Resumo

PEREIRA, Celso et al. Thymic involvement on specific immunotherapy and respiratory allergy to Dermatophagoides pteronyssinus. Rev Port Imunoalergologia [online]. 2012, vol.20, n.1, pp.33-46. ISSN 0871-9721.

Introduction: T cell receptor excision circles (TRECs) on CD31⁺ T cells are related to recent thymic emigrant cells (RTEs).Aim: Evaluation of specific immunotherapy effects on number of TREC in peripheral T cells in patients allergic to Dermatophagoides pteronyssinus (Dpt). Method: 85 respiratory allergic patients (both genders), 41 (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 underwent 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 count was performed in CD4⁺CD31⁺ and CD8⁺CD31⁺ cells. The results were expressed per 100,000 RTE-related cells. Samples from 10 healthy individuals (Control - Group III) were obtained using the same method. Results: The value of TRECs on RTEs was constant in control groups. Group I patients’ TREC count 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 also demonstrated enormous individualchanges, particularly on TRECs/CD4⁺CD31⁺ cell assay. Basal values in Group III were significantly higher than those observed in active patient groups. Conclusions: Thymic functional activity has early involvement in the allergic reaction and SIT. IgEmediated 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 in the central mechanism of this therapy.

Palavras-chave : Allergy mechanism; asthma; CD31 cells; Dermatophagoides pteronyssinus; lymphocytes; nasal challenge test; rhinitis; specific immunotherapy; TREC.

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