Seasonal Allergens Research Articles

Omalizumab Is Equally Effective in Persistent Allergic Oral Corticosteroid-Dependent Asthma Caused by Either Seasonal or Perennial Allergens: A Pilot Study.

Omalizumab is marketed for chronic severe asthma patients who are allergic to perennial allergens. Our purpose was to investigate whether omalizumab is also effective in persistent severe asthma due to seasonal allergens. Thirty patients with oral corticosteroid-dependent asthma were treated with Omalizumab according to the dosing table. For each patient with asthma due to seasonal allergens, we recruited the next two consecutive patients with asthma due to perennial allergens. The dose of oral methyl prednisolone (MP) was tapered at a rate of 2 mg every two weeks after the start of treatment with omalizumab depending on tolerance. At each monthly visit, a forced spirometry and fractional exhaled nitric oxide (FeNO) measurement were performed and the accumulated monthly MP dose was calculated. At entry, there were no differences between groups in terms of gender, body mass index or obesity, year exacerbation rate, monthly dose of MP, FeNO and blood immunoglobuline E (IgE) values, or spirometry (perennial: FVC: 76%; FEV1: 62%; seasonal: FVC: 79%; FEV1: 70%). The follow-up lasted 76 weeks. One patient in each group was considered a non-responder. Spirometry did not worsen in either group. There was a significant intragroup reduction in annual exacerbation rate and MP consumption but no differences were detected in the intergroup comparison. Omalizumab offered the same clinical benefits in the two cohorts regardless of whether the asthma was caused by a seasonal or a perennial allergen. These results strongly suggest that allergens are the trigger in chronic asthma but that it is the persistent exposure to IgE that causes the chronicity.

A comparison of the difference in symptom scores between seasonal and perennial allergens using the Nasal Allergen Challenge method

A comparison of the difference in symptom scores between seasonal and perennial allergens using the Nasal Allergen Challenge method

Th17 responses are not altered by natural exposure to seasonal allergens in pollen-sensitive patients.

BackgroundAllergic rhinitis affects 10–30 % of the global population and this number is likely to increase in the forthcoming years. Moreover, it commonly co-exists with allergic asthma as a chronic allergic respiratory syndrome. While the involvement of Th2 cells in allergy is well understood, alterations of pro-inflammatory Th17 responses remain poorly characterized. The aim of our study was to determine whether natural seasonal allergen exposure causes changes in T cell subset characteristics in patients with allergic rhinitis and asthma.MethodsSixteen patients with allergic rhinitis/atopic asthma (9M, 7F; age 31.8 ± 12.1) and 16 healthy controls were recruited into the study (9M, 7F; age 31.2 ± 5.3). Blood samples were collected from the patients 1–3 months before pollen season (visit 1), within 7 days of the appearance of pollen/initiation of allergic symptoms (visit 2) and 2 weeks after visit 2 following the introduction of symptomatic treatment with antihistamines (visit 3). Flow cytometry was used to assess major T cell subsets (naïve, central memory, effector memory and CD45RA+ effector) and key T cell cytokine production (IFNγ, IL-17A, TNF and IL-4) using intracellular staining. Data were analyzed using repeated measures ANOVA and paired t test.ResultsAs expected, an increase in the percentage of IL‐4+ CD4+ cells was observed during natural pollen exposure in patients with allergic respiratory syndrome. No significant changes were observed in the production of other cytokines, including Th17 cells, which tended to be lower than in the control population but unchanged during pollen exposure. Introduction of antihistamine treatment led to only moderate changes in cytokine production from CD4 and CD8 T cells. Selective changes in CD8+ T cells were observed during natural pollen exposure including a decrease in transient cells (with features of CD45RA+ and CD45RO+ cells) and a decrease in the percentage of central memory cells in the peripheral circulation. Within the CD4 cell group the total percentage of CD45RA positive CD4 cells was increased during pollen exposure.ConclusionsTh1 and Th17 responses are not altered during pollen season but allergen exposure affects T cell activation and memory cell status in patients with allergic respiratory syndrome.Electronic supplementary materialThe online version of this article (doi:10.1186/s13223-016-0157-6) contains supplementary material, which is available to authorized users.

