Allergenic pollens and pollinosis in Italy: recent advances

Variations in airborne pollen and spores in urban Guangzhou and their relationships with meteorological variables

Airborne pollen causes various types of allergies in humans, and the extent of allergic infection is related to the presence of different types of sporo-pollen and existing meteorological conditions in a certain area. Therefore, an aeropalynological study of 72 airborne samples with a hydrofluoric acid (HF) treatment was conducted in the Haizhu district of Guangzhou, China, in 2016, to identify the temporal variations in airborne sporo-pollen and the relationship between airborne sporo-pollen concentrations and different meteorological variables in Guangzhou, China. Forty-five types of airborne pollen, seven types of airborne spores, and some undetermined sporo-pollen taxa were identified with two separate plant habitats occurring during this period (from January to December 2016): arboreal pollen (tree-based) and non-arboreal pollen (herb, shrub, aquatic, liane, etc.). Furthermore, the daily records of four key meteorological variables (temperature, precipitation, relative humidity, and wind speed) were acquired to distinguish the pollen seasons and correlated with Spearman's rho test to establish a pollen-weather data book with the seasonal variations. The two leading seasons were identified based on pollen abundance: spring and autumn. Among them, the primary dominant sporo-pollen families during the spring season were Poaceae, Pinaceae, Euphorbiaceae, Moraceae, Microlepia sp., and Polypodiaceae. Conversely, Artemisia sp., Asteraceae, Cyperaceae, Poaceae, Alnus sp., Corylus sp., Myrtaceae, and Rosaceae were the dominant pollen species during autumn. However, few pollen grains were identified in January, May-July, and December. The statistical analysis revealed that temperature had both positive and negative correlations with sporo-pollen concentrations. However, precipitation and relative humidity had a strong impact on the sporo-pollen dispersion and exhibited a negative correlation with the sporo-pollen concentrations. The wind speed had a positive but strong correlation with the sporo-pollen concentration during the study period. Some inconsistent results were found due to environmental variations, vegetation type, and climate change around the study area. This study will facilitate the identification of pollen seasons to prevent the occurrence of pollen-related allergies in the Guangzhou city area.

Pollen and Fungal Spores Evaluation in Relation to Occupants and Microclimate in Indoor Workplaces

Indoor air quality depends on many internal or external factors mutually interacting in a dynamic and complex system, which also includes indoor workplaces, where subjects are exposed to many pollutants, including biocontaminants such as pollen and fungal spores. In this context, the occupants interact actively with their environment through actions, modifying indoor environmental conditions to achieve their own thermal comfort. Actions such as opening/closing doors and windows and turning on/off air conditioning could have effects on workers’ health. The present study explored the contribution of human occupants to pollen and fungal spore levels in indoor workplaces, combining aerobiological, microclimate, and worker monitoring during summer and winter campaigns. We evaluated the overall time spent by the workers in the office, the workers’ actions regarding non-working days and working days, and non-working hours and working hours, during two campaigns of pollen and fungal spore monitoring. Our results showed that the biocontaminant values depend on many mutually interacting factors; hence, the role of all of the factors involved should be investigated. In this regard, aerobiological monitoring should be a valid tool for the management of occupational allergies, providing additional information to improve occupational health protection strategies.

The Clinical Utility of Pollen Counts

In this review, we describe how pollen counts are performed, the health effects caused by exposure to varying amounts of pollen, the clinical utility of reporting pollen counts to the public, and how that information can be used by patients who have allergies to improve their health. The public is very interested in pollen counts, particularly if the counts provide a forecast of expected pollen exposure for the next few days. Traditional pollen counts are labor-intensive; poorly distributed; and, since the counts are usually 1-day-old, do not provide forecasts that can be acted on. New methods that provide short- and long-term pollen forecasts can provide this information to allergic individuals so that they can respond to changing outdoor conditions. Studies of the relationship between artificial and natural exposure to pollen and development of symptoms have provided improved understanding into how much pollen it takes to cause symptoms. Thresholds for pollen counts that trigger symptoms vary by pollen type, sensitivity of the population, and interactions with other atmospheric exposures. Strategies to inform the public when the pollen count poses a health risk have been proposed along with computerized systems that provide personalized pollen alerts. The best performing public notification system was a "traffic light system" that reported pollen exposure as low, 0-30; intermediate, 31-50; or high, 51-150. This system outperformed other threshold systems used in Sweden and in Britain/Denmark. Continued improvements in pollen forecasting models combined with data provided by automated pollen counters and better public reporting should permit allergic individuals and urban planners to adapt effectively to changes in outdoor aeroallergen exposures.

