Early Acute T Cell-Mediated Rejection and Kidney Allograft Outcomes

Area of Science:

• Nephrology
• Transplantation Immunology
• Clinical Pathology

Background:

• Early acute T cell-mediated rejection (TCMR) in kidney transplant recipients is often considered clinically benign.
• However, its treatment response and impact on long-term graft survival are poorly understood.

Purpose of the Study:

• To evaluate the incidence, treatment response, and long-term graft outcome associations of early TCMR in kidney transplant patients.
• To challenge the notion of TCMR being clinically benign.

Main Methods:

• An observational cohort study included 5,762 adult kidney transplant recipients across six centers (US and Europe) from 2013-2019.
• Evaluated TCMR incidence, clinical/histological treatment responses, and associations with graft survival using biopsies and clinical data.

Main Results:

• 13.6% of patients developed TCMR. 36% showed clinical deterioration and 32% had persistent TCMR despite treatment, indicating frequent resistance.
• Clinical and histologic responses were discordant; persistent TCMR significantly increased graft loss risk (HR 3.21), independent of clinical response.
• Increasing tubulointerstitial inflammation showed a graded association with adverse outcomes and graft loss.

Conclusions:

• TCMR is common, frequently treatment-resistant, and persistent TCMR is strongly linked to inferior long-term graft survival.
• Clinical improvement does not always correlate with histologic response, highlighting the need for better monitoring.
• Findings necessitate a re-evaluation of TCMR's clinical significance and underscore the need for targeted therapies.