Acute T-cell-mediated rejection of the renal allograft is a serious posttransplant challenge that requires administration of high-dose immunosuppressive drugs with considerable side effects; therefore, specific targeting of T-cell responses may improve both prevention and treatment of T-cell-mediated rejection. A potential candidate for this purpose is interferon regulatory factor 4 because of its implication in differentiation and function of T cells. Our aim was to evaluate the frequency of the rs872071A>G and rs12203592C>T single-nucleotide polymorphisms of the interferon regulatory factor 4 gene and association of these 2 polymorphisms with the gene expression of programmed cell death 1 and Helios in patients with T-cell-mediated rejection versus stable recipients.Sixty recipients with T-cell- mediated rejection and 60 age-matched and sex-matched stable recipients were recruited. Two single-nucleotide polymorphisms of interferon regulatory factor 4 gene, as well as the expression of programmed cell death 1 and Helios genes in peripheral blood mononuclear cells, were investigated with real-time polymerase chain reaction.Programmed cell death 1 gene expression was reduced in patients with T-cell-mediated rejection versus stable recipients (P = .03). The frequency of rs872071A>G and rs12203592C>T single-nucleotide polymorphisms showed no significant difference between groups. Presence of the rs12203592C>T single-nucleotide polymorphism was directly correlated with the expression of programmed cell death 1 gene (P = .049), and rs872071A>G positivity was directly correlated with Helios gene expression (P = .008), which suggests an inhibitory role for interferon regulatory factor 4 on programmed cell death 1 and Helios molecules.Programmed cell death 1 gene expression was lower in patients with T-cell-mediated rejection versus stable recipients. Low-expressing singlenucleotide polymorphisms of interferon regulatory factor 4 could enhance the downstream gene expression of programmed cell death 1 and Helios immunoregulatory molecules. Therefore, specific inhibition of interferon regulatory factor 4 may promote tolerance induction in the allograft.