Changes in gene expression caused by insect venom immunotherapy responsible for the long-term protection of insect venom-allergic patients

Background: Insect venom immunotherapy (VIT) is the only causative treatment of insect venom allergy (IVA). The immunological mechanism(s) responsible for long-term protection achieved by VIT are largely unknown. A better understanding is relevant for improving the diagnosis, prediction of anaphylaxis, and monitoring and simplifying treatment of IVA. Objective: To find genes that are differentially expressed during the maintenance phase of VIT and after stopping, to get clues about the pathways involved in the long-term protective effect of immunotherapy. Methods: Whole genome gene expression analysis was performed on RNA samples from 50 patients treated with VIT and 43 healthy controls. Patients were divided into three groups: (1) before the start of VIT; (2) on maintenance phase of VIT for at least 3 years still receiving injections; and (3) after VIT. Results: Of all 48,804 probes present in the array, 48,773 transcripts had sufficient data for further analysis. The list of genes that were differentially expressed (at least log2 FC > 2; P < .05 corrected for multiple testing) during the maintenance phase of VIT as well as after successful VIT contains 89 entities. The function of these genes affects cell signaling, cell differentiation, and ion transport. Conclusion: This study shows that a group of genes is differentially expressed both during and after VIT in comparison with gene expression in patients before VIT. Although the results of this study should be confirmed prospectively, the relevance of these findings is supported by the fact that they are related to putative mechanisms of immunotherapy. Ann Allergy Asthma Immunol. 2011;106:502-510.