Patients with idiopathic recurrent miscarriage have abnormally high TGF\xdf+ blood NK, NKT and T cells in the presence of abnormally low TGF\xdf plasma levels

Li Zhu,Gerhard Opelz,Hristos Karakizlis,Rolf Weimer,Haihao Wang,Mostafa Aly,Naruemol Ekpoom,Volker Daniel,Eman Ibrahim,Bettina Toth,Ruben Jeremias Kuon,Christian Morath

doi:10.1186/s12865-019-0290-3

Abstract

BackgroundPreviously, we demonstrated up-regulated activated CD4+ and CD8+ T lymphocytes as well as up-regulated cytotoxic NK cells in the blood of patients with idiopathic recurrent miscarriage. In the present study, we tried to identify deficiencies in counter-regulating immune mechanisms of these patients.MethodCytokines were determined in NK cells and in plasma samples of 35 healthy controls, 33 patients with idiopathic recurrent miscarriage, 34 patients with end stage renal disease, 10 transplant patients early and 37 transplant patients late post-transplant using flow-cytometry and luminex. In addition, cytokines were studied in supernatants of cell cultures with peripheral blood mononuclear cells stimulated in-vitro with tumor cell line K562.ResultsPatients with idiopathic recurrent miscarriage exhibited the highest absolute cell counts of circulating TGFß1+ NK, NKT and T lymphocytes and the lowest TGFß1 plasma levels of all study groups (for all p < 0.050). In-vitro, peripheral blood mononuclear cells of patients with idiopathic recurrent miscarriage showed high spontaneous TGFß1 production that could not be further increased by stimulation with K562, indicating increased consumption of TGFß1 by activated cells in the cell culture. Moreover, patients with idiopathic recurrent miscarriage had abnormally high IL4+ as well as abnormally high IFNy+ NK cells (p < 0.010) but similar IL10+ NK cell numbers as female healthy controls and showed the lowest plasma levels of IL10, TGFß3, IL1RA, IL1ß, IL5, IL6, IL8, IL17, TNFα, GM-CSF, TPO and VEGF and the highest plasma levels of G-CSF, FGF-basic, CCL3 and CXCL5 as compared to female HC and female transplant recipients (for all p < 0.050).ConclusionsPatients with idiopathic recurrent miscarriage show an activated immune system that can hardly be stimulated further and cannot be efficiently down-regulated by up-regulated TGFß1+ and IL4+ NK, NKT and T lymphocytes which are present concomitantly in these patients. The strongly decreased TGFß and IL10 plasma levels indicate deficient down-regulation and reflect a dysbalance of the immune system in patients with idiopathic recurrent miscarriage. These findings may be relevant for explaining the pathogenesis of idiopathic recurrent miscarriage.

Highlights

We demonstrated up-regulated activated CD4+ and CD8+ T lymphocytes as well as upregulated cytotoxic NK cells in the blood of patients with idiopathic recurrent miscarriage
Data are given as median ± interquartile range transplant patients (Additional file 1: Figure S1a + b), idiopathic recurrent miscarriage (iRM) patients showed higher absolute counts of IL4+, TGFß+ and IFNy+ NK, NKT and T cells than male and female healthy controls (HC), End stage renal disease (ESRD) patients and patients late post-transplant (p < 0.050)
The similar trends of relative and absolute cell numbers suggest a strong up-regulation of cell subsets with immunosuppressive (IL4 and TGFß) as well as immunostimulatory (IFNy) phenotype in iRM patients compared to female HC and female transplant recipients

Summary

Introduction

We demonstrated up-regulated activated CD4+ and CD8+ T lymphocytes as well as upregulated cytotoxic NK cells in the blood of patients with idiopathic recurrent miscarriage. Almost half of the cases remain unexplained and are treated empirically, using progesterone supplementation, anticoagulation, and/or immunomodulatory approaches [1] Immunological causes, such as immunological rejection or development of an intrauterine micromilieu that is harmful for fetus and pregnancy, are suspected reasons for idiopathic recurrent miscarriage (iRM) [2, 3]. In transplant recipients with good long-term graft outcome, high cytotoxic NK cells were associated with impaired graft outcome whereas high immunoregulatory IL10 + CD56bright NK cells were associated with good long-term graft function. We hypothesize that iRM patients exhibit a continued inflammatory immune response during the second trimester that cannot be counter-regulated by increasing inhibitory immune mechanisms, which eventually results in an unfavorable intrauterine micromilieu that is harmful for the fetus and results in the loss of pregnancy

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Results

Discussion

Conclusion