Evaluation of Renal Biopsies for BK Virus Nephropathy in Non-Renal Transplant Immunosuppressed Patients

OBJECTIVE: Although BK virus nephropathy (BKVN) has mostly been reported to occur in transplanted kidneys, there has been a gradual increase in cases of BKVN in the native kidney. This study was directed towards investigating the incidence of BKVN in patients undergoing renal biopsy due to acute kidney injury (AKI) who were also immunosuppressed due to a condition other than organ transplantation. MATERIAL and METHODS: Out of the 1223 patients undergoing renal biopsy for various conditions between January 2001 and January 2013, 52 patients who underwent a biopsy for AKI and were immunosuppressed at the time of the biopsy were included into the study. After renal biopsies of all patients were reevaluated, all biopsy specimens were exposed to immunohistochemical staining for SV40 antibody. RESULTS: Of the 52 patients, 29 had primary glomerulonephritis, 18 had secondary glomerulonephritis and 5 had a malignancy. All patients except one case of acute lymphoblastic leukemia and one case of non-Hodgkin lymphoma were immunosuppressed due to immunosuppressive therapy. None of the patients had any signs of BKVN on immunohistochemical staining of renal biopsy specimens. CONCLUSION: Failure to detect BKVN in this study may be because BKV causes gradual impairment of renal functions and the sample did not include patients frequently observed to have BKVN in the native kidney.