CD24+ decidual stromal cells: a novel heterogeneous population with impaired regulatory T cell induction and potential association with recurrent miscarriage.

OBJECTIVE: To explore the heterogeneity of CD24+ decidual stromal cells (DSCs) in patients with recurrent miscarriages (RMs). DESIGN: We have discerned that the expression of CD24 serves to differentiate two stable and functionally distinct lineages of DSCs. The heterogeneity of CD24+ DSCs has been scrutinized, encompassing variances in stromal markers, transcriptional profiles, metabolic activity, and immune regulation. SETTING: Department of Reproductive Immunology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University; Shanghai Institute of Immunity and Infection, Chinese Academy of Science. PATIENTS: A total of 129 early decidual samples were obtained, comprising 36 from healthy donors and 93 from patients with RMs. Blood samples were collected before the surgical procedure. Paraffin-embedded segments from 20 decidual samples of patients with RMs were obtained. INTERVENTIONS: None. MAIN OUTCOME MEASURES: The flow cytometry was used to quantify the expression of CD24+ DSCs in both healthy donors and patients with RMs, although it also evaluated the cellular heterogeneity. To ascertain the transcriptomic profiles of CD24+ DSCs by reanalyzing our single-cell transcriptomic data. Additionally, to measure the metabolomic activity of CD24+ DSCs from patients with RMs, ultraperformance liquid chromatography-mass spectrometry was employed. Through the implementation of a coculture system, we unraveled the role of CD24+ DSCs in immune regulation. RESULTS: Patients with RMs exhibit a notable enrichment of CD24+ DSCs, revealing a pronounced heterogeneity characterized by variations in stromal markers and transcriptional profiles. The heightened enrichment of CD24+ DSCs may play a pivotal role in triggering decidual inflammation and dysfunction in decidualization. Furthermore, CD24+ DSCs showed diverse metabolic activities and impeded the induction of naïve CD4+ T cells into regulatory T cells through the abundant secretion of 3-hydroxyisovaleric acid. Finally, our investigations have revealed that intraperitoneal administration of 3-hydroxyisovaleric acid in mouse models can elevate the risk of RM. CONCLUSION: We have successfully identified a disease-associated subset of CD24+ decidual stromal cells that could potentially contribute to the development of RM through the impairment of decidual immune tolerance. Targeting these specific CD24+ DSCs might hold promising prospects for therapeutic interventions in the clinical management of RM.

Assessment of the Levels of Peripheral Lymphocytes Subpopulation in Healthy Women of Childbearing Age: a Prospective Cohort Study.

BACKGROUND: To evaluate changes in the levels of the peripheral lymphocyte subpopulation (PBLS) during the menstrual cycle in healthy women of childbearing age (HWOBA), for establishing a normal reference range. METHODS: Flow cytometric analysis was performed for the assessment of the levels of PBLS during one menstrual cycle in HWOBA. Moreover, ovulation was monitored. The multivariable logistic regression models were used to evaluate the effects of age and body mass index (BMI) on PBLS. RESULTS: The levels of PBLS including CD3+, CD3+CD4+, CD3+CD8+, CD19+, CD16+CD56+ lymphocytes and ratio of Th1/Th2 cells, were relatively stable during the menstrual cycle. However, each increment in age (year) was proportional to a decrease (14%) in the level of CD8+ T cells and an increase (10%) in the level of CD19+ B cells (p < 0.05). Increased BMI was inversely proportional to the level of CD16+CD56+ natural killer (NK) cells. Thus, the normal reference intervals for PBLS in HWOBA were established. CONCLUSIONS: The levels of PBLS can be used for daily monitoring of immune status in HWOBA. Notably, age and BMI may affect PBLS level. The normal reference ranges for PBLS levels can provide a basis for the research and treatment of recurrent pregnancy loss.

Association between Peripheral CD19+ B Cells and Reproductive Outcome in Women with Recurrent Implantation Failure.

BACKGROUND: To investigate the roles of T, B, and natural killer (NK) cells in pregnancy outcome of women with recurrent implantation failure (RIF). METHODS: This retrospective cohort study enrolled 196 patients with RIF. Peripheral lymphocyte subsets were measured before and during pregnancy. The relationship between pregnancy outcome and level of lymphocytes was analyzed. RESULTS: Peripheral CD19+ B cells in women who experienced miscarriage were significantly lower than those who subsequently had live birth. After adjusting for potential confounders in the multiple logistic regression models, each 1% increment in the peripheral CD19+ B cells before pregnancy [odds ratio (OR): 0.93] and during early pregnancy (OR: 0.83) was associated with a significantly decreased risk of miscarriage (p < 0.05). The risk of mis-carriage in patients with ≥ 15% CD19+ B cells before and during pregnancy was 39% and 21% lower, respectively, than in their counterparts with < 15% CD19+ B cells. The association between CD19+ B cells and the risk of miscarriage was nonlinear. CONCLUSIONS: Measurement of peripheral CD19+ subsets may help predict the pregnancy outcome in women with RIF.

Elevated percentage of CD3+T cells and pregnancy outcome in women with recurrent pregnancy loss.

BACKGROUND: Even though the immune factor is not yet established as a cause of recurrent pregnancy loss (RPL), tons of other studies have shown that a significant proportion of immune abnormalities exist in RPL. METHODS: We conducted a retrospective cohort study with 850 women who were diagnosed with RPL. The percentages of CD3+, CD3+CD4+ and CD3+CD8+T cells of each participant, detected by flow cytometry, were obtained before pregnancy and at 6 weeks of gestation as part of their routine medical examination. RESULTS: Peripheral blood CD3+ T cells prior to pregnancy (at baseline), increased significantly in women who had a miscarriage compared with the subsequent live birth group. Moreover, the percentage of CD3+ and CD3+CD4+T cells during pregnancy increased significantly as compared with the baseline level. After adjusting for potential confounders, the multiple regression equation showed that the CD3+ T cells <67.84% was associated with the risk of miscarriage (OR 1.05, 95% CI, 1.01 to 1.11, p = .04). Additionally, a nonlinear relationship was observed between the percentage of CD3+T cells and the risk of miscarriage. CONCLUSIONS: The risk of miscarriage increased as the percentage of population with CD3+ value below 67.84% has increased, nevertheless, the miscarriage risk did not increase further when the level of CD3+T cells was >67.84%.