Whole blood flow cytometric analysis of Ureaplasma-stimulated monocytes from pregnant women

•Vaginal colonisation with Ureaplasma spp. is common.•Ureaplasma spp. are known to cause inflammation-driven preterm birth.•Ureaplasma parvum stimulates monocyte cytokine response regardless of maternal colonisation.•Ureaplasma spp. colonisation does not tolerise monocytes to subsequent stimulation.

We hypothesised that circulating monocytes of women with vaginal colonisation with Ureaplasma spp., genital microorganisms known to cause inflammation-driven preterm birth, would elicit a tolerised cytokine response to subsequent in vitro Ureaplasma parvum serovar 3 (UpSV3) stimulation. Using multi-parameter flow cytometry, we found no differences with regard to maternal colonisation status in the frequency of TNF-α-, IL-6-, IL-8- and IL-1β-expressing monocytes in response to subsequent UpSV3 stimulation (P > 0.10 for all cytokines). We conclude that vaginal Ureaplasma spp. colonisation does not specifically tolerise monocytes of pregnant women towards decreased responses to subsequent stimulation.