40.2%), parental atopic diseases were more prevalent in each of the atopic groups. Significant associations of the parents' and child's disease were obvious for eczema and hay fever. Low gestational age (LGA) was more frequent in children with any atopy or with an allergic asthma (odds ratio (OR) 1.7; 95% confidence interval (CI) 1.02-2.97; OR 2.8; 95% CI 1.5-5.4). Hay fever and allergic asthma occurred less frequently in girls (OR 0.5; 95% confidence interval 0.3-0.8; OR 0.6; 95% CI 0.4-0.9). In conclusion, our data underline the importance of parental atopy for the clinical outcome in the offspring. In addition, LGA appears to be a risk factor for allergic asthma and for general atopy in later life.