Interleukin-8 is an indicator of intraamniotic infection

Abstract

Objective: The purpose of this study was to examine the relationship between asymptomatic intrauterine infection and levels of proinflammatory cytokines in amniotic fluid, maternal and fetal blood.

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Methods: Amniotic fluid of 23 pregnants with high risk of intrauterine infection was received by amniocentesis before amniotomy or cesarean section. Anhydrous period lasted from 1 till 6 hours. All patients had no sexually transmitted diseases and pathogenic microorganisms in cervical/vaginal culture. Cesarean sections were performed in 8 cases for the usual obstetric indication. 15 women delivered per vias naturales. Proinflammatory cytokines such as interleukin- l-alpha (IL-la), interleukin-l-beta (IL-lb), interleukin-8 (IL-8) and tumor necrosis alpha factor (TNF-a) were tested by double-antibody enzyme immunoassay.

Results: All patients were divided in to two groups according to the results of placenta’s histology examination. Group I was composed of women (n=12) without histologic responses of intraamniotic infection. Group 2 comprised (n=11) women with histologic evidence of inflammation (parietal decidutitis or choriodecidutitis, funiculitis). In these pregnants amniotic fluid levels of all three cytokines were elevated. In maternal blood elevated levels of IL-8 (253 ± 12 pg/ml, p < 0,001) and TNF-a (245 ± 11 Pg/ml, P < 0,001) were identified. Fetal funic blood from mothers of 1-st group was characterized by higher levels of TNF-a (306 ± 24 pg/ml, p < 0,001) and IL-lb (48 ± 4 pg/ml, p < 0,001). Only amniotic fluid level of IL-8 (786 ± 81 pg/ml, p < 0,001) was directly correlated with the presence of fetal inflammatory responses and the absolute neutrophil count of funic blood.

Conclusions: lnterleukin-8 is a cytokine produced by human decidua in response to bacterial products. High levels of interleukin-8 in amniotic fluid can be regarded as an indicator of intraamniotic infection.