Fig. 2
From: Applications, challenges and prospects of mesenchymal stem cell exosomes in regenerative medicine
The injection of Exo may lead to allo-/xeno-reactive T cell responses via the activity of APCs located inside the hepatic and splenic tissues. In addition, systemically injected Exo can be sequestrated in pulmonary and hepatic vascular beds. Another issue regarding Exo application is the promotion of thrombosis in the vascular niche. Harboring infectious agents via Exo can lead to transmission of these particles into the in vivo milieu