Cellular allergen stimulation test with acetylsalicylic acid-lysine is not a useful test to discriminate between asthmatic patients with and without acetylsalicylic acid sensitivity.

BACKGROUND

The aspirin provocation test, considered to be the gold standard in the diagnosis of aspirin sensitivity, may be associated with severe adverse reactions; thus, alternative procedures with a higher safety profile are highly desirable. Although the cellular antigen stimulation test (CAST) has been proposed to be such an alternative, there is limited information about its clinical usefulness.

OBJECTIVE

It was the aim of our study to evaluate the clinical usefulness of CAST in the diagnosis of aspirin sensitivity.

MATERIAL AND METHODS

Patients with aspirin-sensitive asthma and/or nasal polyps (n = 40), patients with aspirin-tolerant asthma and/or nasal polyps (n = 13) and healthy volunteers (n = 26) were included. A 2-day, single-blind placebo-controlled oral aspirin provocation test was performed. In vitro release of cysteinyl leukotrienes (Cys-LTs) by peripheral blood leukocytes was measured after stimulation with both stimulation buffer and lysine aspirin (2.5 mg/ml) by CAST.

RESULTS

Baseline Cys-LT levels were similar among the 3 groups. After lysine aspirin stimulation, the net increase in Cys-LTs was significantly higher in patients with aspirin sensitivity (median 91 pg/ml, interquartile range 22-206) compared with aspirin-tolerant patients (20 pg/ml, range 0-46) and healthy controls (23 pg/ml, range 0-71; p = 0.004). The assay had a sensitivity of 25%, a specificity of 92.3%, and positive and negative predictive values of 28.7 and 90.7%, respectively.

CONCLUSION

Although the leukocytes of patients with aspirin sensitivity produce higher amounts of Cys-LTs as measured by CAST, the low sensitivity and predictive values limit the clinical usefulness of this test in the diagnosis of aspirin sensitivity.