Comparison of immunology tests for determining sensitisation to mouse proteins in laboratory animal workers

Abstract

Background: Laboratory animal workers exposed to mice can develop IgE-mediated allergy to mouse proteins: 15% develop sensitisation and 10% clinical symptoms of allergy. The gold standard test for sensitisation to mouse proteins is presence of serum specific IgE; skin prick tests (SPT) are also used.

Aim: To determine the proportion of laboratory workers sensitised to mouse proteins with discordant immunology results.

Methods: Laboratory workers exposed to mice were recruited to the SPIRAL (Safe Practice In Reduction of Allergy in Laboratories) study. Sensitisation was determined by the presence of serum specific IgE to Mus m 1 (mouse urinary protein) and mouse epithelium using immunoCAP methods (positive result >0.35kU/L) and by SPT to mouse epithelium (positive result=saline-adjusted mean wheal diameter of ≥3mm).

Results: 14/203 (7%) participants who had SPT performed and specific IgE to Mus m 1 tested had discordant results with most having positive serology and a negative SPT. (table 1)

93 participants had specific IgE to both mouse epithelium and Mus m 1 tested, of whom 7 (8%) had discordant results. (table 2)

Conclusion: Laboratory workers may be sensitised to Mus m 1 or mouse epithelium. Testing for just one of these proteins and/or using a single method (serology or SPT) may miss occasional cases. This is of importance in both research studies and clinical practice.