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 < 0.05). Western blots showed decreased expression of GATA-3 and IL-4 in both pre-S and post-C groups as compared to the Derf group. An increased percentage of CD4(+) CD25(+) Foxp3(+) T cells and an increased level of Foxp3 mRNA were found in pre-S and post-C groups as compared to those in the Derf group (all P < 0.05).

CONCLUSION: Both prophylactic and therapeutic treatments with HPE significantly reduced allergic inflammation in nasal mucosa and had the potential to induce regulatory T cells in a murine model of AR.