© 2013 Turkish Journal of Immunology. All rights reserved.Objectives: This study aims to test tolerance-breaking molecules in an immunotherapy model. Patients and methods: Asthmatic patients (n=3) with successful subcutaneous immunotherapy were enrolled to study. Peripheral blood mononuclear cells isolated from heparinized blood were cultured in the absence or existence of immunotherapy allergens and control allergens, under interleukin (IL)-1b, IL-6, TLR4- and TLR8-ligand stimulation for five days. CD4+ T cell proliferation was investigated by flow cytometry, with CFSE dilution method. Results: All patients were CD4+ T cell unresponsive to immunotherapy allergens. This unresponsiveness was broken by IL-1b stimulation; however, it was maintained in the presence of certain control allergens. Conclusion: It is requisite to understand peripheral tolerance mechanisms and influential factors on these pathways to minimize the incidence of allergic diseases. It is possible to develop more effective and novel peripheral tolerance induction modalities by defining the factors which are capable of breaking peripheral tolerance.