Differences in lymphocyte subsets of spiral artery associated with impaired vascular remodeling in hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy (HDP) is assumed to be triggered by incomplete remodeling of the decidual spiral arteries. We examined the lymphocyte subsets and identified immune differences in the spiral arteries between HDP and normal pregnancies, and between remodeled and non-remodeled arteries such as the muscular artery and acute atherosis. One hundred seventy-three patients with HDP diagnosed at our hospital between 2008 and 2017 were included. Patients with a normal course of delivery and patients with premature birth after 34 weeks without pathological changes and abnormalities in the pregnancy course were included in the control group. The infiltrating lymphocytes were evaluated using immunohistochemistry. Acute atherosis was observed in 56 patients (32.4%) of all HDP patients. In patients that presented HDP with acute atherosis, the density of CD8⁺ T cells and CD4⁺ T cells was higher in the acute atherosis than those in the non-remodeled muscular artery. CD4⁺ T cells were more abundant in the non-remodeled muscular artery compared to the remodeled artery. In control patients, the density of CD4⁺ T cells was higher in the non-remodeled muscular artery than that in the remodeled artery; there was no difference in the density of CD56⁺ natural killer cells. There was no difference in the density of CD3⁺ T cells and CD56⁺ natural killer cells in the remodeled artery between patients presenting HDP with acute atherosis and control patients. These immune differences may cause changes in local cytokine balance around the spiral artery, contributing to the development of HDP.