Abstract

CARDOSO, Bárbara Kong et al. Positive prick test to parietaria: What´s the meaning?. Rev Port Imunoalergologia [online]. 2016, vol.24, n.4, pp.211-217. ISSN 0871-9721.

Background: In most cases a positive prick test (PT) to parietaria goes along with positive PT to other pollens. On the other hand, a significant percentage of this patients don´t presenta rPar j2 specific IgE, which is currently considered as a marker to parietaria allergy. Objective: To define predictive criteria for allergy to parietaria pollen in patients with a positive PT to this pollen. Methods: We collected the medical records, PT results and rPar j 2 specific IgE levels of 64 patients with a positive PT to parietaria - wheal with mean diameter equal or larger then 3mm. Using the CHAID algorithm (Qui-squared Automatic Interaction Detection) we were able to create a classification tree of parietaria allergy (considering “true allergy” the positivity of specific IgE to rPar j 2). Results: In our study group, 36 were female and mean age was 25.0±15,0; 70.3% had a positive PT to dust mites, 84.4 % to grass pollen, 84.4% to olive tree pollen and 62.5% to “other pollens” (non grass nor olive tree pollen). Predictive factors identified by the best model were the ratio between mean diameters of histamine and parietaria PT wheals, the patient gender and the result of the PT to “other pollens”. Therefore, patients with a PT wheal to parietaria larger than histamine that were female hada rPar j 2 positive in 100% of the cases. In the other hand, a PTwheal to parietaria equal or smaller to histamine followed by a positive PT to “other pollens” were related to a 95.5% probability of negative rPar j 2IgE. The computed tree estimated risks were: re-substitution 0.16 (standard error 0.04) and cross-validation 0.19 (standard error 0.05). Conclusion: Basic allergological patient evaluation allowedto create a predictive model of parietaria pollen allergy with a reasonable performance

Keywords : Algorithms; parietaria pollinosis; predictive modeling; recombinant par j 2 allergen.

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