Patient Selection

This study was approved by the institutional review board at Mayo Clinic. The primary objective was to compare differences in immune responses between placentas with villitis of unknown etiology (VUE) and controls by imaging, gene expression, and tissue typing. Ten subjects with a positive high-grade VUE diagnosis by Amsterdam guidelines [20] (and no morphologic, clinical, or laboratory evidence of infection) were gestational age matched with ten subjects without any placental pathology. Specifically, any cases with plasma cell villitis, granulomas, or acute villitis/intervillositis/chorioamnionitis were excluded. We also excluded VUE cases that resulted in a demise to minimize potential confounding variables related to this multifactorial outcome. Residual formalin-fixed paraffin-embedded tissue was utilized after routine histopathologic assessment by a pathologist. Only samples that had been in blocks less than 1 year were included to maximize tissue quality.