Short-term effects of wasp-venom immunotherapy on the expression of the receptor for interleukin-7 (IL-7) on peripheral blood CD4+ T cells

Introduction
Induction of allergen tolerance through venom immunotherapy (VIT) remains the most effective therapeutic tool in the treatment of patients allergic to hymenoptera venom. To date, majority of beneficial effects of VIT (and specific immunotherapy in general) have been associated with the alteration of phenotype and function of CD4+ T cells. Homeostasis and survival of CD4+ T cells is strictly related to signaling mediated by interleukin-7 (IL-7) and its receptor, IL-7R (CD127). To date, however, there are no data on the effects of hymenoptera venom immunotherapy on IL-7 nor IL-7R.

Aim
Here, we evaluated short-term effects of wasp venom SIT on the expression of IL-7R on peripheral blood CD4+ T cells in wasp venom-sensitive patients within first 3 months of VIT.

Material and methods
Peripheral blood was collected from wasp venom-sensitive patients in the course of ultra-rush immune therapy using Venomenhal Wespe (HAL Allergy). Assessment of IL-7 receptor within CD4+ lymphocytes was performed using immunostaining with fluorochrome-labeled monoclonal antibodies and flow cytometric analysis.

Results
Although we found a trend to decreased expression of IL-7 receptor on CD4+ T cells within first 24 h of immunotherapy, however, in total, we did not demonstrate significant differences in frequencies of IL-7R-positive CD4+ T cells.

Conclusions
Acquired results suggest that wasp venom SIT does not seem to affect frequencies of CD4+CD127+ T cells at early stages of therapy. However, no data on effects of VIT on T cell phenotype in long-term observation justify need for further studies on hymenoptera VIT effects on IL-7/IL-7R axis in context of allergen tolerance induction.