Acute blood neutrophilia induced by short-term compost dust exposure in previously unexposed healthy individuals.

OBJECTIVES

Systemic effects of organic dust inhalation have been described in farming environments. The purpose of this study was to examine whether a single exposure at a biowaste composting facility could also exert systemic effects in healthy volunteers not previously exposed to organic dust from such facilities.

METHODS

Seventeen subjects (age 20-35 years) were exposed to organic dust for 2 h (exposure day) during moderate exercise; 12 of these subjects also took part in a control experiment (control day). Spirometry was performed before and immediately after the exposure. White blood cell counts and levels of tumor-necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in peripheral blood were determined before and 3 h after exposure.

RESULTS

Exposures did not result in significant changes in lung function or blood cytokine levels. In contrast, the number and percentage of neutrophils increased during the exposure day [median (range) percent change of percentages 14 (-2; 67) %; P=0.002], but not during the control day [5 (-22; 35) %; P=0.66). Furthermore, there was a decrease in the number and percentage of eosinophils during the exposure day [-47 (-57; 0.0) %; P=0.002], whereas the change during the control day was smaller [-8 (-56; 71) %; P=0.68].

CONCLUSION

Short-term exposure of healthy, young subjects to organic dust from composting facilities had opposite effects on the numbers of blood neutrophils and blood eosinophils. These effects, though mild, suggest that even during a limited period of moderate work a sufficient amount of bioactive material can be deposited in the lung to elicit acute systemic alterations.