Laboratory animal allergy is preventable in modern research facilities.

BACKGROUND: Historical data suggest 15% of laboratory animal workers develop IgE sensitisation and 10% symptoms of laboratory animal allergy (LAA), including occupational asthma. Individually ventilated cages (IVCs) are replacing conventional open cages; we sought to evaluate their impact on the development of LAA. METHODS: We surveyed 750 laboratory animal workers and measured airborne Mus m 1 (mouse allergen) levels in seven UK institutions. We compared the prevalence of sensitisation to mouse proteins (by specific IgE assay or skin prick test) and of work-related allergic symptoms in IVC-only and open cage units. RESULTS: Full-shift Mus m 1 levels were lower in IVC than open cage units (geometric mean 1.00 (95% CI 0.73-1.36) versus 8.35 (95% CI 6.97-9.95) ng·m-3; p<0.001), but varied eight-fold across the IVC units (geometric mean range 0.33-4.12 ng·m-3). Primary analyses on data from 216 participants with ≤3 years exposure to mice revealed a lower prevalence of sensitisation in those working in IVC units compared with conventional cage units (2.4% (n=2) versus 9.8% (n=13); p=0.052). Sensitisation in IVC units varied from 0% to 12.5%; the use of fitted respiratory protection was less common in IVC units where prevalence of sensitisation was higher. Work-related allergy symptoms were more frequently reported by mouse-sensitised individuals (46.7% versus 10.9%; p<0.001) and only by those working in open cage units. CONCLUSION: In contemporary practice, LAA is now largely preventable with the use of IVC systems and the judicious use of appropriate respiratory protection.

Measurement of Specific IgG4 Anti-mouse Urine Antibodies.

IgG4 and its role in immune tolerance has been investigated widely. Symptom reduction and improved clinical outcomes in immunotherapy trials are associated with significant increases in allergen-specific IgG4 antibodies. Natural immune tolerance observed in beekeepers and cat owners has also been associated with elevated levels of bee venom and cat allergen-specific IgG4, respectively. Functionally, allergen-specific IgG4 has been shown to reduce the binding of IgE-allergen complexes to B cells, a key step in the initiation of the type 1 hypersensitivity allergic response. In laboratory animal allergy, IgG4 has been described as a "protective/blocking" antibody. However, a consensus on the exact relationship between exposure, IgG4, and tolerance has yet to be reached. In this chapter, we review the factors that require consideration when developing an ELISA for the quantification of allergen-specific IgG4.