RAST using crude and purified anti-IgE

Area of Science:

• Immunology
• Allergy Diagnostics
• Biochemistry

Background:

• The Radioallergosorbent Test (RAST) is a common method for detecting specific IgE antibodies.
• The sensitivity of RAST can be influenced by the purity of the anti-immunoglobulin E (anti-IgE) reagent used.
• Comparing crude and purified anti-IgE is crucial for optimizing RAST performance.

Purpose of the Study:

• To compare the sensitivity of RAST using crude versus purified anti-IgE reagents.
• To evaluate the diagnostic agreement between RAST and skin-prick tests for various allergens.
• To determine optimal conditions for allergosorbent preparation and validate RAST positivity criteria.

Main Methods:

• RAST assays were performed on sera from 248 detergent factory workers using both crude and purified anti-IgE.
• Allergens tested included grass pollens, Aspergillus fumigatus, and the detergent enzyme Alcalase.
• Skin-prick tests were used as a comparative diagnostic method.

Main Results:

• Purified anti-IgE demonstrated higher sensitivity in RAST compared to crude anti-IgE for detecting circulating IgE.
• Improved agreement between positive RAST and skin tests was observed when skin reactions ≥3 mm were considered positive.
• Antigen non-specific binding with crude anti-IgE could lead to false positives, particularly with Alcalase.

Conclusions:

• Immunosorbent-purified anti-IgE enhances RAST sensitivity for IgE detection.
• Refined criteria for positive RAST results improve diagnostic correlation with skin tests.
• Optimized allergosorbent preparation and reagent purity are key for accurate allergy diagnosis.