Eosinophil cationic protein and eosinophil protein X: human amniotic fluid concentrations and gestational tissue content at term.

The aim of this study was to determine the presence and concentration of immunoreactive eosinophil cationic protein (ECP) and eosinophil protein X (EPX) in human amniotic fluid at term and assess labour-associated changes in their mean concentrations. In addition, ECP and EPX content in term amnion, choriodecidua and placenta obtained before and after labour and delivery was established. Immunoreactive ECP and EPX were identified in all samples of amniotic fluid (n=47) and gestational tissue (n=60) assayed. EPX was quantitatively more abundant than ECP in both amniotic fluid and gestational tissues. In amniotic fluid, ECP and EPX concentrations increased 8-fold (P<0.02) and 1.5-fold (P<0.02), respectively, with labour onset. In gestational tissues, a labour-associated change in tissue content was only identified for ECP in choriodecidua, which increased 1.9-fold with labour and delivery (P<0.01). The labour-associated increase in amniotic fluid concentrations of ECP and EPX demonstrated in this study is consistent with the well-characterized role of these proteins in inflammatory reactions. It remains to be established whether the observed increase in ECP and EPX amniotic fluid concentrations is an epiphenomenon of labour onset or is involved causally in this process.