Enhanced S100B expression in T and B lymphocytes in spontaneous preterm birth and preeclampsia

Application value of serum S100B combined with glucose metabolism indexes in predicting adverse pregnancy outcomes of patients with severe preeclampsia

S100 calcium-binding protein B (S100B) and glucose control are reflective of maternal-fetal risks. We investigated the value of serum S100B combined with fasting blood glucose (FBG)/hemoglobin A1c (HbA1c) in evaluating the pregnancy outcomes of patients with severe preeclampsia (SPE). The clinical characteristics of SPE patients/controls were collected. FBG/HbA1c and serum S100B levels were measured, with their correlations analyzed. SPE patients were subdivided into adverse/non-adverse outcome groups based on follow-up results. The value of different indexes in predicting pregnancy outcomes was analyzed. SPE patients showed higher systolic blood pressure, diastolic blood pressure, urine protein, and body mass index and lower platelets, gestational age at delivery, and infant birth weight than healthy controls. FBG and HbA1c were positively correlated with serum S100B. SPE patients with adverse outcomes exhibited increased serum S100B and FBG/HbA1c levels. The area under the curve of serum S100B + FBG/HbA1c in evaluating adverse pregnancy outcomes of SPE patients was 0.8412 (77.05% sensitivity/84.21% specificity), higher than either alone. Serum S100B and FBG/HbA1c were independent risk factors for adverse outcomes of SPE patients. Overall, serum S100B positively-correlates with FBG/HbA1c in SPE patients. Serum S100B and FBG/HbA1c are independent risk factors, and their combination has high value on predicting adverse pregnancy outcomes of SPE patients.

B Cells Induce Early-Onset Maternal Inflammation to Protect against LPS-Induced Fetal Rejection

The maternal balance between B regulatory (Breg) cells and inflammatory B cells is of central importance for protection against preterm birth (PTB). However, the impact of B cell signaling in early maternal and fetal immune responses on inflammatory insults remains underinvestigated. To understand which role B cells and B-cell-specific signaling play in the pathogenesis of PTB, the later was induced by an injection of LPS in B cell-sufficient WT mice, CD19-/-, BMyD88-/- and µMT murine dams at gestational day 16 (gd 16). WT dams developed a strong inflammatory response in their peritoneal cavity (PC), with an increased infiltration of granulocytes and enhanced IL-6, TNF-α, IL-17 and MCP-1 levels. However, they demonstrated a reduced NOS2 expression of PC macrophages 4 h after the LPS injection. Simultaneously, LPS-challenged WT dams upregulated pregnancy-protective factors like IL-10 and TARC. The concentrations of inflammatory mediators in the placental supernatants, amniotic fluids, fetal serums and gestational tissues were lower in LPS-challenged WT dams compared to CD19-/-, BMyD88-/- and µMT dams, thereby protecting WT fetuses from being born preterm. B cell deficiency, or the loss of B-cell-specific CD19 or MyD88 expression, resulted in an early shift from immune regulation towards inflammation at the fetomaternal interface and fetuses, resulting in PTB.

IL-10 Producing B Cells Protect against LPS-Induced Murine Preterm Birth by Promoting PD1- and ICOS-Expressing T Cells

B cells and in particular IL-10-secreting B cells emerge as important players in immune balance during pregnancy. We have recently revealed that CD19-deficient (CD19^−/−), B cell-specific IL-10-deficient (BIL-10^−/−) and B cell-deficient µMT pregnant mice are highly susceptible to LPS-induced preterm birth (PTB). We aimed to analyze the ability of IL-10-secreting cells to protect from PTB and the underlying mechanisms. Wild type (WT), CD19^−/−, BIL-10^−/− and µMT mice were treated with LPS at gd16 and the cellular immune response was investigated 24 h later. LPS-treated BIL-10^−/− dams showed a more pronounced PTB phenotype compared to WT, CD19^−/− and µMT females, and increased inflammatory and reduced anti-inflammatory mediator concentrations in the peritoneal cavity and serum. CD19^−/−, BIL-10^−/− and µMT mice displayed altered immune cell population frequencies in the blood and uterus with lower numbers of IL-10-secreting B cells and T cells. BIL-10^−/− mothers presented decreased frequencies of uterine CD4+CD25+Foxp3+ Treg cells. Co-stimulatory molecules are critical for feto-maternal tolerance and IL-10 secretion. We found dysregulated PD-1 expression in peripheral blood and ICOS expression in the uterus of CD19^−/−, BIL-10^−/− and µMT dams. Our data show that B cell-specific IL-10-signaling is essential for a balanced maternal immune response to an inflammatory stimulant that cannot be hampered without IL-10-secreting B cells.