The pathophysiology of
asthma, current treatment guidelines, and emerging immunomodulating treatments are reviewed.
Asthma is a
chronic disease of
inflammation, which left untreated, may result in irreversible lung damage. Inhaled
antigens elicit a T-helper cell type-2 response, leading to the production of
immunoglobulin E (
IgE) and eosinophil sensitization. Eosinophil infiltration into the airway is thought to play an important role in chronic
inflammation and increases several weeks before an acute exacerbation in moderate to severe
asthma. The updated guidelines from the National
Asthma Education and Prevention Program and the National Institutes of Health focus on the use of daily antiinflammatory treatment in patients with persistent
asthma. Inhaled
corticosteroid (ICS)
therapy remains the cornerstone for controlling mild and moderate
asthma, but when used in higher doses for moderate-to-severe
asthma it may cause
long-term adverse effects, including
osteoporosis and
glaucoma. Step-up
therapy should be the combination of a long-acting beta-agonist (LABA) and an ICS.
Leukotriene modifiers may provide additional symptom control in patients with moderate to severe
asthma but have not been shown to be as cost-effective as monotherapy. Newer entities focus on direct immune modulation and include
monoclonal antibodies targeting various inflammatory-response
receptors (IgE,
interleukin [IL]-2, IL-4, and IL-5).
Phosphodiesterase-4 (PDE-4) inhibitors may be effective for
chronic obstructive pulmonary disease, but have not delivered consistent results for controlling
asthma.
Cytokine-receptor antagonists and leukocyte-suppressing antiinflammatory drugs (LSAIDs) are currently under investigation and have yielded promising preliminary results as alternatives for the treatment of
asthma. Current and emerging
therapies for the management of chronic
inflammation in
asthma include ICSs, LABAs,
leukotriene modifiers,
monoclonal antibodies,
PDE-4 inhibitors,
cytokine-receptor antagonists, and LSAIDs.