Activated cleaved caspase-3, GFP and CD45 multiplex IHC for detection of apoptotic cells in chimeric corneas after irregular PTK. At 7 days, 14 days and 21 days after PTK, two to four activated cleaved caspase-3 expressing cells (arrows) were detected in each section evaluated of all three corneas at each time point. More than 95% of these apoptotic cells were also GFP+ and CD45+, indicating that many invading bone marrow-derived cells, including fibrocytes, undergo apoptosis at some point more than four days after irregular PTK. Blue is DAPI staining of cell nuclei. Negative control IHC was performed for all antigens without primary antibody and no staining was detected (not shown). 400X mag.