Human placental extract reduces allergic inflammation in a murine allergic rhinitis model

Objectives/Hypothesis In this study, we addressed the immunotherapeutic potential of human placental extract (HPE) in a murine allergic rhinitis (AR) model and explored its immunological mechanisms. Study Design In vivo study using an animal model. Methods HPE was administered to BALB/c mice before sensitization with allergen (Dermatophagoides farinae [Derf]) (pre‐S group) or after allergen challenge (post‐C group). The groups were compared with Derf‐treated mice that received no HPE (Derf group) and phosphate buffered saline (PBS)‐treated mice (control). Allergic symptom scores, eosinophil counts, and serum Derf‐specific IgE levels were measured. mRNA expression levels of interferon (IFN)‐γ, T‐bet, interleukin (IL)‐4, GATA‐3, and Foxp3 in nasal mucosa were determined by real‐time polymerase chain reaction. IFN‐γ, T‐bet, IL‐4, and GATA‐3 were confirmed by Western blotting analysis. Spleen CD4+CD25+Foxp3+ T cells were detected using flow cytometry. Results Rubbing motions, serum Derf‐specific IgE, GATA‐3 mRNA levels, IL‐4 mRNA levels, and tissue eosinophil counts were decreased in both pre‐S and post‐C groups (all P