Allergen-specific immunotherapy in pediatric allergic asthma.

Allergen-specific immunotherapy (AIT) is the only curative way that can change the immunologic response to allergens and thus can modify the natural progression of allergic diseases. There are some important criteria which contributes significantly on efficacy of AIT, such as the allergen extract used for treatment, the dose and protocol, patient selection in addition to the severity and control of asthma. The initiation of AIT in allergic asthma should be considered in intermittent, mild and moderate cases which coexisting with other allergic diseases such as allergic rhinitis, and in case of unacceptable adverse effects of medications. Two important impact of AIT; steroid sparing effect and preventing from progression to asthma should be taken into account in pediatric asthma when making a decision on starting of AIT. Uncontrolled asthma remains a significant risk factor for adverse events and asthma should be controlled both before and during administration of AIT. The evidence concerning the efficacy of subcutaneous (SCIT) and sublingual immunotherapy (SLIT) for treatment of pediatric asthma suggested that SCIT decreases asthma symptoms and medication scores, whereas SLIT can ameliorate asthma symptoms. Although the effectiveness of SCIT has been shown for both seasonal and perennial allergens, the data for SLIT is less convincing for perennial allergies in pediatric asthma.

Lack of allergy to timothy grass pollen is not a passive phenomenon but associated with the allergen-specific modulation of immune reactivity.

Timothy grass (TG) pollen is a common seasonal airborne allergen associated with symptoms ranging from mild rhinitis to severe asthma. The aim of this study was to characterize changes in TG-specific T cell responses as a function of seasonality. Peripheral blood mononuclear cells (PBMCs) obtained from allergic individuals and non-allergic controls, either during the pollen season or out of season, were stimulated with either TG extract or a pool of previously identified immunodominant antigenic regions. PBMCs from allergic subjects exhibit higher IL-5 and IL-10 responses in season than when collected out of season. In the case of non-allergic subjects, as expected we observed lower IL-5 responses and robust production of IFN-γ compared to allergic individuals. Strikingly, non-allergic donors exhibited an opposing pattern, with decreased immune reactivity in season. The broad down-regulation in non-allergic donors indicates that healthy individuals are not oblivious to allergen exposure, but rather react with an active modulation of responses following the antigenic stimulus provided during the pollen season. Transcriptomic analysis of allergen-specific T cells defined genes modulated in concomitance with the allergen exposure and inhibition of responses in non-allergic donors. Magnitude and functionality of T helper cell responses differ substantially in season vs. out of season in allergic and non-allergic subjects. The results indicate the specific and opposing modulation of immune responses following the antigenic stimulation during the pollen season. This seasonal modulation reflects the enactment of specific molecular programmes associated with health and allergic disease.

Pre-Coseasonal vs Perennial Sublingual Immunotherapy for Seasonal Allergens Dosing Regimen: Long-Term Benefits, Adherence, and Cost-Effectiveness—Is There a Difference?

Allergen immunotherapy (AIT) is to date the only disease-modifying and etiological treatment for IgE-mediated respiratory allergies. In France and Italy, the main route of administration of AIT for respiratory allergies is currently constituted by sublingual allergen immunotherapy (SLIT). In other European countries, the marketing is growing. In the USA, SLIT is increasingly taking hold, too. Various SLIT regimens have been employed to date for respiratory allergies induced by pollen, which constitutes a major atopic sensitizer in Europe and North America: continuous (all year-round), pre-seasonal only, co-seasonal only, and pre-coseasonal. The best maintenance SLIT regimen is a pivotal issue to clinicians. In fact, a continuous regimen may pose problems of adherence, and patients could be reluctant to take a treatment when they are symptom-free, out of the pollen season. In addition, a continuous treatment carries on a relevant economic cost. Obviously, the economic aspect may not be primary on safety and efficacy. Data provided evidence of short-term, sustained, and post-treatment efficacy of pre-coseasonal regimen. However, further head-to-head studies are required to establish whether discontinuous SLIT regimens are associated with better safety and/or major very long-lasting and preventative benefits than perennial SLIT regimens.

