Method to develop a regional guide for the allergenic potential of tree pollen.

Allergic rhinitis, caused by airborne pollen, is a common disease with a great impact on the quality of life for patients and high costs for society. Prevention of high pollen concentrations in the air is relevant for creating a safe environment for allergic patients. Due to climate change, the heat in cities during the summer is a recurring problem. The local climate can be improved by using the cooling properties of trees, providing shade and cooling by evapotranspiration. When deciding which tree species will be planted, it is important to take into account the allergenicity of the pollen that the tree produces. Available guides, used all over the world, on the allergenicity of pollen are very divers in content and interpretation and not applicable for the Netherlands. In this study a method is described to develop a guide for the allergenic potential of tree pollen in a region, in this case the Netherlands. For the most common tree species in the Netherlands the scientific knowledge on the allergenicity of the pollen was collected, followed by an inventory on regional pollen abundance. Subsequently, the sensitization pattern in a patient group with possible inhalation allergy was analyzed. Based on these data allergenicity of the tree pollen was classified into five classes. Eight tree species/genera of the 61 most planted tree species in the Netherlands are considered to have a very strong to moderate allergenic potential. We propose to use this methodology to develop regional-specific guides classifying the allergenic potential of tree pollen.

A new portable sampler to monitor pollen at street level in the environment of patients.

Allergic rhinitis caused by pollen exposure is one of the most common allergic diseases. Therefore monitoring pollen levels in ambient air is an important tool in research and health care. Most European monitoring stations collect airborne pollen at rooftop levels for measurements in the larger surrounding of the sampling station, and not in the direct environment of sensitized subjects. Here we present the development and evaluation of a portable pollen sampler, called "Pollensniffer", that was designed to collect pollen in the immediate environment of allergic subjects. Validation of the Pollensniffer against the standard volumetric pollen sampler showed for most pollen types high correlations between the number of pollen collected by those two devices (Spearman's Correlation Coefficient > 0.8); the Pollensniffer appeared to collect on average 5.8 times more pollen per hour than the static sampler. Pollen monitoring was performed using this Pollensniffer at street level at 3 different locations in the city of Leiden during 22 weeks in 2017 and 21 weeks in 2018, during three 15-min periods a day and at one day in the week. The results showed that the pollen levels for birch and grass pollen can significantly differ from location to location and per time of day. Furthermore, the Pollensniffer measurements at street level showed that birch and grass pollen grains were detected 1 1/2 and 2-3 weeks, respectively, before detection at rooftop level. The street measurements show that allergic subjects can encounter varying pollen levels throughout the city and that they can be exposed to grass and birch pollen and may experience hay fever symptoms, even before the sampler at rooftop level registers these pollen.

Quality of Life and Traditional Outcome Results at 1 Year in Elderly Patients Having Critical Limb Ischemia and the Role of Conservative Treatment.

INTRODUCTION: Revascularization is the cornerstone of the treatment of critical limb ischemia (CLI), but the number of elderly frail patients increase. Revascularization is not always possible in these patients and conservative therapy seems to be an option. The goals of this study are to analyze the 1-year quality of life (QoL) results and mortality rates of elderly patients with CLI and to investigate if conservative treatment could be an acceptable treatment option. METHODS: Patients with CLI ≥70 years old were included in a prospective observational cohort study in 2 hospitals in the Netherlands between 2012 and 2016 and were divided over 3 treatment modalities: endovascular therapy, surgical revascularization, and conservative treatment. The World Health Organization Quality of Life (WHOQoL-Bref) instrument, a generic QoL assessment tool that includes components of physical, psychological, social relationships and environment, was used to evaluate QoL at baseline, 6 months, and 1 year. RESULTS: In total, 195 patients (56% male, 33% Rutherford 4, mean age of 80) were included. Physical QoL significantly increased after surgical (10.4 vs 14.9, P < .001), endovascular (10.9 vs 13.7, P < .001), and conservative therapy (11.6 vs 13.2, P = .01) at 1 year. One-year mortality was relatively low after surgery (10%) compared to endovascular (40%) and conservative therapy (37%). CONCLUSION: The results of this study could not be used to designate the superior treatment used in elderly patients with CLI. Conservative treatment could be an acceptable treatment option in selected patients with CLI unfit for revascularization. Treatment of choice in elderly patients with CLI is based on multiple factors and should be individualized in a shared decision-making process.

Persistence of treatment with 5-grass pollen tablets in patients with allergic rhinitis: a real-life study.

