Mountain cedar pollen induces IgE-independent mast cell degranulation, IL-4 production, and intracellular reactive oxygen species generation

Cedar pollens cause severe allergic disease throughout the world. We have previously characterized allergenic pollen glycoproteins from mountain cedar (Juniperus ashei) that bind to allergen-specific immunoglobulin E (IgE). In the present report, we investigated an alternative pathway of mast cell activation by mountain cedar pollen extract through IgE-independent mechanisms. We show that mountain cedar pollen directly induces mast cell serotonin and IL-4 release and enhances release induced by IgE cross-linking. Concomitant with mediator release, high levels of intracellular reactive oxygen species (ROS) were generated, and both ROS and serotonin release were inhibited by anti-oxidants. These findings suggest that alternative mechanisms exist whereby pollen exposure enhances allergic inflammatory mediator release through mechanisms that involve ROS. These mechanisms have the potential for enhancing the allergenic potency of pollens.     

Mouse mast cell tryptase mMCP-6 is a critical link between adaptive and innate immunity in the chronic phase of Trichinella spiralis infection

Although the innate immune function of mast cells in the acute phase of parasitic and bacterial infections is well established, their participation in chronic immune responses to indolent infection remains incompletely understood. In parasitic infection with Trichinella spiralis, the immune response incorporates both lymphocyte and mast cell-dependent effector functions for pathogen eradication. Among the mechanistic insights still unresolved in the reaction to T. spiralis are the means by which mast cells respond to parasites and the mast cell effector functions that contribute to the immunologic response to this pathogen. We hypothesized that mast cell elaboration of tryptase may comprise an important effector component in this response. Indeed, we find that mice deficient in the tryptase mouse mast cell protease-6 (mMCP-6) display a significant difference in their response to T. spiralis larvae in chronically infected skeletal muscle tissue. Mechanistically, this is associated with a profound inability to recruit eosinophils to larvae in mMCP-6-deficient mice. Analysis of IgE-deficient mice demonstrates an identical defect in eosinophil recruitment. These findings establish that mast cell secretion of the tryptase mMCP-6, a function directed by the activity of the adaptive immune system, contributes to eosinophil recruitment to the site of larval infection, thereby comprising an integral link in the chronic immune response to parasitic infection.     

Transport of airborne pollen into the city of Thessaloniki: the effects of wind direction, speed and persistence

We examined the effect of the wind vector analyzed into its three components (direction, speed and persistence), on the circulation of pollen from different plant taxa prominent in the Thessaloniki area for a 4-year period (1996–1999). These plant taxa were Ambrosia spp., Artemisia spp., Chenopodiaceae, Corylus spp., Cupressaceae, Olea europaea, Pinaceae, Platanus spp., Poaceae, Populus spp., Quercus spp., and Urticaceae. Airborne pollen of Cupressaceae, Urticaceae, Quercus spp. and O. europaea make up approximately 70% of the total average annual pollen counts. The set of data that we worked with represented days without precipitation and time intervals during which winds blew from the same direction for at least 4 consecutive hours. We did this in order to study the effect of the different wind components independently of precipitation, and to avoid secondary effects produced by pollen resuspension phenomena. Factorial regression analysis among the summed bi-hourly pollen counts for each taxon and the values of wind speed and persistence per wind direction gave significant results in 22 cases (combinations of plant taxa and wind directions). The pollen concentrations of all taxa correlated significantly with at least one of the three wind components. In seven out of the 22 taxon-wind direction combinations, the pollen counts correlated positively with wind persistence, whereas this was the case for only two of the taxon-wind speed combinations. In seven cases, pollen counts correlated with the interaction effect of wind speed and persistence. This shows the importance of wind persistence in pollen transport, particularly when weak winds prevail for a considerable part of the year, as is the case for Thessaloniki. Medium/long-distance pollen transport was evidenced for Olea (NW, SW directions), Corylus (NW, SW), Poaceae (SW) and Populus (NW).     

