Changes of intermediate monocytes in peripheral blood of patients with preeclampsia and their significance

Abstract

Objective To explore the role of peripheral blood intermediate monocytes in the pathogenesis of preeclampsia. Methods Fifty-two patients with established preeclampsia in Binhai County People's Hospital from October 2014 to October 2015, 42 healthy pregnant women and 42 healthy non-pregnant women were enrolled in this study. The percentage of intermediate monocyte subsets, ratio of positive cells and mean fluorescence intensity (MFI) of Toll-like receptor (TLR) 2, TLR4, CD64, and triggering receptor expressed on myeloid cell-1(TREM-1), and MFI of intracellular tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 were evaluated by flow cytometry. The concentrations of IL-6, IL-8, IL-1β, IL-12P70 and TNF-α in serum were analyzed using Luminex liquid phase chip technology. Independent two samples t-test, analysis of variance, Mann-Whitney U test, Kruskal-Wallis test and Pearson correlation analysis were used for statistical analysis. Results Percentage of intermediate monocytes was higher in preeclampsia patients [10.4%(5.3%-19.9%)] than in healthy pregnant women [6.6%(4.9%-7.8%)], and both were higher than in non-pregnant women [3.8%(2.4%-5.0)%] (all P<0.05). The ratio of TLR4 and CD64 positive intermediate monocytes [(60.1±12.5)% vs (24.9±8.8)%; (85.3±5.4)% vs (67.4±7.5)%] (t were 15.416 and 13.437, both P<0.05), and MFI of TLR4 (50.3±10.2 vs 26.8±8.6), TREM-1(35.6±4.1 vs 28.6±4.7) and CD64 (39.8±5.2 vs 28.9±4.8) (t were 11.898, 7.707 and 10.454, all P<0.05) were higher in preeclampsia patients than in healthy pregnant women. MFI of intracellular IL-6 (32.3±4.7 vs 28.6±3.5) and TNF-α (44.6±6.3 vs 36.7±8.3) in intermediate monocytes of preeclampsia patients was also significantly higher than that of healthy pregnant women (t were 4.239 and 5.245, both P<0.05). Serum concentrations of IL-6, IL-8 and TNF-α were higher in preeclamptic patients than in healthy pregnant women and non-pregnant women (all P<0.05). Furthermore, a positive correlation was found between the percentage of intermediate monocytes and the serum levels of IL-6 and TNF-α in preeclamptic patients (r were 0.397 and 0.347, both P<0.05). Conclusions Monocyte subpopulations from preeclamptic patients are abnormally skewed toward intermediate monocytes which have high expressions of TLR4, TREM-1 and CD64, and secret more proinflammatory cytokines such as IL-6 and TNF-α. Therefore, intermediate monocytes are specifically altered in preeclamptic patients and may play a role in the pathophysiology of preeclampsia. Key words: Pre-eclampsia; Monocytes; Cytokines