Nasal response in patients with diisocyanate asthma.

BACKGROUND: To date, no studies have assessed nasal and bronchial response to diisocyanates during specific inhalation challenges (SIC). OBJECTIVES: This study was performed to assess nasal response during SIC with diisocyanates (nasal and oral breathing) in patients with suspected occupational asthma due to these agents. METHODS: Fourteen patients with suspected clinical history of diisocyanate-induced asthma were challenged with diisocynates in a 7m3 chamber. Nasal response testing during challenges was assessed by acoustic rhinometry, peak nasal inspiratory flow (PNIF), and visual analog scale (VAS), alongside bronchial responses. RESULTS: Eleven patients had a significant asthmatic response to diisocyanates. None reported clear work-related nasal symptoms. In patients with positive bronchial response to diisocyanates, nasal mean minimal cross-sectional area (MCA) decreased by 26.9%, nasal volume at 5 cm decreased by 33.5%, and PNIF decreased by 28.3%, all from baseline. A positive nasal response was elicited in 45%, 54%, and 45% of patients, respectively. A significant increase in VAS was observed in 4 patients. Three patients with negative bronchial response had a negative nasal response. CONCLUSION: SIC revealed an objective nasal response in around 50% of patients with occupational asthma due to diisocyanates, in spite of the fact that none of them reported work-related nasal symptoms. The clinical significance of this finding is a poor association between nasal symptoms at work and an objective nasal response during positive SIC with diisocyanates.

Occupational asthma caused by triglycidyl isocyanurate.

BACKGROUND: Several cases of allergic contact dermatitis, two cases of occupational asthma from over one decade ago and one case of hypersensitivity pneumonitis have been documented in painters who use polyester powder paint containing triglycidyl isocyanurate (TGIC). METHODS: We report a 28-year-old female who, 4 months after beginning work in a powder-coating factory, developed asthma-like symptoms. In her workplace, aluminium frames were treated with an electrostatic powder paint containing 2.5-10% TGIC. RESULTS: Serial peak-flow measurements performed during both working and non-working periods demonstrated peak-flow variability of up to 46% on work days. Bronchial methacholine test results also varied between times at work and away from work. PC(20) methacholine was 0.32 mg/ml and fraction of exhaled nitric oxide (FENO) was 18 ppb. A controlled exposure challenge was performed with a placebo yielding no changes in FEV(1) over a 24-hour period. On visit 2, the patient was placed in the chamber and exposed to TGIC (4% in lactose) at a mean concentration of 3.61 mg/m(3) for a total of 15 min. A 20% fall in FEV(1) from baseline was elicited at 10 min, together with cough and wheezing. No late response was demonstrated. Twenty-four hours after the challenge, neither methacholine PC(20) nor FENO levels varied from baseline values. No IgE was detected by ELISA testing and no IgE-binding bands were found by immunoblot analysis of patient and control serum. CONCLUSIONS: The aforementioned results demonstrate that TGIC inhalation induced immunologic occupational asthma, although no IgE mechanism was evidenced.