Immunoregulatory Role of HLA-G in Allergic Diseases.

Allergic diseases are sustained by a T-helper 2 polarization leading to interleukin-4 secretion, IgE-dependent inflammation, and mast cell and eosinophil activation. HLA-G molecules, both in membrane-bound and in soluble forms, play a central role in modulation of immune responses. Elevated levels of soluble HLA-G (sHLA-G) molecules are detected in serum of patients with allergic rhinitis to seasonal and perennial allergens and correlate with allergen-specific IgE levels, clinical severity, drug consumption, and response to allergen-specific immunotherapy. sHLA-G molecules are also found in airway epithelium of patients with allergic asthma and high levels of sHLA-G molecules are detectable in plasma and bronchoalveolar lavage of asthmatic patients correlating with allergen-specific IgE levels. Finally, HLA-G molecules are expressed by T cells, monocytes-macrophages, and Langerhans cells infiltrating the dermis of atopic dermatitis patients. Collectively, although at present it is difficult to completely define the role of HLA-G molecules in allergic diseases, it may be suggested that they are expressed and secreted by immune cells during the allergic reaction in an attempt to suppress allergic inflammation.

Exposure to positively- and negatively-charged plasma cluster ions impairs IgE-binding capacity of indoor cat and fungal allergens

Background Environmental control to reduce the amount of allergens in a living place is thought to be important to avoid sensitization to airborne allergens. However, efficacy of environmental control on inactivation of airborne allergens is not fully investigated. We have previously reported that positively- and negatively-charged plasma cluster ions (PC-ions) reduce the IgE-binding capacity of crude allergens from Japanese cedar pollen as important seasonal airborne allergens. Cat (Felis domesticus) and fungus (Aspergillus fumigatus) are also important sources of common airborne allergens in living spaces throughout the year, and early sensitization with those allergens is considered to be a risk factor for future development of allergic rhinitis, pollinosis and asthma. The aim of this study is to examine whether the PC-ions reduce the IgE-binding capacity of a cat major allergen (Fel d 1) and fungal allergens in an experimental condition.Methods Fel d 1, crude fungal extract, or a fungal major allergen Asp f 1, was treated with PC-ions for 6 h in an experimental cylindrical apparatus. Sham-treated allergens were prepared in the same experimental apparatus without generation of PC-ions. The degradation of the PC-ions-treated Fel d 1 was analyzed by SDS-PAGE, and the IgE-binding capacity of the PC-ions-treated allergens was analyzed by ELISA inhibition assay.Results Exposure of Fel d 1, crude fungal extract and Asp f 1 to PC-ions significantly decreased protein content of Fel d 1 or Asp f 1, respectively. SDS-PAGE analysis suggested that the decreased Fel d 1 content upon exposure with PC-ions was attributable to protein degradation. ELISA inhibition indicated that the PC-ions treatment significantly impaired IgE-binding capacities of Fel d 1, crude fungal allergens, and Asp f 1 compared to sham treatment.Discussion Our data suggest that treatment with PC-ions not only reduce indoor cat and fungal allergens, but also impair their allergenicity.Conclusion These results suggest that environmental control with PC-ions is useful for inactivation of indoor cat and fungal allergens.

