Effect of Adjuvanted and Standard Sublingual Immunotherapy on Respiratory Function in Pure Rhinitis Due to House Dust Mite over a 5-Year Period

Abstract

Background: Allergen-specific immunotherapy (AIT) still remains the only causal treatment for IgE mediated respiratory diseases (rhinitis/asthma) In addition to the observed clinical decrease in symptoms, AIT can provide a long-lasting and preventive effect. In particular it can modify the progression from rhinitis to asthma. Methods: The study was observational, open, non randomized, controlled, prospective and performed in a real-life setting. Patients with pure mite-induced allergic rhinitis were followed-up, receiving adjuvanted SLIT (aSLIT), standard SLIT (sSLIT) or drug treatment alone, according to their preference starting between 2008 and 2009. The possible onset of asthma, changes in pulmonary function and bronchial hyperreactivity (BHR) were assessed over a 5-year horizon. Also the onset of new sensitizations and symptoms-medication score (SMS) were evaluated. Results: One hundred forty two patients fulfilling the inclusion criteria were assessed at baseline, and 124 had the 5-year evaluation (age range 8-57, 69 male). After 5 years of treatment, new sensitizations appeared differentially among treatments with 58.1% of new sensitizations in the drug treatment group, 13.2% in the sSLIT patients, and 8.1% in the aSLIT patients. At the end of 5 years, SMS significantly changed (P < 0.001) in all groups, with a negative trend for controls, as compared to the SLIT treatments. The SMS decreased in both SLIT groups at 5 years, with no change in patients on drug treatment alone. The use of salbutamol (absent at baseline), showed an overall increase only in the group receiving drugs alone with a significant difference at 5 years (P < 0.001). Considering the MCh challenge, there was a difference among treatments (P < 0.001) in PD20 after 5 years: the control group had a lower PD20 at 5 years. No significant difference in PD20 was detected between sSLIT and aSLIT. The FEV1 significantly decreased in controls, with no change in the sSLIT group and a significant increase in aSLIT as compared to sSLIT. Discussion: Despite the limitations inherent to a real-life setting study (absence of randomization and control, small sample size, lack of intermediate timepoint assessment) the results of this study evidenced that the investigated SLIT product, either adjuvanted or not, had a positive effect on the evolution of respiratory allergy due to house dust mite. Conclusion: In the real life setting, considering a 5-year period, aSLIT and sSLIT reduced the onset of new sensistizations and maintained intact the pulmonary function, as compared to patients receiving drug treatment alone.

Preventing the development of asthma: stopping the allergic march

“…Aside from allergen avoidance for the prevention of asthma and atopy, targeting allergic sensitization through immunotherapy, has been studied in the prevention of asthma and atopy in several controlled trials (Table 2). 9,12,13,15,16,47 The role of immunotherapy in prevention of new sensitization as well as in mitigation of asthma symptoms has been appreciated since the 1960s. 48 Immunotherapy can improve the likelihood that a known asthmatic will outgrow his asthma.…”

“…9 Sublingual immunotherapy (SLIT) has been extensively studied for asthma and atopy prevention. 12,13,15,16 In one prospective, randomized controlled, proof of concept study in infants at high risk of atopy, the intervention group was treated with HDM oral immunotherapy, twice daily for one year, while the control was treated with placebo. While the study confirmed decreased sensitization to common allergens in the intervention group, there was no effect on the development of AD, food allergy, or wheeze.…”

“…15 In patients sensitized to HDM who were treated with SLIT, spirometry and bronchoprovocation via methacholine were studied and confirmed that SLIT, over a 5-year period, had a significant protective effect on pulmonary function, as compared to a control group of sensitized individuals who did not receive immunotherapy. 12 Furthermore, a recent metanalysis evaluated allergen immunotherapy in those with AR and found a statistically significant reduction in the development of asthma in the two years following completion of immunotherapy. 11 It is unclear if this benefit is pervasive.…”

“…3 Preventing the inception of this allergic progression, as well as halting its advance, is pivotal in asthma prevention. Aggressive therapies in infants with AD, 4,5 global blocking of allergic inflammation with daily inhaled steroids, 6 the role of allergic sensitization, 7,8 immunotherapy, [9][10][11][12][13][14][15][16] respiratory infections, [17][18][19][20] and dietary interventions 21,22 have been evaluated in asthma and atopy prevention. Biologic therapy for susceptible toddlers, 23 and modulation of the respiratory microbiome through killed bacterial lysates are being investigated.…”