Airway inflammation and functional changes after exposure to different concentrations of isocyanates.

Abstract

BACKGROUND:

Isocyanates are a common cause of occupational asthma (OA).

OBJECTIVES:

We sought (1) to examine whether asthmatic reactions to isocyanates could be induced at concentrations as low as 1 ppb in subjects with OA caused by isocyanates previously diagnosed in our center and (2) to compare the inflammatory and functional changes after exposure to 1 and 15 ppb of isocyanates with similar total doses (concentration of isocyanates x duration of exposure).

METHODS:

Specific inhalation challenges were performed in 12 asthmatic subjects with previously confirmed OA caused by isocyanates. Eight subjects were exposed to 1 ppb at 10% of the dose of isocyanates that induced an asthmatic reaction at the time of the diagnosis. Seven subjects were exposed to the same total dose of isocyanates by using concentrations of 1 and 15 ppb 1 month apart.

RESULTS:

Exposure to 1 ppb at 10% of the dose that had induced functional changes at the time of diagnosis induced an asthmatic reaction in 3 of 8 subjects. There was a significant correlation between the percentage of maximum decrease in FEV(1) after exposure to 1 ppb and the increase in sputum neutrophils (rho = 0.8). By keeping the total dose (concentration of isocyanates x duration of exposure) of isocyanates similar, 4 of 7 subjects experienced an asthmatic reaction after exposure to 1 ppb, whereas only one subject experienced an 18.5% decrease in FEV(1) after exposure to 15 ppb.

CONCLUSION:

Isocyanates can induce functional and inflammatory changes (mainly neutrophilic) at concentrations as low as 1 ppb. For the same total dose of exposure, low concentrations of isocyanates are as harmful as or even more harmful than higher concentrations for subjects with OA to isocyanates.

• Authors: Catherine Lemière, Philippe Romeo, Simone Chaboillez, Caroline Tremblay, Jean-Luc Malo
• Journal: The Journal of allergy and clinical immunology (J Allergy Clin Immunol) Vol. 110 Issue 4 Pg. 641-6 (Oct 2002) ISSN: 0091-6749 [Print] United States
• PMID: 12373274 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Isocyanates

Topics

• Administration, Inhalation
• Adult
• Aged
• Asthma (chemically induced, pathology, physiopathology)
• Dose-Response Relationship, Drug
• Female
• Forced Expiratory Volume (drug effects)
• Humans
• Isocyanates (administration & dosage, pharmacology)
• Male
• Middle Aged
• Neutrophils (pathology)
• Occupational Diseases (pathology, physiopathology)
• Osmolar Concentration
• Sputum (cytology)