Microvascular Inflammation of Kidney Allografts and Clinical Outcomes

The clinical relevance of microvascular inflammation in kidney transplants remains unclear, posing diagnostic and therapeutic challenges. This multicenter cohort study assessed biopsy specimens from 6798 patients across 30 European and North American centers between 2004 and 2023. The 2022 Banff Classification introduced two new phenotypes probable antibody-mediated rejection and microvascular inflammation without donor-specific antibodies or C4d deposition, expanding rejection diagnostics.

Among 16,293 biopsy specimens, 788 met criteria for the newly recognized microvascular inflammation phenotypes, 641 of which were previously classified as non-rejection cases. Patients with microvascular inflammation without antibody-mediated features had twice the risk of graft failure (hazard ratio 2.1; 95% CI, 1.5 to 3.1) compared to those without rejection, while probable antibody-mediated rejection showed increased transplant glomerulopathy progression. These findings highlight the importance of integrating microvascular inflammation phenotypes into precision diagnostics and future therapeutic strategies

The clinical relevance of microvascular inflammation in kidney transplants remains unclear, posing diagnostic and therapeutic challenges. This multicenter cohort study assessed biopsy specimens from 6798 patients across 30 European and North American centers between 2004 and 2023. The 2022 Banff Classification introduced two new phenotypes probable antibody-mediated rejection and microvascular inflammation without donor-specific antibodies or C4d deposition, expanding rejection diagnostics.

Among 16,293 biopsy specimens, 788 met criteria for the newly recognized microvascular inflammation phenotypes, 641 of which were previously classified as non-rejection cases. Patients with microvascular inflammation without antibody-mediated features had twice the risk of graft failure (hazard ratio 2.1; 95% CI, 1.5 to 3.1) compared to those without rejection, while probable antibody-mediated rejection showed increased transplant glomerulopathy progression. These findings highlight the importance of integrating microvascular inflammation phenotypes into precision diagnostics and future therapeutic strategies