Ragweed skin test responsiveness correlates with specific immunoglobulin E levels.

Area of Science:

• Immunology
• Allergology
• Clinical Medicine

Background:

• Objective assessment of atopy is crucial for diagnosing allergic rhinitis.
• Commonly used objective measures include serum eosinophils, total and specific immunoglobulin E (IgE), and skin testing.

Purpose of the Study:

• To investigate the relationship between in vitro allergy tests and in vivo skin test responsiveness.
• To compare eosinophil counts, total IgE, and specific IgE radioallergosorbent test (RAST) measurements with endpoint skin test titrations for ragweed allergy.

Main Methods:

• Forty subjects with moderate to severe ragweed-allergic rhinitis and positive skin-prick tests participated.
• Endpoint skin tests involved intradermal injections of standardized short ragweed extract dilutions.
• Measurements included eosinophil counts, total IgE, and ragweed-specific IgE RAST.

Main Results:

• Ragweed-specific IgE showed significant correlation with endpoint skin test wheal and erythema concentrations (r = -0.714 and r = 0.862, respectively; p < 0.001).
• A significant relationship was observed between ragweed-specific IgE and total IgE (r = 0.72; p < 0.01).
• No significant correlations were found between blood eosinophils and any of the in vitro or in vivo allergy measures.

Conclusions:

• Skin test responsiveness to ragweed correlates with in vitro ragweed-specific IgE levels.
• However, in vitro and in vivo tests are not interchangeable for assessing the degree of IgE-mediated sensitivity in allergic rhinitis.