Tolerability and efficacy of house dust mite AIT

Role of immunotherapy in the treatment of allergic asthma

Allergen-specific immunotherapy (SIT) induces clinical and immunological tolerance as defined by persistence of clinical benefit and associated long-term immunological parameters after cessation of treatment. Although the efficacy of SIT has been shown in terms of reducing symptoms, medication consumption and ameliorating quality of life in both allergic rhinitis and asthma, there has long been some controversies about effectiveness of SIT in the treatment of allergic asthma. The type of allergen, the dose and protocol of immunotherapy, patient selection criteria, the severity and control of asthma, all are significant contributors to the power of efficacy in allergic asthma. The initiation of SIT in allergic asthma should be considered in case of coexisting of other allergic diseases such as allergic rhinitis, unacceptable adverse effects of medications, patient’s preference to avoid long-term pharmacotherapy. Steroid sparing effect of SIT in allergic asthma is also an important benefit particularly in patients who have to use these drugs in high doses for a long-time. Symptomatic asthma is a risk factor for systemic reactions and asthma should be controlled at the time of administration of SIT. Both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) have been found to be effective in patients with allergic asthma. Although the safety profile of SLIT seems to be better than SCIT, the results of some studies and meta-analyses suggest that the efficacy of SCIT may appear better and earlier than SLIT in children with allergic asthma.

Subcutaneous and sublingual immunotherapy: Where do we stand?

Though symptoms of allergic diseases can be reduced by the use of drugs such as corticosteroids, antihistamines or leukotrien antagonists, the only treatment directed to change the natural course of allergic disease is allergen-specific immunotherapy (SIT). Its efficacy can last years after the cessassion of the treatment. SIT brings on regulatory T cells with the capacity to generate interleukin-10 and transforming growth factor-b, restricts activation of mast cells and basophils, and shifts antibody isotype from IgE to the noninflammatory type immunoglobulin G4. Subcutaneous (SCIT) and sublingual (SLIT) immunotherapy are the two most used ways at the present for applying SIT. These two treatments were demonstrated to be effective on reducing symptoms and medication use, in prevention of new sensitizations and in protecting from progression of rhinitis to asthma. The safety of SLIT appears to be better than SCIT although there have been a few head to head comparisons. In order to overcome compliance problems or possible systemic side effects which may be faced during this long-term treatment, recent investigations have been focused on the implementation of allergens in quite efficacious and safer ways.