To investigate the possible association of IL-23R gene single-nucleotide polymorphisms (SNPs) with ITP and the association with the clinical outcome of pulsed high-dose dexamethasone (HD-DXM) therapy, four SNPs in the IL-23R gene, rs10889677, rs1884444, rs7517847, and rs11209032, were tested in a cohort of 75 ITP subjects and 81 controls by direct sequencing.