Sublingual immunotherapy induces spirometric improvement associated with IL-10 production: Preliminary reports

Background: Sublingual immunotherapy (SLIT) has been demonstrated to be able of inducing immunologic changes as evidenced by IL-10 production. Forced expiratory flow between 25% and 75% of the vital capacity (FEF_25-75) may be considered a good marker of early bronchial involvement in patients with pure allergic rhinitis. Objective: The aim of this study was to evaluate the possible association of IL-10 production with FEF_25-75 values in patients with perennial allergic rhinitis (PAR) successfully treated with SLIT. Methods: 19 patients with PAR were studied: 9 successfully assumed SLIT for 3 years, 10 were considered as control. In vitro IL-10 production was evaluated after SLIT. Spirometry and bronchodilation test were performed in all subjects at baseline and after 3 years. Results: After 3 years, FEF_25-75 values significantly (p = 0.0131) increased in SLIT group (80.5 ± 6.7), whereas they significantly (p = 0.0021) decreased in non-treated patients (60.8 ± 2.62). In addition, SLIT-induced increase of FEF_25-75 values is significantly associated with IL-10 production (p = 0.0025). Conclusions: This study provides the first evidence that SLIT is capable of improving early bronchial involvement in patients with pure allergic rhinitis and this functional effect may be associated with immunological changes, such as the induction of IL-10 production.