EXHALED NITRIC OXIDE AND AEROALLERGEN SENSITIZATION IN ASTHMATIC CHILDREN

Introduction: The examination of nitric oxide in exhaled air concentration in children suffering from asthma and to establish the relation with the degree of sensitization to aeroallergens.
 Material and Methods: The examination included fifty-two children (aged 12.40 ± 2.35 years), twenty-eight male (53.85%) and twenty-four female (46.15%), with the average length of suffering from asthma 8.33 ± 3.93 years. The degree of sensitization to aeroallergens was determined by skin prick testing and assessed using the atopic index (AI).
 Results: The average value of FeNO in exhaled air of children suffering from stable allergic asthma was 43.92 ± 35.63 ppb, and after a four week anti-inflammatory treatment it decreased to 34.92 ± 32.04 ppb (p<0.05). In relation to AI, the level of FeNO in exaled air was 41.00 vs. 40.69 vs 50.88 ppb, in the given order without statistically significant difference. The highest values of FeNO in exhaled air were present in children suffering from a mixed type of sensitisation, 56.85 ppb (Me 48.50) in comparison to sensitisation to seasonal allergens 15.29 ppb (Me 12) and indoor allergens 32.22 ppb (Me 26). Allergic rhinitis, the duration of asthma and the gender were not significantly related to the values of FeNO in exhaled breath, while significant was the negative correlation between the body mass index and FeNO, r = -0,43 (p˂0.01).
 Conclusion: Children suffering from allergic asthma possess increased values of nitric oxide in exhaled air, which is a useful indicator of daily dosage adjustment in patients treated with anti-inflammatory drugs

Allergen-induced early and late asthmatic responses to inhaled seasonal and perennial allergens.

The allergen bronchoprovocation (ABP) test is a validated model to study asthma pathophysiology and response to treatments. The inhibitory effect of agents on the allergen-induced late asthmatic response (LAR) is a predictor of their efficacy in asthma treatment. However, it is difficult to predict the magnitude of a LAR, which may vary according to immune responsiveness and the type of allergen used for ABP. To determine the relationship between the magnitudes of early asthmatic response (EAR) and LAR in mild asthmatic subjects according to the type of allergen inhaled and its determinants. This is a retrospective analysis of a large database of ABPs, all performed with a common standardized methodology. Patients were either challenged with house dust mites (HDMs), animals or pollens allergens. EAR was defined as a ≥20% fall in forced expiratory volume in 1s (FEV1 ) <3h following ABP and LAR as a ≥15% fall in FEV1 between 3 and 7h post-ABP. The ratio of EAR % fall in FEV1 /LAR % fall in FEV1 was compared between the groups of subjects according to the allergen used for ABP. Data from 290 subjects were analysed: 87 had an isolated EAR and 203 had a dual response (EAR+LAR). Dual responders had a significantly lower baseline PC20 , a more marked fall in FEV1 at EAR, and a trend towards higher baseline sputum eosinophil percentages. The ratio of EAR over LAR was significantly lower in HDM compared with pollen ABP, indicating a larger LAR for a similar EAR. No correlations were observed between the ratio of EAR over LAR and the various parameters recorded in the different groups analysed. Different mechanisms may be involved in modulating the magnitude of the LAR, according to the type of allergen. HDM seems to induce a stronger LAR than pollens, animal allergens being intermediary in this regard.

Seasonal variation of birch and grass pollen loads and allergen release at two sites in the German Alps

