Unmasking the Silent Threat: COVID-19's Pervasive Impact on Renal Allografts

Growing evidence has highlighted the substantial effects of COVID-19 on kidneys, ranging from mild proteinuria to severe acute kidney injury. However, comprehensive assessments of histopathological features in renal allograft biopsies are lacking.

Seventeen kidney transplant recipients with COVID-19 between March 2020 and November 2022 were evaluated. Clinical characteristics, pathological findings, and outcomes were studied.

Six kidney transplant recipients (35.3%) developed acute kidney injury, leading to the requirement for hemodialysis. COVID-19 severity, as indicated by pneumonia (P = .028) and hospitalization (P = .002), was significantly associated with development of acute kidney injury. Most patients with COVID-19 (82.4%) showed considerably increased proteinuria levels (82.4%), along with presence of new-onset microscopic hematuria (35.3%) and nephrotic syndrome (58.8%). Tubular viral inclusionlike changes were detected in 47.1% of cases and were associated with a higher risk of graft loss (75%). Thrombotic microangiopathy and endothelial cell swelling in glomeruli were prevalent, highlighting extensive endothelial cell injury. Most recipients (88.2%) experienced rejection after COVID-19, with graft loss occurring in 46.7% of these cases. Biopsies revealed collapsing (n = 5), noncollapsing (n = 3), and recurrent (n = 2) focal segmental glomerulosclerosis, as well as acute tubulointerstitial nephritis (n = 3), crescentic glomerulonephritis with immunoglobulin A nephropathy (n = 1), and membranoproliferative glomerulonephritis (n = 1), in 129.7 ± 33 days. Eight patients experienced graft loss (8.2 ± 2 mo posttransplant). Hospitalization (P = .044) and viralinclusion-like nuclear changes in tubules (P = .044) significantly influenced graft survival. Collapsing (60%) and noncollapsing (66.7%) focal segmental glomerulosclerosis increased the risk of graft loss.

COVID-19 has had a multifaceted and enduring effect on renal allografts, urging the need for meticulous monitoring and tailored management strategies to mitigate the risk of severe kidney-related complications and graft loss in this vulnerable population.