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ALLERGIES
vere asthma. Several other once-daily long-acting muscarinic antag- may have a broader spectrum of effects are in development. Aller-
onists (LAMAs) are also in development. gens bind to a low-affinity IgE receptor (FcεRII, CD23) as well as
the high-affinity receptor FcεRI on several immune cells, including
ICSs are currently the most effective anti-inflammatory therapy T- and B-lymphocytes and so more targeted monoclonals have po-
for asthma and work in almost every patient. However, all currently tential.
available ICSs are absorbed from the lungs and thus have the po-
tential for systemic side effects. This has led to efforts to find safer Specific allergen immunotherapy by subcutaneous injection
ICSs, with reduced oral bioavailability, reduced absorption from the (SCIT) is effective in controlling allergic asthma and will often les-
lungs, or inactivation in the circulation. Dissociated steroids attempt son the need for other pharmaceuticals. High dose sublingual im-
to separate the side-effect mechanisms from the anti-inflammatory munotherapy (SLIT), although still an off-label treatment, is
mechanisms. This is theoretically possible because side effects are becoming a more convenient and safer alternative to injections and
largely mediated via transactivation and the binding of glucocorti- is showing great promise with selected allergens, particularly dust
coid receptors to DNA, whereas anti-inflammatory effects are largely mites; however, longer-term studies and comparison with ICSs and
mediated via transrepression of transcription factors through a with SCIT are needed.
nongenomic effect. Dissociated steroid agonists have a greater effect
on the transactivation than transrepression and thus may have a bet- Asthma therapy has always been, and will continue to be, a chal-
ter therapeutic ratio. lenge for both the physician and the patient. But we are continually
seeing profound advancements in asthma therapy, which is an en-
Monoclonal antibodies that block IgE are now used in the treat- couraging sign for all of us.
ment of selected patients with severe allergic asthma. Both omal-
izumab and mepolizumab are expensive, so patients must be selected Jeffrey S. Hallett, MD, is a board certified allergist with Certified
carefully for a trial of therapy. More potent anti-IgE antibodies that Allergy and Asthma of San Antonio.
visit us at www.bcms.org 21
