Laboratory diagnosis of respiratory allergy to Cupressaceae: Better performance using juniper pollen extract rather than cypress pollen extract

C. Klingebiel , D. Charpin , Jean-Louis Mege (1) , J. Vitte (1)

1 URMITE - Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes

Background. Cypress pollen is the primary cause of respiratory allergy in the Mediterranean area. Its diagnosis is based on a history of respiratory symptoms during the winter period, together with confirmatory skin prick tests and, if necessary, serum assays for allergen-specific IgE (sIgE). Since the introduction of molecular allergens, the search for sIgE directed against the pectate lyase Cup a 1, a major allergen of cypress pollen, is sometimes used as a first-line laboratory test. Objective. To identify the most efficient laboratory tool for the work-up of cypress pollen sensitization. Methods. We compared the analytical value of three Cupressaceae sIgE tests, commonly used for patients with cypress pollinosis: cypress pollen (Cupressus sempervirens) extract, juniper pollen (Juniperus ashei) extract and pectate lyase Cup a 1 cypress allergen. We assayed the sera of 309 patients living in the Southern French region of Provence with a clinical history of cypress pollen allergy. The tests were carried out using the ImmunoCAP method (Thermo Fisher) in a private clinical laboratory (LBM multisite BIOPLUS, n=233) and in a university hospital (Assistance publique Hopitaux de Marseille) (n = 76) laboratory. Results. The major cypress allergen Cup a 1 and the juniper pollen extract yielded highly concordant results, both in terms of positive or negative results and for the sIgE level. The cypress pollen extract, which is poor in the major allergen, underestimated the level of sIgE and was subject to false negative results for values less than 5 kUA/L. Conclusion. The juniper pollen extract has better sensitivity for detection of Cupressaceae sIgE compared to cypress pollen extract and those results are well-correlated with the results of sIgE directed against Cup a 1. Our results support the use of juniper pollen extract instead of cypress pollen extract for sIgE assays; this is similar to the choice for skin prick tests being used currently in our practice. First-line testing for sIgE to Cup a 1 is not recommended by the current international consensus. (C) 2016 Elsevier Masson SAS. All rights reserved.

Domaines: Maladies infectieuses

C. Klingebiel, D. Charpin, Jean-Louis Mege, J. Vitte. Laboratory diagnosis of respiratory allergy to Cupressaceae: Better performance using juniper pollen extract rather than cypress pollen extract. Revue francaise d'allergologie, 2016, 56 (6), pp.452-461. ⟨10.1016/j.reval.2016.03.004⟩. ⟨hal-01455805⟩