Placenta accreta is associated with decreased decidual natural killer (dNK) cells population: a comparative pilot study

ObjectivePlacenta accreta is a general term describes abnormal adherent placenta to the uterine wall. When the chorionic villi invade the myometrium, the term placenta increta is appropriate. Nowadays, it is one of the increasing causes of materno-fetal morbidities and mortality. The aim of this research was to evaluate density of decidual natural killer cells (dNK, CD56+bright) in decidua basalis in patients with placenta accreta.Study designWe recruited 76 patients from Ain Shams Maternity Hospital between June 2012 to August 2013, they were divided into study subgroup (A) which included 10 patients who underwent cesarean hysterectomy due to unseparated placenta accreta, study subgroup (B) included 16 patients with separated placenta accreta, a comparison group included 25 patients with placenta previa and a control group included 25 patients with normally situated placenta. All patients underwent elective cesarean delivery. Decidual biopsies were taken during the operation. An immunohistochemical staining for (dNK, CD56+bright) and a semi quantitative scoring were done. One-way ANOVA and Fisher Exact tests were used for statistical correlation.ResultsThe mean dNK cells scores were (0.4 ± 0.5, 1.9 ± 1, 3.3 ± 0.5 and 3.5 ± 0.5) for study subgroups (A), (B) comparison and control groups respectively) with a highly significant statistical difference (P < 0.001). There was a significant statistical difference between study subgroups (A) and (B) P = 0.002 .There was an insignificant statistical correlation between dNK scores and number of previous uterine scars (P = 0.46).ConclusionThese findings suggest that low dNK score was associated with cases of morbidly adherent placenta accreta.