Does skin prick test correlate with basophil-associated mite-specific IgE in atopic children?

Skin prick test (SPT), as the standard diagnostic tool for immediate hypersensitivity to aeroallergens, is an expression of IgE-dependent mediator release from dermal mast cells. Though probably involved in the late-phase response, peripheral blood basophils (PBB) don't seem to participate in the immediate hypersensitivity response in the skin. We aimed to assess a possible correlation between the SPT to mites and levels of basophil-associated mite-specific IgE. We sequentially enrolled 15 children with allergic rhinitis and documented class > II mite sensitization, mean age 13 years (range 9.5-18), 11 males, 4 females. Symptoms score was determined using a validated questioner. SPT area under the curve (AUC) for 10 common respiratory allergens was measured in all patients. Heparinized blood after basophil enrichment, was lysed with CHAPS. Determination of allergen-specific and total IgE in serum and cell lysate supernatant was performed using standard commercial kits. Basophil-associated, mite-specific IgE could be reliably determined only in 10 patients with a skin reaction greater than 70 mm2, OR 36 (95% CI 1.8-732, p = 0.02). We found a strong linear correlation (R2 = 0.74, p = 0.001) between mite-specific basophil-associated IgE density (IgE molecules per cell) and the SPT AUC. This finding suggests that skin mast cell precursors and basophil both bind specific IgE at a common site prior to the arrival of mast cells to the skin.