Leukotriene D4 bronchial provocation test: methodology and diagnostic value.

BACKGROUND

Although leukotriene D4 (LTD4) is a potent bronchoconstrictor, little is known about airway responsiveness to LTD4 in asthmatics with different inflammation phenotypes.

OBJECTIVES

To establish the methodology and investigate the distribution characters of airway responsiveness, diagnostic value and safety of LTD4 bronchial provocation test.

METHODS

LTD4 bronchial provocation tests were performed in 62 asthmatics and 21 normal controls. Airway responsiveness was assessed based on the cumulative dosage causing a 20% fall in FEV(1) (PD(20)FEV(1)-LTD4) and was expressed as (median, interquartile range). The fall in spirometric parameters was plotted showing the distribution characters. The diagnostic value was assessed using receiver operation characteristic (ROC) curve. All adverse events were recorded during the test.

RESULTS

Airway responsiveness to LTD4 was significantly higher in asthmatics (0.410 nmol, 0.808 nmol) as compared with normal controls (5.00 nmol, 0.00 nmol). The decrease in spirometric parameters varied after bronchoprovocation, which was negatively correlated with PD(20)FEV(1)-LTD4, among which FEV(1) had a maximal slope (r = -0.524, P = 0.000). High diagnostic value (AUC: 0.914, 95%CI: [0.855, 0.974]) was revealed by ROC curve. The major adverse events were dyspnea (82.3%), chest tightness (72.6%), wheezing (32.3%) and coughing (25.8%) in asthmatics, which could overall be recovered within 15.0 minutes after inhalation of 200 ∼ 400 mcg salbutamol MDI. No serious adverse event was reported.

CONCLUSION

The established procedure of LTD4 bronchial provocation test is effective in the diagnosis of asthma and is well tolerated. Future studies are necessary to provide more evidences in terms of safety and efficacy. This may be helpful upon further application in clinical practice.