Parietaria Allergy: An Intriguing Challenge for the Allergist

Parietaria pollen is the most important cause of pollen allergies in the Mediterranean area, as Parietaria is widespread in this region. Many issues are associated with Parietaria allergy, including the duration of the pollen season (many doctors in fact believe that it lasts throughout the year), pollen load (which seems to be increasing over time), the impact of age (on IgE production and symptom severity), inflammatory changes (after pollen exposure), and the choice of allergen immunotherapy (AIT). In addition, molecular diagnostics allows for the defining of a correct diagnosis, differentiating between mere sensitization and true allergy. This review considers these topics and will hopefully help the allergist in clinical practice. Parietaria allergy is an intriguing challenge for the allergist in clinical practice, but it may be adequately managed by knowing the peculiarities of respective territories and the clinical characteristics of each patient.

Monosensitization and polysensitization in allergic rhinitis

BACKGROUND

Polysensitization is common in patients with allergic rhinitis (AR) and may affect clinical feature. However, there are patients who remain monosensitized.

OBJECTIVE

This cross-sectional study aimed at evaluating a large cohort of AR patients to define the percentage and the features of mono- and poly-sensitized subjects.

METHODS

This observational cross-sectional study included a large group of AR patients: 2415 subjects (1958 males, mean age 24.6 ± 5 years) were consecutively evaluated. Symptom severity, type and number of sensitizations, and AR duration were considered.

RESULTS

621 patients (25.7%) were monosensitized: 377 to Parietaria, 194 to house dust mites, 19 to birch, 17 to grasses, 12 to molds, 2 to olive, and 1 to cypress. There was no difference between mono- and polysensitized patients concerning the duration of rhinitis (6 ± 2.14 years vs 6 ± 3.7). Severity of symptoms was higher in polysensitized patients than in monosensitized (p<0.05); in addition, there was a difference among monosensitized patients: Parietaria-allergy induces the most severe symptoms.

CONCLUSION

This study conducted in a large AR population might suggest that monosensitized and polysensitized AR patients could constitute two different categories. In addition, the specific type of allergy may condition the clinical feature.

Thirty-year survey on airborne pollen concentrations in Genoa, Italy: relationship with sensitizations, meteorological data, and air pollution

BACKGROUND

Pollen allergy represents a relevant health issue. Betulaceae sensitization significantly increased in Genoa, Italy, in the last decades. This study investigated possible relationships among pollen count, meteorological changes, air pollution, and sensitizations in this city during a 30-year period.

METHODS

Betulaceae, Urticaceae, Gramineae, and Oleaceae pollen counts were measured from 1981 to 2010 in Genoa. Sensitization to these pollens was also considered in large populations of allergic patients. Meteorological parameters and pollutants were also measured in the same area.

RESULTS

Betulaceae sensitization increased over time. All pollen species significantly increased over this time. Pollen season advanced for Betulaceae and Urticaceae. Only Urticaceae season significantly increased. Temperature increased while rainfall decreased over the time. Pollutants significantly decreased. There were some relationships between pollen changes and climatic and air pollution parameters.

CONCLUSION

This 30-year study conducted in an urbanized area provided evidence that Betulaceae sensitization significantly increased, pollen load significantly augmented, and climate and air pollution changed with a possible influence on pollen release.

Nasal resistance and allergic inflammation depend on allergen type

BACKGROUND

Allergic rhinitis is characterized by inflammatory cell infiltrate and increased nasal airflow resistance.

OBJECTIVE

The aim of this study was to evaluate the relationship between sensitization type, inflammatory cell pattern, and nasal airflow resistance in a group of rhinitics with monosensitization.

METHODS

Seventy-seven subjects (40 males and 37 females, with a mean age of 33 +/- 4.4 years) suffering from allergic rhinitis were studied. Skin prick test, nasal cytology and electronic rhinomanometry were assessed in all subjects.

RESULTS

The number of subjects monosensitized to house dust mites was 23, to grasses 20, to cypress 17, to Parietaria 11, and to olive tree 6. Significant differences were observed between each type of allergen sensitization concerning both the nasal airflow resistance (p = 0.002) and the nasal cytology pattern: eosinophils (p = 0.004), degranulated eosinophils (p = 0.002), mast cells (p = 0.006) and degranulated mast cells (p = 0.008). Furthermore, goblet cells were higher in house dust mite-sensitized subjects compared with the pollen-sensitized group (p = 0.018), in which a prevalence of eosinophils, degranulated eosinophils, mast cells and degranulated mast cells was observed (p = 0.049, p < 0.001, p = 0.022 and p = 0.007, respectively). Nasal resistances were higher in the pollen group (p = 0.001).

