“…The mononuclear phagocyte system (MPS) [previously termed reticuloendothelial system (RES)] encompasses monocytes, macrophages, and other cells present in liver, spleen, and lungs, and contributes to EV sequestration and clearance ( Rao et al, 2015 ; Smyth et al, 2015 ). Indeed, following in vivo administration, EVs accumulate in the liver, spleen and/or lung; an occurrence widely observed in EVs derived from dendritic ( Wei et al, 2017 ), MSCs ( Grange et al, 2014 ), myoblasts ( Wiklander et al, 2015 ; Charoenviriyakul et al, 2017 ), kidney ( Lai et al, 2014 ), glial ( Lai et al, 2014 ), melanoma ( Peinado et al, 2012 ; Takahashi et al, 2013 ; Imai et al, 2015 ; Charoenviriyakul et al, 2017 ), macrophages ( Charoenviriyakul et al, 2017 ), and placental ( Tong et al, 2017 ; Nguyen et al, 2021 ) cells. With phagocytosis central to clearance, EVs avoid engulfment through surface presentation of anti-phagocytic signals including immunomodulatory receptors, most commonly CD47 ( Chao et al, 2012 ; Rodriguez et al, 2013 ; Kaur et al, 2014 ; Kamerkar et al, 2017 ; Tang Y. et al, 2019 ), PD-L1 ( Gordon et al, 2017 ; Hsu et al, 2018 ; Cordonnier et al, 2020 ; Daassi et al, 2020 ), CD24 ( Barkal et al, 2019 ), CD31 ( Brown et al, 2002 ), and CD44 ( Vachon et al, 2007 ; Amash et al, 2016 ), that act as “don’t eat me” signals to phagocytic cells, potentially prolonging their EV half-life in circulation.…”