Methods of creating cells expressing specific platelet alloantigens by combining gene editing techniques and cell culture differentiation or expansion techniques employing pluripotent cells, including the steps of transfecting pluripotent cells with a plasmid encoding one or more guide RNAs targeting within a platelet alloantigen target locus and a nuclease in the presence of an HDR repair oligo and culturing the resulting cells to expand their numbers or to create a differentiated cell type of interest.