Structural and Immunological Features of PR-10 Allergens: Focusing on the Major Alder Pollen Allergen Aln g 1.

Today, allergies have become a serious problem. PR-10 proteins are clinically relevant allergens that have the ability to bind hydrophobic ligands, which can significantly increase their allergenicity potential. It has been recently shown that not only the birch pollen allergen Bet v 1 but also the alder pollen allergen Aln g 1, might act as a true sensitizer of the immune system. The current investigation is aimed at the further study of the allergenic and structural features of Aln g 1. By using qPCR, we showed that Aln g 1 was able to upregulate alarmins in epithelial cells, playing an important role in sensitization. With the use of CD-spectroscopy and ELISA assays with the sera of allergic patients, we demonstrated that Aln g 1 did not completely restore its structure after thermal denaturation, which led to a decrease in its IgE-binding capacity. Using site-directed mutagenesis, we revealed that the replacement of two residues (Asp27 and Leu30) in the structure of Aln g 1 led to a decrease in its ability to bind to both IgE from sera of allergic patients and lipid ligands. The obtained data open a prospect for the development of hypoallergenic variants of the major alder allergen Aln g 1 for allergen-specific immunotherapy.

Simplified AIT for allergy to several tree pollens-Arguments from the immune outcome analyses following treatment with SQ tree SLIT-tablet.

BACKGROUND: The SQ tree SLIT-tablet (containing birch extract) proved clinically significant effects during the pollen season for birch as well as alder/hazel. Immune outcomes of this treatment for allergens from multiple birch homologous trees need further investigation. We hypothesize that birch pollen extract AIT modulates a highly cross-reactive immune response and that this may be the basis for the observed clinical cross-protection. METHODS: Blood samples were collected from 397 birch allergic patients during SQ tree SLIT-tablet or placebo treatment (1:1) for up to 40 weeks. Serum IgE and IgG4 specific to birch, and birch homologous tree pollens from alder, hazel, hornbeam, beech and chestnut were measured by ImmunoCAP. IgE-Blocking Factor (IgE-BF) for alder, birch and hazel during treatment was measured by Advia Centaur and blocking effects for birch and all these birch homologous tree pollens were further investigated by basophil activation (BAT). Antibody readouts were investigated in patient subsets. T-cell responses (proliferation) to allergen extracts and peptide pools (group 1 allergens) were investigated in T-cell lines from 29 untreated birch pollen-allergic individuals. RESULTS: Significant Pearson correlations between serum IgE towards birch, alder, hazel, hornbeam and beech were observed (r-values > .86). T-cell reactivity was observed throughout the birch homologous group. Almost identical kinetics for changes in IgE towards birch, alder and hazel were observed during treatment and similar species-specific changes were seen for serum-IgG4 . IgG4 reactivity towards birch and alder, hazel, hornbeam and beech correlated significantly at end-of-treatment (r-values > .72). Treatment resulted in similar IgE-BF kinetics for alder, birch, and hazel and blocking of BAT for multiple trees in most actively treated patients investigated. CONCLUSIONS: Systematic analyses of T-cell and antibody cross-reactivities before and during birch pollen extract AIT provide the immunological basis for the observed clinical effect of SQ tree SLIT-tablet treatment of tree pollen allergy induced by multiple trees in the birch homologous group.

Allergenicity at component level of sub-pollen particles from different sources obtained by osmolar shock: A molecular approach to thunderstorm-related asthma outbreaks.

