Sample preparation. The sample preparation protocols used for this study are those used in a previous study and detailed in the Supplementary Information. In brief, bone marrow aspirates from all patients were processed to isolate mononucleate cells by centrifugation and kept frozen until use. Before use, cells were washed, check for vitality, transferred onto poly-lysinated CaF2 optical substrates and fixed in 2% (vol) paraformaldehyde.