PTPRC and keratoconus: Indeed, FACS sorting followed by confocal microscopy revealed some CD45+F4/80hiCD31hi cells to be doublets of F4/80hi KC and CD31hi endothelium (Fig. 2E), whereas the majority of CD31hi cells exhibited punctate colocalized surface staining of CD45 and F4/80 indicative of endothelial cells to which surface membrane from KC was tightly adhered (Fig. 2E).