Abstract

CHAMBEL, Marta et al. Polysensitization to pollens analyzed and re-interpreted with ImmunoCAP ISAC®. Rev Port Imunoalergologia [online]. 2012, vol.20, n.3, pp.211-219. ISSN 0871-9721.

Background: ImmunoCAP ISAC® aims in vitro detection of serum specific IgE (sIgE) to multiple molecular allergens. Objectives: To analyze the results of ImmunoCAP ISAC®(ISAC) in patients with respiratory allergy and apparent polysensitization to pollens. Methods: We selected 34 patients with respiratory allergy and positive skin prick tests (SPT) to 2 or more pollen extracts. In all, sIgE to mollecular allergens was determined by ISAC. We analyzed the results obtained for the pollens tested with both methods (grass, parietaria, mugwort, salsola, olive tree, plane tree, birch). Results: Median age was 18 years, 56% were males. In SPT, grasses were responsible for the highest number of sensitizations (n=33) and birch for the lowest (n=10). With ISAC, the highest number of positivities was for grass (n=31 patients), with birch in second place (n=20), the last being plane tree (n=6). For most pollens, there was a higher number of positive results with SPT than with ISAC. The concordance between the methods is high for grass (91%), ranging between 79% and 47% for the other pollens. With exception of birch, the discordant cases mainly result from positive SPT and negative ISAC results for the same pollen. For birch, the discordant cases result from the opposite phenomenon. Cases with discordant results had highest frequency of sensitization to panallergens (Phl p 7, Phl p 12, Bet v 2, Bet v 4). Discussion: The best concordance between methods was for grass pollen. For the other pollens, there was a considerable number of patients in which ISAC was negative, although SPT were positive to the same pollen. In a high percentage, this was associated with sensitization to panallergens, suggesting that these may be responsible for falsely positive results in SPT, resulting in apparent polysensitization. ISAC gives a useful contribution to discriminate between polysensitization and cross -reaction in some patients, allowing us to reformulate therapeutic strategy

Keywords : Cross-reactivity; ImmunoCAP ISAC; panallergens; pollen; polysensitization.

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