Less vegetated mountainous areas may provide better conditions for allergy sufferers. However, atmospheric transport can result in medically relevant pollen loads in such regions. The majority of investigations has focused on the pollen load, expressed as daily averages of pollen per cubic meter of air (pollen grains/m³); however, the severity of allergic symptoms is also determined by the actual allergen content of this pollen, its pollen potency, which may differ between high and low altitudes. We analysed airborne birch and grass pollen concentrations along with allergen content (birch: Bet v 1, grass: Phl p 5) at two different altitudes (734 and 2650 m a.s.l.) in the Zugspitze region (2009–2010). Back-trajectories were calculated for the high altitude site and for specific days with abrupt increases in pollen potency. We observed several days with medically relevant pollen concentrations at the highest site. In addition, a few days with pollen were not associated with allergens and vice versa. The calculated seasonal mean allergen release per pollen grain was 1.8–3.3 pg Bet v 1 and 5.7 pg Phl p 5 in the valley and 1.1–3.7 pg Bet v 1 and 0.7–1.5 pg Phl p 5 at the high altitude site. Back-trajectories revealed that high pollen potency at the higher site was generally associated with south-westerly to south-easterly (birch), or northerly (grass) wind directions. By investigating days with sudden increases in pollen potency, however, it was difficult to draw definitive conclusions on long- or short-range transport. Our findings suggest that people allergic to pollen might suffer less at higher altitudes and further indicate that a risk assessment relying on the actual concentration of airborne pollen does not necessarily reflect the actual allergy exposure of individuals.

Effect of alcaftadine 0.25% on ocular itch associated with seasonal or perennial allergic conjunctivitis: a pooled analysis of two multicenter randomized clinical trials.

PurposeSeasonal and perennial allergic conjunctivitis represent the majority of cases of ocular allergy. This analysis was designed to evaluate the efficacy and safety of once-daily alcaftadine 0.25% in preventing ocular itching associated with seasonal or perennial allergic conjunctivitis.Subjects and methodsPooled data from two double-masked, multicenter, placebo-controlled studies using the conjunctival allergen challenge (CAC) model of allergic conjunctivitis were analyzed. Subjects randomized to receive treatment with alcaftadine 0.25% or placebo were challenged with seasonal (grass, ragweed, trees) or perennial (cat dander, cat hair, dog dander, dust mites, cockroach) allergens, 16 hours after treatment instillation. The primary efficacy measure was subject-evaluated mean ocular itching at 3 minutes post-CAC. Secondary measures included ocular itching at 5 and 7 minutes post-CAC. The proportion of subjects with minimal itch (itch score <1) and zero itch (itch score =0), and safety were also assessed.ResultsA total of 189 subjects enrolled in the two studies were treated with alcaftadine or placebo. Overall, 129 subjects were challenged with seasonal allergens and 60 subjects were challenged with perennial allergens. Alcaftadine 0.25% achieved a statistically significant reduction in mean itch score at 3, 5, and 7 minutes post-CAC compared with placebo in subjects challenged with seasonal allergens (P<0.0001 at all time points) and those challenged with perennial allergens (P<0.0001 at all time points). A higher percentage of subjects treated with alcaftadine compared with placebo achieved minimal itch (P≤0.001 versus placebo at all time points) and zero itch (P<0.05 at all time points except 7 minutes for perennial) when challenged with either seasonal or perennial allergens. No treatment-related or serious adverse events were reported.ConclusionOnce-daily alcaftadine 0.25% ophthalmic solution was well tolerated and demonstrated effective relief of ocular itching in subjects challenged with allergens classic for triggering either seasonal or perennial allergic conjunctivitis.

Allergy test: Seasonal allergens and performance in school

Seasonal pollen allergies affect approximately 1 in 5 school age children. Clinical research has established that these allergies result in large and consistent decrements in cognitive functioning, problem solving ability and speed, focus and energy. However, compared to air pollution, the impact of pollen and seasonal allergies on achievement in schools has received less attention from economists. Here, I use data on daily pollen counts merged with school district data to assess whether variation in the airborne pollen that induces seasonal allergies is associated with performance on state reading and math assessments. I find substantial and robust effects: A one standard deviation in ambient pollen levels reduces the percent of 3rd graders passing ELA assessments by between 0.2 and 0.3 standard deviations, and math assessments by between about 0.3 and 0.4 standard deviations. I discuss the empirical limitations as well as policy implications of this reduced-form estimate of pollen levels in a community setting.

Choosing the optimal dose in sublingual immunotherapy: Rationale for the 300 index of reactivity dose.

