BK Virus Infection Is Associated with Hematuria and Renal Impairment in Recipients of Allogeneic Hematopoetic Stem Cell Transplants

Cumulative incidence and timing of development of BK viruria and viremia for the prospectively monitored cohort (n=57).

Relationship between both median (left panel) and maximum (right panel) levels of urinary BKV and degree of microscopic hematuria post-HSCT. A direct relationship was seen between higher median and maximum levels of urinary BKV with greater amounts of microscopic hematuria. RBC=red blood cells.

Impact of BK viremia on change in creatinine post-HSCT. Change in creatinine represents the difference between the maximum post-HSCT creatinine level and the pretransplant baseline creatinine. BK viremia was the factor having the greatest absolute effect on creatinine elevation in this study: the creatinine rise was 1.62mg/dL in patients with BK viremia, but only 0.64mg/dL in those without BKV in the blood (P=.001).

Photomicrographs of the pathologic findings in 2 patients with biopsy-proven BK virus-induced nephropathy. (A) (top panel) High-powered view of enlarged tubular epithelial cells showing viral cytopathic effect and intranuclear inclusions in 1 of the 2 affected patients in our study. Glomeruli and vascular structures are normal; (B) (middle panel) SV40 immunohistochemical stain further demonstrating the intranuclear viral inclusions in the same patient (SV40 and BKV share a significant region of homology); (C) (bottom panel) similar pathologic findings in the kidney of the second patient in our study with BKV nephropathy.

Relationship between timing and magnitude of BK viremia and creatinine rise in the 2 patients who had persistently positive blood BKV levels and who developed BKV nephropathy and end stage renal failure. (A) (top panel) corresponds to the first patient described in the text; (B) (bottom panel) corresponds to the second patient described in the text.