RationaleVenom immunotherapy for allergy to honeybee stings is highly efficacious, but IgE-mediated systemic reactions frequently complicate treatment. Short, allergen-derived T cell peptides are potentially safer, but HLA polymorphism confers huge diversity to such epitopes, making the selection of peptides for therapy difficult. Texier et al (J Immunol 2000;164:3177-84) characterized T cell peptides of phospholipase A2 (PLA2, the major allergen of honeybee venom) by binding affinity for commonly expressed HLA-DRB1 molecules. We assessed the effect on immunological parameters of treatment with an HLA-DR-based PLA2 peptide mixture.MethodsIn an open study, 12 volunteers allergic to honeybee venom received 9 injections of PLA2 peptides, with 6 untreated subjects serving as controls. At baseline and at 3 months, the late-phase cutaneous reaction to bee venom was measured, and peripheral blood mononuclear cells (PBMC) were extracted for stimulation assays.ResultsPeptide-treated subjects had a decrease in the late-phase cutaneous reaction to bee venom (baseline 63.8mm, outcome 47.5mm, p=0.02) which was significant compared to control volunteers (p=0.03). The proliferation of bee-venom stimulated PBMC decreased in treated subjects (baseline stimulation index 16.5, outcome 6.3, p<0.01), which was significant compared to controls (p=0.01). Peptide treatment significantly reduced the production of IL-13 by PBMC (baseline 871.2pg/ml, outcome 183.9 pg/ml, p<0.01) and IFN-γ (baseline 388.3pg/ml, outcome 183.9pg/ml, p<0.01), associated with increased production of IL-10 (baseline 36.64pg/ml, outcome 69.3pg/ml, p=0.02).ConclusionsHLA-DR based PLA2-derived T cell peptides have potential in the treatment of bee-venom hypersensitivity since they modify surrogate markers of allergy.