BACKGROUND: The so-called "thunderstorm asthma" (TA) is an uncommon but dramatic outbreak of asthma attacks occurring during a thunderstorm in the pollen and moulds season. Mechanisms which make the pollen able to enter the deeper airways and provoke severe asthma symptoms are still unclear. OBJECTIVE: To test the hypothesis that sub-pollen particles (SPPs) originated from the rupture by an osmotic shock of pollen associated with TA contain allergens. METHODS: After hydration, SPPs released from pollen grains of grass, pellitory, olive, cypress, ragweed and birch were isolated and determined by microscopy. Allergens were determined by in vitro ELISA inhibition tests indirectly using the sera from 10 polyreactive patients. An inhibition <50% was considered as negative, 50%-75% moderate and > 75% complete. RESULTS: The inhibition experiments showed that the SPPs from birch and cypress were unable to inhibit serum IgE reactivity to Bet v 1 and Cup a 1, respectively. Ragweed SPPs inhibited ragweed pollen extract and Amb a 1 by 75.8 ± 0.11% and 81.2 ± 0.15%, respectively. Olive and pellitory SPPs retained almost the whole IgE-binding capability in all cases tested. Grass SPPs inhibited 32 ± 0.06% of Lolium perenne Lol p 1 and 65% of Phleum pratense extracts, but results were highly variable for individual allergens (97.5%-0.03% for Phl p 2, 45.3 ± 0.12% for Phl p 5, 24.7 ± 0.22% for Phl p 6, and 38.3 ± 0.2% for Phl p 1). CONCLUSIONS: Inhibition experiments confirm the hypothesis that SSPs obtained after the osmotic shock of pollen involved in TA, namely grass, pellitory and olive tree pollen, contain allergens and therefore they can induce severe asthma attacks during thunderstorms.

The prevalence of oral symptoms caused by Rosaceae fruits and soybean consumption in children; a Japanese population-based survey.

BACKGROUND: Pollen food Syndrome (PFS) to Rosaceae fruits and soybean, related to Bet v 1 homologue sensitization has been reported increasingly throughout Japan, possibly due to the wide distribution of alder. METHODS: In 2015, we conducted a school-based questionnaire survey among two age groups; students in primary school (Years 1-2) and secondary school (Years 8-9) from each of the 47 prefectures of Japan. We analyzed the prevalence, demographic and clinical characteristics of children with oral symptoms to Rosaceae fruits/soybean; defined as oral symptoms occurring shortly after ingesting apple, peach, cherry or soybean. Additionally, we assessed the correlation between the prevalence and external data on alder sensitization rates by prefecture. RESULTS: Responses from 41,264 primary and 35,302 secondary school students were analyzed. The prevalence of oral symptoms to Rosaceae fruits/soybean was 0.99%, 95%CI: 0.89-1.09% and 2.75%, 95%CI: 2.59-2.93% among each age group, respectively. Children with oral symptoms were more likely to have parental and personal history of allergic disease compared to those without symptoms. Oral symptoms were experienced more often in children with severe spring allergic rhinitis or have both allergic rhinitis and wheeze. There was a strong correlation between the prevalence of oral symptoms and alder sensitization rates by prefecture among both age groups (r = 0.63, p < 0.001 and r = 0.76, p < 0.001, respectively). CONCLUSIONS: Oral symptoms to Rosaceae fruits/soybean, which is suggestive of PFS was reported by 1-3% Japanese school children. It was associated with the geographic alder sensitization rate, supporting the underlying sensitization to Bet v 1.

Decreased viability and proliferation of CHANG conjunctival epithelial cells after contact with ultraviolet light-irradiated pollen.

CONTEXT: Contact with pollen is the major reason for the development of allergic symptoms on the ocular surface leading to a significant increase of allergic diseases worldwide. Environmental changes such as increased ultraviolet (UV) radiation and air pollution are discussed as contributory causes for this increase. OBJECTIVE: We investigated the effect of UV light on the histamine content of pollen and examined if an irradiation of pollen affects the viability and proliferation of conjunctival cells. MATERIALS AND METHODS: Alder (Alnus glutinosa) and hazel (Corylus avellana) pollen were irradiated for different time periods with sunlight, UV-A or UV-B light and the histamine content was analysed and compared with non-irradiated pollen. Conjunctival epithelial cells (CHANG cells) were exposed to irradiated and non-irradiated pollen followed by an assessment of cell viability with the colorimetric MTS test and the impedance-based measurement of cell proliferation using the xCELLigence real-time analysis system. RESULTS: UV light irradiation increased the histamine level of alder and hazel pollen in a dose-dependent manner. CHANG cells treated with irradiated pollen induced a statistically significant higher decrease of cell viability than treatment with non-irradiated pollen. DISCUSSION AND CONCLUSIONS: Our results indicate that UV light is able to alter pollen thus making them more harmful for conjunctival cells.

Diarylheptanoids from Alnus nepalensis attenuates LPS-induced inflammation in macrophages and endotoxic shock in mice.

