Isocyanate-induced occupational asthma: immunologic and challenge studies.

Suh, Jung Eun; Park, Hae Sim; Kim, Seong Jin; Rhu, Nam Soo; Cho, Dong Ill; Kim, Jae Won; Kyung, Nan Ho

doi:1992.39.6.490

Tuberc Respir Dis > Volume 39(6); 1992 > Article

Original Article

Tuberculosis and Respiratory Diseases 1992;39(6):490-501.
DOI: https://doi.org/10.4046/trd.1992.39.6.490 Published online December 1, 1992.

Isocyanate-induced occupational asthma: immunologic and challenge studies.

Jung Eun Suh¹, Hae Sim Park², Seong Jin Kim², Nam Soo Rhu², Dong Ill Cho², Jae Won Kim², Nan Ho Kyung³

¹Department of Chest Medicine, Seoul Seodaemoon City Hospital, Seoul, Korea
²Department of Chest Medicine, National Medical Center, Seoul, Korea
³Department of Internal Medicine, Ewha UniverSity College of Medicine, Seoul, Korea

Abstract

Background
Isocyanate is the most significant cause of occupational asthma in this country. The mechanism of isocyanate induced bronchoconstriction is unclear. Subjects and Methods: To observe its immunologic and clinical findings, we performed methacholine bronchial challenge test (MBCT), toluene diisocyanate (TDI).bronchoprovocation test (BPT) and RAST to TDI-, diphenylmethane diisocyanate (MDI)-, and hexamethylene diisocyanate (HDI)-human serum albumin (HSA) conjugate in 22 isocyanate-sensitive asthmatic workers.
Results
BPT revealed early (11), dual (5), and late only (6) asthmatic responses. Their latent period ranged from 3 to 120 months (mean:45. 9 months). Three cases (13 . 6%)showed a negative response on initial MBCT, but following MBCT performed 24 hours after TDI-BPT revealed the development of airway hyperresponsiveness. Twelve (54 .5%) workers had increased specific IgE to TDI-HSA, seven (31. 8%) had to MDI-HSA, and nine (40.9%) had to HDI-HSA conjugate. The prevalence of specific IgE was not associated with latent period, type of asthmatic responses, smoking, and atopic status. After 3 months, avoidance from workplace, airway hyperresponsiveness was improved in 10 (38 .3%) among 12 followed cases.
Conclusions
It is suggested that isocyanate can induce IgE-mediated bronchoconstriction in 59 _1 % of isocyanate-sensitive asthmatic workers. Isocyanate-induced asthma can occur even though MBCT showed a negative result, and measurement of the changes of airway hyperresponsiveness after isocyanate-BPT could be helpful to diagnose isocyanate-sensitive asthma.

Key Words: Occupational asthma, Methacholine bronchial challenge test, Toluene diisocyanate, Specific IgE antibody