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IgE levels detectable in patients after 5 year venom immunotherapy protection

Patients who underwent venom immunotherapy had a significant decrease in immunoglobulin E levels yet still had detectable immunoglobulin levels despite the immunotherapy providing protective benefits, according to recent research.

“When a patient fulfills the temporal criterion for [venom immunotherapy duration (VIT)] duration (at least 5 years) but still has positive [serum specific] IgE tests, a mean IgE decrease ranging from 58% to 70% compared to baseline is likely to be expected,” Valerio Pravettoni, MD, of the Clinical Allergy and Immunology Unit and Foundation IRCCS Ca’ Granda, Ospedale Maggiore Policlinico in Milan, Italy, and colleagues wrote. “This decrease could be less striking in elderly patients or in [patients] with a higher pre-treatment Mueller grade [systemic allergic reactions (SR)]. The measurement of venom-specific IgE levels remains the best in vitro parameter to monitor VIT, as demonstrated by follow-up studies of patients with long-lasting protection.”

Pravetoni and colleagues retrospectively evaluated 232 patients with a yellow jacket venom allergy and grouped them based on their exposure to the venom over a 5-year immunotherapy period: 84 patients were placed in a never strung group, 72 patients were placed in a group that had been stung and protected within the first 3 years, and 76 patients were placed in a group that was stung and protected within the last 2 years, according to the abstract. Researchers compared IgE levels during VIT and found that IgE levels had decreased compared with baseline levels (X² = 346.029, P < .001), with significantly higher IgE levels for patients with more recent stings and IgE levels after 5 years having significant correlation with factors such as age (F = 6.672, P =.002) and Mueller grade (F = 2.778; P = .012).

After VIT, patients were followed up from 1 year to 10 years, and 35.2% of patients were stung but did not have an allergic reaction, Pravettoni and colleagues noted. – by Jeff Craven

Disclosure: The researchers report no relevant financial disclosures.