Isocyanate-induced occupational asthma: challenge and immunologic studies

Area of Science:

• Occupational Medicine
• Immunology
• Pulmonology

Background:

• Isocyanates, particularly toluene diisocyanate (TDI), are primary causes of occupational asthma (OA) in Korea.
• Spray painters represent a significant demographic affected by TDI-induced OA.

Purpose of the Study:

• To investigate the prevalence and clinical significance of serum-specific IgE antibodies to isocyanate-human serum albumin (HSA) conjugate in TDI-induced OA patients.
• To explore the relationship between specific IgE levels and clinical parameters, including bronchial challenge test responses and airway hyperresponsiveness.

Main Methods:

• Analysis of 43 patients with confirmed TDI-induced OA.
• Bronchial challenge tests (TDI and methacholine) to assess airway sensitivity.
• Radioallergosorbent test (RAST) to detect serum-specific IgE antibodies to isocyanate-HSA conjugate.

Main Results:

• 81% of patients were spray painters.
• 40% of patients exhibited high serum-specific IgE antibodies to isocyanate-HSA.
• Specific IgE levels did not correlate with TDI-bronchial challenge response types, smoking status, atopy, rhino-sinusitis, systemic symptoms, or methacholine hyperresponsiveness.
• A significantly longer latency period was observed in patients with high specific IgE levels (p < 0.05).

Conclusions:

• Approximately 40% of isocyanate-induced occupational asthma cases in this cohort were associated with high specific IgE antibodies to isocyanate-HSA.
• The presence of specific IgE antibodies to isocyanate-HSA does not appear to correlate with most clinical parameters in TDI-induced OA.