Modified Th2 responses at high-dose exposures to allergen: using an occupational model

Area of Science:

• Immunology
• Occupational Health
• Allergology

Background:

• Allergen exposure and its link to allergy and asthma are complex.
• High cat allergen exposure can lead to specific antibody responses without sensitization or asthma risk, termed a 'modified Th2 response'.
• Longitudinal studies indicate reduced allergy and asthma risk with high allergen exposure levels.

Purpose of the Study:

• To examine the relationship between aeroallergen exposure, specific IgE, IgG, and IgG(4) antibody production, and symptom prevalence in an occupational setting.
• To investigate the role of specific antibody subclasses in modulating allergic responses to occupational allergens.

Main Methods:

• A cross-sectional survey was conducted among 689 employees exposed to rats in pharmaceutical facilities across the UK.
• Participants provided blood samples and completed questionnaires on allergen exposure and symptoms.

Main Results:

• Highest rat allergen exposure correlated with reduced sensitization and symptoms.
• Increased exposure intensity led to a higher frequency of individuals producing substantial amounts of specific IgG and IgG(4) antibodies.
• Individuals handling more rats showed higher IgG(4)/IgE ratios.
• The risk of work-related chest symptoms was lower in those producing both specific IgE and IgG(4) compared to those with specific IgE only.

Conclusions:

• High occupational exposure to rat allergen is linked to decreased specific IgE and symptoms, but increased specific IgG and IgG(4) production.
• Co-production of specific IgG(4) with specific IgE may offer protection against work-related chest symptoms compared to specific IgE production alone.