Respiratory symptoms and ex vivo cytokine release are associated in workers processing herring

To determine the prevalence of respiratory symptoms among workers processing herring and assess ex vivo cytokine release in response to agents at their workplace.

We applied a questionnaire, and performed skin prick testing and pulmonary investigations in 36 workers at two herring factories, using 31 municipal workers as controls. In a whole blood assay (WBA), venous blood from the subjects was incubated with lipopolysaccharide (LPS), beta(1,3)-glucan or sterile-filtered, fish constituents such as skin and rinsing water. We determined the IL-1beta and IL-8 release in the plasma by chemiluminescence ELISA.

Among smoking fish-factory workers the forced vital capacity (FVC) was higher (per cent predicted 92.0 vs 85.0; P=0.028) than among municipal workers. Fish rinsing water induced WBA IL-8 release to higher levels than LPS and glucan. Among non-smokers the induced IL-1beta release for rinsing water ( P=0.007) and the IL-8 release for skin ( P=0.001) and meat ( P=0.003) were higher in fish-factory workers than in municipal workers. The IL-1beta release for rinsing water ( P=0.028) and skin ( P=0.041) was higher among non-smokers than among smokers, and so was the IL-8 release for rinsing water ( P=0.008).

Assessing the cytokine release by use of the WBA we identified substances in the occupational environment with a pro-inflammatory potential comparable to that of LPS. The cytokine release for fish constituents was highest among non-smoking fish-factory workers. The results suggest a priming effect of the work exposure.