Diarylheptanoids, a group of plant secondary metabolites are increasingly recognized as potential therapeutic agents. The aim of study was to ascertain the anti-inflammatory profile of diarylheptanoids from Alnus nepalensis against lipopolysaccharide (LPS)-induced inflammation in macrophages and endotoxic shock in mice. Extracts prepared from dried leaves of A. nepalensis using standard solvents were tested against LPS-induced inflammation in macrophages. Among all, butanol extract (ANB) has shown most significant inhibition of pro-inflammatory cytokines without any cytotoxicity. HPLC analysis of ANB showed the presence of diarylheptanoids. The diarylheptanoids were further isolated and tested in-vitro for anti-inflammatory activity. Treatment of isolated diarylheptanoids (HOG, ORE and PLS) was able to reduce the production and mRNA level of pro-inflammatory cytokines (TNF-α and IL-6). Furthermore, we demonstrated that it inhibited the expression of NF-kB protein in LPS-induced inflammation in macrophages. In-vivo efficacy and safety profile of ANB revealed that oral treatment of ANB was able to improve the survival rate, and inhibited the production of pro-inflammatory cytokines in serum, attenuated vital organ injury in a dose dependent manner without any toxic effect at higher dose in mice. The results suggest that diarylheptanoids from A. nepalensis can be considered as potential therapeutic candidates for the management of inflammation related diseases.

[Exposure to alder, hazel and birch pollen and PM10 dust concentration in Krakow in 2010-2015].

PM10, one of the air pollution components has a significant effect on plant pollen by the deposition on the surface of pollen grains, morphological changes of pollen walls and interference in the structure of the allergenic proteins. The aim of the study was to verify whether and in what weather conditions the concentration of pollen of alder, hazel and birch coincides with the elevated level of PM10 in Kraków, in 2010-2015. In the days when the alder pollen concentration exceeded 95 PG/m3, causing severe inhalant allergy symptoms and the concentration of hazel pollen was >80 PG/m3 and the admissible level of PM10 was exceeded, the maximum air temperature ranged from 5.1 to 22.6oC, the days were dry (humidity <60%), without precipitation and mostly windless. High concentration of birch pollen and exceeded admissible level of PM10 concentration were found in more than 60% of the days in the city center. In 70.3% of the days in which the birch pollen concentration reached values that caused the symptoms of asthma (>155 PG/m3), the dust concentration was exceeded (>50µg/m3), and rainfall and wind speed of 1-3 m/s occurred. Symptoms in people allergic to trees pollen in Kraków can be exacerbated during periods when the standard limits of PM10 are exceeded. Such situations have occurred mostly in March (pollen of alder and hazel) and April (birch pollen), especially in the city center.

Prevalence of ragweed allergy in rural Geneva - a pilot study.

OBJECTIVE: The prevalence of ragweed allergy is increasing worldwide. Ragweed distribution and abundance is spreading in Europe in a wide area ranging from the Rhone valley in France to Hungary and Ukraine, where the rate of the prevalence can peak at as high as 12%. Low-grade ragweed colonisation was seen in Geneva and Ticino, less than two decades ago. There were fears that allergies to ragweed would increase Switzerland. The intent of this study was to assess the rate of prevalence of sensitisation and allergy to ragweed in the population living in the first rural Swiss setting where ragweed had been identified in 1996, and to evaluate indirectly the efficacy of elimination and containment strategies. MATERIAL AND METHODS: In 2009, 35 adults in a rural village in the Canton of Geneva were recruited. Data were collected by means of questionnaires and skin-prick tests were done on each participant. The study was approved by the local Ethics Committee. RESULTS: Based on questionnaires, 48.6% had rhinitis (95% confidence interval [CI] 32.9-64.4; n = 17/35) and 17.1% asthma (95% CI 8.1-32.6; n = 6/35). Atopy was diagnosed in 26.4% (95% CI 12.9-44.4) of the sample (n = 9/34). Ragweed sensitisation was found in 2.9% (95% CI 0.7-19.7; n = 1/34), mugwort sensitisation in 2.9% (95% CI 0.1-14.9; n = 1/35), alder sensitisation in 17.1% (95% CI 6.6-33.6; n = 6/35), ash sensitisation in 12.5% (95% CI 3.5-29.0; n = 4/32) and grass sensitisation in 22.9% (95% CI 10.4-40.1; n = 8/35). Ragweed (95% CI 0.1-14.9; n = 1/34) and mugwort allergies (95% CI 0.1-14.9; n = 1/35) were both found in 2.9% of the population. CONCLUSION: This study showed a surprisingly low incidence of ragweed sensitisation and allergy, of 2.9% and 2.9%, respectively, 20 years after the first ragweed detection in Geneva. The feared rise in ragweed allergy seems not to have happened in Switzerland, compared with other ragweed colonised countries. These results strongly support early field strategies against ragweed.