Sublingual immunotherapy (SLIT) is an effective and well-tolerated method of treating allergic respiratory diseases associated with seasonal and perennial allergens. In contrast to the subcutaneous route, SLIT requires a much greater amount of antigen to achieve a clinical effect. Many studies have shown that SLIT involves a dose–response relationship, and therefore it is important to use a proven clinically effective dose from the onset of treatment, because low doses are ineffective and very high doses may increase the risk of side effects. A well-defined standardization of allergen content is also crucial to ensure consistent quality, potency and appropriate immunomodulatory action of the SLIT product. Several methods of measuring antigenicity are used by manufacturers of SLIT products, including the index of reactivity (IR), standardized quality tablet unit, and bioequivalent allergy unit. A large body of evidence has established the 300 IR dose of SLIT as offering optimal efficacy and tolerability for allergic rhinitis due to grass and birch pollen and HDM, and HDM-induced moderate, persistent allergic asthma. The 300 IR dose also offers consistency of dosing across a variety of different allergens, and is associated with higher rates of adherence and patient satisfaction. Studies in patients with grass pollen allergies showed that the 300 IR dose has a rapid onset of action, is effective in both adults and children in the short term and, when administered pre-coseasonally in the long term, and maintains the clinical benefit, even after cessation of treatment. In patients with HDM-associated AR and/or asthma, the 300 IR dose also demonstrated significant improvements in symptoms and quality of life, and significantly decreased use of symptomatic medication. The 300 IR dose is well tolerated, with adverse events generally being of mild or moderate severity, declining in frequency and severity over time and in the subsequent courses. We discuss herein the most important factors that affect the selection of the optimal dose of SLIT with natural allergens, and review the rationale and evidence supporting the use of the 300 IR dose.

Women are more vulnerable to allergy than man in Gfsa city, Tunisia

The prevalence of allergies has vastly increased over recent decades due to air pollution and climate change. The present study aims to identify any seasonal variations in the allergens, to help prevent and treat allergic diseases; and investigate any correlations between the reported allergens and other biotic parameters, namely age and sex. The study included 67 subjects (49 female and 18 male; age range 10-73 years) who visit the Department of Pneumology and Oto-rhino-laryngology of the Regional Hospital of Gafsa, between August 2007 and September 2008. The allergic condition of these patients was confirmed by measuring allergen specific IgE levels using the multiple allergen simultaneous test-chemoluminescent assay (MAST-CLA). A total of 30 allergens were tested and classified into seven groups: tree and grass pollen, herbaceous pollen, animal dander, moulds, latex, cockroaches and mites. The seasonal distribution of allergens shows that the frequency of respiratory allergy was mainly observed during spring corresponding to the pollination season. However, the detection of some seasonal allergens, such as olive pollen, outside the pollination season can be explained by the cross-reactivity between allergens. The age range of patients with sensitivity was found to be between 10 and 73 years, with the most sensitive patients aged between 20 and 50 years. The sex variable was significantly associated with the studied allergens since sensitization was present more frequently in women than in men.

Homes of low-income minority families with asthmatic children have increased condition issues.

The home is increasingly associated with asthma. It acts both as a reservoir of asthma triggers and as a refuge from seasonal outdoor allergen exposure. Racial/ethnic minority families with low incomes tend to reside in neighborhoods with low housing quality. These families also have higher rates of asthma. This study explores the hypothesis that black and Latino urban households with asthmatic children experienced more home mechanical, structural condition-related areas of concern than white households with asthmatic children. Participant families (n = 140) took part in the Kansas City Safe and Healthy Homes Program, had at least one asthmatic child, and met income qualifications of no more than 80% of local median income; many were below 50%. Families self-identified their race. Homes were assessed by environmental health professionals using a standard set of criteria and a specific set of on-site and laboratory sampling and analyses. Homes were given a score for areas of concern between 0 (best) and 53 (worst). The study population self-identified as black (46%), non-Latino white (26%), Latino (14.3%), and other (12.9%). Mean number of areas of concern were 18.7 in Latino homes, 17.8 in black homes, 13.3 in other homes, and 13.2 in white homes. Latino and black homes had significantly more areas of concern. White families were also more likely to be in the upper portion of the income. In this set of 140 low-income homes with an asthmatic child, households of minority individuals had more areas of condition concerns and generally lower income than other families.

