Pollen Survey By Volumetic Sampler In Beijing City And Cross-reactivity Research Between Ragweed And Mugwort In Vitro

Backround:Airborne Pollen in the environment is a main cause of seasonal rhinitis and asthma. Severity of symptoms is a quantitatively related to pollen concentration.Pollen survey is clinically valuable,and pollen grading may facilitate the explanation of pollen report. Artemisia(Ar) and Ambrosia(Am) are both Compositae.Artemisia is one of important aeroallergen in late summer and autumn in Beijing,but Ambrosia pollen is uncommon in air.Am-specific IgE or Am positive skin test was reported in many patients who is sensitive to Ar.What kind of the specific immunotherapy and its clinical application are under discussion.Object:To investigate concentration and to define pollen season with some common airborne pollen.To classify cypress and mugwort pollen concentration;and to investigate the potential cross- reactivity between mugwort and ragweed pollen or not.1 Pollen sampling was performed with a volumetric Burkard sampler from march to October 2007.2 Monosensitive Patients to mugwort or cypress pollen were included.Symptom scores and mugwort or cypress pollen concentration were analyzed.According to the results,mugwort and cypress pollen concentration grade were classified.3 According to skin internal test on mugwort and ragweed pollen,patients were devided into 2 groups:A:Ar~+/Am~-;B:Ar~+/Am~+.10 patients's serum were chosen to do laboratory test.western-blot,RAST inhibition and immunoblot inhibition assays were performed.Results:1 From March to October of 2007,there are two peaks of pollen concentration. One peak of tree pollen was found from March to May,and another one of weed pollen is from August to October.The highest pollen concentration was 315g/m~3 in spring and tree pollen was the main gredian.944g/m~3 was the highest pollen concentration in late summer and autumn,and weed pollen was the main component;There were three kinds of pollen in downtown of Beijing, weed(56%),tree(42%),grass(2%).2 Pollen composition during spring(March to May):there were more than ten kinds of tree pollen in the city,Broussonetia L'Herit ex Vent.(22%), Fraxinus L.(21%),CUPRESSACEAE(16%),Populus L.(8%), BETULACEAE(7%),GINKGOACEAE(6%),SalixL.(6%),Quercus L.(5%),PINACEAE(4%),others(5%,including Morns L.,Ailanthus Desf. And unknown).3 Pollen composition during late summer and autumn(from August to October):there were three kinds of pollen in the city,Cannabis L.and Humulus L.(51%), Artemisia L.(31%),CHENOP-PDIACEAE and AMARANTHACEAE(14%).4 The character of pollen season in 2007:some common pollens season start date and end date were:CUPRESSACEAE(3.13-4.12),Fraxinus L.(4.5-5.5);BETULACEAE(4.17-5.22);ArtemisiaL.(8.8-10.8);Humulus L.(8.8-10.6);during their pollen season,total pollen count,highest concentration and average concentration were:CUPRESSACEAE (16070grains,293g/m~3,36g/m~3),Fraxinus L.(20534grains,177g/m346g/m~3); BETULACEAE(4867grains,45g/m~3,13g/m~3);Artemisia L.(63389gains, 267g/m~3,71g/m~3);Humulus L.(107136gains,672g/m~3,115g/m~3);pollen season were during Artemisia L.and Humulus L.pollen season,the average daily pollen concentration were 124g/m~3,and 71g/m~3,with highest concentration as 672g/m~3;and 267 g/m~3;According to the records of pollen concentration and pollen seasons,pollen calendar of Beijing city was drew.5 Cypress pollen concentration is positively related to clinical symptom. Spearman coefficient is 0.804,P＜0.001;The grade of the cypress pollen concentration are:low concentration≤9g/m~3,moderate concentration≥10g/m~3, and high concentration≥20g/m~3;very high concentration≥70g/m~3 respectively;6 Artemisia L.pollen concentration is also positively related to clinical symptom. Spearman coefficient is 0.847,P＜0.001;The class of the Artemisia L.pollen concentration are:low concentration≤14g/m~3;moderate concentration≥15g/m~3; high concentration≥40g/m~3;very high concentration≥120 g/m~3.7 Ragweed sensitivity was significantly associated with mugwort hypersensitivity: all of ragweed hypersensitive patients were also sensitized to mugwort,whereas 28/123(22.8%)mugwort hypersensitive patients were sensitized to ragweed too. In RAST inhibition test,pre-incubation with ragweed pollen extract did not cause reduction in mugwort IgE reactivity,pre-incubation with mugwort pollen had no impact on ragweed IgE reactivity in two patients',but another patient's ragweed IgE reactivity was decreased to 83%;Immunoblot inhibition experiments showed that pre-incubation with mugwort pollen can decrease low molecular weight proteins IgE reactivity to ragweed allergens,but not to the molecular of 20kd or more.CONCLUSION:1 It is the first time to monitor the concentration of airborn pollen in Beijing with Burkard sampler.2 It is the first time to classify the concentration of cypress and mugwort.3 Weed and tree pollen are the main pollens in Beijing city.4 Pollen of mugwort,Cannabis L.and Humulus pollen is the main aero pollen during late summer and autumn,but not ragweed.5 There is cross-reactivity between 12kd protein in ragweed and mugwort pollen;6 There is no exact cross-reactivity between main protein in ragweed and mugwort pollen.