Mucosal brush biopsy of the oral cavity to detect local, peanut-specific immunoglobulin E.

Background: This study compares the ability of mucosal brush biopsy (MBB) from 2 separate locations in the oral cavity to detect peanut-specific immunoglobulin E (IgE) in patients who report adverse oral cavity reactions when ingesting peanuts.

Methods: Twenty patients who reported a history of oral cavity itching or swelling when ingesting peanuts underwent either MBB of the dorsal tongue (n = 10) or the vestibule (n = 10). Serum testing for total and peanut-specific IgE, using standard immunofluorescent assay, was obtained for all patients. Total and specific IgE for each location were compared. Additionally, the correlation between MBB and peanut-specific IgE on serum was determined using Fisher's exact probability testing.

Results: Peanut-specific IgE was detected in 3 of 10 (30%) MBB specimens from the dorsal tongue and in 10 of 10 (100%) MBB specimens from the vestibule. The mean peanut-specific IgE on MBB (kU/L) in the dorsal tongue group was 0.03 vs 0.17 in the vestibule group (p = 0.0002). No significant association was noted for peanut-specific IgE between MBB and serum testing (p = 1.0).

Conclusion: This study demonstrates for the first time that peanut-specific IgE can be detected using MBB in the oral cavity of patients who are symptomatic when consuming peanuts. The vestibule was a superior location compared to the dorsal tongue for oral cavity MBB, correlating very well with self-reported symptoms. Peanut-specific IgE on MBB overall did not correlate well with serum testing for peanut-specific IgE.