Amniotic fluid biomarkers predict the severity of congenital cytomegalovirus infection

Cytomegalovirus (CMV) is the most common intrauterine infection, leading to infant brain damage. Prognostic assessment of CMV-infected fetuses has remained an ongoing challenge in prenatal care, in the absence of established prenatal biomarkers of congenital CMV (cCMV) infection severity. We aimed to identify prognostic biomarkers of cCMV-related fetal brain injury. Global proteome analysis was performed in mid-gestation amniotic fluid samples, comparing fetuses with severe cCMV to asymptomatic CMV-infected fetuses. The levels of selected differentially-excreted proteins were further determined by specific immunoassays. Employing unbiased proteome analysis in a discovery cohort, we identified amniotic fluid proteins related to inflammation and neurological disease pathways, which demonstrated distinct abundance in fetuses with severe cCMV. Amniotic fluid levels of two of these proteins - the immunomodulatory proteins chemerin and galectin-3-binding-protein - were highly predictive of the severity of cCMV in an independent validation cohort, differentiating between fetuses with severe (N=17) and asymptomatic (N=26) cCMV, with 100-93.8% positive predictive value, and 92.9-92.6% negative predictive value (for chemerin - galectin-3-binding-protein, respectively). Analysis of chemerin and galectin-3-binding-protein in mid-gestation amniotic fluids could be employed in the clinical setting to profoundly improve the prognostic assessment of CMV-infected fetuses.