The influence of sublingual immunotherapy on several parameters of immunological response in children suffering from atopic asthma and allergic rhinitis depending on asthma features.

The clinical efficacy of sublingual immunotherapy (SLIT) has already been proven and is known to be high. Its influence on the immunological system of patients suffering from bronchial asthma was also examined. However, it is still unclear how the polysensitisation, coexistence of other atopic disease and asthma treatment step influence the response to treatment with specific immunotherapy. Herein we evaluate the impact of one-year SLIT on selected markers of immunological response depending on different individual and clinical factors of children suffering from atopic asthma and allergic rhinitis. Twenty-five patients aged 8.1 ± 3.1 years (range 5-15 years), 21 boys and 4 girls, suffering from asthma and allergic rhinitis with polysensitisation to seasonal and non-seasonal allergens, shortlisted for SLIT, were included in the study. Th1 cell and Th2 cell percentages, Bcl-2 expression in T cells, and basophil activation after allergen challenge (house dust mite and/or grass pollen antigen in solution used for skin prick tests) in peripheral blood were measured using flow cytometry. The association between clinical features of asthma and the influence of SLIT on immunological parameters was evaluated with exact Fisher test. No association between the influence of one-year sublingual immunotherapy on immunological system and patients' age, polysensitisation, asthma treatment step, or coexistence of any other atopic diseases was observed. However, an increase of the Th1 percentage in children sensitised against more than three allergens was found more often (at the limit of statistical significance) than in the group of children sensitised against three or less allergens. Based on our results, we cannot point to any subgroup isolated in the study, in which the response of the immunological system to sublingual immunotherapy is more satisfactory than any other. Nevertheless, the increase of Th1 cells may be more specific for polysensitised children.

Predictive value of fractional nitric oxide in asthma diagnosis-subgroup analyses

BackgroundThere are no studies investigating the benefit of using FeNO measurements in correlation with sensitization to perennial and seasonal allergens in children with asthma. ObjectiveTo define the group of children with respiratory symptoms in whose FeNO measurement has predictive value for asthma. We assessed the effect of age, allergy profile, atopy, lung function and the presence of allergic rhinitis on interpretation of FeNO levels for clinical applications. MethodsIt was a retrospective, cross-sectional study. We evaluated data from medical documentation of 1767 children with symptoms of allergic diseases such as asthma and/or allergic rhinitis. We included in the analyses subjects who had the following tests done during diagnostic procedures (single measurement): FeNO, spirometry, specific IgE results. All subjects had undergone a minimum 3-years prospective clinical observation after the first FeNO measurement until the later assignment (or not) of an asthma/allergic rhinitis diagnosis. ResultsWe included 1767 children into the analysis; asthma diagnosis was confirm in 1054 (59.6%) children. We showed that only atopy (OR: 1.9; 95%CI: 1.5–2.4) and presence of allergic rhinitis (OR: 1.6; 95%CI: 1.4–1.9) were independently associated with increased FeNO level. Only among patients with atopy and allergic rhinitis FeNO level (above 23ppb) was associated with asthma diagnosis. Sensitivity, specificity, positive predictive value and negative predictive value of FeNO >23ppb for asthma diagnosis were as follows: 0.9(95%CI: 0.68–0.98), 0.52(95%CI: 0.42–0.61), 0.25(95%CI: 0.16–0.37), 0.97(95%CI: 0.88–0.99). ConclusionWe showed that in children with atopy and with allergic rhinitis a negative predictive value for asthma diagnosis was very high with the optimal cut-off point of FeNO 23ppb. Therefore we showed the utility of FeNO measurements to exclude asthma in the subgroup of patients with atopy and allergic rhinitis.

