. Author manuscript; available in PMC: 2018 Feb 1.

Published in final edited form as: Curr Opin Organ Transplant. 2017 Feb;22(1):46–54. doi: 10.1097/MOT.0000000000000372

Table 2.

Proposed impact of EVs / exosomes in allorecognition pathways

Source of EVs	Context	Semi-direct pathway	Indirect pathway	Outcome
Graft, passenger leukocytes	Transplantation	Co-Stimulation (CD86, CD40)	Co-Stimulation (CD86)	Coordinate indirect pathway T helper cell help → CTL
Graft, passenger leukocytes	Transplantation	Co-Stimulation (CD86, CD40)	Co-Stimulation (CD86)	Efficient allo-sensitization of direct pathway T cells against donor MHC molecules → acute rejection
Maternal cells (microchimerism)	Chronic exposure	Co-Stimulation (CD86)	Co-Inhibition (PD-L1)	“Un-helped” CTL
Maternal cells (microchimerism)	Chronic exposure	Co-Stimulation (CD86)	Co-Inhibition (PD-L1)	Mild acute graft rejection, no chronic rejection