Phenotyping allergic asthma: inheritance, age of onset and severity matter

Published online: November 10, 2017

In the era of personalized medicine, correctly phenotyping patients is of major importance in order to select the best and safest treatment. Asthma is a heterogeneous disease with different clinical expressions and responses to therapy. In recent years, several studies have identified different asthma phenotypes. The allergic phenotype has emerged in all of these reports, but it is unknown whether this phenotype can be further sub-classified. An article published in a recent issue of The Journal of Allergy and Clinical Immunology: In Practice phenotyped patients with allergic asthma using an unbiased approach based on multivariate combined statistical techniques.

In this study, Sendin et al. analyzed 225 patients diagnosed with allergic asthma according to ATS recommendations, with a positive skin prick test to at least one aeroallergen, and concordant symptoms. Combining the information provided by multivariate statistical techniques (multiple correspondence analyses and cluster analysis), 19 variables (out of 54 initial variables) were selected and analyzed based on their contribution to asthma phenotyping.

Using this unbiased statistical approach, three clusters were identified. The first cluster (n=133) consisted of patients with intermittent or mild persistent asthma, without family antecedents of atopy, asthma or rhinitis. This group presented the lowest total IgE levels. This cluster could be named mild atopic asthma without family antecedents. The second cluster (n=65) consisted of patients with mild asthma with a family history of atopy, asthma or rhinitis. Total IgE levels were intermediate. This cluster could be called mild atopic asthma with family antecedents. Finally, the third cluster (n=27) included patients with moderate or severe persistent asthma that needed treatment with corticosteroids and LABAs. In addition, this cluster presented the highest total IgE levels and later age of asthma onset than Clusters 1 and 2. Therefore it could be named late onset moderate-severe atopic asthma.

This study identifies several phenotypes of allergic asthma that differ primarily in family history, age of onset, and severity of asthma. Further studies will be necessary to fully understand the therapeutic and prognostic implications of these phenotypes.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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