Elevated Interferon Regulatory Factor4Levels In Patients With Allergic Asthma

Objective:Allergic asthma is a common inflammatory disease regulated by the T helper (Th) cells. Interferon regulatory factor4(IRF4) plays an important role in Th cells differentiation. This study investigated whether IRF4is involved in the systemic immune responses in allergic asthma patients. Methods:Peripheral blood mononuclear cells (PBMCs) were isolated from allergic asthmatics (n=29) and healthy controls (n=12). The mRNA and protein levels of IRF4in PBMCs were measured by quantitative RT-PCR and western blotting. The frequencies of Thl, Th2and Th17cells were analyzed by flow cytometry. The related cytokine (IFN-γ,IL-4and IL-17) concentrations in plasma and culture supernatants were measured by ELISA. The levels of GATA3, RORγt and FOXP3, the master transcription factors controlling Th2, Th17and T regulatory cells differentiation respectively, were examined by quantitative RT-PCR. Results:The levels of IRF4were elevated in allergic asthmatics compared with those in healthy controls. The frequencies of Th2and Thl7cells as well as the concentrations of Th2-and Th107-related cytokines were higher in plasma from allergic asthma patients than those from healthy controls, similar results were observed in culture supernatants. IRF4mRNA levels were positively correlated with GATA3, RORγt and FOXP3mRNA levels in allergic asthmatics but not in healthy controls. Conclusions:Our results suggested that IRF4may play a role in the systemic inflammation of allergic asthma patients by facilitating the differentiation of Th2and Th17cells at least at the transcriptional level.