Sublingual immunotherapy in asthma does not influence lymphocyte sensitivity to fas stimulation

BACKGROUND: The resistance of T lymphocytes to Fas-mediated apoptosis is an important feature of atopic asthma. The only effective causative treatment of atopic diseases is immunotherapy. Clinical efficacy of sublingual immunotherapy (SLIT) has been already proven, but there is still limited number of studies on its influence on lymphocytes function. OBJECTIVES: The aim of the study was to evaluate whether SLIT could restore the sensitivity of asthmatic T cells to undergo Fas-mediated apoptosis. MATERIALS AND METHODS: Peripheral blood was collected from 12 patients aged 8 ± 2 years suffering from atopic asthma and undergoing sublingual specific immunotherapy. To evaluate sensitivity to Fas-mediated apoptosis, the blood was transmitted to sterile tubes and mixed with purified monoclonal antibody anti-CD95. After incubation, leukocytes were stained with Annexin V, propidium iodide, and monoclonal antibody against CD2 conjugated with phycoerythrincyanin 5.1, and then analyzed with flow cytometry. The procedure was repeated for each patient after 12 months of SLIT. RESULTS: Stimulation with anti-CD95 of T lymphocytes from patients with atopic asthma before treatment increased the number of early apoptotic cells (from 19.5 ± 16.7% before stimulation to 26.6 ± 16.7% Annexin V positive cells after stimulation). After one year of SLIT anti-CD95 still caused an increase of the early apoptotic cells ratio in the lymphocyte population (from 12.4 ± 7.4% before stimulation to 24.7 ± 15.4% Annexin V positive T cells after CD95 stimulation). Although an increasing trend could be observed, differences between the analyzed groups were not statistically significant. CONCLUSIONS: A year of SLIT does not change the sensitivity of T lymphocytes from peripheral blood of children suffering from atopic asthma to Fas-mediated apoptosis.