Diarylheptanoid hirsutenone prevents tumor necrosis factor-alpha-stimulated production of inflammatory mediators in human keratinocytes through NF-kappaB inhibition.

Keratinocytes may play an important role in the pathogenesis of skin disease in atopic dermatitis. Diarylheptanoids such as oregonin and hirstanonol are demonstrated to have anti-inflammatory and anti-oxidant effects. The present study was to investigate the effect of hirsutenone, one of the diarylheptanoids, against tumor necrosis factor (TNF)-alpha-stimulated responses in human keratinocytes. Hirsutenone attenuated the TNF-alpha-induced production of cytokine IL-8, prostaglandin E(2) and chemokine CCL27, and the formation of reactive oxygen/nitrogen species in keratinocytes. Immunosuppressants (dexamethasone and cyclosporin A) inhibited the TNF-alpha-elicited formation of IL-8, prostaglandin E(2) and CCL27, but did not affect formation of reactive species. Bay 11-7085 (an inhibitor of NF-kappaB activation) and anti-oxidant N-acetylcysteine attenuated the TNF-alpha-induced formation of inflammatory mediators and reactive species. Hirsutenone, dexamethasone, cyclosporin A and Bay 11-7085 inhibited the TNF-alpha-induced phosphorylation of inhibitory kappaB and the activation of nuclear factor (NF)-kappaB. The results show that hirsutenone seems to reduce the TNF-alpha-stimulated production of inflammatory mediators in keratinocytes by suppressing the activation of NF-kappaB that may be mediated by reactive oxygen species. The findings suggest that hirsutenone may exert an inhibitory effect against the pro-inflammatory mediator-induced skin disease.

[Correlation of oral allergy syndrome due to plant-derived foods with alder pollen, rbet v 1 and rbet v 2 sensitization in Yokohama region].

BACKGROUND/AIM: Oral allergy syndrome (OAS) to plant foods is often caused by cross-reactivity to pollen. We investigated whether there was any significant correlation between sensitization to the pollen of alder and Japanese cedar flying off in spring and prevalence of OAS in Yokohama region. METHODS: We measured specific IgE antibodies (CAP-FEIA: CAP) against alder and Japanese cedar in 337 outpatients with skin allergy in 2005 (M:F=167:170, 33.4 years of age, on the average). In the patients who showed positive response to CAP against alder and Japanese cedar, we also tested response to CAP against rBet v 1 and rBet v 2. In addition, we statistically analyzed whether there was any correlation between prevalence of OAS and sensitization to the pollen. RESULTS: Ratio of positive response to CAP against alder was 23.4% (79 cases) while that to CAP against Japanese cedar was 73.7% (244 cases). Response to CAP against rBet v 1 and rBet v 2 was tested in 55 cases, and the ratio of positive response to CAP against rBet v 1 was 43.6% (24 cases) while that to CAP against rBet v 2 was 27.3% (15 cases). Prevalence of OAS showed a significant positive correlation (p<0.001) with sensitization to alder, but no correlation with sensitization to Japanese cedar. CONCLUSION: It was suggested that sensitization to alder pollen would be involved in prevalence of OAS in Yokohama region.

Allergen-induced in vitro expression of IL-18, SLAM and GATA-3 mRNA in PBMC during sublingual immunotherapy.

