INCREASED ALLERGEN-SPECIFIC, STEROID-SENSITIVE GAMMA-DELTA T-CELLS INBRONCHOALVEOLAR LAVAGE FLUID FROM PATIENTS WITH ASTHMA

Objective: To test the hypothesis that allergen-specific, steroid-sens itive gamma delta T lymphocytes are increased in bronchoalveolar lavag e fluid of patients with asthma. Design: Case series. Setting: The out patient allergy services at the University of Perugia, Perugia, Italy. Patients: 12 untreated atopic patients (6 children and 6 adults) with mildly symptomatic chronic asthma were studied. Bronchoalveolar ravag e fluid from 10 healthy nonsmoking volunteers and age-matched children with cystic fibrosis (n = 5) or anatomic malformation of the airways (n = 4) served as control samples. Intervention: Three patients receiv ed treatment with deflazacort, 60 mg twice daily, for 1 week. Measurem ents: CD3(+), CD4(+), and CD8(+) T cells from patients and controls we re examined by two-color flow cytometry for coexpression of V delta 1 and V delta 2 isoforms of the gamma delta T-cell receptor. In vitro pu lmonary gamma delta T-cell proliferation in response to a specific all ergen, the apoptotic death of these cells after incubation with 10(-7) M dexamethasone, and bronchoalveolar lavage fluid T-lymphocyte compos ition before and after 1 week of deflazacort therapy were evaluated in 3 Dermatophagoides pteronyssinus-sensitive patients. Results: The pro portion of gamma delta T lymphocytes, primarily CD4(+) or CD4(-) CD8(- ) cells, was higher in asthmatic patients than in controls (P < 0.05 b y one-way analysis of variance). Most lung gamma delta CD4(+) lymphocy tes expressed the gamma delta T-cell receptor V delta 1 chain. These c ells proliferated in response to allergen stimulation, underwent stero id-induced apoptosis in vitro, and disappeared after systemic steroid treatment. Conclusions: Allergen-specific, steroid-sensitive gamma del ta T cells may be one of the cellular components involved in the airwa y inflammation that characterizes allergic bronchial asthma.