Expansion of circulating Foxp3+D25bright CD4+ T cells during specific venom immunotherapy

Autor: Pereira-Santos, M. C., Baptista, A. P., Melo, A., Alves, R. R., Soares, R. S., Pedro, E., Pereira-Barbosa, M., Victorino, R. M. M., Sousa, A. E.
Přispěvatelé: Repositório da Universidade de Lisboa
Jazyk: angličtina
Rok vydání: 2007
Předmět:
Zdroj: Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP
Popis: Journal compilation © 2007 Blackwell Publishing Ltd, Clinical and Experimental Allergy © 2007 The Authors
BACKGROUND: Venom immunotherapy (VIT) induces long-lasting immune tolerance to hymenoptera venom antigens, but the underlying mechanisms are not yet clarified. Regulatory T cells are thought to play an important role in allergic diseases and tolerance induction during specific immunotherapy. AIM: Characterize longitudinally the impact of VIT on the pool of circulating regulatory T cells. METHODS: Fourteen hymenoptera venom-allergic patients with severe reactions (grades III-IV) were studied before, 6 and 12 months after starting ultra-rush VIT. Freshly isolated peripheral blood mononuclear cells were surface stained with a panel of markers of T cell differentiation and intracellularly for CTLA-4 and Foxp3 and analysed by flow cytometry. foxp3 mRNA was quantified by real-time PCR. VIT responses were assessed by measuring specific IgG4 and IgE levels. Eleven individuals with no history of insect venom allergy were studied as controls. RESULTS: VIT induces a significant progressive increase in both the proportion and the absolute numbers of regulatory T cells defined as CD25bright and/or Foxp3+ CD4+ T cells. These changes are not related to alterations in the expression of activation markers or imbalances in the naïve/memory T cell compartments. foxp3 mRNA levels also increased significantly during VIT. Of note, the increase in circulating regulatory T cell counts significantly correlates with the venom-specific IgG4/IgE ratio shift. CONCLUSION: VIT is associated with a progressive expansion of circulating regulatory T cells, supporting a role for these cells in tolerance induction.
APB and RSS received scholarships from GlaxoSmithKline and Fundação para a Ciência e Tecnologia, Portugal, respectively.
Databáze: OpenAIRE
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