Extracellular vesicles in allograft rejection and tolerance

Area of Science:

• Immunology
• Cell Biology
• Transplantation Science

Background:

• Extracellular vesicles (EVs) are crucial for intercellular communication in the immune system.
• EVs from allogeneic transplants influence immune responses, impacting graft rejection or tolerance.
• Their precise role and origin in alloimmunity remain under investigation.

Purpose of the Study:

• To review the current understanding of EVs in T cell allorecognition.
• To discuss mechanisms of EV influence on T cell alloimmunity in transplantation.
• To highlight the potential of EVs as biomarkers for allograft rejection.

Main Methods:

• Review of recent scientific literature on extracellular vesicles and transplantation immunology.
• Analysis of studies investigating EV-mediated immune responses in allogeneic settings.
• Synthesis of data on EV involvement in T cell activation and allorecognition.

Main Results:

• Donor-derived EVs can initiate inflammatory alloresponses via T cell activation (MHC cross-dressing and semi-direct allorecognition), leading to acute rejection.
• EVs are implicated in immune tolerance, as seen in pregnancy and liver allografts.
• EVs in blood and urine from allografts show potential as rejection biomarkers.

Conclusions:

• Extracellular vesicles play a dual role in transplantation, contributing to both rejection and tolerance.
• Understanding EV mechanisms is key to manipulating immune responses in allograft recipients.
• EVs represent promising non-invasive biomarkers for monitoring transplant health.