RAGE (NF-B activator) is a novel membrane cell-surface receptor with role in inflammation. S100A12 (proteomic biomarker of inflammation) is a ligand for RAGE. sRAGE competitively inhibits RAGE ligands. Studies were conducted to understand the relationships among RAGE, sRAGE and S100A12 in the amniotic fluid (AF) and fetal tissues of women with PTL in the presence or absence of intra-AF infection/inflammation (IAI/I).
AF was retrieved by amniocentesis in 93 consecutive women stratified as follows: i) +AFC: positive AF culture, n=20, GA=27.1±0.7wks; ii) −AFC: negative AF culture, n=30, GA=28.7±0.9 wks; iii) 2nd trim. control, n=15, GA=18.5±0.4wks; iv) 3rd trim. control, n=28, GA=36.7±0.4wks. sRAGE and IL-6 levels were measured by highly specific immunoassay. Each sample was subjected to mass spectrometry (SELDI) for detection of S100A12. Fetal membranes, cord and placenta were stained for RAGE and S100A12 protein.
The S100A12 [10.4kDa] biomarker was present in 70%(14/20) of women with +AFC but only in 10%(3/30) of women with –AFC(p<0.001). Its presence correlated with AF levels of IL-6 (r=0.63, p<0.001) and AF WBC count (r=0.71, p<0.001). No control had the S100A12 SELDI biomarker peak. Levels of the inhibitor sRAGE were not influenced by presence or absence of IAI/I but increased directly with