BACKGROUND: In patients with allergic rhinitis, treatment adherence to allergen immunotherapy varies greatly in randomized and real-life studies. OBJECTIVE: To evaluate the use of a 5-grass pollen tablet as sublingual immunotherapy, its treatment persistence, and the reasons for discontinuation in a real-life clinical setting. METHODS: This multicenter, prospective, open-label, noncontrolled observational study evaluated the use of sublingual immunotherapy with a 5-grass pollen tablet in a cross-sectional population of patients (≥5 years old) with grass pollen-induced allergic rhinitis with or without asthma. The primary objective was to determine the percentage of patients persisting with treatment across 1 season in a pre-co-seasonal scheme. Secondary objectives included evaluation of reasons for treatment discontinuation, safety and adverse events; effectiveness (based on physician and patient assessments), and treatment compliance. RESULTS: The study included 196 patients (49.2% male, mean age 27.5 years, range 5.3-65.7 years), with treatment provided by 47 participating physicians. Sixty-seven percent of patients had polysensitivity and 32% had coexistent asthma. On average, patients were treated for 7 months with the 5-grass pollen tablet. After 1 month, 85% of all patients persisted with treatment, and 70% persisted after 7 months. Treatment discontinuation was due chiefly to known side effects (mild to moderate local allergic reactions). Most patients reported symptom improvement; 80% of all patients intended to continue treatment next season. CONCLUSION: Most patients with allergic rhinitis treated pre-co-seasonally with a 5-grass pollen tablet persisted with treatment after the first pollen season. Patients were willing to continue their treatment in the following season owing to improvement of symptoms.

The relevance of patient-reported outcomes in a grass pollen immunotherapy trial in children and adolescents with rhinoconjunctivitis.

BACKGROUND: Patient-reported outcomes (PROs) are the only instruments available to assess the efficacy of an intervention in patients with allergic rhinoconjunctivitis. As allergic rhinoconjunctivitis is a systemic disease, it is now recommended to use not only PROs focusing at classical symptoms, but also health-related quality of life (HRQL) instruments in immunotherapy trials. METHODS: A previously published immunotherapy trial in children and adolescents (6-18 yr) with hay fever provided us with data to assess the relevance of two of these additional outcome measures, the disease-specific rhinoconjunctivitis quality of life questionnaire (RQLQ) and the generic COOP/WONCA-charts (CWC). A PRO was considered relevant if it was responsive to pollen exposure and at least had a moderate correlation with the classical symptoms of allergic rhinoconjunctivitis. Furthermore, we evaluated a post-season PRO, that is, a global assessment of symptoms (GAS). This assessment is used in clinical trials as a tool for selecting participants with sufficient symptoms and in daily practice to evaluate the patient's complaints during the preceding season. We assessed the correlation of this retrospective score with the actual symptoms during the previous pollen season. RESULTS: Data from 36 children and 63 adolescents were analysed. On the basis of the total scores of the paediatric and adolescent version of the RQLQ, both questionnaires were considered relevant as they were responsive to exposure and showed a moderate to strong correlation with the rhinoconjunctivitis symptoms. However, in both children and adolescents, 40% of the RQLQ items were not relevant according to our definition. The CWC as a whole and the separate charts appear less relevant because of the weak correlations with the daily symptom score from the diary. The correlation between our post-season GAS and the in season daily symptom score was weak. CONCLUSION: The paediatric and adolescent RQLQ are relevant, but could be shortened as they contain a substantial number of irrelevant items. The CWC are not relevant in the monitoring of children and adolescents with allergic rhinoconjunctivitis caused by grass pollen. The retrospective GAS does not sufficiently reflect the actual symptoms during the preceding season.

Randomized double-blind placebo-controlled trial of sublingual immunotherapy in children with house dust mite allergy in primary care: study design and recruitment.

BACKGROUND: For respiratory allergic disorders in children, sublingual immunotherapy has been developed as an alternative to subcutaneous immunotherapy. Sublingual immunotherapy is more convenient, has a good safety profile and might be an attractive option for use in primary care. A randomized double-blind placebo-controlled study was designed to establish the efficacy of sublingual immunotherapy with house dust mite allergen compared to placebo treatment in 6 to 18-year-old children with allergic rhinitis and a proven house dust mite allergy in primary care. Described here are the methodology, recruitment phases, and main characteristics of the recruited children. METHODS: Recruitment took place in September to December of 2005 and 2006. General practitioners (in south-west Netherlands) selected children who had ever been diagnosed with allergic rhinitis. Children and parents could respond to a postal invitation. Children who responded positively were screened by telephone using a nasal symptom score. After this screening, an inclusion visit took place during which a blood sample was taken for the RAST test. RESULTS: A total of 226 general practitioners invited almost 6000 children: of these, 51% was male and 40% <12 years of age. The target sample size was 256 children; 251 patients were finally included. The most frequent reasons given for not participating were: absence or mildness of symptoms, absence of house dust mite allergy, and being allergic to grass pollen or tree pollen only. Asthma symptoms were reported by 37% of the children. Of the enrolled children, 71% was sensitized to both house dust mite and grass pollen. Roughly similar proportions of children were diagnosed as being sensitized to one, two, three or four common inhalant allergens. CONCLUSION: Our study was designed in accordance with recent recommendations for research on establishing the efficacy of sublingual immunotherapy; 98% of the target sample size was achieved. This study is expected to provide useful information on sublingual immunotherapy with house dust mite allergen in primary care. The results on efficacy and safety are expected to be available by 2010. TRIAL REGISTRATION: the trial is registered as ISRCTN91141483 (Dutch Trial Register).

