Effect of tree and grass pollens and fungal spores on spring allergic rhinitis: a comparative study

Allergy to oak pollen in North America

Background: Oak pollen is an important allergen in North America. The genus Quercus (oak) belongs to the family Fagaceae under the order Fagales. Objective: The objective of this article was to narratively review the oak pollen season, clinical and epidemiologic aspects of allergy to oak pollen, oak taxonomy, and oak allergen cross-reactivity, with a focus on the North American perspective. Methods: A PubMed literature review (no limits) was conducted. Publications related to oak pollen, oak-related allergic rhinitis with or without conjunctivitis, and oak-related allergic asthma were selected for review. Results: Oak species are common throughout the United States and contribute up to 50% to overall atmospheric pollen loads. Mean peak oak pollen counts can reach >2000 grains/m³. The start of the oak pollen season generally corresponds to the seasonal shift from winter to spring based on latitude and elevation, and may begin as early as mid February. The duration of the season can last > 100 days and, in general, is longer at lower latitudes. In the United States, ∼30% of individuals with allergy are sensitized to oak. The oak pollen season correlates with increased allergic rhinitis symptom-relieving medication use and asthma-related emergency department visits or hospitalizations. Oak falls within the birch homologous group. Extensive immunologic cross-reactivity has been demonstrated between oak pollen and birch pollen allergens, and, more specifically, their major allergens Que a 1 and Bet v 1. The cross-reactivity between oak and birch has implications for allergy immunotherapy (AIT) because guidelines suggest selecting one representative allergen within a homologous group for AIT, a principle that would apply to oak. Conclusion: Allergy to oak pollen is common in North America and has a substantial clinical impact. Oak pollen allergens are cross-reactive with birch pollen allergens, which may have implications for AIT.

Human exposure to airborne pollen and relationships with symptoms and immune responses: Indoors versus outdoors, circadian patterns and meteorological effects in alpine and urban environments

Pollen exposure is a major cause of respiratory allergies worldwide. However, it is unclear how everyday exposure is related to symptoms and how allergic patients may be affected spatially and temporally. Hence, we investigated the relationship of pollen, symptoms and immune responses under a controlled regime of 'high-low-moderate' pollen exposure in urban versus alpine environment. The research was conducted in 2016 in two locations in Germany: urban Augsburg (494 m) and Schneefernerhaus (UFS) on Zugspitze mountain (2656 m). Monitoring of airborne pollen took place using Hirst-type volumetric traps. On UFS, both indoor and outdoor samples were taken. Grass pollen allergic human volunteers were monitored daily during the peak of the grass pollen season, in Augsburg, on UFS, then again in Augsburg. Nasal biosamples were obtained throughout the study to investigate immune responses. All symptoms decreased significantly during the stay on UFS and remained low even after the return to Augsburg. The same was observed for nasal total IgE and IgM levels and for nasal type 2 cytokines and chemokines. Augsburg showed higher pollen concentrations than those on UFS. At all sites, pollen were present throughout each day, but were more abundant in Augsburg during morning. On UFS, outdoor pollen levels were up to 6-fold higher than those indoors. Nasal, ocular and pulmonary symptoms correlated with current and previous days' pollen concentrations and relative humidity. Stays in low-exposure environments during the peak pollen season can be an efficient means of reducing allergic symptoms and immune responses. However, in alpine environments, even occasional pollen exposure during short intervals may still trigger symptoms because of the additional environmental stress posed onto allergics. This highlights the need for the consideration of additional environmental factors, apart from symptom diaries and immune responses, so as to efficiently predict high-risk allergy periods.

Efficacy and safety of grass sublingual immunotherapy tablet, MK-7243: a large randomized controlled trial

BACKGROUND

In North America, few studies have evaluated sublingual immunotherapy for allergic rhinitis with or without conjunctivitis (AR/C); pediatric data are sparse. The authors report findings from the largest published immunotherapy trial yet conducted in adults and children.

OBJECTIVE

To evaluate grass sublingual immunotherapy tablet (MK-7243) treatment in subjects with AR/C.

METHODS

North American subjects (5-65 years old) with grass allergy were randomized 1:1 to once-daily MK-7243 (2,800 BAU Phleum pratense) or placebo. The first dose was given at the investigator's office; subsequent doses were self-administered at home. The primary end point was total combined score (TCS; rhinoconjunctivitis daily symptom score [DSS] plus daily medication score [DMS]) over the entire grass pollen season (GPS). Key secondary end points included entire-season DSS, DMS, peak-season TCS, and rhinoconjunctivitis quality-of-life questionnaire scores. Safety outcomes included adverse events (AEs).

