The influence of house dust mite sublingual immunotherapy on the TSLP‐OX40L signaling pathway in patients with allergic rhinitis

Background This study aimed to investigate the clinical efficacy of sublingual immunotherapy (SLIT) with house dust mite (HDM) extract and to examine T helper 2 (Th2)‐type immune responses mediated by the thymic stromal lymphopoietin (TSLP‐OX40L) signaling pathway in patients with moderate to severe allergic rhinitis (AR) after 12‐month HDM SLIT. Methods Forty‐six cases of HDM‐sensitized patients with persistent AR in southern China were enrolled in this study. Clinical efficacy of SLIT was assessed by determining the individual nasal symptom score (INSS) and total nasal symptom score (TNSS) after 12‐month HDM SLIT. Moreover, the TSLP‐OX40L signaling pathway was investigated through measurements of TSLP by enzyme‐labeled immunosorbent assay (ELISA) and OX40L by quantitative reverse transcription polymerase chain reaction (qRT‐PCR) and flow cytometry. Results After 12 months of HDM SLIT, TNSS and INSS were significantly decreased overall compared with baseline values ( p < 0.001). By the end of the 12‐month HDM SLIT, TNSS had declined by ∼50% compared with baseline, and the corresponding level of TSLP in nasal lavage decreased significantly ( p < 0.05). The level of OX40L messenger RNA (mRNA) in blood was markedly decreased significantly after 12‐month HDM SLIT compared with baseline ( t = 12.300, p < 0.05). Furthermore, significant decreases in OX40L expression on the surface of peripheral blood mononuclear cells (PBMCs) ( t = 13.100, p < 0.05) and OX40L expression on the surface of CD11c+CD86+ cells in PBMCs ( t = 9.946, p < 0.05) after 12‐month HDM SLIT were observed. Conclusion HDM SLIT downregulated Th2‐type immune responses mediated by the TSLP‐OX40L signaling pathway in patients with persistent moderate to severe AR.