Challenging Issues in Diagnosis and Screening of BK Virus Nephropathy in Kidney Transplant Recipients, A Multicenter Experience in Iranian Population.

INTRODUCTION: BK virus nephropathy (BKVN) is an important complication of kidney transplantation and kidney biopsy remains the gold standard for its diagnosis. Urine/serum polymerase chain reaction (PCR) is a more sensitive diagnostic method, although it has some potential limitations. METHODS: This study enrolled all kidney transplant recipients who underwent kidney transplant biopsy, collected from three medical centers. Urine and serum PCR results of the patients were also collected from the molecular laboratories. The cut-off value for positive viral DNA load in serum and urine were > 104 and > 107 copies/mL, respectively. Sensitivity, specifity, positive and negative predictive values (PPV, NPV) and cut off values for PCR results were compared with pathologic diagnosis among laboratories. RESULTS: Among 369 biopsy samples, 33 (8.9%) had definite diagnosis of BKVN. PCR results were available for 138 cases. Three patients with definite BKVN had negative PCR results. In 22 patients, PCR was positive without evidence of BKVN. The overall sensitivity, specificity, PPV and NPV of PCR for detecting BKVN, based on a unique cut-off value, were 88, 81, 51, and 97%; respectively. The overall accuracy of PCR in all laboratories was high (82 to 86%), however significant inter-laboratory differences in sensitivity and specificity was found . A 2-log difference in threshold value for positive results was observed in one laboratory. CONCLUSION: PCR may show a significant variability between different laboratories. Interpretation of PCR results using a single cut-off value for all laboratories, may decrease the sensitivity for the diagnosis and screening of BKVN.  DOI: 10.52547/ijkd.7143.

Routine immunohistochemistry study for polyomavirus BK nephropathy in transplanted kidney biopsies, is it recommended?

BACKGROUND: Early diagnosis and treatment of Polyomavirus BK Nephropathy (PVBKN) is a challenging issue in the management of patients with kidney transplantation. Currently, histopathologic diagnosis is the gold standard method for diagnosis of PVBKN. However, typical viral inclusions may not be found in early stages of the PVBKN and should, instead, be diagnosed using immunohistochemistry (IHC) study. There is no clear consensus about routine IHC tests in the pathologic evaluation of transplanted kidney biopsy samples. MATERIAL AND METHODS: The current study was conducted on transplanted kidney biopsy samples, since 2016 to 2019. The patients who have presented with new onset of allograft dysfunction, at least 2 weeks after transplantation surgery, were included in our study. All these biopsy samples were evaluated with routine renal biopsy stains as well as IHC for SV40 (Simvian Virus 40) antigen. The identification of typical nuclear virus inclusion body and any nuclear positive staining on IHC (≥1+ positive result) were considered as definite evidence of PVBKN. Sensitivity, specificity, Positive Predictive and Negative Predictive Values (PPV and NPV) of histopathologic assessment without IHC study were evaluated. RESULTS: Among 275 included cases, 18 (6.5%) patients with PVBKN were diagnosed. In patients with PVBKN, typical viral inclusions were detected in 14 samples (77.7%), on primary histopathological examination. However, virus-infected cells were identified just after IHC study in 4 (22.2%) of patients. Sensitivity, Specifity, PPV and NPV of morphologic histopathological assay without IHC for detection of PVBKN was 77.7, 100, 100 and 98.4% respectively. CONCLUSION: Routine IHC study for SV40 in all transplanted kidney biopsy samples with new onset of allograft dysfunction, will enhance the diagnostic sensitivity of early stage disease detection.

Development of a kidney transplantation program--inverted funnel approach.

INTRODUCTION: The history of organ shortage has been approached differently by different countries. This review tries to discuss the inverted funnel approach of Iran. METHODS: The whole history of transplants in the country can be divided in three phases of legally regulated living unrelated kidney donation, legislation of brain death donation and lastly how it has been implemented. In each phase, there have been attempts to clarify the role of each sector: the government, professionals, and the public. RESULTS: Based on more than 20 years of experience, it has been shown that kidney transplants from brain dead donors (BDDs) increased from 0.4 per million population (pmp) in 2000 to 2.9 pmp in 2005, 7.9 in 2010, and 15.1 pmp in 2013 and it could eventually change the rate from living source from 20.1 pmp, 24.5 pmp, 21.8 pmp, and 19.5 pmp in these years, respectively. DISCUSSION: It has been shown that the government began to take part when it was convinced that an organ procurement program from BDDs is not a luxury program but can lessen the economic burden on the health budget and be supported by legislations and budget allocation. Professionals took the responsibility not only to make decision makers and the public aware of the subject and adapt the national protocols to consider the general population concerns, but also to train as many medical teams as possible nationwide. Persistence and publishing the results can pave the way for the public to accept the program and take their own responsibilities to solve the problem of organ shortage by taking the opportunity to give life to others after the death of a loved one.