Long term effect and allergic sensitization in newly employed workers in laboratory animal facilities

The aim of this study was to identify targets predicting allergic sensitization to laboratory animals using shift in skin prick test to laboratory animals as primary outcome variable.

In a prospective longitudinal study, personnel who were employed to work with laboratory animals at a medical university were investigated before and 6, 12 and 24 month after the start of employment. Lung function, bronchial challenges, exhaled NO and nasal lavage were performed and blood samples were drawn at all visits.

Seventy subjects attended all four visits and 13 (19%) became sensitized to laboratory animals during the two years of follow up. Lung function (VC and FEV1) deteriorated and blood levels of eosinophils and IL-2 producing lymphocytes increased after 24 months. An increased risk of developing laboratory animal allergy was significantly associated with female sex, atopy, symptoms associated with exposure to laboratory animals, low proportion of blood CD4+ cells, specific IgE to rat and mouse and high total IgE when starting to work with laboratory animals.

A sensitization rate of 19% in 2 years, were demonstrated in laboratory animal workers. Atopy, increased total and specific IgE levels (rat and mouse) were the strongest predictors for laboratory animal sensitization. The progressive lung function impairment over time, observed in the whole study population may indicate that exposure in animal facilities induces harmful effects, irrespective to allergic sensitization.