Abstract
BACKGROUND: Postpartum depression (PPD) is influenced by immune factors, particularly immune cells. The causal relationship between these cells and PPD is unclear. METHODS: Bidirectional two-sample Mendelian randomization (TSMR) analysis was performed to determine the causal relationship between immune cell characteristics and PPD. The main analysis method used was the inverse variance weighted (IVW) method. To ensure the robustness, heterogeneity, and horizontal pleiotropy of the results, a comprehensive sensitivity analysis was conducted. RESULTS: Overall, 28 immune cell phenotypes were identified as causally related to the onset of PPD. Most of them were distributed in the B cell group and the Treg cell group. Further analysis revealed that 13 types of immune cells had a promoting effect on PPD, whereas 15 types of immune cells had a protective effect. In addition, the incidence of PPD was found to be causally related to CD62L on granulocyte [IVW: OR (95%): 1.183 (1.037 to 1.348), P = 0.012]. CONCLUSION: The study unveils the causal link between immune cells and susceptibility to postpartum depression from a genetic standpoint, providing new directions for drug development and precision medicine for PPD treatment.