• The molecular mechanisms of preeclampsia have not been fully understood and multifactorial processes are involved in PE pathogenesis. • The level of miRNA-326 increases in preeclamptic pregnancy, especially in Th17 and CD4+ T cells. • The CD4+ T-cell subset could be an extra source of antiangiogenic factors for the maintenance of this hypertension disorder. Alongside many complications in understanding the etiology of Preeclampsia (PE), several determinants, such as the imbalanced proportion of anti-angiogenic/proangiogenic T-cell subsets, especially CD4+ (Th17/Treg), as well as alterations in the expression profile of related cytokines, miRNAs, and transcription factors might have been implicated in PE pathogenesis. After sample collection and preparation, CD4+ cells were isolated from PE and non-PE pregnant woman and were cultured. Furthermore, analysis such as flow cytometry, real-time PCR, western blotting, and ELISA were performed to assess determinants related to PE manifestation, including sFlt-1, sEng, STAT-3, RORγt, SMAD-7, Foxp3, IL-17, IL-22, Ets-1, and miRNA-326. Our results showed that the miRNA-326 expression level increased in CD4+ Cells and Th17 in PE patients which downregulated Ets-1 expression that acts as a negative control for Th17 development. Furthermore, we showed that the number and expression level of Th17 s and transcription factor ROR γ t escalated, respectively. While Treg and its related transcription factor (Foxp3) demonstrated a decrease. Flow cytometry analysis illustrated that the Th17/Treg ratio increased in PE. Additionally, we demonstrated that expression and concentration levels of cytokines (IL-17 and IL22) and anti-angiogenic molecules (sEng and sFlt-1) soared in isolated CD4+ cells from PE patients, which could be correlated with PE pathogenicity. In conclusion, we comprehensively evaluated immunological factors and molecules involved in PE manifestation. Interestingly, the CD4+ T-cell subset could be an extra source of antiangiogenic factors for the maintenance of this hypertension disorder. [ABSTRACT FROM AUTHOR]