Apolipoprotein A-IV is a candidate target molecule for the treatment of seasonal allergic rhinitis

Background Allergic rhinitis is a global health problem that causes major illnesses and disability worldwide. Allergen-specific immunotherapy (SIT) is the only available treatment that can alter the natural course of allergic disease. However, the precise mechanism underlying allergen-SIT is not well understood. Objective The aim of the current study was to identify protein expression signatures reflective of allergen-SIT—more specifically, sublingual immunotherapy (SLIT). Methods Serum was taken twice from patients with seasonal allergic rhinitis caused by Japanese cedar: once before the pollen season and once during the season. A total of 25 patients was randomly categorized into a placebo-treated group and an active-treatment group. Their serum protein profiles were analyzed by 2-dimensional electrophoresis. Results Sixteen proteins were found to be differentially expressed during the pollen season. Among the differentially expressed proteins, the serum levels of complement C4A, apolipoprotein A-IV (apoA-IV), and transthyretin were significantly increased in SLIT-treated patients but not in placebo-treated patients. Among these proteins, the serum levels of apoA-IV correlated with the clinical symptom-medication scores ( r  = –0.635; P r  = –0.516; P in vitro was greatly reduced after the addition of recombinant apoA-IV in the medium ( P Conclusion Our data will increase the understanding of the mechanism of SLIT and may provide novel insights into the treatment of allergic rhinitis.