Abstract
Bronchial asthma is a chronic disease, characterised by respiratory symptoms, reversible airflow limitation, and/or airway hyperreactivity with symptoms causally related to genetics, environment, viruses, and allergens. The aim of this mini-review is to summarise the body of literature based on studies on efficacy of immunotherapy for the treatment of bronchial asthma in adults. A literature search of the PubMed database was performed using subject headings and keywords related to bronchial asthma and immunotherapy efficacy. Forty studies were identified through this review, of which 30 were immediately considered unsuitable for inclusion. There were 10 controlled trials, reporting on 1780 patients in total. In these studies, asthma manifestations were generally mild to moderate. Allergens tested included: birch pollens, house mite dust, Dermatophagoides, grass pollens, and Parietaria judaica. The allergen extracts were generally administered in the form of sublingual drops and subcutaneous, local, and depot injections. The main outcomes measured in the trials included: asthma control, drug scores, respiratory function, bronchial hyperresponsiveness, and quality of life. Three birch pollen sublingual immunotherapy trials demonstrated a significant reduction in drug scores and improved asthma control. A second pair of trials examined the effectiveness of Dermatophagoides sublingual immunotherapy; while one of these trials reported significant improvement in asthma control, the second trial failed to prove any significant reduction in either asthma control or drug score. House mite dust sublingual immunotherapy proved to be effective in reducing asthma exacerbations and in reducing bronchodilator and steroid use. Grass pollen immunotherapy was carried out using two different methods, namely subcutaneous and depot injections, and both were effective. A single study reported a positive effect for Parietaria judaica immunotherapy given sublingually. In conclusion, the data in this review provide evidence for the efficacy of immunotherapy with specific offending allergens in adults with allergic bronchial asthma but a larger systematic review is recommended.