Chemokine receptor distribution on the surface of peripheral and decidual NK cells. Peripheral and decidual lymphocytes were isolated and quadruple stained as described in “Materials and methods.” The figure shows the chemokine receptor expression on peripheral CD16⁺ NK cells (A), peripheral CD16^– NK cells (B), and decidual CD16^– NK cells (C). The indicated values represent the percentage of cells positive for a certain chemokine receptor of total cell population. FACS staining analysis of CXCR3 (D) and CXCR4 (E) on peripheral CD16^– and CD16⁺ NK cells. The indicated MFI (median fluorescence intensity) values represent the expression level of a certain chemokine receptor on the NK cell population that stained positive for that specific chemokine receptor. One representative experiment is shown of 3 performed.