Salsola Kali sensitization and cross-reactivity with Olea Europea in patients with pollinosis from Alcázar de San Juan, Ciudad-Real, Spain

Abstract

Background : The Allergy Department of Alcázar de San Juan, in the Mancha Centro Hospital (ASJ- MCH), Ciudad- Real, Spain, attends patients with respiratory allergy to pollen of different species, such as Salsola kali . Patients mono- sensitive have symptoms in late sum-mer, in the pollination time of Salsola , but also in spring, when there is pollination time of other species such as Olea europaea . It is de-scribed that patients with IgE specific to a single species can rec-ognize epitopes from others by cross- reactivity. In this research we review the cross reactivity between Salsola kali and Olea europaea in patients from ASJ- MCH. Method : Skin prick test, sIgE measurements and assessment of al-lergic diseases were performed in adults attending the ASJ- MCH. Three groups of 4 patients were constituted: G1 - allergic to Salsola kali ; G2 – allergic to S. kali and also to O. europaea ; G3 – allergic to O. europaea . IgE- reactivity patterns of pooled sera from the 3 groups to proteins from S. kali or O. europea pollen extracts were evaluated by immunoblot. Immunoblotting was also applied to obtain individual allergograms to S. kali proteins. Cross- reactivity was assessed by in-hibited immunoblotting with O. europaea pollen extract. Results : IgE- reactivity patterns from G1 revealed eleven bands in S. kali pollen (9- 223 KDa); although G1 was sIgE negative to O. europeae pollen, several bands (9- 85 KDa) were also detected. G3 sera revealed 17 bands in O. europaea pollen (2- 160 KDa); Despite being sIgE neg-ative S. kali , G3 also identified several bands in this species. In G2, the polysensitized group, many bands from both pollen types were identified, mostly with overlapping MW, suggesting cross- reactivity between S. kali and O. europaea . Individual IgE- reactivity patterns to S. kali showed a band with 40 ± 2 KDa detected by all the patients, probably corresponding to Sal k1 and Sal k 2, and a band with 60 ± 5 KDa detected by 92% of the patients. Bands with 18 ± 1, 14 ± 1 and 12 ± 1 KDa, probably corresponding to Sal k 5, Sal k 4 and Sal k 7, were detected by 58, 50 and 67% of the patients, respectively. Conclusion : These results suggest cross–reactivity between S. kali and O. europaea probably as a result of already described panaller-gens but also of other Sal k allergens. Since both pollen types are highly prevalent in the region, cross- reactivity should be taken into account for individual therapeutic approaches.