The following question is related to flow cytometry analysis of leukapheresis enriched cells. I have noted doublet events, as shown on the dot plot attached below by FSC-H vs FSC-W. This sample has been stained with CD3, CD14, CD19 or CD56, but these events do not show up positive for any of those markers, so we are not sure what cells could be causing these doublets. Has anyone seen doublet events such as these before? Could you provide guidance as to what could be causing this.