RESULTS

One thousand five hundred one subjects were randomized (85% polysensitized, 25% had asthma). MK-7243 yielded improvements vs placebo of 23% in entire-season TCS (median difference -0.98, P < .001), 29% in peak-season TCS (median difference -1.33, P < .001), 20% in entire-season DSS (median difference -0.64, P = .001), 35% in entire-season DMS (mean difference -0.48, P < .001), and 12% in peak-season rhinoconjunctivitis quality-of-life questionnaire (median difference -0.13, P = .027). Efficacy between children and adults was similar. Most AEs were transient local application-site reactions, with no serious treatment-related AEs or anaphylactic shock. Three subjects (1 placebo, 2 MK-7243) had moderate systemic allergic reactions.

CONCLUSION

MK-7243 was effective in polysensitized grass-allergic North American children and adults with AR/C in this large trial, confirming previous research.

Global warming and allergy in Asia Minor

The earth is warming, and it is warming quickly. Epidemiological studies have demonstrated that global warming is correlated with the frequency of pollen-induced respiratory allergy and allergic diseases. There is a body of evidence suggesting that the prevalence of allergic diseases induced by pollens is increasing in developed countries, a trend that is also evident in the Mediterranean area. Because of its mild winters and sunny days with dry summers, the Mediterranean area is different from the areas of central and northern Europe. Classical examples of allergenic pollen-producing plants of the Mediterranean climate include Parietaria, Olea and Cupressaceae. Asia Minor is a Mediterranean region that connects Asia and Europe, and it includes considerable coastal areas. Gramineae pollens are the major cause of seasonal allergic rhinitis in Asia Minor, affecting 1.3-6.4 % of the population, in accordance with other European regions. This article emphasizes the importance of global climate change and anticipated increases in the prevalence and severity of allergic disease in Asia Minor, mediated through worsening air pollution and altered local and regional pollen production, from an otolaryngologic perspective.

Regional pollen load: effect on sensitisation and clinical presentation of seasonal allergic rhinitis in patients living in Ankara, Turkey

BACKGROUND

Although Gramineae pollens are the main reason for seasonal allergy in many parts of Europe, the influence of regional flora on sensitisation and symptoms has always been a topic of interest. The aim of this study was to document the sensitisation to pollens and to evaluate their clinical importance in patients with seasonal allergic rhinitis living in Ankara/central Anatolia.

METHODS

The study included those subjects with seasonal allergic rhinitis living in Ankara. Skin prick testing with a panel of common aeroallergens as well as grass, individual tree and weed pollens predominant in the region was performed. The patients were followed by symptom-medication scores during the same season in which regional pollens were also counted.

RESULTS

The final eligible study consisted of 54 subjects (F/M: 26/28; mean age: 29.4 years). Trees were the most common pollen source consisting of 95 % of the total amount, followed by grasses (3 %) and weeds (2 %). Sensitisation to Gramineae, to at least one weed; and to tree pollens were 100 %, 85.2 % and 94.4 %, respectively. The most common positive skin tests among tree pollens were to Oleaceae (59.2 %), Aesculus (57.4 %); and Tilia (42.5 %) despite low pollen counts. Chenopodiaceae (88 %) and Plantago (63 %) were the most sensitised weed pollens, with high pollen counts. All patients had significant symptoms during May and June.

CONCLUSION

Although Gramineae pollens seem to be major allergens for seasonal allergic rhinitis in Ankara, the particular role of tree pollens and weed pollens cannot be discarded on symptom development in sensitised patients.

The effect of Gencydo injections on hayfever symptoms: a therapeutic causality report

OBJECTIVES

The aim of this study was to study the effect of Gencydo (Weleda AG, Arlesheim, Switzerland) injections on hayfever symptoms.

DESIGN

This is a therapeutic causality report based on the practices of 13 Dutch general practitioners.

SUBJECTS

Thirteen (13) patients with a mean history of hayfever with grass pollen allergy of 9 years duration, who in previous years used conventional hayfever medication because of the severity of symptoms during the pollen season.

INTERVENTIONS

Gencydo injections were given in 12 patients before the onset of and during the grass pollen season, and in one patient during the grass pollen season only.

OUTCOME MEASURES

Nasal and non-nasal hayfever symptom severity, use of rescue medication (antihistamines or corticosteroids), and subjective experiences of patients were used as outcome measures.

RESULTS

Nine (9) of 13 patients showed no increase of symptom severity during the so-called pollen season. Both the mean maximal total nasal symptom score per patient and the mean total nasal symptom score for the entire study group during the days with a grass pollen count >100 were mild. Percentages of individual "strong" or "severe" nasal symptom scores were low. There was no statistically significant difference in mean total nasal symptom score between the period when the pollen count was <100 and the period when it was >100. Conventional rescue medication for hayfever was used only eight times, all by one person. Nine (9) patients (69%) reported an improvement of symptoms (eight patients cited strong improvement and one patient noted slight improvement).

CONCLUSIONS

There are clear indications that Gencydo treatment was effective in a large subgroup of the research population.

