Clinicopathologic analysis of renal biopsies after haematopoietic stem cell transplantation.

AIM: The ever-growing number and increasing survival of haematopoietic stem cell transplantation (HSCT) allow better recognition of its associated renal injuries. We aimed to study the clinicopathologic features of renal biopsies after HSCT by reviewing 13 percutaneous renal biopsies in our institute (Queen Mary Hospital).

METHODS

A retrospective clinicopathologic study of all renal biopsies archived to the Department of Pathology, Queen Mary Hospital during the period January 1999 to December 2006 was performed. Biopsies from patients with HSCT were selected. Clinical data on presentation and follow up were retrieved from hospital records and physicians.

RESULTS

In the 8-year period, a total of 2233 native renal biopsies were archived. Thirteen renal biopsies were selected from 12 patients with HSCT (11 allogeneic, one autologous). All but one patient were male. The age at renal biopsy ranged from 7 to 63 years (median: 32 years). The median interval of renal biopsy after HSCT was 24 months (range 1-134 months). Evidence of graft-versus-host disease was found in nine patients. The most common presentation was significant proteinuria (10 cases) and renal impairment (eight cases). The predominant histological changes were membranous glomerulonephritis (n = 4) and thrombotic microangiopathy (n = 4). One case of focal segmental glomerulosclerosis, IgA nephropathy, minimal change disease, acute tubular necrosis and hypertensive nephrosclerosis were also recorded. Four of our patients died at 0-11 months after renal biopsy. Of the remaining eight patients with a mean follow up of 43.6 months (range, 10-98 months), chronic renal impairment were found in three (37.5%) patients and significant proteinuria also persisted in three. One patient had cytogenetic evidence of relapse of underlying haematological malignancy after HSCT.

CONCLUSION

Among the various renal lesions after HSCT, membranous glomerulonephritis and thrombotic microangiopathy were the most common. Mechanisms of renal injury varied from graft-versus-host disease-associated immune complex deposition to non-immune complex injury on endothelial cells, glomerular epithelial cells and tubular epithelium. Pathologists and clinicians should attend to the histological and temporal heterogeneity of renal injury when managing patients after HSCT.