The FCM analysis of total EVs positive for PD1 and/or PD-L1, isolated from plasma of the 71 MM patients enrolled in the study and expressing at least one of the 3 tetraspanins (CD9, CD63 and CD81), showed that PD1+ EVs were present at high percentage as PD-L1+ EVs while the double positive EVs were much less represented (Supplemental Fig. S1A). Here, CD9 is linked to Miyoshi myopathy.