Effect of high-dose sublingual immunotherapy on respiratory infections in children allergic to house dust mite.

Background: Allergic rhinitis is characterized by eosinophil inflammation. Allergic inflammation may induce susceptibility to respiratory infections (RI). House dust mite (HDM) sensitization is very frequent in childhood. Allergen immunotherapy may cure allergy as it restores a physiologic immune and clinical tolerance to allergen and exerts anti-inflammatory activity.

Objective: This study investigated whether six-month high-dose, such as 300 IR (index of reactivity), HDM-sublingual immunotherapy (SLIT) could affect RI in allergic children.

Methods: Globally, 40 HDM allergic children (18 males; mean age, 9.3 years) were subdivided in 2 groups: 20 treated by symptomatic drugs (group 1) and 20 by high-dose HDM-SLIT (group 2), since September 2012 to April 2013. The daily maintenance dose of HDM-SLIT was 4 pressures corresponding to 24, 4.8, and 60 µg, respectively of the major allergens Dermatophagoides pteronyssinus (Der p) 1, Der p 2, and Dermatophagoides farinae (Der f) 1. RI was diagnosed when at least 2 symptoms or signs, and fever were present for at least 48 hours. A family pediatrician provided diagnosis on a clinical ground.

Results: SLIT-treated children had significantly (p = 0.01) less RI episodes (3.5) than control group (5.45). About secondary outcomes, SLIT-treated children had less episodes of pharyngo-tonsillitis (p < 0.05) and bronchitis (p < 0.005), and snoring (p < 0.05) than control group. In addition, SLIT-treated children had less fever (p < 0.01) and took fewer medications, such as antibiotics (p < 0.05) and fever-reducers (p < 0.01), than control group.

Conclusion: This preliminary study might suggest that also a short course (6 months) of high-dose SLIT, titrated in µg of major allergens, could reduce RI in allergic children.