A novel approach in allergen-specific immunotherapy: combination of sublingual and subcutaneous routes

Background: Subcutaneous allergen-specific immunotherapy (SIT) has an early onset of action, whereas repeated injections and safety concerns have limited its use in the pediatric age group. Meanwhile, the improved safety profile of the sublingual route has been accepted as an alternative despite its relatively late onset of action.

Objective: We sought to improve the efficacy and safety of SIT with a combination of the subcutaneous route in the build-up phase and sublingual maintenance in comparison with the sublingual or subcutaneous routes alone.

Methods: Fifty-one house dust mite-sensitized children with mild-to-moderate asthma were randomized into one of 4 groups to receive either (1) subcutaneous immunotherapy (SCIT), (2) sublingual immunotherapy (SLIT), (3) SCIT plus SLIT, or (4) pharmacotherapy. Clinical parameters were evaluated at baseline and months 1, 4, 12, and 18. Allergen-specific immunoglobulin levels and allergen-induced IL-5, IL-10, IL-13, IL-17, TGF-β, and IFN-γ levels were evaluated as well.

Results: In the SCIT and SCIT plus SLIT groups, the number of asthma attacks and inhaled corticosteroid dosage decreased compared with baseline values at the months 4, 12, and 18 but only at month 12 in the SLIT group. The improvement in visual analog scores for rhinitis was significant only in the SCIT plus SLIT group. Increases in the levels of regulatory and T(H)1 cytokines were observed both in the SCIT and SLIT groups, with some differences in dynamics. Antigen-specific IgG(4) levels increased in the SCIT and SCIT plus SLIT groups but not in the SLIT group. Clinical symptom scores were correlated positively with IL-5 levels and negatively with antigen-specific IgG(4), IFN-γ, and TGF-β levels.

Conclusion: Our novel regimen of immunotherapy, SCIT plus SLIT, appeared promising in that it successfully combined the advantages of the 2 alternatives: rapid onset and potency in SCIT and safety and avoidance of injections in SLIT.