Correlation of Asian dust storm events with daily clinic visits for allergic rhinitis in Taipei, Taiwan

In spring, windblown dust storms originating in the deserts of Mongolia and China head toward Taipei city. These occurrences are known as Asian dust storm (ADS) events. The objective of this study was to assess the possible associations of ADS on the daily clinical visits for allergic rhinitis of residents in Taipei, Taiwan, during the period 1997-2001. Forty-nine dust storms were identified and classified as index days. Daily clinical visits for allergic rhinitis on the index days were compared with clinical visits on the comparison (non-ADS) days. Two non-ADS days for each index day, 7 d before the index day and 7 d after the index day, were selected. The effects of dust storms on clinic visits for allergic rhinitis were prominent 2 d after the event (19%). However, the association was not statistically significant. There may not have been enough power to detect associations resulting from the inadequate sample size of allergic rhinitis visits on ADS days. Further study is needed to clarify this association.

Montelukast for treating fall allergic rhinitis: effect of pollen exposure in 3 studies

BACKGROUND

Montelukast, a potent leukotriene receptor antagonist, is an effective therapy for symptoms of seasonal allergic rhinitis, a disease governed by patients' individual sensitivity and exposure to relevant allergens.

OBJECTIVE

To evaluate the relationship of montelukast treatment effect vs pollen exposure in studies conducted during 3 consecutive fall allergy seasons.

METHOD

A combined analysis of these multicenter, randomized, double-blind, parallel-group studies was performed; 1 of the 3 studies is presented for the first time in this article. After a placebo run-in period, 1,862 symptomatic patients were randomly assigned to receive either a 10-mg montelukast tablet (n = 929) or placebo (n = 933) once daily for 2 weeks. Pollen exposure was summarized by mean daily weed pollen count. The interaction between treatment effect and pollen exposure was evaluated on the primary efficacy endpoint and daytime nasal symptom score, as rated by patients; also evaluated was the influence of the timing of the 2-week treatment period relative to the peak of the weed pollen season.

RESULTS

Montelukast significantly improved daytime nasal symptoms score and individual scores of congestion, rhinorrhea, itching, and sneezing compared with placebo. There was a significant interaction (P < .043) between treatment effect and weed pollen exposure; a larger treatment effect was noted in patients exposed to higher pollen counts. An interaction between treatment effect and timing of treatment in relation to peak pollen season was suggested.

CONCLUSIONS

Montelukast significantly improved daytime nasal symptoms score in patients with seasonal allergic rhinitis, and the effect was greater in patients exposed to higher pollen levels.

Clinical relevance of spore and pollen counts

Many people with allergies monitor daily pollen and spore counts with the belief that they can act on that information to improve their health. Because many factors can affect personal exposure, the value of community-wide counts for an individual is questionable. These factors include the presence of local pollen and spore sources, diurnal variations, weather effects, air pollution, and a particle-free bioaerosol. To take advantage of bioparticulate counts, the public needs to be informed about their meaning and factors that can influence personal exposure.

IgE-mediated asthma and rhinitis I: a role of allergen exposure?

Exposures to airborne protein antigens, aeroallergens, may cause sensitization with production of Th2-dependent antibodies, including IgE. The IgE antibodies and associated cellular responses are responsible for the allergic airway diseases, allergic rhinitis and allergic asthma, which are increasing in societies with Western life style. Aeroallergens may have different potential to sensitize exposed subjects. Thus, there are only a limited number of important groups of aeroallergens, which are those from house dust mites, cockroaches, pets, pollens, and moulds. Allergy follows to a certain extent the pharmacological/toxicological paradigm of dose-response relationship. Unlike effects of pharmacologically and toxicologically active substances, allergens elicit their adverse effects in a two-stage process. In the first stage the immunologically naïve individual is sensitized to the allergen. In the second stage renewed exposure to the allergen elicits the disease response. Also, high concentrations of aeroallergens may induce immunological tolerance. The scientific literature suggests that many environmental factors contribute to the increase in sensitization and development of airway allergies. Nevertheless, the dose-response relationships apply (within certain limits) both to the sensitization itself and to the exacerbation of the diseases. This suggest that exposure reduction may be one of the methods for reduction of risk, in relation to control of the allergic airway diseases.

Prevalence and differential diagnosis of chronic rhinitis

The prevalence and differential diagnosis of rhinitis changes as we progress from birth to senescence. The heavy burden of allergic rhinitis is often overlooked in infants and disregarded in childhood and adolescence. In women, especially during pregnancy, hormonal changes can significantly affect nasal mucosal hyperreactivity and worsen ongoing syndromes. Various types of inflammatory and noninflammatory nonallergic rhinitides become more prevalent in the fifth decade and beyond. The burgeoning elderly population with irritant, atrophic, and medication-related rhinitis will constitute a greater proportion of our practices as the general population ages.