CD9 and graft versus host disease: Then, by means of the Cytoflex platform that easily discriminates nano (100 nm), small (160–500 nm), and large (900nm) EV fractions (Supplementary Figure 1), we found that CD69+ EVs co-express the EV markers CD9 and CD63, and that CD69+ EVs are more represented in GVHD patients serum samples, particularly in the nano EV compartment (Figures 4C, D).