Silicon Deprivation Does Not Significantly Modify the Acute White Blood Cell Response but Does Modify Tissue Mineral Distribution Response to an Endotoxin Challenge

An experiment with rats was conducted to determine whether silicon deprivation affects the acute-phase immune response to an endotoxin challenge. Weanling female rats were assigned to two weight-matched groups of 24; one group was fed a basal diet containing about 1.9 µg Si/kg; the other group was fed the basal diet supplemented with 35 µg Si/kg as arginine silicate inositol complex. After being fed their respective diets for 8 weeks, 12 rats in each group were injected subcutaneously with 1 mg lipopolysaccharide (LPS)/kg body weight; the other 12 rats in each group were injected with deionized water. Two hours after injection, the rats were anesthetized with ether for collection of blood (for plasma), liver and femurs, and then euthanized by decapitation. LPS injection decreased total white blood cell, lymphocyte, monocyte, eosinophil, and basophil counts by 80–90%, but did not affect neutrophil counts. LPS injection also increased plasma tumor necrosis factor-α and osteopontin and decreased plasma hyaluronic acid. Silicon deprivation did not significantly affect any of these responses to LPS. Silicon in liver and silicon, iron, and zinc in femur were increased by LPS injection only in silicon-deprived rats. Silicon deprivation also increased monocyte counts and osteopontin and decreased femur zinc in rats not injected with LPS. The findings indicate that silicon deprivation does not affect the acute-immune phase decrease in inflammatory cell numbers and increase in inflammatory cytokines in response to an endotoxin challenge. Silicon deprivation, however, apparently causes slight chronic inflammation and might influence inflammatory cell proliferation in the chronic-phase inflammatory response.     

Airborne pollen from allergenic herbaceous plants in urban and rural areas of Western Pomerania,NW Poland

This paper presents the course of the pollen season of selected allergenic taxa (Rumex spp., Plantago spp., Urtica spp. and Chenopodiaceae) in two towns with different degrees of urbanisation (urban, the city Szczecin, and rural, the village Gudowo in Western Pomerania, northwest Poland). The study was conducted in the years 2012–2014 with the volumetric method. The pollen of allergenic herbaceous plants was present in the air from early May until the end of September. From among the taxa studied, the genus Rumex is characterised by the longest pollination period, while the genus Urtica by the shortest. The highest percentage contribution of pollen grains to the total pollen count in the air reaching over 90% is from nettle. The pollen seasons determined for the majority of taxa are longer in the city, however the mean pollen grain counts in the air are higher for the rural area.     

Alterations in the immune system in cats fed diets with excess cystine

As part of an ongoing biochemical study in nutrition we examined blood profiles, serum chemistry, lymphocyte transformation and lymphoid pathology in cats fed a diet containing 5% cystine with and without taurine. Automated blood counts of whole blood samples showed a decrease in red blood cell counts accompanied by a significant decrease in hemoglobin and hematocrit in cats fed 5% cystine in the absence of taurine compared to cats fed 0.05% taurine (control). A significant increase was noted in serum cholesterol in cats fed cystine and cystine/taurine compared to cats fed control diets. There were no significant differences in lymphocyte transformation using leukocytes isolated from the spleen and blood with the mitogens, phytohemagglutinin and pokeweed. However, lymphocyte transformation of both spleen and blood without mitogen from the excess cystine group were significantly higher than leukocytes from the 0.05% taurine group (control). Pathological examination of regional lymph nodes, livers, and spleens showed histological abnormalities in cats fed the excess cystine diet. These results indicate that there are alterations in the immune system of cats fed a diet containing 5% cystine with and without dietary taurine.     

Local eosinophil- and mast cell-related responses in abomasal nematode infections of lambs

Abstract Eosinophil numbers in peripheral blood and eosinophil potentiating activity(EPA) and sheep mast cell protease (SMCP) in efferent gastric lymph were monitored in lambs during infections with Ostertagia circumcincta . Worm burdens, eosinophil numbers in bone marrow, abomasal mucosa and gastric lymph node, as well as mast cell numbers and SMCP concentrations in mucosa and mucus, were determined in post mortem samples. In naive lambs, high and relatively uniform worm burdens were present 10 days after primary infection and these were associated with only mild blood and tissue eosinophilia. By day 21 worm burdens were markedly lower and more variable. There was more evidence of eosinophil and mast cell accumulation in mucosa, and numbers in bone marrow were also higher than on day 10. However, neither EPA nor SMCP were detectable in lymph. By contrast, EPA and SMCP were present in substantial amounts in draining lymph within 48 h of challenge (secondary) infection of previously exposed lambs. EPA was inversely related to worm burdens recovered on day 10, as were abomasal mucosal and mucus SMCP concentrations. Elevated eosinophil numbers were also consistently detected in blood, bone marrow, mucosa and gastric lymph node. The results suggest that host immune defence against secondary, but not primary, exposure to O. circumcincta involves a rapidly mobilised local inflammatory component.     