BACKGROUND: Signalling lymphocytic activation molecule (SLAM) and interleukin (IL)-18 induce interferon (IFN)-gamma production from Th1 cells. The allergen-induced SLAM and IL-18 mRNA expressions are increased during subcutaneous immunotherapy (SCIT), but nothing is known about their role during sublingual immunotherapy (SLIT). Transcription factor GATA-3 is associated with Th2 cells but its role in SCIT and SLIT is yet unexplored. This study was undertaken to analyse the allergen induced in vitro mRNA expression of IL-18, SLAM and GATA-3 in peripheral blood mononuclear cells (PBMC) of children with allergic rhinitis (AR) during SLIT. METHODS: Ten patients with AR undergoing pollen SLIT with a weekly dose of 200,000 SQ-U, 10 with 24,000 SQ-U of mixture of Betula verrucosa, Corylus avellana and Alnus glutinosa and 10 with placebo were included. Peripheral blood mononuclear cell were stimulated with birch extract prior to, after 1 and 2 years of the treatment. The mRNA expression was assessed using kinetic real-time RT-PCR (TaqMan); Applied Biosystems, Foster City, CA, USA). RESULTS: The expression of IL-18 mRNA was increased in the high-dose group in comparison to the placebo group after 1 year of therapy (P = 0.028) and had an inverse correlation with the late phase skin reaction after the second study year (r = -0.41, P = 0.041). SLAM mRNA expression increased in the high-dose group from baseline to 1 year (P = 0.028) and correlated with IL-10 (r = 0.96, P < 0.0001) and transforming growth factor-beta (r = 0.80, P = 0.0037) mRNA expression. No significant changes were seen in GATA-3 mRNA expression. CONCLUSIONS: During SLIT, IL-18 and SLAM are upregulated, suggesting that the Th2 type inflammatory response is downregulated during SLIT by increased Th1 type response.

Incidence of Betulaceae pollen and pollinosis in Zagreb, Croatia, 2002-2005.

Pollen allergy is characterized by seasonal allergic manifestations affecting patients during the plant pollen season. The aim of this study was to analyze the Betulaceae pollen pattern in Zagreb (2002-2005) and to determine the incidence of sensitization to these pollen types in patients with seasonal respiratory allergy. Twenty-four-hour pollen counts were carried out using volumetric procedure. Skin prick test were performed on a total of 864 patients aged 18-80< in Zagreb between 2 January-31 December 2004. Pollen of the representatives of the family Betulaceae accounted for a significant proportion of total pollen (34% on an average), predominated by Betula pollen and considerably lower proportion of Alnus sp. and Corylus sp. pollen. Alder and hazel pollen first occurred in the air in February throughout the study period. The highest airborne pollen concentration of these taxa was recorded in February and March. The birch pollen season generally peaked in April. Only 2.67% of patients showed birch pollen monosensitization. The proportion of patients with polysensitization to Betulaceae pollen was considerably greater (12.88%), whereas polysensitization to Betulaceae, Poaceae and Ambrosia pollen was recorded in the highest proportion of patients (26.23%). According to age, the highest and lowest rate of allergy was recorded in the 31-50 and >51 age groups, respectively (46.22% vs 23.12%). Female predominance was observed across all age groups. The patients with monosensitization to birch pollen had the most severe symptoms in April. In the patients with poylsensitization to alder, hazel and birch pollen who developed cross-reaction, initial symptoms occurred as early as February, with abrupt exacerbation in March and April. The most severe condition was observed in the patients allergic to birch, hazel, alder, grass and ragweed pollen, with symptoms present throughout the year and exacerbation in spring and late summer months.

Regional importance of Alnus pollen as an aeroallergen: a comparative study of Alnus pollen counts from Worcester (UK) and Poznan (Poland).

Daily average Alnus pollen counts (1996-2005) from Worcester (UK) and Poznan (Poland) were examined with the aim of assessing the regional importance of Alnus pollen as an aeroallergen. The average number of Alnus pollen grains recorded annually at Poznan was more than 2.5 times that of Worcester. Furthermore, daily average Alnus pollen counts exceeded the thresholds of 100, 500 and 1,000 grains/m3 more times at Poznan than Worcester. Skin prick test results (1996-2005) and allergen-specific IgE (asIgE) measurements using the CAP (Pharmacia) system (2002-2005), were supplied by the Allergic Diseases Diagnostic Centre in Poznan. The annual number of positive skin prick tests to Alnus pollen allergens was significantly related (p<0.05) to seasonal variations in the magnitude of the Alnus pollen catch recorded at Poznan (r=0.70). The symptoms of patients with positive skin prick tests to Alnus pollen allergens were: 51% pollinosis, 43% atopic dermatitis, 4% asthma, 1% chronic urticaria and 1% eczema. On a scale of 0-6, 20.5% of patients examined for serum asIgE in relation to Alnus pollen allergens had asIgE measurements in classes 5 and 6. Alnus pollen is generally considered to be mildly allergenic. However, the amount of Alnus pollen released into the atmosphere in places such as Poznan may increase its impact on the population and make it one of the more important aeroallergens present.

