Ex vivo cytokine production by whole mid-trimester amniotic fluid

We hypothesized that ex vivo measurement of intraamniotic production of immune mediators differed from analysis of these mediators within unincubated amniotic fluid. Mid-trimester amniotic fluid from 72 women were incubated ex vivo with or without 50 ng/ml lipopolysaccharide (LPS). Supernatants and the corresponding unincubated amniotic fluids were tested for interleukin (IL)-6, IL-1 receptor antagonist (IL-1ra), IL-10 and nitric oxide. Ex vivo culture resulted in increased release of IL-6, IL-10 and nitric oxide; IL-1ra levels were decreased following the incubation. A spontaneous preterm birth (SPTB) occurred in 12 (16.7%) of the subjects. Women with a subsequent SPTB had decreased IL-6 and increased IL-10 production following ex vivo culture compared to women with a term delivery. This association was not evident with unincubated amniotic fluids. Conversely, IL-1ra concentrations were elevated in women with subsequent SPTB only in unincubated amniotic fluids. Immune mediator production by ex vivo amniotic fluid culture differs from that present in amniotic fluid supernatants and may provide a more accurate indication of the immune potential of the intraamniotic environment.