Search

Background: Polcalcins are pollen-specific allergens with two EF-hand calcium-binding sites that exhibit strong cross-reactivity. Our objective was to isolate and express the cDNA coding of the EF-hand calcium-binding allergen from lilac pollen and to study cross-reactivity with other polcalcins from related and nonrelated pollen sources with different specific antibodies and sera from two different populations., Methods: Specific cDNA was amplified by PCR, cloned and expressed in Escherichia coli. Purification was achieved by gel permeation and ion exchange chromatographies. ELISA titration and inhibition assays were performed using the recombinant forms of Syr v 3, Ole e 3, Che a 3 and Phl p 7 with sera from two Spanish regions with different sensitization profiles, as well as Phl p 7- and Ole e 3-specific polyclonal rabbit antisera, and an Ole e 3-specific monoclonal antibody., Results: Syr v 3 displays two EF-hand consensus sites and 8863 Da of theoretical molecular mass. The allergen consists of 80 residues with identities ranging from 66 to 87% with polcalcins included in this study. Syr v 3, Ole e 3, Che a 3 and Phl p 7 showed a similar IgG- and IgE-binding capacity although differences at quantitative level were observed depending on the population of patients' sera., Conclusion: Syr v 3 is a polcalcin with structural and antigenic similarities to the members of this family. Diagnosis of polcalcin-sensitized patients could be performed whatever polcalcin used, whereas for immunotherapy, primary sensitization to a particular allergenic source should be considered.

The presence of IgE antibodies to the allergens rBet v 1 and rBet v 2 was investigated in patients with known sensitization to ryegrass (Lolium perenne) and/or olive (Olea europaea) pollen, by comparing a group of 10 patients who had allergic symptoms after ingestion of fruits (A) with a group of 17 patients who had only seasonal respiratory symptoms (B). There was no significant difference between the two groups for total IgE. All patients showed specific IgE to both L. perenne and O. europaea. No specific IgE binding to rBet v 1 was detected in any patient. The incidence of the presence of IgE antibodies to rBet v 2 was 90% in the group with fruit allergy (A) and 35% in group B. We found a significant association between presence of IgE antibodies to rBet v 2 and fruit allergy (P = 0.007). Specific IgE values to O. europaea pollen were higher in the fruit-allergy group than the group without fruit allergy (P = 0.032). In conclusion, pollen-allergic patients with specific IgE to birch pollen profilin show a significantly elevated frequency of fruit allergy.

Background: An association between sensitization to Compositae pollens and hypersensitivity to hazelnut has been previously described. There is no previous in vitro study about crossreactivity between mugwort pollen and hazelnut., Objectives: To study mugwort pollen and hazelnut allergens and to assess if there is IgE crossreactivity between mugwort pollen and hazelnut., Methods: A serum pool formed by 28 individual sera with specific IgE to mugwort pollen and hazelnut was used to investigate IgE crossreactivity. RAST-inhibition, SDS-PAGE/IEF immunoblotting inhibition assays were performed by preincubation of the sera with mugwort pollen and hazelnut., Results: RAST to hazelnut was inhibited up to 63% by mugwort pollen, but the mugwort pollen RAST was only inhibited up to 36% by hazelnut. In SDS-PAGE immunoblotting mugwort pollen showed nine allergens ranging from <16 to 65 kDa and hazelnut had four main allergens: 42 kDa, 17 kDa and <16 kDa (two bands). In the SDS-PAGE immunoblotting inhibition hazelnut partially inhibited all the mugwort pollen bands, except that with 19kDa, whereas mugwort pollen produced a nearly total inhibition of all the hazelnut allergens. In isoelectrofocusing immunoblotting mugwort pollen had two groups of allergens: pI 7.5-8.5 and pI 3.5-5.2 and hazelnut one group of allergens: pI 5.2-5.8. In the isoelectrofocusing immunoblotting inhibition hazelnut produced a partial inhibition of all the bands of mugwort pollen and mugwort pollen partially inhibited all the allergenic bands of hazelnut., Conclusions: The RAST and SDS-PAGE/IEF immunoblotting inhibition results provide evidence of IgE cross reactivity between mugwort pollen and hazelnut allergens. The inhibition of hazelnut by mugwort pollen is higher than the inhibition of mugwort pollen by hazelnut in both RAST inhibition and SDS-PAGE immunoblotting inhibition. These results suggest that mugwort pollen allergens would behave as primary immunogens in the association between sensitivity to mugwort pollen and hazelnut.

