Shift from Th2 to Th1 response in immunotherapy with venoms

Cytokines released from T lymphocytes regulate antibody production by B lymphocytes and releasability of mast cells and basophils. Immune tolerance in specific allergen (Ag) immunotherapy (SIT) might be a consequence of decreased Th2 or increased Th1 response of Ag specific T lymphocytes. We compared function of T lymphocytes in 11 patients with Hymenoptera venom allergy and in 7 healthy volunteers. We followed function of T lymphocytes in 6 patients during SIT. We measured released IL-2, IFN-γ, IL-4 and IL-5 from Ag and mitogens (either with phorbol-miristate-acetate (PMA) and ionomycine or anti-CD3 antibodies) stimulated peripheral blood mononuclear cells (PBMC). After stimulation with Ag PBMC of patients released 86 ± 133 pg/ml IFN-γ and 19.7 ± 20.1 pg/ml IL-4 (Th2 response), PBMCs of healthy controls released 184 ± 116 pg/ml IFN-γ and 4.8 ± 8 pg/ml IL-4 (Th1 response). Spontaneous release of IFN-γ in cultures of PBMC of patients increased after rush SIT (before: 25 ± 31 pg/ml, after 241 ±281 pg/ml, p<0.05). After 6 months of SIT response of PBMCs of patients became similar to response of PBMCs of healthy controls. Time pattern of cytokines secreted from PBMCs after stimulation with PMA and ionomycine was different than after stimulation through T-cell receptor/CD3 complex.