Aims To evaluate the role of RUNX3 in the pathogenesis of ITP.Methods 47 active ITP patients, 18 ITP with remission and 26 age and gender matched healthy control were included.Peripheral blood mononuclear cells (PBMCs) were isolated from ITP and control for isolation of RNA and plasma which were used to measure mRNA level of RUNX3 and T-box transcription factor (T-bet) by quantitative real-time PCR and interferon g (IFN-g) level by ELISA.Meanwhile, protein was extracted from PBMCs for western blot analysis of RUNX3 expression.