title: Prevalence and clinical significance of sterile intra-amniotic inflammation in patients with preterm labor and intact membranes.
abstract: OBJECTIVE
  Inflammation and infection play a major role in preterm birth. The purpose of this study was to (i) determine the prevalence and clinical significance of sterile intra-amniotic inflammation and (ii) examine the relationship between amniotic fluid (AF) concentrations of high mobility group box-1 (HMGB1) and the interval from amniocentesis to delivery in patients with sterile intra-amniotic inflammation.
  
  
  METHODS
  AF samples obtained from 135 women with preterm labor and intact membranes were analyzed using cultivation techniques as well as broad-range PCR and mass spectrometry (PCR/ESI-MS). Sterile intra-amniotic inflammation was defined when patients with negative AF cultures and without evidence of microbial footprints had intra-amniotic inflammation (AF interleukin-6 ≥ 2.6 ng/mL).
  
  
  RESULTS
  (i) The frequency of sterile intra-amniotic inflammation was significantly greater than that of microbial-associated intra-amniotic inflammation [26% (35/135) versus 11% (15/135); (P = 0.005)], (ii) patients with sterile intra-amniotic inflammation delivered at comparable gestational ages had similar rates of acute placental inflammation and adverse neonatal outcomes as patients with microbial-associated intra-amniotic inflammation, and (iii) patients with sterile intra-amniotic inflammation and high AF concentrations of HMGB1 (≥8.55 ng/mL) delivered earlier than those with low AF concentrations of HMGB1 (P = 0.02).
  
  
  CONCLUSIONS
  (i) Sterile intra-amniotic inflammation is more frequent than microbial-associated intra-amniotic inflammation, and (ii) we propose that danger signals participate in sterile intra-amniotic inflammation in the setting of preterm labor.
authors: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA; Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Detroit, MI, USA; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA; Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA.
authors: Roberto
authors: R
authors: Romero
authors: Jezid
authors: J
authors: Miranda
authors: Tinnakorn
authors: T
authors: Chaiworapongsa
authors: Steven J
authors: SJ
authors: Korzeniewski
authors: Piya
authors: P
authors: Chaemsaithong
authors: Francesca
authors: F
authors: Gotsch
authors: Zhong
authors: Z
authors: Dong
authors: Ahmed I
authors: AI
authors: Ahmed
authors: Bo Hyun
authors: BH
authors: Yoon
authors: Sonia S
authors: SS
authors: Hassan
authors: Chong Jai
authors: CJ
authors: Kim
authors: Lami
authors: L
authors: Yeo
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000276:immunology* / Q000378:metabolism; D005260:Female; D024243:HMGB1 Protein / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000453:epidemiology / Q000276:immunology / Q000378:metabolism; D007752:Obstetric Labor, Premature / Q000453:epidemiology* / Q000276:immunology* / Q000378:metabolism; D010920:Placenta / Q000276:immunology* / Q000378:metabolism; D011247:Pregnancy; D011248:Pregnancy Complications / Q000276:immunology* / Q000378:metabolism; D015995:Prevalence
chemical_list: D024243:HMGB1 Protein; C585491:HMGB1 protein, human
keywords: Alarmins; danger signal; high mobility group box-1; polymerase chain reaction with electrospray ionization mass spectrometry; pregnancy; preterm delivery