Objective: We hypothesized that placental cytokeratin (CK) 18 expression and serum levels of tissue polypeptide antigen (TPA), a surrogate marker for CK 18, are increased among women with pregnancy-induced hypertension (PIH).
Methods: Serum levels of TPA were measured in 46 women with PIH and 46 controls, matched for gestational age and parity, using an immunoradiometric assay. Immunohistochemical detection of CK 18 was assessed in placental specimens of 24 women with PIH and 20 controls. Results were correlated to clinical data.
Results: Cytokeratin 18 expression was found in the syncytiotrophoblast of 7 of 20 (35%) and 18 of 24 (75%) placental specimens of controls and women with PIH, respectively (p = 0.008). Median serum levels of TPA in controls and women with PIH were 93.0 U/L (range: 12.5-281.6) and 154.2 U/L (range: 37.3-496.6), respectively (p = 0.001). Serum levels of TPA significantly influenced the odds of presenting with PIH, as well as the odds of developing severe disease (p = 0.003, and p = 0.001, respectively). TPA values were significantly higher among women with severe PIH compared with women with mild PIH and controls, independent of gestational age (p = 0.004). Among women with severe PIH, serum TPA was inversely correlated with fetal birth weight (r = -0.3; p = 0.001)
Conclusion: Cytokeratin 18 is overexpressed in the syncytiotrophoblast of women with PIH. Serum levels of TPA are elevated among women with PIH and correlate with disease severity and low fetal birth weight.