Today inhaled
corticosteroids (ICS) are regarded as the first-line controller anti-inflammatory treatment in the management of
asthma. However, there is an increasing awareness of the risk of
long-term adverse effects of ICS and that
asthma is not only an organ-specific disease but also a systemic and small airway disease. This thinking has called for systemic treatment alternatives to treat
asthma targeting more disease-specific mechanisms without influencing normal physiologic functions. Blocking of disease-specific mediators is a mechanism utilized by anti-
leukotrienes and anti-
immunoglobulin E treatment, each proven to be effective in both
asthma and
allergic rhinitis.Different
cytokine-modifying strategies have been tested in clinical trials with variable results, some disappointing and some encouraging. Anti-
interleukin (IL)-5
monoclonal antibody treatment effectively reduces the number of eosinophils locally in the airways and in peripheral blood in asthmatic patients. Unfortunately, this marked effect on eosinophils was not associated with an improvement in bronchial hyperresponsiveness and/or symptoms. Clinical trials with a recombinant soluble
IL-4 receptor have been somewhat more successful at improving
asthma control and allowing reduction of ICS
therapy in
asthma. Treatment with recombinant
IL-12 had an effect on bronchial hyperresponsiveness and eosinophilic response, but was associated with unacceptable adverse effects. Other interesting
cytokine-modulating treatments include those targeting
IL-9,
IL-10,
IL-12 and IL-13.Immune-modulating treatment with
bacterial antigens represents another strategy, originating from the hypothesis that some
bacterial infections guide the immune system towards a T helper (Th) type 1 immune response. Mycobacterium vaccae, Bacille Calmette-Guerin (BCG) and immunostimulatory DNA sequences have all been tested in clinical trials, with encouraging results. Future
asthma and
allergy treatment will probably include not only one but also two or more disease-modifying agents administered to the same patient.