Can Exhaled Inflammatory Markers Predict a Steroid Response in Wheezing Preschool Children?

Background: The efficacy of inhaled corticosteroids (ICS) varies among wheezing preschool children. Currently, it is not possible to predict which fraction of wheezing children will benefit from an ICS treatment.

Objective: We explored whether fractional exhaled nitric oxide (FeNO) and inflammatory markers in exhaled breath condensate (EBC) can predict an ICS response in preschool wheezers.

Methods: An 8-week ICS study (registered at Clinicaltrial.gov: NCT 00422747; 200 μg; beclomethasone extra-fine daily) was performed in 93 wheezing children (age range 2.0-4.4 years). At baseline, FeNO was determined off-line. EBC was collected using a closed glass-condenser. The acidity of EBC was determined and other EBC markers [interleukin (IL)-1α, IL-2, IL-4, IL-5, IL-10, soluble intercellular adhesion molecule, interferon-γ, eotaxin] were measured using a multiplex immunoassay. The change in airway resistance (Rint) and symptom score following ICS treatment was related to atopy (positive Phadiatop Infant test), FeNO and EBC markers.

Results: Airway resistance and symptoms mildly improved after ICS treatment [median (IQR): 1.4 (1.2-1.7) to 1.3 (1.1-1.5) kPa s/L, symptom score: 26 (23-28) to 28 (24-29), P < 0.01, respectively]. Only IL-10 and atopy had limited predictive value regarding a change in symptoms [β (SE) =-0.13 (0.07), P = 0.08, β (SE) = 2.05 (1.17), P = 0.08, respectively].

Conclusions And Clinical Relevance: We did not find convincing evidence that FeNO and EBC markers could predict an ICS response in preschool wheezers. Recommendations for future studies on this topic are given.