Abstract
BACKGROUND: Gestational diabetes mellitus (GDM) has recently been associated with abnormal profiles of inflammatory cells and cytokines, though the findings remain inconsistent and unclear. AIM: To elucidate the peripheral immune status in GDM. METHODS: We systematically screened databases including Web of Science, PubMed, and EMBASE for eligible studies. Original articles reporting different immune cell levels in GDM compared to normal glucose-tolerance pregnant women were included to extract usable data. The pooled mean difference (MD) with 95% confidence interval (CI) was analyzed as the outcome measure. The Newcastle-Ottawa scale was employed to assess study quality. RESULTS: A total of 19 studies involving various immune cell subgroups were included in our analysis. Specifically, total CD4+ T cells (WMD = 3.08; 95%CI: 0.81-5.35) were significantly increased in GDM groups. In contrast, total lymphocytes (SMD = 0.05; 95%CI: -0.16 to 0.26), CD3+ T cells (SMD = -0.34; 95%CI: -1.01 to 0.32), CD8+ T cells (SMD = 0.21; 95%CI: -0.31 to 0.73), and natural killer T (NKT) Cells (SMD = 0.83; 95%CI: -1.10 to 2.75) showed no significant changes in GDM. Activation markers (HLA-DR+ or CD69+) on CD4+ T cells (WMD = 0.20; 95%CI: 0.06-0.34) were increased in GDM patients. Treg cells, a classical subgroup of CD4+ T cells, showed a decreasing trend in GDM compared to controls (SMD = -0.83; 95%CI: -1.31 to -0.34). These results indicate an abnormal immune status in the peripheral profiles of GDM. CONCLUSION: GDM may not only be a dysglycemia-related condition but also an immune disorder characterized by abnormal peripheral immune profiles, including higher levels of CD4+ T cells and a reduced population of Treg cells. Treating immune dysregulation could be a new direction for GDM management, although further research is needed to understand the precise mechanisms of immune overactivation in GDM.