Efficacy of sublingual immunotherapy for allergic asthma: retrospective meta-analysis of randomized, double-blind and placebo-controlled trials

Clin Respir J. 2014 Apr;8(2):192-205. doi: 10.1111/crj.12058. Epub 2014 Mar 5.


Background: Allergen-specific immunotherapy (SIT) is the only available curative choice with a disease-modifying effect against respiratory allergies. The efficacy of SIT via the sublingual route was demonstrated by a number of clinical trials. This meta-analysis was performed to investigate the clinical efficacy and safety of sublingual-specific immunotherapy (SLIT) for allergic asthma.

Methods: PubMed, EMBASE and the Cochrane Central Register of Controlled Trials were searched for randomized, double-blind and placebo-controlled (DBPC) trials evaluating the efficacy and safety of SLIT on allergic asthma. Subgroup analyses were performed according to age, type of allergen and duration of SLIT treatment.

Results: Sixteen randomized DBPC trials comprising 794 patients in total met the inclusion criteria. The results suggest that SLIT significantly reduces both symptom [standardized mean difference (SMD), -0.74; P=0.006] and medication scores (SMD, -0.78; P=0.02) compared with placebo. SLIT offers a better clinical response in mite sensitive asthmatics but without confirmed proof from subgroup analyses. Prolonged duration of treatment for more than 12 months brings no additive effects. Improvement in the skin prick test was also observed following immunotherapy. There was no consistent effect on forced expiratory volume in 1 s, serum levels of antigen-specific immunoglobulin G4 and immunoglobulin E in the treated group. The risk of adverse effects was relative risk 2.23 (P=0.01).

Conclusions: SLIT is safe and clinically effective in reducing symptoms and medication use for allergic asthma. Our subgroup analyses failed to identify a disproportionate benefit of SLIT in any specific group of asthmatics, but some possible trends did emerge.

Keywords: allergic asthma; meta-analysis; safety; subgroup analysis; sublingual specific immunotherapy; treatment efficacy.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Administration, Sublingual
  • Allergens / administration & dosage*
  • Asthma / epidemiology
  • Asthma / immunology
  • Asthma / therapy*
  • Double-Blind Method
  • Humans
  • Randomized Controlled Trials as Topic
  • Respiratory Hypersensitivity / complications
  • Respiratory Hypersensitivity / immunology
  • Respiratory Hypersensitivity / therapy*
  • Retrospective Studies
  • Sublingual Immunotherapy / methods*


  • Allergens