Microvascular Inflammation: A Silent Threat in Kidney Transplantation ?

Microvascular inflammation is emerging as a significant challenge in kidney transplantation. This condition significantly affects graft survival and requires a tailored approach to patient care. Commonly linked to alloimmune responses, this condition can occur without donor-specific antibodies, complicating both diagnosis and treatment. Given the implications for patients with end-stage renal disease, understanding the various phenotypes of microvascular inflammation and their impact on kidney transplants is essential.

How Does Microvascular Inflammation Impact Kidney Transplants?

This study analyzed over 16,000 kidney transplant biopsies from 6,798 transplant recipients between 2004 and 2023, involving more than 30 transplant centers worldwide. The biopsies were classified into two newly defined categories: 

• Microvascular inflammation without evidence of antibody-mediated rejection;
• Probable antibody-mediated rejection.

The primary assessment criteria included graft loss risk, the progression of transplant glomerulopathy, and the presence of antibody-mediated rejection.

The findings indicate that microvascular inflammation affects 4.8% of kidney transplant biopsies, presenting with highly distinct phenotypes: 3.1% of cases without donor-specific antibodies and 1.7% with probable antibody-mediated rejection.

Additionally, patients with microvascular inflammation—either without evidence of antibody-mediated rejection or with probable antibody-mediated rejection— were found to have a 2.1 and 2.7 times higher risk, respectively, of graft loss compared to patients without rejection. These patients also demonstrate an elevated risk of developing transplant glomerulopathy.

Microvascular Inflammation in Kidney Transplants: A Key Factor in Allograft Survival and Glomerulopathy Progression