Utility of Immunocytochemistry To Improve Sensitivity of BK Virus Detection in Urine of Renal Transplant Patients
Semra Karaburun, Michaell O'Donnell, Pamela H Newcomb, Richard Cartun, Theresa Voytek. Hartford Hospital/ CLP, Hartford, CT
Background: BK virus (BKV), a human polyomavirus, has been recognized as a cause of severe kidney allograft dysfunction. Early diagnosis of BKV nephropathy is important because no specific antiviral therapy exists. The current treatment of BKV nephropathy (BKVN) consists of a reduction in immunosuppressant therapy. Urine cytology, detection of viral DNA in urine or blood, and renal biopsy are the main diagnostic tools. The purpose of this study was to determine whether immunocytochemical staining improves sensitivity for BKV detection compared to routine urine cytology.
Design: 50 urine specimens negative for BKV by routine screening were studied. 8 specimens positive for BKV by routine screening were used as positive controls. Thin prep methodology was used to prepare the slides. The slides were first stained with H&E then independently screened by three observers for BKV noting also any other findings such as atypia, degenerative changes and inflammation. Then, following removal of coverslips and rehydration, stained slides were tested for polyomavirus and evaluated by the same observers. Immunocytochemical identification of polyomavirus was performed using a rabbit polyclonal antibody and Envision+/AEC+ detection (Dako Corporation, Carpinteria, CA). The presence of any nuclear staining was considered as positive regardless of the number of stained cells.
Results: All 8 positive control cases were stained positive immunocytochemically. Of the 50 cases which were negative by routine examination, 8 cases (16%) showed positivity immunocytochemically. The positive cases were not specifically associated with atypia, degenerative changes or inflammation.
Conclusions: Urine cytology is an easy and rapid method of detecting decoy cells in renal transplant patients. However, routine screening does not detect all cases of BKV infection. IHC increases sensitivity of urine cytology screening for BKV by detecting cases with only rare infected cells. IHC should be considered in conjunction with routine screening, because early diagnosis of BKV is important in the management of renal transplant patients.
Tuesday, March 20, 2012 9:30 AM
Poster Session III # 70, Tuesday Morning