Sublingual immunotherapy with grass pollen is not effective in symptomatic youngsters in primary care.

BACKGROUND: Sublingual immunotherapy (SLIT) is considered safer and more convenient than subcutaneous therapy and therefore has been proposed as especially suitable for children and in primary care. Most efficacy studies in children lack power to be conclusive, and all have been performed in referral centers. OBJECTIVE: To investigate the efficacy of SLIT with grass pollen allergen in children and adolescents with rhinoconjunctivitis in a primary care setting. METHODS: Youngsters aged 6-18 years with hay fever were enrolled from general practices and randomly assigned to receive placebo or grass pollen mix for 2 years. The primary outcome was the mean daily total symptom score (scale 0-15) comprising sneezing, itching nose, watery running nose, nasal blockage, and itching eyes during the months May-August of the second treatment year. RESULTS: Out of 204 youngsters randomized, 168 entered the intention-to-treat analysis (91 verum, 77 placebo). The mean daily total symptom score did not differ between participants allocated to verum and those allocated to placebo (difference for verum minus placebo: -0.08, 95%CI, -0.66-0.50; P = .78). No differences were found for rescue medication-free days, disease-specific quality of life, and overall evaluation of the treatment effect. Local side effects were more frequent in the verum group (39% vs 17% of participants; P = .001). CONCLUSION: Sublingual immunotherapy with grass pollen in a primary care setting is not effective in children and adolescents. CLINICAL IMPLICATIONS: Currently, SLIT cannot be recommended for general practitioners as a therapeutic modality in youngsters with grass pollen allergy.

Honeybee interference as a novel aid to reduce pollen exposure and nasal symptoms among greenhouse workers allergic to sweet bell pepper (Capsicum annuum) pollen.

BACKGROUND: In 1999, an extensive study among bell pepper growers showed a prevalence of 53.8% work-related symptoms and 35.4% sensitisation to bell pepper pollen. Experiments with bees to remove pollen from bell pepper flowers have been done for a few years. OBJECTIVES: It was the aim of this study to investigate whether bees can reduce the pollen exposure in bell pepper greenhouses and whether this reduction results in a decrease in allergic complaints in the greenhouse workers. METHODS: Eighteen greenhouses were selected for the study. In each greenhouse, pollen exposure was estimated. In 6 and 3 of the greenhouses, high, respectively low, numbers of honeybees were placed throughout the pollen season of the sweet bell pepper plant. Nine greenhouses without honeybees were used as control. At baseline, as well as after 4 and 8 months, nasal symptoms assessed with a visual analogue score and lung function parameters were used as outcome measure. RESULTS: Forty-four of the 133 employees invited reported work-related symptoms. High numbers of bees reduced the pollen amount in a dose-dependent way to 18% of the baseline exposure. A significant trend relationship between the visual analogue scale in nasal symptoms and the number of colonies of bees was seen. CONCLUSIONS: The interference of bees in bell pepper greenhouses significantly reduces the pollen amount. This reduction is associated with less work-related rhinitis symptoms in allergic greenhouse workers. This intervention study supports the hypothesis that allergic work-related complaints of greenhouse workers, sensitised to bell pepper pollen, are caused by occupational exposure to this pollen in the greenhouse.

Immunoblot and radioallergosorbent test inhibition studies of allergenic cross-reactivity of the predatory mite Amblyseius cucumeris with the house dust mite Dermatophagoides pteronyssinus.

BACKGROUND: In 1999, an extensive study among bell pepper growers showed that a predatory mite, Amblyseius cucumeris, is a potentially relevant source of occupational allergens because 23% of the population had positive skin prick test reactions. OBJECTIVE: To investigate whether cross-reactivity between A. cucumeris and Dermatophagoides pteronyssinus is responsible for the cosensitization to both mite species found in 58.7% of A. cucumeris-sensitized greenhouse workers. METHODS: Fifteen serum samples from greenhouse workers with work-related inhalant allergy and a positive radioallergosorbent test (RAST) reaction to A. cucumeris or D. pteronyssinus were selected for immunoblot analysis using extracts of both mites. A subselection (n = 5) was used for RAST and immunoblot inhibition to investigate potential cross-reactivity. RESULTS: On immunoblot, 2 distinct patterns were observed: one pattern showed common protein bands in A. cucumeris and D. pteronyssinus blots suggestive of cross-reactivity between A. cucumeris and D. pteronyssinus and the other pattern showed no shared protein bands. Dermatophagoides pteronyssinus RAST inhibition with A. cucumeris extract was low in 4 serum samples (<25% inhibition) and nearly absent in 1 serum sample; A. cucumeris RAST inhibition with D. pteronyssinus extract was high in 1 serum sample (75% inhibition), low in 2 serum samples (35% and <15% inhibition), and absent in 2 serum samples. These results were confirmed by immunoblot inhibition experiments. CONCLUSIONS: Amblyseius cucumeris, a new occupational allergen, has species-specific antigens and common antigens that are cross-reactive with the house dust mite D. pteronyssinus.