Clinical and genetic features underlying the response of patients with bronchial asthma to treatment with a leukotriene receptor antagonist.

BACKGROUND: Treatment with antileukotriene drugs results in clinical improvement in many, though not all, patients with asthma. It can be hypothesized that the subpopulation of asthmatic patients, characterized by aspirin intolerance and cysteinyl-leukotriene overproduction, might profit most from antileukotriene treatment. MATERIALS AND METHODS: We compared the clinical response to montelukast in two well-matched groups of patients with mild asthma: 26 aspirin-intolerant asthmatics (AIAs) and 33 aspirin-tolerant asthmatics (ATAs). We also searched for possible predictors of the clinical response among the parameters reflecting the expression and production of cysteinyl-leukotrienes (cys-LTs). This was an 8-week, single-blind, placebo-controlled trial. RESULTS: Following a 3-week montelukast 10 mg day-1 treatment compared with placebo, there was a statistically significant reduction in the mean daytime and nocturnal asthma symptoms and beta 2-agonist use, as well as a significant improvement in the morning and evening peak expiratory flows and quality of life. Both groups showed a similar significant improvement in the parameters studied. Clinical response did not correlate with the baseline urinary LTE4 excretion level. Improvement of asthma was observed mostly in patients with a low baseline and non-IL-5 inducible expression of LTC4 synthase (LTC4S) mRNA in eosinophils. There was a trend toward a better response in carriers of LTC4S allele C, but no relationship to the CC10 genetic polymorphism. CONCLUSIONS: No difference in the clinical response to the montelukast treatment was observed between the AIAs and the ATAs.

Oral and bronchial provocation tests with aspirin for diagnosis of aspirin-induced asthma.

In 35 asthmatic patients with acetylsalicylic acid (aspirin; ASA) intolerance (AIA) and 15 asthmatics tolerating ASA well, the authors compared the diagnostic value of the placebo-controlled oral ASA versus inhaled L-lysine (L) ASA challenges. All AIA subjects gave a history of asthmatic attacks following ingestion of ASA and in all of them the intolerance was confirmed by oral challenge test over the past 10 yrs. Doses of ASA increasing in geometric progression were used in oral tests 10-312 mg (cumulative dose 500 mg); in bronchial tests 0.18-115 mg (cumulative dose 182 mg). Either challenge was considered as positive, if forced expiratory volume in one second (FEV1) dropped at least 20% from the baseline value and/or strong extrabronchial symptoms of intolerance occurred. Urinary leukotriene E4 excretion was determined at baseline and following the challenges. In 24 out of 35 patients the oral test was positive, based on a 20% decrease in FEV1. When including extrabronchial symptoms this was positive in 31 cases. Bronchial L-ASA challenge led to > or =20% fall FEV1 in 21 out of 35 cases, and in 27 cases when including extrabronchial symptoms. No correlation was observed between ASA provocative dose causing a 20% fall in FEV1, determined by the oral route compared to the inhalation route. Urinary LTE4 increased after both challenges the rise being higher following oral as compared to inhalation provocation (p=0.0001). It is concluded that both tests had similar specificity whilst the oral test showed a tendency to higher sensitivity for the clinical diagnosis of acetylsalicylic acid intolerance. The inclusion of extrabronchial symptoms into the criteria of test positivity enhanced the diagnostic value of both procedures. In both tests the highest leukotriene E4 increases were found in the presence of extrabronchial symptoms, suggesting the participation of tissues other than the lung in aspirin induced leukotriene E4 release to urine.