Uterine natural killer cells dysregulation in idiopathic human preterm birth: a pilot study.

OBJECTIVE: To compare between uterine natural killer (uNK) cells in the placental samples of preterm birth and term labor.

STUDY DESIGN: Two-arm case-control study. This study included 60 participants divided into two groups. The first group included 30 cases of idiopathic spontaneous preterm labor and the other group included 30 women who delivered by a spontaneous term vaginal delivery and with no history of previous preterm labor.

RESULT(S): There were no CD16- CD56bright uNK cells in either groups; CD16+ CD56dim uNK cells were present in only 1 case out of 30 term delivery placentae (3.3%), whereas they were found in 21 cases out of 30 (70%) preterm placental samples with a significant statistical difference (p < 0.0001) and OR 67.667, 95% CI (7.95-575.69). CD16+ CD56dim uNK cells were found to be invading both the villi and the decidua in 11 cases (70%), whereas those cells were found invading only the villi in 10 cases (33.3%).

CONCLUSION: CD16+ CD56dim cells are expressed in both the decidua and the villi of patients with idiopathic preterm labor suggesting an association between uNK cells dysregulation and idiopathic human preterm labor.