Background: There is no previous report of Cupressaceae pollinosis in the Madrid area., Objective: To ascertain the presence of Cupressaceae pollinosis in the Madrid area., Methods: Thirty-six patients were studied who had winter pollinosis symptoms and a positive skin test to C. arizonica. They were skin tested with C. sempervirens (Abelló, Madrid), C. arizonica (in-house extract) and other common inhalant allergens (Abelló). Total IgE was measured and specific IgE to C. arizonica, C. sempervirens and J. sabinoides was determined., Results: Six of the patients were only sensitized to Cupressaceae pollens, whereas 30 patients had also sensitivity to other pollens (oleaceae 28, plantain 27, grasses 25, chenopodium 25, compositae 23, Parietaria 9) and 18 patients were also sensitized to other inhalant allergens (animals 17, mites 4, moulds 2)., Conclusion: These results confirm the existence of allergy to Cupressaceae pollens in Madrid (Spain).

We report a case of occupational bronchial asthma and rhinoconjunctivitis caused by Phoenix canariensis (PC) pollen. The canary palm is a type of palm tree, belonging to the Arecaceae family, which is widely distributed in frost-free regions as an ornamental tree. Our patient was referred because he suffered symptoms of bronchial asthma, rhinoconjunctivitis, and contact urticaria when pruning dried leaves from PC during the pollination months. The skin prick test (SPT) with a PC pollen extract was positive, as was the specific IgE to PC pollen determined by Phadezym RAST, indicating an IgE-mediated sensitization. The nonspecific bronchial provocation test (BPT) performed with methacholine disclosed a mild bronchial hyperreactivity, and specific BPT with PC pollen elicited an immediate fall of 25% in FEV1 with respect to baseline. On RAST inhibition studies, a significant cross-reactivity was found between PC pollen and date palm (P. dactylifera) pollen. These results suggest that PC pollen could be a potential allergen in PC-growing areas.

The prevalence of vegetable sensitization in children with pollinosis (Group A; n = 48) and the prevalence of pollen sensitization in children with fruit or vegetable allergy (Group B; n = 42) were studied by means of prick-test and determination of serum specific IgE to several pollens, fruits and vegetables. Fifteen patients from Group A (31%) showed sensitivity to fruits and/or vegetables, but only three of them had any symptoms after ingestions. Twenty nine patients from Group B (69%) showed pollen sensitization, mainly to grass and Compositae pollen. An association was found between sensitivity to Compositae pollen and sensitivity to several fruits and vegetables (Compositae, Fagaceae, Brassica, Betulaceae and Leguminoseae).

The sera of 20 patients with Compositae pollen allergy were investigated for the presence of IgE antibodies reacting against sunflower pollen by means of RAST and immunoblotting studies. Thirteen IgE-binding bands were detected with molecular weights ranging from 14.4 to 94 kd. Two of these bands, with molecular weights of 24 and 25 kd, contained major allergens that reacted strongly with 100% (24 kd) and 95% (25 kd) of the sera, respectively. Cross-reactivity between sunflower and other Compositae pollens (mugwort, marguerite, dandelion, golden rod, and short ragweed) was revealed by RAST and immunoblotting inhibition experiments. Mugwort pollen exhibited the greatest degree of allergenic homology (cross-reactivity) with sunflower pollen, whereas at the other end of the spectrum, short ragweed showed less cross-reactive epitopes.

Summary Background Several Ca2+ -binding proteins, which possess EF-hand sites with a high sequence similarity, have been found to be able to induce Type-I allergy. Objective To study whether the common EF-hand sequential motifs can be involved in the IgE-reactivity of these proteins, thus being responsible of a degree of cross-reactivity among different Ca2+ -binding proteins. Methods Two olive pollen allergens, Ole e 3 and Ole e 8, have been used in the study. Parvalbumin and calmodulin were included in immunological analyses. Sera from patients allergic to olive pollen, as well as Ole e 3- and Ole e 8-specific rabbit antisera were used in indirect enzyme-linked immunosorbent assay (ELISA), ELISA inhibition assays and immunobloting. Conformational analyses (circular dichroism spectra and thermal stability) and specific immunodetection assays were performed in the presence and the absence of Ca2+ . Chemical breakdown and high-performance liquid chromatography (HPLC) was used to obtain fragments from Ole e 3 containing a single EF-hand motif. Results Thirty-four (17%) and 16 (8.2%) out of 195 sera from patients allergic to olive pollen contained specific IgE against Ole e 3 and Ole e 8, respectively. The IgE-binding of 12 allergic sera diminished up to 22% for Ole e 3 and to 82% for Ole e 8, when depleted Ca2+ . A pool of these sera recognized the two olive allergens and parvalbumin, but at very different extent. Inhibition of the IgE-binding was only achieved between two olive allergens. No structural relationships between Ole e 3 and Ole e 8 were established when specific polyclonal antisera against both proteins were used. Conclusion EF-hand Ca2+ -binding sites can not be considered as general allergenic motifs responsible for the cross-reactivity between Ca 2+ -binding allergens. Different families of Ca 2+ -binding allergens have specific epitopes that could be involved in the... [ABSTRACT FROM AUTHOR]