p53 Immunostaining Can Be Used as a Sensitive Measure to Detect BK Viral Infection in Renal Allograft Biopsies
WN Wiesend, W Li, MA Farinola, MT Rooney, F Lin, PL Zhang. William Beaumont Hospital, Royal Oak, MI; University of Texas Health Science Center, Houston, TX; Geisinger Medical Center, Danville, PA
Background: New Banff criteria have been proposed to stratify BK virus infection in renal transplants into stage I (early focal), stage II (extensive) and stage III (late sclerosing). This study was performed to determine if p53 can be used as a sensitive marker to assist in diagnosing BK virus infection in the renal allograft biopsy.
Design: Renal transplant biopsies from both control group (n =16, no BK virus infection) and BK group (n = 13, with known positive BK virus in urine by PCR tests) were immunohistochemically stained for BK virus (SV40) and p53. The nuclear staining intensity was graded on a scale of 0 to 3+ and positive percent involvement in the renal parenchyma was recorded.
Results: Staining intensity. None of the biopsies from the control group was positive for BK virus staining (0/16). 13/16 cases showed weak (1+) to moderate (2+), fine granular, complete nuclear staining for p53 (reactive epithelial changes without nuclear atypia). 3/16 cases were negative for p53 staining, using paraffin embedded tissue. In the BK group, 9/13 cases stained strongly positive (2-3+) and 3/13 stained weakly positive (1+) for BK virus. 12/13 cases in the BK group showed strong (3+) p53 nuclear staining with nuclear translucent halos. Positive staining percent. 8/13 cases of the BK group showed higher percent of p53 positive staining (10 to 30%) when compared to BK positive staining (1 to 5%). In 3/13 cases of subtle BK infection, focal BK infection was confirmed by a unique pattern of strong p53 staining with nuclear halos. Two (2/13) non-conclusive cases in BK group. The first nonconclusive case (non-conclusive #1) was that of a small biopsy sample that stained negatively for BK virus but focal strongly positive for p53 by immunohistochemistry, but was positive for BK virus in the urine cytology within 1 week. The other non-conclusive case (non-conclusive #2) showed weak BK staining in two tubular cells that had normal nuclear size, but p53 staining was negative. This case was called suspicious for early BK infection.
Conclusions: Our data suggest that the unique pattern of p53 staining (with nuclear halos) may be useful to assist in confirming the presence of subtle BK virus infection (stage I) or more accurately estimating the extent of BK virus infection in the renal allograft biopsy (stage II).
Category: Kidney (does not include tumors)
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 227, Wednesday Afternoon