Childhood asthma: Novel endotyping by cytokines, validated through sensitization profiles and clinical characteristics.

Background: Specific allergy sensitization pattern, using "component‐resolved diagnosis" (CRD), is a central component of allergy and asthma in childhood. Besides this, allergic asthma has been characterized by a Th2‐shifted endotype with elevation of classical Th2 cytokines. Recently, other endotypes with distinct mechanisms focusing on cytokine regulation evolved, yet those pathways are still not well understood. Objective: (a) To define reproducible immunological endotypes using cytokine expression in an asthma cohort and (b) to characterize their sensitization profile and clinical phenotype. Methods: Supernatants from PBMCs of 234 children (median age 10 years) of an asthma cohort were analysed for cytokine expressions. The children were split into a training (n = 49) and validation (n = 185) group. The training group was used to identify immunological endotypes by clustering cytokine expressions, which were then assessed regarding clinical characteristics and specific IgE of recombinant allergen components. Next, our findings were validated in the validation group. Results: We identified novel endotypes based on primarily unstimulated cytokine expression. One endotype showed an IFN‐γ/Interleukin (IL)‐17/IL‐5 predominance, a different sensitization pattern (high in birch/apple; p <.01), and inferior lung function (p <.01). A second endotype grouped young children with food allergy and reduced lung function. Our findings were reproducible in the validation group. Conclusion and clinical relevance: We identified two novel clinical asthma endotypes via cytokine expression pattern with distinct sensitization patterns. These novel findings are critical for clinical guidance and open avenues for identifying underlying mechanisms and more patient‐specific therapies. [ABSTRACT FROM AUTHOR]