Asthma related to Alternaria sensitization: an analysis of skin-test and serum-specific IgE efficiency based on the bronchial provocation test

作者：Fernandez C^*; Bevilacqua E; Fernandez N; Gajate P; de la Camara A G; Garcimartin M; Vives R; Rodriguez J

来源：Clinical and Experimental Allergy, 2011, 41(5): 649-656.

DOI：10.1111/j.1365-2222.2010.03645.x

• allergic asthma
• alternaria serum-specific IgE
• alternaria skin tests
• logistic regression
• ROC curve

Background
It is difficult to find a causal relationship between exposure to Alternaria spores and the development of asthma symptoms in sensitized individuals due to the complexity of clinical situations in which positive diagnostic tests are often found.
Objective
To analyse the diagnostic efficiency of skin testing (ST) and serum-specific IgE to Alternaria, based on the results of a bronchial specific challenge with Alternaria extracts.
Methods
Seventy-four asthmatic patients sensitized to Alternaria underwent a specific bronchial challenge with this mould. Skin-testing weal sizes, serum-specific IgE values (CAP-system) and bronchial challenge results were analysed by receiver operating characteristics curves (ROC curves) and logistic regression. The sensitivity, specificity, positive and negative predictive values were calculated for different cut-off points.
Results
Bronchial challenges to Alternaria elicited a positive result in 45 patients (61%). Skin prick testing almost perfectly predicted the outcome of bronchoprovocation tests (area under the ROC curve of 0.957), whereas intradermal skin testing had moderate efficacy. A negative result for skin prick test (SPT) showed a 4% probability of a positive bronchial challenge in the logistic regression analysis. However, weals around 5.5 mm in diameter had 90% probability of a positive challenge. Quantification of serum-specific IgE correctly classified 86% of the cases. In the logistic regression analysis, a CAP value >= 16 kU(A)/L predicted a positive bronchial challenge result with 99% accuracy, whereas for a CAP value < 0.35 kU(A)/L, this probability was 33%.
Conclusions and Clinical Relevance
Most asthmatic patients with positive SPT results to Alternaria would have a positive bronchial challenge. As atmospheric mould levels may vary significantly with the weather conditions, sensitized patients should be instructed on the risk situations, environmental control measures and the importance of correct medication compliance. Immunotherapy with Alternaria could also be taken into account as a valid therapeutic option.

• 出版日期2011-5