Interleukin-6 and interleukin-8 in cervical fluid in a population of Swedish women in preterm labor: relationship to microbial invasion of the amniotic fluid, intra-amniotic inflammation, and preterm delivery.
BACKGROUND
Intrauterine infection and inflammation in women with preterm labor are related to adverse perinatal outcome. Due to its subclinical nature, a correct diagnosis depends on retrieval of amniotic fluid. Amniocentesis is, however, not performed as a clinical routine because of its invasiveness. Hypothetically, cytokines in the cervical fluid may represent an alternative diagnostic approach. The aim was to examine cervical interleukin (IL)-6 and IL-8 in relation to microbial invasion of the amniotic fluid, intra-amniotic inflammation, and preterm birth in women in preterm labor.


METHODS
Women with singleton pregnancies in preterm labor (<34 weeks of gestation) and intact membranes were included. Cervical (n = 91) and amniotic fluids (n = 56) were collected. Polymerase chain reaction for Ureaplasma urealyticum and Mycoplasma hominis and culture for aerobic and anaerobic bacteria were performed. IL-6 and IL-8 were analyzed with enzyme-linked immunosorbent assay.


RESULTS
Non-lactobacillus-dominated biota was detected in cervical secretion in 25% (22/89) and the presence of micro-organisms in the amniotic fluid in 16% (9/56) of the patients. The presence of U. urealyticum in the cervical fluid (21/46) was associated with significantly higher levels of IL-6 in the secretion. IL-6 and IL-8 were significantly higher in cervical fluid of women with intra-amniotic infection and inflammation and in women who delivered < or =7 days and/or before 34 weeks of gestation. Cervical IL-6 > or = 1.7 ng/ml was related to intra-amniotic inflammation (relative risk: 2.67; range: 1.50-4.74) and had a sensitivity, specificity, positive predictive value, and negative predictive value of 58, 83, 75, and 69%, respectively, in the identification of intra-amniotic inflammation. Similar data were obtained for IL-8 > or = 6.7 ng/ml.


CONCLUSIONS
High levels of cervical IL-6 and IL-8 are moderately predictive of intrauterine infection/inflammation and preterm delivery.
Holst
Rose-Marie
RM
Perinatal Center, Department of Obstetrics and Gynecology, Institute for the Health of Women and Children, Sahlgrenska University Hospital, Göteborg, Sweden. rose-marie.holst@vgregion.se
Mattsby-Baltzer
Inger
I
Wennerholm
Ulla-Britt
UB
Hagberg
Henrik
H
Jacobsson
Bo
B
D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism / Q000382:microbiology; D015415:Biomarkers / Q000378:metabolism; D002584:Cervix Uteri / Q000378:metabolism* / Q000382:microbiology*; D015331:Cohort Studies; D004269:DNA, Bacterial / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D019535:Mycoplasma hominis / Q000235:genetics / Q000302:isolation & purification; D007752:Obstetric Labor, Premature / Q000175:diagnosis* / Q000378:metabolism / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013548:Sweden; D016990:Ureaplasma urealyticum / Q000235:genetics / Q000302:isolation & purification
D015415:Biomarkers; D004269:DNA, Bacterial; D015850:Interleukin-6; D016209:Interleukin-8