Peripheral blood NK cells reflect changes in decidual NK cells in women with recurrent miscarriages.

Objective: We aimed to investigate if peripheral blood natural killer (pNK) cell levels are correlated with decidual NK (dNK) cell levels, and if chemokine expression has any role in dNK cell regulation.

Methods: of study Decidual tissues of women having two or more miscarriages with normal karyotype were collected after miscarriage and an immuno-histochemisty study was made. pNK cells were evaluated using flow cytometric analysis.

Results: The %CD3(-)/56(+) and %CD3(-)/56(+)/16(+) pNK cells showed a significant correlation with mean number of CD56(+) dNK cells. The number of decidual CD16(+) cells was significantly higher in women with elevated pNK (> or =15%) than that of normal pNK (<15%). The %CD3(-)/56(+) and %CD3(-)/56(+)/16(+) pNK cells showed an inverse correlation with duration of gestation. The CCL3(+) and CXCL12(+) cells were present in the decidua; however, staining intensity was not correlated with number of dNK cells.

Conclusions: The pNK cell levels reflect changes in dNK cell levels. This implicates that pNK cell level is a clinically useful marker to predict pregnancy outcome. Further study is needed to examine if elevated pNK cells enhance recruitment of dNK cells in the decidua.