ABSTRACT
Human Polyoma BK virus is a DNA virus that has many transmission methods including feco-oral, respiratory, transplacental and from donor tissue with a usual unnoticed primary infection. Reactivation of Polyoma BK virus occurs in immunsuppressed patients such as pregnant females, cancer patients, patients with human immunodeficiency virus type 1 infection and recipients of renal or other allografts. Reactivation in renal transplant patients manifest as renal dysfunction resembling acute graft rejections and my be complicated with graft loss. In this study we aimed to evaluate different pathological and molecular methods in diagnosis and monitoring BK virus nephropathy [BKVN]. Twenty renal transplant patients represented with renal dysfunction manifested clinically and by elevation in serum creatinine level were investigated by means of histopathological examination of renal biopsy specimen, detection of decoy cells in urine cytology specimen and detection of Ployoma BK DNA in urine and plasma by PCR. Three patients out of 20 [15%] were diagnosed as BKVN positive by urine cytology, histpathological examination of renal biopsy and by detection of BK virus DNA in urine and plasma. Not all these methods were approved to be useful in monitoring our positive cases after reduction modification of the immunosuppressive therapy. Detection of decoy cells in urine cytology specimen and detection of Polyoma BK virus DNA in urine were the most efficient and reliable methods for monitoring BKVN