Clinical efficacy and safety of sublingual immunotherapy with tree pollen extract in children.

BACKGROUND: Subcutaneous immunotherapy has been the principal approach of immunotherapy in the treatment of allergic diseases. Several clinical studies with birch, alder or hazel pollen extract conducted as subcutaneous immunotherapy have been published suggesting a well-tolerated and clinically effective treatment. Only a few clinical studies of sublingual immunotherapy (SLIT) with these allergens have been published. This study investigated the clinical efficacy, safety and dose-response relationship of SLIT in children suffering from rhinoconjunctivitis with/without asthma. METHODS: Eighty-eight children (5-15 years) with a history of tree pollen-induced allergic rhinoconjunctivitis with/without seasonal asthma for >or=2 years were included. Allergy to tree pollen was confirmed by positive skin-prick test, positive specific IgE and positive conjunctival provocation test. The extract used was a glycerinated mixture of Betula verrucosa, Corylus avellana and Alnus glutinosa 100,000 SQ-U/ml. Children were randomized into three groups receiving SLIT 5 days a week for up to 18 months; dose group 1: accumulated weekly dose of 24,000 SQ-U; dose group 2: accumulated weekly dose of 200,000 SQ-U; and placebo. RESULTS: In the birch pollen season, dose group 2 showed a significant reduction of symptom (P = 0.01) and medication scores (P = 0.04) compared with placebo. Dose group 1 showed a significant reduction of symptom scores (P = 0.03). There were no statistical differences between dose groups 1 and 2. All children tolerated the treatment well. CONCLUSION: SLIT with tree pollen extract provided dose-dependent benefits in tree pollen-allergic children in terms of significantly reduced symptoms and medication use. The treatment was well tolerated.

Sublingual immunotherapy in children modulates allergen-induced in vitro expression of cytokine mRNA in PBMC.

BACKGROUND: During subcutaneous immunotherapy (SCIT), there is a local mucosal shift from Th2 to Th1 type cytokine predominance and downregulation of interleukin (IL)-5 and eosinophilia. According to recent studies IL-10- and transforming growth factor (TGF)-beta-induced tolerance is another key phenomenon in SCIT. Few data to date is available on mechanisms and roles of these cytokines in sublingual immunotherapy (SLIT). SCOPE: This study was undertaken to analyse the allergen-induced in vitro mRNA expression of IL-4, IL-5, IL-10, TGF-beta and interferon (IFN)-gamma during SLIT in peripheral blood mononuclear cells (PBMC) of children with allergic rhinitis (AR). METHODS: Ten patients with AR undergoing pollen SLIT with a weekly dose of 200,000 SQ-U, 10 with a weekly dose of 24,000 SQ-U of glycerinated mixture of Betula verrucosa, Corylus avellana and Alnus glutinosa and 10 with placebo were included in the study. Peripheral blood mononuclear cell samples were collected and stimulated with pollen allergen extract prior to the treatment, after 1 and 2 years of the treatment. The cytokine mRNA expression was assessed using kinetic real time reverse transcription polymerase chain reaction (RT-PCR; TaqMan). RESULTS: The in vitro allergen-induced mRNA expression of IL-5 by PBMC in the placebo group at 1 (P = 0.0065) and 2 (P = 0.013) years of therapy were increased in comparison with the highest dose. The expression of IL-10 mRNA was increased in the highest dose group (P = 0.0016) and the lower dose group (P = 0.034) at 2 years of therapy when compared with placebo. The change in the expression of allergen-induced TGF-beta had an inversed correlation with the change of IL-5 (r = -0.38, P = 0.036) and positive correlation with the change of IL-10 (r = 0.58, P = 0.0019). CONCLUSIONS: Sublingual immunotherapy induced a dose-dependent systemic allergen-specific immunological response in children with AR. During high-dose SLIT, there was activation of regulatory cytokine IL-10 and an inhibitory effect on IL-5 expression increase that was associated with TGF-beta.