Airborne pollen grains in Yalova,Turkey, 2004

In this study, airborne pollen grains of Yalova province were investigated using VPSS 2000 from January to December 2004. During studying period, a total of 22409 pollen grains/m³ which belonged to 46 taxa and 74 unidentified pollen grains were recorded. From the identified taxa, 26 belong to arboreal and 20 to non-arboreal plants. Total pollen grains consist of 80.50% arboreal, 19.17% non-arboreal plants and 0.33% unidentified pollen grains. In the investigated region, from arboreal plant taxa Platanus spp. (29.08%), Cupressaceae/Taxaceae (21.22%), Pinus spp. (7.34%), Alnus spp. (4.75%), Castanea spp. (3.03%), Quercus spp. (3.07%), Olea spp. (2.50%), Acer spp. (2.21%), Corylus spp. (1.41%) and Fagus spp. (1.15%), and from non-arboreal plant taxa Poaceae (10.01%), Asteraceae (2.86%), Plantago spp. (1.47%) and Artemisia spp. (1.11%) were responsible for the greatest amounts of pollen.     

Annual pollen spectrum in the air of Palma de Mallorca (Balearic Islands, Spain)

This aeropalynological study documented the pollen of 13 taxa with the highest concentration in the air of Palma de Mallorca during the years 2004–2010, using a Hirst-type volumetric spore trap. The taxa were Cupressaceae, Olea europaea, Platanus hispanica, Pinus spp., Parietaria judaica, Urtica membranacea, Quercus ilex, Poaceae, Chenopodiaceae/Amaranthaceae, Plantago spp., Castanea sativa, Pistacia lentiscus and Betula spp. These taxa accounted for 91.85 % of the total annual pollen recorded during the period. The mean annual pollen index was 20,027. The highest pollen counts occurred in February–June, representing 88.74 % of the annual total collected. Every year, there was a substantial increase in the concentration and types of pollen from March to May, followed by a decrease from July to January. The maximum annual total pollen count was recorded in 2005 with 25,870 and the minimum in 2009 with 14,726. The mean daily average pollen concentration count showed a declining trend over the study period. With respect to seasonal phases analysed, the later phase of the pollen season is more variable than the beginning. To observe the overall dynamics of the different pollen types better, a pollen calendar was established for Palma de Mallorca. The pollen calendar had typical Mediterranean features and is a useful tool for allergological and botanical awareness.     

The Effects of Dietary Iron and Capsaicin on Hemoglobin,Blood Glucose,Insulin Tolerance,Cholesterol, and Triglycerides,in Healthy and Diabetic Wistar Rats

ObjectiveOur aim was to assess the effects of dietary iron, and the compound capsaicin, on hemoglobin as well as metabolic indicators including blood glucose, cholesterol, triglycerides, insulin, and glucose tolerance.ResultsHealthy rats fed a low-iron diet exhibited significantly reduced total cholesterol and triglyceride levels, compared with rats fed a control diet. Significantly reduced blood lipid was also provoked by low dietary iron in diabetic rats, compared with those fed a control diet. Insulin, and glucose tolerance was only improved in healthy rats fed the low-iron diet. Significant increases in total cholesterol were found in diabetic rats fed a high-iron diet, compared with healthy rats fed the same diet, although no statistical differences were found for triglycerides. Hemoglobin levels, which were not statistically different in diabetic versus healthy rats fed the high-iron diet, fell when capsaicin was added. Capsaicin also provoked a fall in the level of cholesterol and triglycerides in diabetic animals, versus diabetics fed with the high iron diet alone. In conclusion, low levels of dietary iron reduced levels of serum triglycerides, hemoglobin, and cholesterol, and significantly improved insulin, and glucose tolerance in healthy rats. In contrast, a high-iron diet increased cholesterol significantly, with no significant changes to triglyceride concentrations. The addition of capsaicin to the high-iron diet (for diabetic rats) further reduced levels of hemoglobin, cholesterol, and triglycerides. These results suggest that capsaicin, may be suitable for the treatment of elevated hemoglobin, in patients.     

