Sublingual immunotherapy (SLIT), a type of allergen-specific immunotherapy, improved symptoms, lung function, and airway inflammation in children with allergic asthma and rhinitis, according to a study published in Clinical and Molecular Allergy.
Allergen-specific immunotherapy is the only treatment with the potential to alter the disease course of allergic asthma and rhinitis, particularly in children. SLIT has been shown to be safe and effective in children with these conditions. However, efficacy outcomes in randomized controlled trials were assessed using patient-reported outcomes, not objective measures.
Recently, several markers that can be used to monitor immune-related changes in respiratory allergic disorders have been identified. The only validated non-invasive marker for measuring eosinophilic inflammation in asthma is fractional exhaled nitric oxide (FeNO).
Researchers sought to demonstrate the efficacy of SLITOR (Serbian registered vaccine for sublingual allergen specific immunotherapy) for allergic asthma and rhinitis as measured by patient-reported symptoms, medication usage, pulmonary function, and eosinophilic airway inflammation via FeNO levels.
Of 59 children (age range, 7 to 18) with allergic asthma, allergic rhinitis, or both, 34 were treated with SLIT plus asthma drug therapy and 25 were treated with asthma drug therapy only. Outcomes were assessed at baseline, 1 year, and 2 years.
At 2 years, symptom scores for allergic rhinitis (nasal congestion, nasal pruritus, rhinorrhea, sneezing) and asthma (shortness of breath, cough, chest tightness, wheezing) were significantly lower than baseline scores for both treatment groups. SLIT treatment reduced all symptom scores to a greater degree than asthma drug therapy alone (P <.001 for all comparisons).
At 1 and 2 years, patients receiving SLIT also decreased the use of intranasal corticosteroids, inhaled corticosteroids, and β2 agonists compared with the control group (P <.001 for all comparisons). The use of leukotrienes and anti-histamines was also lower in the SLIT group, but this effect was observed only at 2 years (P <.001 for all comparisons).
On pulmonary function testing, forced expiratory volume at 1 second (FEV1) progressively improved over time with SLIT (P =.036), while FEV1 remained unchanged in the control group (P =.048).
FeNO concentrations were significantly lower in the SLIT group than in the control group at all assessment time points. However, significant reductions in FeNO levels over time occurred in patients receiving SLIT (P <.001), while no changes in FeNO levels were observed in patients receiving standard asthma drug therapy.
No serious adverse events were reported. There were only 3 mild to moderate adverse reactions, which involved gastrointestinal complaints and were self-limited.
“These findings suggest that SLIT may have preventive effects, showing in children with intermittent asthma and [allergic rhinitis] a lower occurrence of persistent airway inflammation,” the investigators wrote.
The investigators also noted that by assessing the combined outcomes of symptoms, lung function, and FeNO levels, they were able to identify the phenotype of patients most likely to respond to SLIT.
Djuric-Filipovic I, Caminati M, Filipovic D, Salvottini C, Zivkovic Z. Effects of specific allergen immunotherapy on biological markers and clinical parameters in asthmatic children: a controlled-real life study. Clin Mol Allergy. 2017;15:7. doi: 10.1186/s12948-017-0064-5