CONCLUSIONS

This study provides evidence that inflammatory cell pattern and nasal resistance depend on the type of allergen sensitization.

Long distance transport of ragweed pollen as a potential cause of allergy in central Italy

BACKGROUND

Ambrosia pollen is an important allergen in North America and, as recently discovered, in some European countries. In Italy, the most affected area is the northeast, whereas ragweed has not been reported in the central and southern parts of the country.

OBJECTIVE

To identify the source of ragweed pollen detected in Florence and Pistoia in central Italy.

METHODS

Ragweed pollen data were collected in Florence and Pistoia for a 6-year period (1999-2004). The relationship between pollen counts and local ground prevalent wind directions was evaluated with analysis of variance and the least significant difference test. Weather conditions were also evaluated on a large-scale circulation pattern by analyzing weather maps and air mass back trajectories.

RESULTS

A highly statistically significant relationship between daily prevailing wind direction and pollen count was found in the period under investigation; the ragweed pollen peaks were recorded when winds from northeast in Florence and north-northeast in Pistoia were observed. The synoptic weather situation and the path of back trajectories suggest an area around southern Hungary as a possible source of Ambrosia pollen. Furthermore, the pollen count was above the clinical threshold several times in both Florence and Pistoia.

CONCLUSIONS

Several factors indicate that the detection of ragweed pollen in central Italy is due to long distance transport. Taking into consideration the high allergenicity of Ambrosia pollen, the present findings, if confirmed, suggest that the number of sensitized individuals might significantly increase in the near future.

The natural history of allergy: the development of new sensitizations in asthmatic children

Allergy is an important risk factor for asthma in children as most of asthmatic children are sensitized. The aim of the study was to investigate the natural course of sensitizations in a group of children (340) at the onset of asthmatic symptoms. We subdivided children in three groups depending on the age at first visit (3-7-11 years) and followed them for 4 years. All children underwent three visits, each including skin prick test, every two years. In the 3-year age group (n = 133), 59% of children were sensitized at first visit, but the percentage increase to 88% at third visit. When looking only at allergic children at first visit (261), we demonstrated that polysensitization became higher than monosensitization since the age of 11. Analysis of sensitization distribution over the time revealed that house dust mites were prominent from the age of 3 years. Parietaria and grass pollens as well as olive pollen significantly increased, particularly during the 4-year follow-up in the 7-year group. Analysis of sensitization score demonstrated that the age range from 3 to 11 is at high risk to polysensitization. In conclusion, this study provides evidence that sensitization is frequent in asthmatic children, polysensitization represents the natural history of allergy and the type of immune response should appear different for each allergen.

The role of climate on the geographic variability of asthma, allergic rhinitis and respiratory symptoms: results from the Italian study of asthma in young adults

BACKGROUND

Variations in the prevalence of respiratory symptoms according to geo-climatic factors could provide important clues to the knowledge of the aetiology of asthma.

METHODS

Geo-climatic variations in the prevalence of current asthma, allergic rhinitis and chronic cough, and phlegm were assessed on a random sample of 18 873 subjects (response rate = 72.7%) from different climatic regions of Italy. An ecological analysis, supported by robust statistical methods, was employed to investigate potential trends.

RESULTS

The prevalence of all symptoms was significantly heterogeneous throughout the peninsula. Only asthma-like symptoms showed a north-south trend: the prevalence increased at a decreasing latitude [odds ratio (OR) varies from 0.92 to 0.96, P < 0.05], at a decreasing distance from the sea (OR: 0.90-0.93 for 30 km distance, P < 0.05), at higher annual mean temperatures (OR: 1.11-1.14, P < 0.05) and at smaller annual temperature ranges (OR: 0.94-0.95, P < 0.05). Of the geo-climatic variables considered, temperature range had the greatest influence on most asthma-like symptoms. No association was found between geo-climatic variables and allergic rhinitis or chronic cough and phlegm.

CONCLUSIONS

Asthma prevalence seems to be significantly affected by climate as asthma-like symptoms were more common in central-southern Italy, with a Mediterranean climate, than in areas with a continental climate (northern Italy).

