Studies also indicate that women with preeclampsia primarily express the inhibitory and not the stimulatory KIR receptors for uNK cells and that women with a KIR AA genotype, i.e., predictive of expression of the inhibitory KIRs KIR2DL-1, KIR2DL-2, KIR2DL-3, and KIR2DL-5, are at increased risk for developing preeclampsia [101]. This evidence concerns the gene KIR2DL1 and preeclampsia.