title: T cell receptor excision circles (TREC) and recent thymic migrant cells in specific immunotherapy and respiratory allergy to Dermatophagoides pteronyssinus.
abstract: BACKGROUND
  T cell receptor excision circles (TREC) on CD31+ T cells are related to recent thymic emigrant cells (RTEs). The involvement of the functional thymic tissue occurs early in the IgE-mediated allergic reaction, and in response to specific immunotherapy (SIT).
  
  
  OBJECTIVE
  Evaluation of specific immunotherapy effects on TREC number in peripheral T cells in patients allergic to Dermatophagoides pteronyssinus (Dpt).
  
  
  METHODS
  85 respiratory allergic patients (both genders), 41 of them (Group II) under maintenance treatment to Dpt SIT (21 sublingual-SLIT, and 20 subcutaneous-SCIT), were selected. The allergic patients (Group I) without specific treatment were submitted to an allergen challenge test (22 nasal and 22 conjunctival). Peripheral cell analysis was performed immediately before treatment and 60 or 240 minutes after allergenic extract administration. TREC quantification was performed in CD4+CD31+ and CD8+CD31+. The results were expressed per 100.000 cells related to RTEs. Samples from 10 healthy individuals (Control - Group III) were obtained with the same method.
  
  
  RESULTS
  The value of TRECs on RTEs was constant in control groups. For Group I patients (nasal or conjunctival test), TREC quantification in CD31+ T cells showed relevant individual changes, even in the patients tested earlier (60 minutes), and statistical significant at 240 minutes. Both SCIT and SLIT had also demonstrated enormous individual changes, particularly on TRECs/CD4+CD31+ cells assay. Basal values in Group III were significantly higher than those observed in active patients groups.
  
  
  CONCLUSIONS
  Thymic functional activity is earlier involved in the allergic reaction and SIT IgE-mediated allergy is able to induce RTEs in the periphery, particularly TRECs/CD4+CD31+ cells. Both SLIT and SCIT showed reduced RETs in the periphery, probably due to maturation of regulatory T cells. Our results suggest a crucial role of the functional thymic tissue on the central mechanism of this therapy.
authors: Immunoallergy Department, Coimbra University Hospital, Coimbra Portugal. celsopereira.pt@gmail.com
authors: C
authors: C
authors: Pereira
authors: G
authors: G
authors: Loureiro
authors: A
authors: A
authors: Martinho
authors: A
authors: A
authors: Paiva
authors: B
authors: B
authors: Tavares
authors: D
authors: D
authors: Machado
authors: R
authors: R
authors: Nunes
authors: S
authors: S
authors: Pedreira
authors: A
authors: A
authors: Henriques
authors: M L
authors: ML
authors: Pais
authors: A
authors: A
authors: Segorbe-Luís
mesh_terms: D000328:Adult; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002465:Cell Movement; D002469:Cell Separation; D040002:Dermatophagoides pteronyssinus / Q000276:immunology; D003888:Desensitization, Immunologic; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology* / Q000628:therapy; D008297:Male; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000276:immunology; D060888:Real-Time Polymerase Chain Reaction; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology
chemical_list: D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011948:Receptors, Antigen, T-Cell