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Aims of this study were to define (1) whether toluene diisocyanate (TDI) bronchial hyper-responsiveness persists in subjects with occupational asthma after long-term cessation of exposure; (2) whether evolution of specific bronchial TDI sensitization and symptoms and functional abnormalities of asthma were coincident, and (3) the determinants at the time of diagnosis of patients’ outcome. Twenty-five nonatopic spray painters with occupational asthma due to TDI were re-examined 58 ± 7 (46–73) months after removal from exposure. On both examinations, the severity of asthmatic symptoms and the need for antiasthma treatment over the past 12 months were graded and lung function tests, measurement of airway responsiveness to methacholine (PD20), circulating total IgE and TDI-HSA specific IgE, skin tests with common inhalant allergens and specific bronchial challenge with TDI were carried out. Seven subjects were still TDI-reactors and 18 lost reactivity to it. All persistent reactors had still asthma and their symptom score, medication score, FEV1, PD20 and serum IgE were unchanged between assessments. In the 18 subjects no longer responsive to TDI, 8 had still features of asthma: their symptom and medication score had improved significantly, but FEV1, PD20 and serum IgE had not significantly changed; the other ten patients no longer reactors to TDI were also asymptomatic and their PD20 had become normal. The duration of symptomatic exposure to TDI was the only feature at diagnosis that differentiated patients with persistent TDI airway hyper-responsiveness and asthma from those who were no longer responsive to TDI but still asthmatic and those who were no longer responsive to TDI and no longer asthmatic (4 ± 1. 6; 2. 1 ± 0. 8; 0. 6 ± 0. 3 years, respectively; p < 0. 001). Our study demonstrates that airway sensitization to TDI and symptoms and functional airway abnormalities of asthma can persist for years after cessation of exposure and may have different outcome. If avoidance of the offending agent takes place within few months after the development of symptoms, remission of asthma and of TDI bronchial hyper-responsiveness can occur, whereas waiting for years makes it too late to cure asthma and, in the end, to reverse specific sensitization. [ABSTRACT FROM AUTHOR]

Copyright of Italian Journal of Neurological Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Italian Journal of Neurological Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The aim of this study was to evaluate the outcome of the specific inhalation challenge test (SIC) in 160 subjects with suspected baker's asthma and to assess its relation to total flour dust levels and to personal characteristics such as specific skin sensitisation, non-specific bronchial hyper-responsiveness (NSBH) and atopy. Methods: We investigated the outcome of SIC tests performed with wheat flour in six Italian laboratories. For each subject, data was available regarding skin sensitisation to wheat flour, NSBH, atopy, forced expiratory volume at 1 s (FEV1) monitoring and airborne flour dust in the challenge chamber measured by the gravimetric method (total dust in mg/m3). Results: The SIC test was positive for early asthma in 42 subjects (26%) and for late/dual asthma in 18 (11%). Positive outcome to SIC was significantly associated with NBSH (odds ratio, OR: 3.5, 95% CI: 1.6–7.7) and skin sensitisation to wheat flour (OR: 3.1, 95% CI: 1.3–7.0). Exposure level to wheat flour was less than or equal to 10 mg/m3 in 12% of individuals, ranged between 11 and 30 mg/m3 in 43% and exceeded 30 mg/m3 in 45%. The outcome of SIC was always negative among workers not skin sensitised to wheat flour and without NSBH and atopy. An increasing prevalence of positive SIC was observed among workers with one or more of the above-mentioned personal characteristics whose challenge exposure was greater than 10 mg/m3 ( P < 0.001). Conclusion: Procedures currently adopted for wheat flour dust exposure during SIC need to be better standardised in order to avoid excessive airborne dust exposure. Over-exposure seems to be of no use for the diagnosis and risks making the asthmatic reaction worse, particularly in patients who are both sensitised to wheat allergens and have NSBH and/or atopy. [ABSTRACT FROM AUTHOR]