Host sex,size, and hemoparasite infection influence the effects of ectoparasitic burdens on free‐ranging iguanas

Investigations focusing on host–ectoparasite interactions in animals have revealed asymptomatic to severe health and fitness consequences suggesting that species mobilize different interspecific response mechanisms. Fewer studies, however, have examined intraspecific responses to ectoparasitic burdens. In this study, we analyzed host health and fitness responses to increasing ectoparasite burdens along with the presence/absence of hemoparasites of free‐ranging insular rock iguanas (Cyclura cychlura) in The Bahamas. Using hematology, plasma biochemistry, as well as body condition and growth rate comparisons, we failed to find significant associations of tick burdens with annual growth rate, corticosterone, packed cell volume, total white blood cell, and heterophil, monocyte, eosinophil or hemoglobin measures. We did, however, find mixed and significant associations of tick burdens with lymphocyte and basophil counts, heterophil‐to‐lymphocyte ratios, and body condition indices. These associations varied by sex, size, and hemoparasite infection status suggesting that different life stages of iguanas may invest differently in immune responses, and impacts may be modulated based on size and sex of hosts, and coinfection status.     

Effect of dietary ghee – the anhydrous milk fat on lymphocytes in rats

Lymphocytes are important components of the immune system. Dietary lipids affect the functioning of the immune system. Changes in the lipid composition of the lymphocyte membrane is a case in point. Membrane structural changes are reflected in the altered function of the cell. Lymphocyte proliferation and lymphocyte rosetting are membrane associated phenomena. Ghee, is a clarified butter product, commonly used in the Indian diet. It is rich in saturated fatty acids and also contain oxysterols which are generated on prolonged heating of ghee. Male weanling rats were fed 2.5% (of the total fat levels) of fresh or thermally oxidized ghee for a period of 8 weeks. The control rats were fed groundnut oil. Lipid composition of lymphocytes in ghee fed rats showed changes. In vitro lipid peroxidation of lymphocyte membranes increased by 26% in oxidized ghee fed rats. Na⁺K⁺ ATPase activity was decreased in oxidized ghee fed rats (18%). Lymphocyte proliferation was reduced in ghee fed rats (32%), compared to the controls, irrespective of the mitogens used (ConA or PHA), or the tissue (splenocytes or peripheral blood lymphocytes). Oxysterols present in oxidized ghee are the likely agents inhibiting lymphoproliferation. Rosetting of lymphocytes decreased in the fresh ghee fed rats by 16% and in oxidized ghee fed rats by 25%. Membrane fluidity declined in the oxidized ghee fed rats. It is concluded that feeding ghee results in decreased proliferation of lymphocytes. Also, feeding oxidised ghee results in decreased proliferation of lymphocytes through alterations in the structure of the lymphocyte membranes in the rat.     

Staining properties of duodenal mast cells in 48/80-treated rats

Summary Mast cells in the tongue, mesentery and lamina propria of the duodenal mucosa in normal and 48/80-treated rats were observed at different time intervals. The tissues were studied comparatively after staining with toluidine blue, acridine orange or alcian bluesafranin. Under the experimental conditions used, the mast cells in the tongue and mesentery showed constant positive reactions to toluidine blue and acridine orange, both of which failed to demonstrate the presence of mast cells in the lamina propria of the duodenal mucosa. The combined alcian blue-safranin stain elicited a safranin-positive reaction in the mast cells of the tongue and mesentery and an alcian blue reaction in those of the lamina propria of the duodenal mucosa. This alcianophilia of the duodenal mast cells was not affected by compound 48/80. On the other hand, the safranin stain of the tongue and mesentery mast cells was altered to alcian blue by the drug. The results are discussed in the light of recent developments in mast cell research.This work was supported by grant MA-2236 of the Medical Research Council of Canada.     

武汉市武昌地区气传致敏花粉调查研究

应用曝片法连续365d收集武昌地区3个调查点的气传花粉,全年共检出花粉48643粒,分属28个科、属。一年中出现2次花粉高峰,即3～4月份,8～9月份。其中优势花粉为悬铃木属（Platanus）、柏科（Cupressaceae）、松属（Pinus）、蒿属（Artemisia）等;最主要的致敏花粉为蒿属、豚草属（Ambrosia）。对影响本地区空气中花粉飘散的因素,几种优势花粉的致敏特点及其临床意义作了初步探讨。     

Diet composition and foraging ecology of Asian elephants in Shangyong, Xishuangbanna, China

