Flow-assisted quantification of in vitro activated basophils in the diagnosis of wasp venom allergy and follow-up of wasp venom immunotherapy.

Abstract

BACKGROUND:

Correct identification of the culprit venom is a prerequisite for specific venom immunotherapy (VIT). Despite the efficacy of VIT, issues as how to monitor treatment and when to discontinue maintenance therapy remain to be established.

METHODS:

To evaluate diagnostic performances of the basophil activation test (BAT) in wasp venom allergy, 80 patients with a definite history of wasp venom anaphylaxis (systemic reactors) and 14 wasp-stung asymptomatic controls (stung controls) were enrolled. Venom-induced basophil activation was analyzed flow cytometrically by double-labeling with anti-IgE and anti-CD63. Results were compared to wasp IgE levels and results of a venom skin test (VST). To establish whether the BAT constitutes a candidate marker to monitor VIT, the BAT was repeated in 22 patients on the 5th day of a build-up course and after 6 months of maintenance VIT. Whether the BAT could contribute in the decision of discontinuing VIT was assessed in a cross-sectional analysis in 30 patients receiving treatment for 3 years.

RESULTS:

Comparison between systemic reactors and stung controls revealed a sensitivity of 86.4% and specificity of 100% for venom IgE, and sensitivity of 81.8% for VST, respectively. In contrast to stung controls, patients demonstrated dose-dependent venom-induced basophil activation. The BAT attained a sensitivity of 83.8% and specificity of 100%. At the end of the build-up course, no effect of VIT on the BAT was demonstrable. When the BAT was repeated after 6 months of treatment, submaximal stimulation of the cells demonstrated a significant decreased CD63 expression (P < 0.04). Patients having VIT for 3 years also demonstrated significantly lower venom-induced CD63 expression (P < 0.001). After 3 years, 60% of the patients had a negative BAT for submaximal stimulation of the cells whereas only 17.9% of the patients had negativation of wasp IgE.

CONCLUSIONS:

The BAT is a reliable instrument for the diagnosis of wasp venom anaphylaxis and might constitute an instrument to monitor wasp VIT.

• Authors: D G Ebo, M M Hagendorens, A J Schuerwegh, L M-N Beirens, C H Bridts, L S De Clerck, W J Stevens
• Journal: Cytometry. Part B, Clinical cytometry (Cytometry B Clin Cytom) Vol. 72 Issue 3 Pg. 196-203 (May 2007) ISSN: 1552-4949 [Print] United States
• PMID: 17111386 (Publication Type: Comparative Study, Evaluation Study, Journal Article)
• Copyright: Copyright 2006 International Society for Analytical Cytology

Chemical References

• Wasp Venoms
• Immunoglobulin E

Topics

• Adolescent
• Adult
• Aged
• Basophil Degranulation Test
• Basophils (immunology)
• Blood Cell Count (methods)
• Desensitization, Immunologic (methods)
• Female
• Flow Cytometry
• Follow-Up Studies
• Humans
• Hypersensitivity, Immediate (blood, diagnosis)
• Immunoglobulin E (analysis)
• In Vitro Techniques
• Male
• Middle Aged
• Skin Tests
• Wasp Venoms (immunology)