Exhaustion of CD8

Area of Science:

• Immunology
• Transplantation
• Dermatology
• Oncology

Background:

• Immunosuppressive therapy is crucial for preventing graft rejection in kidney transplant recipients (KTR).
• However, immunosuppression significantly elevates the risk of non-melanoma skin cancer (NMSC), particularly in elderly KTR.
• Understanding T cell differentiation in KTR is vital for managing NMSC risk.

Purpose of the Study:

• To investigate the differentiation patterns of CD8+ regulatory T cells (Tregs) and responder T cells (Tresps) in KTR.
• To differentiate between healthy KTR, those developing de novo NMSC, and those with pre-existing NMSC.
• To identify potential biomarkers for NMSC development and recurrence in KTR.

Main Methods:

• Analysis of recent thymic emigrant (RTE) cell differentiation into memory and effector T cells (Tregs and Tresps).
• Comparison of T cell differentiation pathways in KTR groups: healthy, de novo NMSC, and pre-existing NMSC.
• Assessment of T cell exhaustion profiles in relation to age and NMSC status.

Main Results:

• Increased RTE Treg and Tresp differentiation via CD31+ memory cells, leading to abundant central memory (CM) cells, was observed in KTR who developed de novo NMSC.
• This was associated with an elevated CD8+ Treg/Tresp ratio, suggesting its utility as a marker for de novo NMSC.
• Age-related differentiation shifts, including Tresp exhaustion and accumulation of terminally differentiated effector memory (TEMRA) Tresps, were noted, especially in elderly KTR with NMSC.

Conclusions:

• Immunosuppressive therapy appears to inhibit CD8+ Treg differentiation more than CD8+ Tresp differentiation, leading to an exhausted Tresp profile.
• This T cell dysregulation may contribute to impaired cancer immunity in elderly KTR.
• Targeting T cell differentiation could offer a therapeutic strategy to enhance cancer immunity in KTR.