The composition of the diet and the foraging ecology of the Asian elephant in its natural habitat were studied from 1998 to 2000 in the Shangyong National Natural Reserve located at Xishuangbanna, China, using field observation and dung analysis. A total of 106 plant species were recorded as being eaten by Asian elephants, 83 of which were identified in the elephants' dung. The plant families that contributed to a major proportion of the elephants' diet in the study area were: Gramineae (8 spp., 10.0%), Moraceae (7 spp., 9.9%), Papilionaceae (4 spp., 8.4%), Araliaceae (3 spp., 6.6%), Vitaceae (3 spp., 5.7%), Apocynaceae (3 spp., 4.6%), Musaceae (1 spp., 4.2%), Zingiberaceae (3 spp., 3.7%), Myrsinaceae (3 spp., 3.6%), Rosaceae (3 spp., 3.6%), Euphorbiaceae (5 spp., 3.3%), Ulmaceae (2 spp., 3.0%) and Mimosaceae (4 spp., 2.9%). The most important plants in the elephants' diet were Ficus spp. (Moraceae, 9.0%), Dendrocalamus spp. (Gramineae, 4.5%), Musa acuminata (Musaceae, 4.2%), Microstegium ciliatum (Gramineae, 3.5%) and Amalocalyx yunnanensis (Apocynaceae, 3.1%). Asian elephants consumed a variety of plants in terms of life forms, including trees, vines, shrubs and herbs. Early successional plant species constitute a higher proportion of the diet than late successional plants (42 spp. taking 59% vs. 32 spp. taking 37%). Browsing species accounted for a larger proportion of the diet compared to grazing species (77 spp. taking 91% vs. 6 spp. taking 9%). The number of plant taxa (species, genus, family) in elephants' diet each month negatively correlated with monthly rainfall and mean temperature. The study may help to develop proper strategies for wildlife management especially with regard to the human-elephant conflict, which is now a serious issue in the conservation of Asian elephants in this area.     

Immunomodulatory effects of ovine serum immunoglobulin in the growing rat

This study aimed to determine whether orally administered ovine serum immunoglobulin (Ig) modulates aspects of immunity such as phagocytosis, lymphocyte proliferation, cytokine production, intestinal and plasma Ig concentrations in growing rats. Forty-five male Sprague-Dawley rats (n = 15/group) were used in the 21-day study, and fed a basal control diet (BD; no Ig) or two test diets: freeze-dried ovine Ig (FDOI) and inactivated ovine Ig (IOI). Phagocytic activity of peripheral blood leukocytes and lymphocyte proliferation in the presence of the mitogen concanavalin A (ConA) was greater (P < 0.05) for the FDOI-fed rats than for the BD- and IOI-fed groups. ConA-stimulated and unstimulated spleen cell culture produced higher (P < 0.05) interferon-γ and interleukin-4, respectively, from rats fed the FDOI than rats fed the BD diet. In the jejunum, ileum and plasma, rats fed FDOI produced higher (P < 0.05) concentrations of secretory IgA (sIgA) than rats fed IOI or BD. Rats fed the FDOI diet had greater jejunal (P = 0.037) and lower plasma (P = 0.025) rat IgG concentrations than rats fed either BD or IOI. In conclusion, an ovine Ig fraction selectively modulated various indices of immune function.     

Incidence of allergenic pollen of Acer spp., Fraxinus spp. and Platanus spp. in the city of La Plata, Argentina: preliminary results

This work studies the airborne pollenconcentrations of Acer spp.,Fraxinus spp. and Platanus spp. sincethe pollen of these three taxa has beencharacterized as etiological agents ofpollinosis. These tree species are present inlarge amounts in the streets of La Plata city.The aeropalynological monitoring was performedwith a Hirst-type spore trap (Lanzoni VPPS,2000). The emission period of the three taxaextends from approximately late August to October.The maximum cumulative totalof arboreal pollen was found to be 30824.7from September 12 to 18. This period coincideswith the peak of total pollen concentration.Pollen grains trapped were analysed andexpressed as daily averages of 5-hour bandsper day during the whole year. Maximum pollenconcentration was registered between 10 a.m.and 2 p.m. During the studied period, 67 patients examinedat the Allergy Service of ``Hospital Interzonalde Agudos R. Rossi' (La Plata) showed allergicdisease. These allergenic episodes may beproduced by the large amount of pollen trees inthe city area.     

