Specific immunotherapy in asthma: efficacy and safety.

The use of specific immunotherapy (SIT) to treat asthma has been, and still is, a matter of debate, and there are no clear or unequivocal indications in the official documents. This is partly due to the fact that there are few studies specifically designed to assess asthma, that none of such studies had a formal sample size calculation, and that objective parameters of pulmonary function have been assessed only sporadically. Nonetheless, there are good quality studies for both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) where asthma symptoms were evaluated, and showing positive results. Moreover, several favourable meta-analyses are available, although their validity is limited by the great heterogeneity of the trials included. The disease modifying effect of SIT, that is the capacity of preventing asthma onset should be also taken into account. Concerning the safety, fatalities seem to be an exceptional event and in Europe no fatality has been reported over the last two decades. Uncontrolled asthma is universally recognized as the most important risk factor for severe adverse events. In conclusion both SLIT and SCIT can be used in asthma associated with rhinitis (which is the most common condition), provided that asthma is adequately controlled by pharmacotherapy. In such case, a measurable clinical benefit on asthma symptoms can be expected. On the other hand, SIT cannot be presently recommended as single therapy when asthma is the unique manifestation of respiratory allergy.