Utility of Fluorescence In Situ Hybridization in Diagnosing BK Viral Nephropathy in Renal Allograft Biopsies.
Zhen Wang, Bryce P Portier, Jonathan C Myles, Andres Chiesa-Vottero, Rosemary Neelon, Gary Procop, Raymond R Tubbs. Cleveland Clinic, OH
Background: BK nephropathy may complicate post transplant immunosuppression with potential graft loss if not appropriately managed. Early detection is essential to management which may include a reduction in immunosuppression. Conversely, if the cause of increasing renal insufficiency is acute rejection, immunosuppression may be increased. PCR based screening is sensitive and specific for BK virus detection within urine and blood, however fluorescence in situ hybridization (FISH) as a methodology to detect BK virus in formalin fixed paraffin embedded (FFPE) renal allograft tissue biopsies has not been previously evaluated.
Design: Data was retrieved from the Cleveland Clinic (CC) electronic medical record from 1/2005 to 12/2009 wherein patient's were included if they had a history of renal transplantation, subsequent renal biopsy preformed at CC, and documented blood or urine BK virus PCR performed concurrently at time of biopsy. A total of 40 patients were identified that met inclusion criteria. The presence or absence of viral inclusions on H&E as reviewed by medical renal pathologists (JLM and ACV) were recorded. FISH was then performed in both patient and positive control tissues using 1) a BK specific DNA probe (red) and 2) CEP8 centromeric probe (green) as a control for successful hybridization. Probe hybridization time was two hours, enabling same day resulting. FISH results were reported as positive or negative.
Results: FISH detected BK virus in 15 (38%) cases; while H&E viral inclusions within tubular epithelial nuclei were defined as positive in 3 cases (7.5%), suspicious in 15, and negative in 22. PCR performed on urine and blood identified BK virus in the same 15 cases that were identified by FISH, plus one additional case. The agreement between FISH and PCR was 97.5%. The agreement between the presence of viral inclusions on H&E and PCR was 67.5%. In relation to PCR, the sensitivity and specificity of FISH was 93.8% and 100% respectively. In relation to PCR, the sensitivity and specificity of finding viral inclusions on H&E was 18.8% and 100% respectively.
Conclusions: FISH performed for BK virus using FFPE renal allograft biopsies performs similarly to that of PCR based viral detection within blood and urine. The sensitivity of the FISH assay is superior to detection of BK viral inclusions on H&E stained slides. Finally, utilizing FISH for BK virus identification is straightforward, offers a short turn around time, and requires no variation from standard FISH protocol, thus making it a viable option for BK virus identification.
Category: Kidney (does not include tumors)
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 273, Wednesday Afternoon