Onset of allergy and asthma symptoms in extra-European immigrants to Milan, Italy: possible role of environmental factors

BACKGROUND

Allergy and asthma are typical disorders of the affluent societies. Migrants from developing to industrialized countries seem to be at increased risk of allergy and asthma development.

OBJECTIVE

To evaluate time of onset, spectrum of sensitization and clinical features in a population of extra-European immigrants to Milan, Italy, complaining of allergy and asthma symptoms.

METHODS

Data regarding 243 extra-European immigrants checked at an allergy clinic from 1994 to 2000 were collected retrospectively. The demographic data were compared with those of the extra-European immigrants living in Milan at the end of 1999.

RESULTS

The patients were complaining of asthma (63.7%), rhinoconjunctivitis (56.7%), rhinitis alone (21%) or urticaria (3%). One hundred and eighty-seven out of 222 patients (84.3%) declared they were healthy before migrating and allergy/asthma symptoms started to appear after their arrival in Italy, namely after an average period of 4 years and 7 months. The proportion of male patients was lower than the proportion of men in the extra-European immigrant population (48% vs. 55%), suggesting that in adult immigrants allergy and asthma are more common in women than in men. Furthermore, there was an over-representation of Central-South Americans attending the clinic, which seemed to be due to a genetic predisposition to allergy/asthma development. When data were analysed for single countries, a trend towards an increased risk of allergy and asthma was found in immigrants from all Central-South American countries. A skin test positivity for at least one inhalant allergen was found in 196 out of 232 patients (81%), and the spectrum of allergic sensitization was similar to that of the Italian population living in the North of Italy.

CONCLUSION

Most extra-European immigrants declared that they were healthy at home and that allergy and asthma symptoms had appeared after immigration to Milan; lifestyle and environmental factors in a western industrialized city seem indeed to facilitate allergy/asthma onset in immigrants from developing countries. Allergy/asthma risk seems to be different in different ethnic groups.

Purification and characterization of the main allergen of Plantago lanceolata pollen, Pla l 1

English plantain (Plantago lanceolata) pollen is an important cause of pollinosis in the temperate regions of North America, Australia and Europe. However, very little is known about its allergen composition. The aim of this study was to identify plantain allergens, and to isolate and characterize a major allergen. Allergens were identified by immunoblotting with individual allergic patients' sera. Isolation of the major allergen was achieved by sequential reverse-phase and size-exclusion HPLC. Allergenic characterization was performed by ELISA and immunoblotting after SDS-PAGE with sera from plantain-allergic patients. N-terminal amino acid sequence was established by Edman degradation. Allergograms showed that 13 out of the 14 sera assayed had IgE to a group of proteins with a molecular weight in the range of 16-20 kd, that turned out to be different isoforms or variants of the major allergen Pla l l. Eighteen amino acid residues from the N-terminal end of one of the isoforms, and 10 of three others, were sequenced, and a partial sequence identity with Ole e 1 was found. Prevalence of specific IgE to purified Pla l 1 in plantain allergic patients was 86%, and represents about 80% of the total IgE-binding capacity of the plantain extract. The most relevant allergen from P.lanceolata pollen, Pla l 1, has been purified and characterized. This contributes to a greater knowledge of the allergen composition of this important weed, and clears the way for the standardization of plantain allergen products in terms of major allergen content.

Ash (Fraxinus excelsior)-pollen allergy in central Europe: specific role of pollen panallergens and the major allergen of ash pollen, Fra e 1

BACKGROUND

The role of ash (Fraxinus excelsior) pollen as a cause of spring pollinosis in central Europe has received little attention. It is not clear whether ash pollen is a primary cause of sensitization or whether it is implicated through cross-sensitization to other pollens.

METHODS

Over a 22-month period, ash pollen was included in a screening series for inhalant allergies. Pollen data were documented from 1976 through 1999. The frequency of IgE-binding to the ash-specific allergen Fra e 1 and pollen panallergens, respectively, was compared by Western blot between mono- (n = 6), oligo- (n = 16), and polysensitized (n=25) patients.

RESULTS

Of 5,416 consecutive patients sensitized to any pollen, 920 (17.6%) had a positive skin prick test to ash. Total pollen counts varied extensively between years (229-5,351) as did peak concentrations (23-837 grains/m3/24 h). Western blotting revealed Fra e 1 sensitization in 100% of monosensitized, 93% of oligosensitized, but only 44% of polysensitized patients. IgE against profilins (Fra e 2), Ca-binding proteins (Fra e 3), and carbohydrate epitopes in the three groups was found in 0/0/17%, 0/19/31%, and 32/72/60%, respectively. At least 50% of sera from patients with Fra e 1 sensitization did not bind with the protein in Western blots under reducing conditions.