Clinico-immunologic evaluation of allergy to Himalayan tree pollen in atopic subjects in India--a new record.

Exposure to local pollen allergens has a direct bearing on the prevalence of allergic symptoms among the inhabiting atopic population. The populations in the Himalayas and around it are exposed to a variety of pollen grains from trees growing in the region, but the pollen-population interaction has not been clinically investigated. Himalayan tree pollen from five different taxa, i.e. Alnus nitida (AN), Betula utilis (BU), Cedrus deodara (CD), Mallotus phillipensis (MP) and Quercus incana (QI) were evaluated for their allergenicity in the Indian population by in vivo (skin prick test) and in vitro (ELISA) clinico-immunological methods. The presence of specific IgE against these tree pollen in the sera of skin test positive patients was taken as evidence for sensitization to these pollen. The average skin positivity in atopic populations recorded at different allergy centers in India varied from 2.2% against AN, to 4.7% against MP pollen. Significantly raised specific IgE against these pollen were observed in the sera of hypersensitive patients. The sensitization pattern to Himalayan tree pollen in these atopic populations varied. It was concluded that skin prick test positivity and raised IgE antibodies specific to AN, BU, CD, MP and QI established Himalayan tree pollen as important sensitizers in the atopic populations of India. A high incidence of skin sensitivity was observed to pollen antigens of Cedrus deodara, Mallotus phillipensis and Quercus incana in patients of Chandigarh residing in the hills and foothills of the Himalayas while Alnus nitida, Betula utilis and Cedrus deodara were important sensitizers in Delhi patients. The skin sensitization pattern against these pollen was in accordance with the level of exposure to these pollen of the subjects residing in that part of the country.

[Polyclonal antisera to birch pollen allergen for the air allergen screening]. / Poliklonal'nye antisyvorotki protiv allergena pyl'tsy berezy dlia skrininga aéroallergenov.

The cross reactivity of the pollen allergens of birch (Betula pendula), hazel (Corylus avelana), alder (Alnus glutinosa), wormwood (Artemisia absinthium), oak (Quercus robur) and ashtree (Fraxinus excelsior) was studied by the methods of the enzyme immunoassay and gel diffusion with the use of rabbit polyclonal antisera (PAS) prepared against birch pollen allergen. PAS was shown to be greatly related to all above-mentioned allergens with the exception of oak pollen allergen. PAS was found capable of forming precipitates in the layer of agar gel only with birch pollen allergen. A proposal was made to use PAS, in view of the established specific features of its immunochemical properties, in the development of test systems for the ecological monitoring of biotopes.

Abortive pollen germination: a mechanism of allergen release in birch, alder, and hazel revealed by immunogold electron microscopy.

BACKGROUND: Pollen from early-flowering trees (eg, birch, alder, hazel) represent major seasonal allergen sources. The effects of rain on the release of allergens from tree pollen has thus far not been studied at the ultrastructural level. OBJECTIVE: This study was designed to investigate the effects of rain on the morphology of pollens from early-flowering trees and of potential rain-induced mechanisms of allergen release. METHODS: Freshly collected pollen grains (birch, alder, and hazel) were exposed under controlled conditions to rainwater. Changes of pollen morphology and the release of allergens were analyzed by scanning electron microscopy. The release of allergen-bearing submicronic particles was studied by field emission scanning electron microscopy and transmission electron microscopy in conjunction with immunogold staining by using antibodies with specificity for the major allergens. RESULTS: Scanning electron microscopy showed that freshly isolated pollen grains from birch, alder, and hazel have abortive germination in rainwater. Abortive pollen germination is characterized by the formation of short pollen tubes, which rupture at their tips and release micronic and submicronic particles containing major allergens. Immunogold transmission electron microscopy provided evidence that the allergens are transported through the pollen tubes during germination. CONCLUSIONS: Rainwater-induced release of allergen-bearing submicronic particles from abortively germinated tree pollens may represent a mechanism of allergen release, with important implications on the induction of asthma as well as on current methods for measuring environmental allergen exposure.