Clinical and immunological aspects on recurrent pregnancy loss

Sammanfattning: Paper I. Effects of low molecular weight heparin on the polarization and cytokine profile of macrophages and T helper cells in vitro. Sci Rep 2018. In paper I low molecular weight heparin (LMWH) in vitro effects on activation and polarization of central regulatory immune cells, such as Th cells and macrophages, were assessed, since LMWH has been widely used as an empiric treatment in recurrent pregnancy loss (RPL) and its immunological effects are not fully known. Isolated blood monocytes and T helper (Th) cells under different activation and polarizing conditions were cultured without or with LMWH at different concentrations. LMWH exposure induced an activated phenotype of macrophages, with high expression of HLA-DR and CD206 assessed by flow cytometry, associated with increased secretion of Th17-associated CCL20, and decreased secretion of CCL2 (M2-associated) and CCL22 (Th2), as measured by multiplex bead array. In accordance, LMWH exposure to Th cells reduced the proportion of CD25highFoxp3+ regulatory Tcells, and intensified IFN-γ secretion. Collectively, a mainly pro-inflammatory effect was noted on two essential tolerance-promoting cells, suggesting that potential immunological effects of LMWH may be effective mainly at an earlier gestational age to provide an appropriate implantation process in women with recurrent miscarriage. Paper II. Low-molecular-weight-heparin increases Th1- and Th17-associated chemokine levels during pregnancy in women with unexplained recurrent pregnancy loss: a randomized controlled trial. Sci Rep 2019.In paper II we investigated whether LMWH could modulate immune responses in vivo during pregnancy of women with unexplained RPL. A Swedish open multi-centre randomized controlled trial included 45 women treated with tinzaparin and 42 untreated women. Longitudinally collected plasma samples were obtained at gestational weeks (gw) 6, 18, 28 and 34 and analyzed by multiplex bead technology for levels of 11 cytokines and chemokines, chosen to represent inflammation and T-helper subset-associated immunity. LMWH-treated and untreated women showed differences during pregnancy of the Th1-associated chemokines CXCL10 (p = 0.01), CXCL11 (p < 0.001) and the Th17- associated chemokine CCL20 (p = 0.04), while CCL2, CCL17, CCL22, CXCL1, CXCL8, CXCL12, CXCL13 and IL-6 did not differ. Significantly higher plasma levels of CXCL10 and CXCL11 in treated women were detected at gw 28 and 34, compared to the untreated ones. Thus, a potential proinflammatory effect, linked mainly to Th1 immunity, was shown, suggesting an unfavorable effect of LMWH treatment, since Th1 responsea are responsible for breaking the fetal-maternal immune tolerance. Paper III. First-trimester trophoblasts obtained by chorionic villus sampling maintain tolerogenic and proteomic features in successful pregnancies despite a history of unexplained recurrent pregnancy loss. Am J Reprod Immunol. 2020.In paper III we investigate the “local” immune changes in women with RPL, since they potentially could reveal important mechanisms in RPL. Supernatants from superfluous chorionic villus sampling material culture was used in an ex vivo model, to determinate the immune proteomics profile and to perform functional assays for M2 like macrophages and regulatory T cells polarization, assessed by flow cytometry technique. Chorionic villi, human fetally derived placental tissue, were shown to induce an M2 like-phenotype and an expansion of Treg cells in an ex vivo model, and these immunological properties were maintained despite a history of RPL. Accordingly, no differences in the inflammation proteomic profile were found in RPL, compared to controls. Trophoblasts in an ex vivo model thus maintain tolerogenic and proteomic profile features in successful pregnancies, despite a history of RPL.