Persistence of IgE-associated allergy and allergen-specific IgE despite CD4+ T cell loss in AIDS.

The infection of CD4+ cells by HIV leads to the progressive destruction of CD4+ T lymphocytes and, after a severe reduction of CD4+ cells, to AIDS. The aim of the study was to investigate whether HIV-infected patients with CD4 cell counts <200 cells/µl can suffer from symptoms of IgE-mediated allergy, produce allergen-specific IgE antibody responses and show boosts of allergen-specific IgE production. HIV-infected patients with CD4 counts ≤200 cells/µl suffering from AIDS and from IgE-mediated allergy were studied. Allergy was diagnosed according to case history, physical examination, skin prick testing (SPT), and serological analyses including allergen microarrays. HIV infection was confirmed serologically and the disease was staged clinically. The predominant allergic symptoms in the studied patients were acute allergic rhinitis (73%) followed by asthma (27%) due to IgE-mediated mast cell activation whereas no late phase allergic symptoms such as atopic dermatitis, a mainly T cell-mediated skin manifestation, were found in patients suffering from AIDS. According to IgE serology allergies to house dust mites and grass pollen were most common besides IgE sensitizations to various food allergens. Interestingly, pollen allergen-specific IgE antibody levels in the patients with AIDS and in additional ten IgE-sensitized patients with HIV infections and low CD4 counts appeared to be boosted by seasonal allergen exposure and were not associated with CD4 counts. Our results indicate that secondary allergen-specific IgE production and IgE-mediated allergic inflammation do not require a fully functional CD4+ T lymphocyte repertoire.

Allergic sensitization in Canadian chronic rhinosinusitis patients

BackgroundChronic rhinosinusitis (CRS) is a societal burden and cause of morbidity in Canada; however, the prevalence of allergic sensitization in Canadian CRS patients has remained poorly characterized.ObjectiveIn this study, we used skin prick test (SPT) and specific immunoglobulin E (sIgE) and G (sIgG) titers to regionally relevant allergen sources in order to determine whether allergic sensitization is more prevalent in CRS patients compared to chronic idiopathic urticaria (CIU) control patients.MethodsOne hundred and fifty eight subjects (19–70 years of age) were recruited into the study. 101 subjects had a confirmed diagnostic history of CRS and 57 subjects with a clinical diagnosis of CIU were recruited as controls. Enrolled subjects underwent SPT to a panel of perennial and seasonal allergens and sIgE titers were quantified to selected environmental allergen mixes (grass, mold, and tree species) using Phadia ImmunoCAP. sIgG was additionally quantified to Alternaria alternata, Aspergillus versicolor, Cladosporium herbarum, and Stachybotrys atra. Differences between CRS and control CIU patient SPT and serological data were examined by chi-squared analysis and analysis of variance.ResultsReactivity to at least one SPT extract occurred in 73% of CRS patients. Positive SPT reactivity to A. alternata (odds ratio (OR): 4.34, 95% confidence interval: 1.57, 12.02), cat (OR: 3.23, 95% CI: 1.16, 9.02), and ragweed (OR: 2.31, 95% CI: 1.02, 5.19) extracts were more prevalent in patients with CRS (p < 0.05). Although dust mite and timothy grass sensitization approached statistical significance in the chi-squared analysis of SPT data, other common perennial and seasonal allergens were not associated with CRS. No statistically significant differences were observed between mean sIgE and sIgG titers in CRS and control patients.ConclusionsThis study supports previous data that suggests A. alternata sensitization is associated with CRS; however, these findings additionally highlight the contribution of other regionally important allergens including cat and ragweed.