Abstract

BACKGROUND:
In workers exposed mostly to laboratory animals (LA), symptoms may be due to irritants or allergens. Correct aetiological diagnosis is important for health surveillance.

OBJECTIVES:
This study aims to test whether work-related (WR) allergen-induced symptoms are associated with a cytokine profile distinct from that due to irritants.

METHODS:
In a cross-sectional study (n=114), WR respiratory and/or skin symptoms were assessed through a standardised clinical examination and sensitisation to rat and/or mouse allergen determined by serum immunoglobulin E. Serum cytokine concentrations were measured by multiplex assays. The predefined cytokine profiles 'sensitiser' (interleukin (IL)-4, IL-5, IL-13, eotaxin-1) and 'irritation' (IL-8, IL-17A, IL-17F, IL-22) were considered positive, when =3 concentrations exceeded the 95th percentile of the asymptomatic non-sensitised group. Results were examined by hierarchical clustering analyses (HCA) and multiple linear regression. Explorative analyses were carried out for nine additional cytokines. Exposure to allergens and endotoxin was assessed in a subpopulation.

RESULTS:
The prevalence of the profile 'irritation' was comparable in 28 symptomatic non-sensitised workers and 71 asymptomatic non-sensitised workers. HCA showed that nearly all symptomatic non-sensitised workers were gathered in two subclusters, characterised by high IL-17A levels, but different IL-8 levels. Multiple linear regression identified drug consumption and current complaints as confounders. Sensitised subjects were too few (n=14) for testing the profile 'sensitiser'.

CONCLUSIONS:
In this unselected population of LA workers, the profile 'irritation' did not prove to be a valuable health surveillance tool. Low power precluded assessment of the profile 'sensitiser'. The increased IL-17A concentration may originate from irritative constituents of organic dust.

Full Text

Comments

Studies of laboratory animal allergy have consistently shown a large number of workers with work-related asthma or rhinitis but negative IgE to rat and mouse allergens. The current study starts with the hypothesis that those with negative IgE have irritant responses to the animal allergens and can be safely redeployed to areas with some but lesser exposure. If true this is important, but I believe not yet substantiated. The cross-sectional study identified 29 with work-related symptoms and negative IgE, and found their cytokine profiles indistinguishable from workers with negative IgE and no symptoms. They did however fall into 2 subsets with raised IL17A with and without raised IL8. The study was compromised by finding only 8 workers with positive IgE and work-related symptoms. The authors concluded that "In this unselected population of LA workers, the profile ‘irritation’ did not prove to be a valuable health surveillance tool. Low power precluded assessment of the profile ‘sensitiser’. The increased IL-17A concentration may originate from irritative constituents of organic dust.

4/30/2017