Role of specific IgE, IgG and IgG4 antibodies to corn dust in exposed workers

BACKGROUND & METHODS: To evaluate the role of specific antibodies to corn dust (CD) and their relationship to respiratory dysfunction, we detected serum specific IgE(sIgE), IgG(sIgG) and IgG4(sIgG(4)) antibodies by ELISA in 42 employees working in the animal feed industry and 27 unexposed controls. RESULTS: Our survey revealed that 15 (34.9%) subjects had work-related respiratory dysfunction associated with or without nasal symptoms. Among these subjects, eight had airway hyper-responsiveness to methacholine. Significant differences were noted in sIgE and sIgG(4) between exposed and unexposed groups (p=0.04, p=0.00 respectively), but no difference was noted in sIgG (p=0.1). Although there was no significant difference in the prevalence of specific IgE antibody between symptomatic (29%) and asymptomatic groups (19%, p=0.55), the specific IgE levels were significantly higher in symptomatic workers than in asymptomatic workers (p=0.03). Specific IgG antibody was detected in 1(6%) symptomatic and 4(15%) asymptomatic workers (p=0.46). Specific IgG(4) antibody was detected in 11(73%) of symptomatic and 21(78%) of asymptomatic workers (p=0.90). The higher prevalence of sIgG(4) antibody was noted in workers with sIgE antibody (p=0.001). The correlation between sIgG and exposure duration was significant (r=0.36, p=0.02). There was no association between the prevalence of sIgE, sIgG, and sIgG(4) to exposure intensity, smoking or atopic status. CONCLUSION: These results suggested that the existence of sIgG and sIgG4 might represent a response to CD exposure, and that some unexposed subjects had sIgG to CD. Specific IgE might play a role in the development of respiratory symptoms.