Objective To investigate the aberrant expressions of TNF-α and TGF-β1 in peripheral blood mononuclear cells (PBMCs) and placental tissues in patients with early sponta- neous abortion Methods Using the technique of semi-quantitative reverse transcript-polymerase chain reaction (RT-PCR), TNF-α mRNA and TGF-β1 mRNA in PBMCs were measured in spon- taneous abortion group (30 cases), normal pregnancy group (25 cases) and non- pregnant group (25 cases). The expressive intension of TNF-α protein and TGF-β1 protein in placental tissues was also identified by immunohistochemistry. Results Both levels of TNF-α mRNA and TGF-β1 mRNA expressed in PBMCs were significantly different between the three groups respectively (P<0.05). Levels of TNF- α in syncytiotrophoblastic and cytotrophoblastic cells of the two aborted groups were substantially higher than those of the non-pregnant group (P<0.01), but the levels of TGF-β1 in syncytiotrophoblastic cells of the two aborted groups were markedly lower than those of the non-pregnant group (P<0.01). Conclusion There is potential relation between TGF-β1 at the fetomaternal interface and spontaneous abortion. TGF-β1 may contribute to the maintenance of pregnancy, and low-level expression of TGF-β1 may be associated with pregnancy failure. Objective To investigate the aberrant expressions of TNF-α and TGF-β1 in peripheral blood mononuclear cells (PBMCs) and placental tissues in patients with early spontaneous abortion Methods Using the technique of semi-quantitative reverse transcript-polymerase chain reaction (RT- PCR), TNF-α mRNA and TGF-β1 mRNA in PBMCs were measured in spontaneous abortion group (30 cases), normal pregnancy group (25 cases) and non-pregnant group (25 cases). The expressive intension of TNF- α protein and TGF-β1 protein in placental tissues was also identified by immunohistochemistry. Results Both levels of TNF-α mRNA and TGF-β1 mRNA expressed in PBMCs were significantly different between the three groups respectively (P <0.05). Levels of TNF- α in syncytiotrophoblastic and cytotrophoblastic cells of the two aborted groups were substantially higher than those of the non-pregnant group (P <0.01), but the levels of TGF-β1 in syncytiotrophoblastic cells of the two aborted groups were markedly lower than those of the non-pregnant group (P <0.01). Conclusion There is a potential relation between TGF-β1 at the fetomaternal interface and spontaneous abortion. TGF-β1 may contribute to the maintenance of pregnancy, and low-level expression of TGF -β1 may be associated with pregnancy failure.