Endotoxin-induced cytokine production of monocytes of third-trimester pregnant women compared with women in the follicular phase of the menstrual cycle.

Abstract

Little is known about the function of the innate immune response during pregnancy. We therefore investigated monocyte cytokine production, as a measure of monocyte function, in pregnant women compared with nonpregnant women. Whole blood of women in the follicular phase (day 5-6) and of healthy pregnant women (30 weeks) was collected and stimulated with endotoxin (2 microg/mL). After incubation for 4 hours (37 degrees C, 5% carbon dioxide), red blood cells were lysed and white blood cells were permeabilized, followed by staining with anti-CD14 (fluorescein isothiocyanate labeled) and with phycoerythrin-labeled tumor necrosis factor-alpha, interleukin-1beta, or interleukin-12. The cells were analyzed by flow cytometry after fixation. Results are expressed as a percentage cytokine producing cells after endotoxin stimulation. Statistical analysis was performed with the Mann-Whitney U test (P <.05). Compared with the percentage endotoxin-induced cytokine producing peripheral monocytes in women in the follicular phase, this percentage in pregnancy was decreased for interleukin-12 (mean 6.63 +/- 1.34 vs 3.34 +/- 0.87, P <.05) and tumor necrosis factor-alpha (mean 50.20 +/- 5.80 vs 31.29 +/- 5.57, P >.05). No significant difference was seen in the production of interleukin-1beta (mean 58.22 +/- 11.09 vs 47.18 +/- 7.88, P >.05). The percentage of interleukin-12 and tumor necrosis factor-alpha producing monocytes is decreased in pregnant women compared with nonpregnant women, suggesting that pregnancy is a proinflammatory state.