PURPOSE OF THE STUDY.
This study sought to determine factors that could predict clinical response to allergen immunotherapy (AIT) in children.
A total of 185 children aged 4 to 14 years with persistent mild asthma based on Global Initiative for Asthma (GINA) guidelines or a diagnosis of persistent allergic rhinitis based on Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines were included. The mean age was 8.0 years; 50% of patients were affected by rhinitis only. All patients were sensitized to house dust mite (HDM), and 89% were polysensitized.
Charts of the 185 participants were retrospectively analyzed. Children were included based on a clinical history of asthma and/or rhinitis for at least 1 year attributable to HDM sensitization which was confirmed by positive skin-prick test (SPT) response and the presence of serum specific immunoglobulin E (sIgE) for both Dermatophagoides pteronyssinus and Dermatophagoides farinea. All patients completed at least 3 years of subcutaneous house dust mite immunotherapy. Patients treated with concomitant perennial allergens were not excluded. Baseline information was obtained before initiation of immunotherapy, which included serum analysis of total IgE (tIgE), sIgE to relevant allergens, and blood eosinophil counts. Atopic family history, early-life exposure to tobacco smoke, and tobacco smoke exposure at the time of onset of respiratory symptoms were documented. Clinical effectiveness of AIT was assessed based on improvement of clinical symptoms and reduction in use of concomitant medications.
AIT was considered effective in 70% of patients. When the patient groups were compared on the basis of their pretreatment parameters, early tobacco smoke exposure, atopic family history, tIgE levels >965 kU/L, and a sIgE/tIgE ratio ≤6% were associated with an ineffective clinical response to AIT. A tIgE level <965 kU/L was associated with an effective clinical response with a 91% sensitivity and 55% specificity. tIgE level was superior to sIgE or sIgE/tIgE ratios in predicting a clinical response. No correlations between the number of concomitant allergens or the age of the child and the clinical response to AIT were observed.
Children with early exposure to tobacco smoke, a positive family history for atopy, higher levels of tIgE, and a lower sIgE/tIgE ratio are less likely to have an effective clinical response to subcutaneous HDM immunotherapy.
AIT is an effective therapy for improving allergic asthma and allergic rhinitis, but efficacy can be variable. The parameters that were found to be associated with an ineffective response to house dust mite AIT in this study largely reflect an overall greater degree of atopic disease. However, it should be noted that the majority of patients did achieve an effective response, so AIT should not be deferred, but rather, patients with the described characteristics should be counseled more appropriately on the likelihood of a clinical benefit. Additional studies addressing the limitations of this study, including its retrospective nature, lack of a placebo group, and use of nonvalidated assessments of symptom improvement are needed to confirm predictive factors for efficacy of AIT.
- Copyright © 2015 by the American Academy of Pediatrics