Abstract Hymenoptera venom immunotherapy (VIT) is usually effective in inducing long-term tolerance to the allergen. In patients with a clonal mast cell disease (CMD) and Hymenoptera venom-induced anaphylaxis (HVA), however, life-long VIT is recommended, as tolerance to the venom is often lost after VIT termination. We compared blood samples from CMD and non-CMD patients with severe HVA before and more than 3 years under VIT to identify differences that might explain the lack of long-term tolerance in CMD patients. Serum tryptase, IgE, IgG4, KIT D816V variation, as well as circulating T and B cell subsets were analyzed. In addition, the cytokine response of wasp venom-stimulated PBMCs was measured. VIT-treated CMD patients had higher numbers of CD8 effector memory T cells (TEM), while VIT-treated non-CMD patients showed higher frequencies of CD8 central memory T cells (TCM) compared to patients prior to VIT. The IL-6 response to wasp venom was lower in CMD patients, regardless of anaphylaxis and therapy status. The generation of CD8 TCMs during VIT may be necessary for long-term tolerance to wasp venom after VIT.
Teufelberger et al. (Fri,) studied this question.