In vitro pollen germination in Hypericum perforatum L. and Hypericum rumeliacum Boiss

In vitro pollen germination and pollen tube growth investigations are valuable tools used in identification of the effects of environmental factors and genotypic differences on pollen viability, pollen germination and tube elongation. In this study pollen viability, in vitro pollen germination capacity, abnormality ratios and tube length in germinated pollens of Hypericum perforatum L. and H. rumeliacum Boiss. were investigated. Both of these species has spheroid-shaped and tricolporate pollen grains. The diameters of Hypericum perforatum and H. rumeliacum pollens were found as 24 +/- 3 microm and 19 +/- 2 microm, respectively. Pollen viability of H. perforatum and H. rumeliacum was found as 83% and 72%, respectively. The germination percentages were found as 12.85% for H. perforatum and 64.42% for H. rumeliacurm. Tube lengths in germinated pollens of both taxa were measured approximately as 95.25 +/- 38 microm in H. perforatum and 165.92 +/- 53 microm in H. rumeliacium 4 h after inoculation. In germinated pollen grains of H. perlbratum and H. rumeliacumn abnormality percentages were determined as 13.23% and 43.97%, respectively. In germinated pollens of these two species, highly significant (P < 0.00001) differences in in vitro germination percents and abnormality percents were observed. Abnormalities such as swollen tube tip, branched tube, spiralled tube and excessive tube formation were observed in pollen tubes. The results of this study showed that there were obvious differences in pollen germinability between these two species growing under the same environmental conditions.     

An observation study of airborne pollen fall in Didim (SW Turkey): years 2004–2005

Pollen grains in the atmosphere of Didim, collected using a Durham sampler, were investigated in 2004 and 2005. Weekly pollen grains per square centimetre were calculated. Over a period of 2 years, 17,518 pollen grains/cm² belonging to 40 taxa and unidentified pollen grains were recorded. In 2004, 9,879 pollen grains were counted per cm², and in 2005 the value was 7,639 per cm². The majority of pollen grains investigated were Pinus spp. (45.58%), Cupressaceae/Taxaceae (13.49%), Olea spp. (9.19%), Platanus spp. (7.62%), Gramineae (6.33%), Pistacia spp. (4.34%), Morus spp. (3.81%), Quercus spp. (2.02%), Abies spp. (1.39%), and Plantago spp. (1.11%). During the month of April, 40.46% of total pollen grains were recorded. According to our results, pollen season durations for the dominated pollen grains in Didim were: the 7th–33rd weeks for Pinus spp., nearly the whole year except summer for Cupressaceae/Taxaceae, the 17th–29th weeks for Olea spp., the 10th–24th weeks for Platanus spp., the 8th–46th weeks for Gramineae, the 8th–20th weeks for Pistacia spp., the 11th–21st weeks for Morus spp., the 17th–21st weeks for Quercus spp., the 9th–27th weeks for Abies spp., and the 7th–26th weeks for Plantago spp.     

Fifteen years' record of airborne allergenic pollen and meteorological parameters in Thessaloniki,Greece

A pollen calendar has been constructed for the area of Thessaloniki and relationships between pollen transport and meteorological parameters have been assessed. Daily airborne pollen records were collected over a 15-year period (1987-2001), using a Burkard continuous volumetric pollen trap, located in the centre of the city. Sixteen allergenic pollen types were identified. Simultaneously, daily records of five main meteorological parameters (mean air temperature, relative humidity, rainfall, sunshine, wind speed) were made, and then correlated with fluctuations of the airborne pollen concentrations. For the first time in Greece, a pollen calendar has been constructed for 16 pollen types, from which it appears that 24.9% of the total pollen recorded belong to Cupressaceae, 20.8% to Quercus spp., 13.6% to Urticaceae, 9.1% to Oleaceae, 8.9% to Pinaceae, 6.3% to Poaceae, 5.4% to Platanaceae, 3.0% to Corylus spp., 2.5% to Chenopodiaceae and 1.4% to Populus spp. The percentages of Betula spp., Asteraceae (Artemisia spp. and Ambrosia spp.), Salix spp., Ulmaceae and Alnus spp. were each lower than 1%. A positive correlation between pollen transport and both mean temperature and sunshine was observed, whereas usually no correlation was found between pollen and relative humidity or rainfall. Finally, wind speed was generally found to have a significant positive correlation with the concentrations of 8 pollen types. For the first time in the area of Thessaloniki, and more generally in Greece, 15-year allergenic pollen records have been collected and meteorological parameters have been recorded. The airborne pollen concentration is strongly influenced by mean air temperature and sunshine duration. The highest concentrations of pollen grains are observed during spring (May).