Age-related changes in CD4+T and NK cell compartments may contribute to the occurrence of pregnancy loss in advanced maternal age

A recent study characterized novel immune cell subsets (T, NK, and gamma delta T cell subsets) related to recurrent pregnancy loss (RPL). This study aims to assess whether these RPL-related immune cell subsets are affected by aging. The percentages of peripheral blood immunes cells from nulligravida women (NGW), women with a history of normal pregnancy (NP), and women with a history of pregnancy loss (PL) were detected by flow cytometry. The correlations between maternal age and cell percentages were assessed. We found a significant positive correlation between PL and maternal age. The percentages of effector memory CD4+ T (CD3+ CD4+ CD45RA? CCR7?), terminally differentiated CD4+ T (CD3+ CD4+ CD45RA+ CCR7?), and mature NK cells (CD3? CD56+lo) significantly increased with maternal age. A significant decrease in the percentage of Naive CD4+ T cells (CD3+ CD4+ CD45RA+ CCR7+) with age was observed in women from the NP group. Women aged 35 or older had significantly higher percentages of effector memory CD4+ T cells, terminally differentiated CD4+ T cells, and mature NK cells than younger women. Maternal age positively correlates with terminally differentiated CD4+ T, effector memory CD4+ T, and mature NK cell percentages. In contrast, an inverse correlation was observed between Naive CD4+ T cell and age among women from the NP group. Our findings indicate that agerelated CD4+ T and NK cell dysregulation might be involved in the pathogenesis of PL in women with advanced maternal age. The underlying mechanism needs further investigation.