Kidney Pathology after Hematologic Cell Transplantation-A Single-Center Observation Study of Indication Biopsies and Autopsies.

Hematopoietic cell transplantation (HCT) is an increasingly used treatment for hematologic malignancies as well as for nonmalignant diseases. Kidney impairment remains an important early and late post-transplantation complication. Although numerous histopathological changes have been reported, the pathophysiology remains incompletely understood. Furthermore, correlations between clinical findings and morphological changes have not been well studied. Between 2000 and 2016, 17 recipients of allogeneic (n = 12) or autologous (n = 5) HCT underwent kidney biopsy for either proteinuria or deterioration of kidney function at our center. The most common biopsy findings were therapy-related changes with thrombotic microangiopathy (n = 5), calcineurin inhibitor toxicity (n = 4), and membranous glomerulonephritis (n = 3), representing the majority of cases in this category. In addition, kidney findings from 137 autopsies performed between 1995 and March 2017 were analyzed. The most common changes were acute kidney injury (n = 55), most likely due to the patients' premortal deteriorated state, and thrombotic microangiopathy (n = 14). Several cases demonstrated involvement by either infectious agents (n = 6) or tumors (n = 9). Distinct kidney diseases, such as glomerulonephritis, were rare (3% of cases). Uncommon and yet rarely described diagnoses for this patient cohort were IgG4-related tubulointerstitial nephritis and fibrillary nephritis. This study provides a comprehensive overview of the histomorphological findings in kidney biopsy specimens from HCT recipients. Along with treatment-related complications, one putative correlate of chronic GVHD of the kidney could be documented: membranous glomerulonephritis. In contrast, no morphological correlate of acute GVHD of the kidney was identified. Findings at the time of autopsy varied greatly, spanning a wider range than those of indication biopsies.