Figure 1: Visualization of the transplacentally acquired maternal cells. Combined morphological and FISH analysis confirmed the presence of transplacentally acquired maternal lymphocytes in patient 1 using the X and Y chromosomes probes. On the left (a), cells stained with Giemsa, and on the right (b) the same cells with FISH using dual-color XY DNA probe. XY genotype shows one green and one red FISH signals; XX genotype—two green signals. L = lymphocyte, YL = young lymphocyte, and PMN = polymorphonuclear cell.