CONCLUSIONS

Ash pollen should be considered a relevant factor and distinct entity in spring pollinosis. In all, only 20% of positive skin tests to ash appear to result from cross-sensitization to pollen panallergens.

Prevalence of pollinosis in the Basque Country

BACKGROUND

The prevalence of allergic diseases, mainly pollinosis, has increased within the last decades. Our study aimed to determine the prevalence of sensitization to Poaceae pollen in the Basque Country. This is a region of northern Spain, with an area of 7261 km2 and a population of 2109009 inhabitants. Two different climatic regions may be distinguished in the Basque Country (the Atlantic and the Oceanic).

METHODS

A transversal study was carried out on 2216 subjects, aged 10-40 years. A personal interviewwas carried out in order to compile study data, by means of a questionnaire that had been previously validated with a clinical history and an allergy study.

RESULTS AND CONCLUSIONS

Our results show the prevalence of pollinosis in the Basque Country to be 10.6% (C.I. 95% 9.35-11.96%) without significant differences between men and women. The prevalence in the Atlantic climate area (9.71%) was lower than in the Oceanic climate area (13.61%). There were no differences between persons living in a rural environment (10.87%) and those living in an urban setting (10.51%). Pollinosis was more frequent in individuals aged 10-20 (11.41%) and 20-30 (12.54%) than those aged 30-40 years (7.43%). Three features significantly distinguished pollinic from nonpollinic patients: 1) a more common complaint of symptoms after ingestion of Rosaceae fruits or nuts (10.2%) 2) a family history of atopy (8.8%) 3) a greater occurrence of bronchial asthmatic symptoms (23%).

Local nasal immunotherapy with extract in powder form is effective and safe in grass pollen rhinitis: a double-blind study

BACKGROUND

Local nasal immunotherapy has been studied, by means of an extract in powder form, in patients with allergic rhinitis caused by grass pollen.

METHODS

Thirty-two patients allergic to grass were studied for 37 weeks in a double-blind controlled trial. Subjects were selected on the basis of a positive history, skin test result, RAST finding, and result of intranasal challenge to grass pollen. Two 16-patient groups were randomly assigned to active or placebo treatment. The treatment lasted 26 weeks (14 for the build-up phase, 12 for the maintenance period).

RESULTS

No significant differences were observed in nasal symptoms during the treatment. During the pollen season the mean weekly symptom and medication scores were significantly lower in the treated group, compared with the control group, even considering each allergic symptom separately. Moreover, only in the treated group was a significant increase of specific nasal threshold to grass pollen observed after treatment.

CONCLUSIONS

This study indicates that local nasal immunotherapy with allergen in powder form can be a suitable alternative to the traditional subcutaneous immunotherapy in terms of clinical efficacy and safety in grass-allergic rhinitis.

Local nasal immunotherapy for birch allergic rhinitis with extract in powder form

BACKGROUND

Traditional subcutaneous immunotherapy has been proved effective in birch pollenosis. It has, however, some drawbacks as systemic reactions, which are rare but important. Local nasal immunotherapy (LNIT) represents a potential safer route of allergen administration.

OBJECTIVE

To study the clinical efficacy and safety of local nasal immunotherapy by means of an extract in powder form as treatment of birch allergic rhinitis.

METHODS

Thirty birch allergic patients have been selected on the basis of a positive history, skin test, radioallergosorbent test assay (RAST) and specific nasal challenge. Two 15 patient groups were randomly assigned to the active treatment or to the placebo one. Treatment lasted 22 weeks (14 for the build-up phase and eight for maintenance period) and symptoms were recorded during the treatment and the birch pollen season.

RESULTS

The clinical efficacy of LNIT is suggested by a significant reduction of medication score only in the treated group during the pollen season, although the symptom score was significantly lower in the treated group for 1 week only. Moreover, a significant increase of specific nasal threshold dose was observed after treatment only in the active treated group. Mild adverse reaction to LNIT, limited to the upper respiratory tract, were reported during the treatment in the active group, but they did not interfere with LNIT schedule. No asthmatic or systemic reaction were observed.

CONCLUSIONS

This study indicates that LNIT with allergen in powder form has proven clinically effective in the treatment of birch allergic rhinitis. Further studies are needed to establish whether this treatment can be considered a real alternative to the traditional subcutaneous immunotherapy in birch allergic rhinitis.