Predictive score using umbilical vein leucine‐rich α‐2 glycoprotein as a useful biomarker for diagnosing histological chorioamnionitis in preterm infants

AIM: We investigated the value of leucine-rich α-2 glycoprotein (LRG) in cord blood for diagnosing histological chorioamnionitis (HCAM) in preterm infants. METHODS: This prospective cohort study included 68 infants, born between 22 and 31 weeks of gestation, comprising 29 infants without and 39 infants with HCAM. Maternal, infant, and cord blood inflammatory markers were compared between the groups, and expression levels were compared using immunohistopathological staining of placental tissue. RESULTS: The umbilical vein leucine-rich α-2 glycoprotein (UV-LRG) and gestational age were independent risk factors for HCAM (odds ratio OR 2.395, 95% confidence interval CI 1.230-4.663, OR 0.678, 95% CI 0.492-0.934, respectively). The predictive score was calculated as follows: 9.575 + (-0.386) × gestational age + 0.756 × UV-LRG. The predictive score (area under the curve 0.802, 95% CI 0.696-0.958) appeared to be a reliable diagnostic model for HCAM and outperformed other inflammatory markers. At a cut-off value of 0.852, the predictive score showed a sensitivity of 57.1% and specificity of 93.1% for diagnosing HCAM. Immunohistopathological evaluation of the placenta revealed stronger LRG expression in the trophoblasts (TBs) and stroma in the group with HCAM than in the group without UV-LRG levels correlated positively with the immunohistopathological LRG intensity in the TBs and stroma. CONCLUSIONS: The predictive score using UV-LRG is a more useful biomarker than the other inflammatory markers for HCAM diagnosis. Investigating the mechanism by which TBs produce LRG and by which LRG migrates from the TBs to the stroma may help elucidate HCAM pathogenesis.