Background High prevalences of work-related respiratory symptoms in relation to organic dust exposure have been reported in the potato processing industry, but the responsible effect mechanisms are not known.
Objective To study the possible role of a type III allergy in aetiology. Methods Specific immunoglobulin G (IgG) and IgG4 subclass antibodies against occupational airborne antigens were determined in sera from 131 potato processing workers and 36 non-exposed controls. Personal exposure to airborne antigens was measured, and a preliminary biochemical characterization was carried out.
Results Specific IgG was detectable in almost all sera, but levels were significantly (P<0.01) higher in potato processing workers compared with controls. Specific IgG4 was detectable in half of the workers' sera, but in none of the control sera. The antigens involved appeared to be heat-labile potato proteins. Antibody levels increased during the processing campaign in most workers, and this increase was dependent on the level of antigen exposure. Both the difference in IgG titres between the occupationally exposed group and the non-exposed group, and the exposure-related increase in specific IgG titres seemed to be mainly due to specific antibodies of the IgG4 subclass. Specific antibodies showed a non-significant tendency to lower levels in workers with work-related respiratory symptoms.
Conclusion Occupational respiratory exposure in the potato processing industry leads to a strong humoral immune response, most pronounced for lgG4 subclass antibodies. Type III allergy is, however, unlikely to play a predominant role in the aetiology of respiratory effects.