Non-eosinophilic occupational asthma due to exposure of Merbau and Bangkirai Wood

Objectives: To evaluate the association between exposure to wood dust and occupational asthma and investigate the immunopathogenesis behind the disease by examining IgE, CD4, and eosinophil levels. Methods: Subjects were diagnosed with occupational asthma based on the findings derived from the questionnaire titled “Work-Related Asthma Questionnaire” and Peak Expiratory Flow Rate (PEFR) variability for two weeks. Exposure to wood dust exposure was measured using a personal dust sampler for two days on the subjects during working hours. Results: Out of the 104 samples chosen for the study, 17% of the subjects were diagnosed with occupational asthma. Analysis showed that there were correlations between exposure to wood dust exposure and occupational asthma (r = 0.384, p = 0.000). ROC methods revealed that exposure to wood dust was 70.5 mg/m3/year, which is associated with a greater risk of occupational asthma, especially in light of the higher values measured for sensitivity at 87.5% and specificity at 75%. Study findings showed that exposure to wood dust was significantly correlated with higher serum CD4 level (r = 0.455, p = 0.000). However, eosinophil level did not correlate with CD4 level or exposure to wood dust. Conclusion: Exposure to Merbau and Bangkirai wood is indeed a risk factor for occupational asthma. The process of how exposure to wood induces occupational asthma can be defined as a non-eosinophilic mechanism and denotes a significant correlation between occupational asthma and the elevated presence of CD4 serum.