Immune Monitoring of Kidney Allografts

Current strategies for posttransplant monitoring of kidney transplants consist of measuring serial serum creatinine levels, clinical follow-up, and in some programs, protocol biopsies. These strategies may be insufficient to predict acute rejection in kidney transplants, which remains the major factor affecting long-term transplant outcomes. Immune monitoring may conceptually be divided into strategies for detecting humoral rejection (eg, donor-specific antibody) or cellular rejection. Cellular rejection markers may be separated further into those related to cytotoxic T lymphocytes (granzyme A/B, perforin, Fas ligand, and serpin B9), regulatory T cells (FOXP3), and CD4 T cells (the chemokines CXCL9, CXCL10, CXCL11, CCL2, and fractalkine, as well as TIM-3). Finally, transcriptomic changes and renal tubular injury markers also may be useful for detecting early inflammatory changes post-kidney transplant. Ultimately, novel strategies for monitoring the immune status of the kidney transplant may lead to early therapeutic intervention and improved kidney transplant outcomes.