Near-ground effect of height on pollen exposure.

The effect of height on pollen concentration is not well documented and little is known about the near-ground vertical profile of airborne pollen. This is important as most measuring stations are on roofs, but patient exposure is at ground level. Our study used a big data approach to estimate the near-ground vertical profile of pollen concentrations based on a global study of paired stations located at different heights. We analyzed paired sampling stations located at different heights between 1.5 and 50 m above ground level (AGL). This provided pollen data from 59 Hirst-type volumetric traps from 25 different areas, mainly in Europe, but also covering North America and Australia, resulting in about 2,000,000 daily pollen concentrations analyzed. The daily ratio of the amounts of pollen from different heights per location was used, and the values of the lower station were divided by the higher station. The lower station of paired traps recorded more pollen than the higher trap. However, while the effect of height on pollen concentration was clear, it was also limited (average ratio 1.3, range 0.7-2.2). The standard deviation of the pollen ratio was highly variable when the lower station was located close to the ground level (below 10 m AGL). We show that pollen concentrations measured at >10 m are representative for background near-ground levels.

Ragweed allergy: Pollen count and sensitization and allergy prevalence in two Italian allergy centers.

BACKGROUND: Ragweed allergy represents a challenge for allergists due to its increase in some geographic areas, mainly northern Italy. OBJECTIVES: To compare two allergy centers in northern Italy by analyzing both the pollen count and the patient characteristics (sensitization and allergy prevalence) over a 10-year period. METHODS: Pollen counts for 10 years (2004-2013) were evaluated and compared in the two centers. Characteristics of patients who were sensitized and allergic to ragweed were analyzed. RESULTS: There was a significantly higher pollen count in Busto Arsizio than in Novi Ligure (p < 0.001). The patients who were seen in the Busto Arsizio center showed more frequent sensitization (p < 0.01) and allergy (p < 0.05) to ragweed than patients who were seen in the Novi Ligure center. The pollen count was significantly (p < 0.01) associated with sensitization and allergy difference. Allergic asthma was more frequent (p < 0.05) in Busto Arsizio. CONCLUSIONS: The pattern of sensitization and allergy prevalence seemed to be associated with ragweed pollen pressure, such as quantity. The knowledge of the pollen count is relevant in clinical practice, mainly for the management of patients with allergy.

Long-term comparison of sublingual immunotherapy vs inhaled budesonide in patients with mild persistent asthma due to grass pollen.

BACKGROUND: Few studies have compared the effects of immunotherapy and inhaled steroids. The main limitation of such studies is the long duration required to fully appreciate the effects of immunotherapy. OBJECTIVE: To compare the effects of inhaled budesonide and sublingual immunotherapy (SLIT) in mild persistent asthma for up to 5 years. METHODS: Patients with mild persistent asthma and rhinitis due to grass pollen were enrolled in an open randomized controlled trial. After a run-in season, they were randomized to either budesonide, 800 microg/d, in the pollen season or continuous grass SLIT for 5 years. All patients received rescue medications. Symptoms were evaluated by diary cards filled out from May to July at baseline and after 3 and 5 years. In-season nasal eosinophils and bronchial hyperresponsiveness were also assessed. RESULTS: Fifty-one patients were enrolled and 46 completed the study. The bronchial symptom scores and the use of bronchodilators decreased significantly in both groups, but the improvement was greater in the SLIT patients at 3 and 5 years. The nasal symptom score and the intake of nasal steroids decreased only in the SLIT group, and the difference vs the budesonide group was always significant. In the SLIT group vs the budesonide group, a statistically significant decrease of nasal eosinophils was found at 3 and 5 years (P < .01). The bronchial hyperresponsiveness improved significantly only in the SLIT group. CONCLUSION: In patients with grass pollen-induced asthma, in the long term SLIT was equally effective as inhaled budesonide in treating bronchial symptoms and provided an additional benefit in treating rhinitis symptoms and bronchial hyperresponsiveness.

Effects of sublingual immunotherapy for multiple or single allergens in polysensitized patients.

BACKGROUND: Sublingual immunotherapy (SLIT) has proven efficacy in treating respiratory allergy. OBJECTIVE: To compare the clinical and functional effects and the effect on nasal eosinophils of SLIT with either single or combination allergens. METHODS: We performed an open-labeled, controlled, 4 parallel-group randomized study with 58 patients sensitized to birch and grasses only who had rhinitis and bronchial hyperreactivity in both pollen seasons. Patients were recruited for the study from January 1, 1999, to June 30, 2001. The patients received SLIT for birch, SLIT for grass, SLIT for birch and grass, or drugs only. Symptom and medication scores, forced expiratory volume in 1 second, bronchial hyperreactivity, and nasal eosinophil counts were evaluated in both pollen seasons at baseline and after 2 and 4 years. RESULTS: Ten patients dropped out and 48 completed the study. No change in all the considered parameters vs baseline was seen in patients treated with drugs only. Those patients receiving SLIT for grass or birch had a significant clinical improvement and nasal eosinophil reduction vs baseline and vs patients who did not receive SLIT in the target season (P < .01) but also in the unrelated pollen season (P < .05). The patients receiving SLIT for grass and birch improved as well, and their improvement in clinical symptoms and inflammation was significantly greater than in patients treated with SLIT for the single allergens. Minor changes were seen in the forced expiratory volume in 1 second, since it remained within the reference range in the whole population. CONCLUSION: In patients sensitized to grass and birch, SLIT with the 2 allergens provided the best clinical results. Nevertheless, SLIT with birch only or grass only also provided a measurable improvement in the grass season and birch season, respectively.

Flexible approaches in the design of subcutaneous immunotherapy protocols for Hymenoptera venom allergy.

BACKGROUND: Venom immunotherapy is an effective method for the treatment of Hymenoptera venom allergy. Different extracts and treatment schedules are available. OBJECTIVE: To compare the safety and efficacy of immunotherapy in 3 cohorts of patients sensitized to Vespula species. METHODS: In this open study, 43 patients were treated with a subcutaneous aqueous extract for induction and maintenance (AA), 34 with a subcutaneous depot extract for induction and maintenance (DD), and 29 with subcutaneous aqueous and subcutaneous depot extracts for induction and maintenance, respectively (AD). Cluster schedules were followed to reach maintenance, and adverse effects during treatment and after naturally occurring stings were recorded. RESULTS: Depot immunotherapy was better tolerated mainly owing to the lower frequency of local adverse effects in the induction phase (5.9% vs 42.5% and 1.3% vs 5.1% on a per patient and per dose basis, respectively; P < .001 for both) and for effects occurring within 60 minutes after vaccination (2.9% vs 19.2% and 0.2% vs 2.8% on a per patient and per dose basis; P = .03 and P < .001, respectively). Furthermore, 19 of 20 AA, 9 of 9 AD, and 10 of 10 DD patients who were restung experienced only minor local effects. CONCLUSIONS: Venom immunotherapy is efficacious. Although there was no decrease in systemic reactions, depot immunotherapy to Vespula venom induced fewer early local adverse effects. Patients undergoing an induction phase with an aqueous extract can benefit from switching to a depot extract during maintenance. Increasing the flexibility of the immunization schedules may improve compliance with this potentially lifesaving treatment.