Non-eosinophilic occupational asthma due to exposure of merbau and bangkirai wood.

Abstract

Objectives: To evaluate association between wood dust exposure and occupational asthma, and investigate immunopathogenesis behind the disease by examining IgE, CD4, and eosinophil level.Methods: Subjects diagnosed with occupational asthma using Work Related Asthma Questionnaire and PEFR variability for two weeks. Wood dust exposure measured by personal dust sampler for two days during working time.Results: Among 104 samples, 17 % diagnosed with occupational asthma. Analysis showed that there were correlation between wood dust exposure and occupational asthma ( r) = 0,384; p = 0,000). ROC methods revealed that wood dust exposure 70,5 mg/m3/year associated with greater risk of occupational asthma, with sensitivity of 87,5 % and specificity 75 %. Wood dust exposure was significantly correlated with serum CD4 level, r 0,455, p 0,000. Eosinophil level did not correlate with CD4 level nor wood dust exposure.Conclusion: Merbau and bangkirai wood dust exposure is one of risk factor of occupational asthma. Occupational asthma due to these wood exposure is a non eosinophilic mechanism, and associated with elevated of CD4 serum level.