title: Interleukin 18 messenger RNA and proIL-18 protein expression in chorioamniotic membranes from pregnant women with preterm prelabor rupture of membranes.
abstract: OBJECTIVE
  To quantify the expression of IL-18 mRNA and protein in the chorioamniotic membranes of pregnant women with PPROM and correlate expression with histological chorioamnionitis.
  
  
  METHODS
  A case control study that included 42 pregnant women not in labor in the following groups: PPROM (n=28) and controls with intact membranes submitted to selective cesarean section at term (n=14). Expression of IL-18 mRNA in chorioamniotic membranes was determined by real-time polymerase chain reaction, and IL-18 protein expression was measured by western blot. Histopathological analyses and immunolocalization of IL-18 by immunohistochemistry were also performed. Analyses were performed using the Mann-Whitney or Fisher's exact tests and the group effect was considered significant if the adjusted p-values were <0.05 and the magnitude of change was greater than 2-fold for mRNA expression.
  
  
  RESULTS
  IL-18 mRNA was present in 100% of samples and no difference in expression was observed between term vs. PPROM membranes (fold-change 0.12; p=0.88). In the PPROM group, no difference was observed in IL-18 mRNA regarding gestational age (fold-change 0.11; p=0.42) or the presence of histological chorioamnionitis (fold-change 0.26; p=0.15). ProIL-18 was present in all samples. IL-18 was immunolocalized to amnion, chorion and decidua cells, with intense immunohistochemical staining at the choriodecidual junction.
  
  
  CONCLUSIONS
  Chorioamniotic membranes are sources of IL-18 mRNA and proIL-18, and their expression is unrelated to PPROM or histological chorioamnionitis.
authors.affiliation: Botucatu Campus, Department of Pathology, Botucatu Medical School, Univ. Estadual Paulista, SP, Brazil. jpolettini@fmb.unesp.br
authors.forename: Jossimara
authors.initials: J
authors.lastname: Polettini
authors.forename: Eliane Passarelli
authors.initials: EP
authors.lastname: Vieira
authors.forename: Mariana Perlati dos
authors.initials: MP
authors.lastname: Santos
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Peraçoli
authors.forename: Steven S
authors.initials: SS
authors.lastname: Witkin
authors.forename: Márcia Guimarães
authors.initials: MG
authors.lastname: da Silva
mesh_terms: D000328:Adult; D000367:Age Factors; D000650:Amnion / Q000378:metabolism*; D016022:Case-Control Studies; D002821:Chorioamnionitis / Q000378:metabolism; D002823:Chorion / Q000378:metabolism*; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000378:metabolism*; D020073:Gravidity; D006801:Humans; D020382:Interleukin-18 / Q000235:genetics / Q000378:metabolism*; D011247:Pregnancy; D011498:Protein Precursors / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D055815:Young Adult
chemical_list: D020382:Interleukin-18; D011498:Protein Precursors; D012333:RNA, Messenger