Prevalence Of BK Virus Infection Research Articles

POS-099 BK POLYOMAVIRUS NEPHROPATHY IN RENAL TRANSPLANT PATIENTS: A RACE WITH TIME?

BK polyomavirus-associated nephropathy (BKVAN) affects up to 15% of renal transplant recipients and is an important cause of graft failure. Higher prevalence of BK virus infection in recent years has been correlated with declining acute rejection rates and the use of potent immunosuppressive agents.

Screening for Polyomavirus Viruria Like Early Detection of Human Polyomavirus Infection and Replication: The Results of a Single-Center Observation

Polyomavirus (PV) infection and PV-associated nephropathy (PVAN) are some of the most important problems in kidney transplantation. Our objective was to determine the incidence of PV viruria and PV replication in single-center Polish kidney transplant recipients (KTR). Urine samples from 155 cadaveric KTR were analyzed for PV viruria using quantitative real-time polymerase chain reaction and the patients were followed prospectively. The PV replication was recognized when the urine level was >107 PV DNA copies/mL of urine. Based on the PV DNA analysis, the patients were divided into 3 groups: Group 1 (n = 87; 56.1%) without viruria, Group 2 (n=44; 28.4%) with viruria but without PV replication, and Group 3 (n =24; 15.5%) with PV replication. The presence of PV viruria was correlated with the type of immunosuppressive regimen, strongly associated with tacrolimus intake. There was no correlation between viruria and mycophenolate daily dose in the study population. In Group 3 there were 6 patients (3.9%) with high viruria (>1010 copies/mL), and 5 patients from this group had confirmed PVAN in allograft biopsy. The prevalence of BK virus infection in KTR is similar to that reported in studies from other countries. We confirmed that PV viruria can be both a good screening for PV infection and a good predictor of PVAN. Tacrolimus was the most important predictor of PV viruria and PV replication in KTR.

Lower Prevalence of BK Virus Infection in African American Renal Transplant Recipients

Because the occurrence of BK virus (BKV) nephritis is far less frequent than BK viremia or viruria, analysis of risk factors for BKV nephritis as an endpoint could lead to erroneous findings. We undertook a prospective study to evaluate the risk factors for the occurrence of BKV infections using BK viruria and viremia as endpoints. Two hundred forty renal only transplant recipients were prospectively enrolled into our institutional review board-approved single center study to evaluate various aspects of posttransplant BKV infection. All patients were followed up for a minimum of 6 months posttransplant. Of the 240 subjects, 154 were whites, 61 African Americans, and 25 belonged to other races. A total of 94 developed BKV infection (any degree of BK viruria or viremia) whereas 146 developed no infection. Among these, 33 had BK viruria alone, 61 had BK viremia with viruria and 25 had significant viremia defined as BKV DNA more than 10,000 copies/mL of plasma. Lower proportion of African Americans developed BKV infection, 14 of 61 (23%), as opposed to whites, 67 of 154 (47%). Logistic regression model showed lower risk of any BKV infection in African American recipient race (OR, 0.38; 95% CI, 0.17-0.82; P=0.016) and higher risk of significant BKV infection with occurrence of acute rejection (OR, 3.9; 95% CI, 1.31-11.8; P=0.015). The Kaplan-Meier analysis shows a trend toward greater freedom from BKV infection in African Americans as opposed to other racial groups (P=0.33). Renal transplant recipients of African American race had a lower risk of posttransplant BKV infection compared with whites, independent of other confounding risk factors.

Polyomavirus BK Replication in Liver Transplant Candidates with Normal Renal Function

Polyomavirus-associated nephropathy (PVAN) has a predilection for kidney rather than for other solid organ transplants such as the liver. Immunosuppression is widely recognized to be a major risk factor for PVAN development. Since end-stage liver disease (ESLD) patients are immunocompromised and immunosuppression is a major cause of BK virus reactivation, we sought to evaluate BK virus replication in patients listed for liver transplantation. From April to October 2010, we enrolled 20 patients listed for liver transplantation. BK virus load was measured by quantitative real-time polymerase chain reaction on plasma and urine samples. Viremia occurred in only 1 among 20 patients. We hypothesized that in ESLD patients, the low prevalence of BK virus infection may be related to the prevalent impairment of antibacterial immunity rather than to the viral-specific one. In BK virus reactivation, not only the immunodepressive state itself, but also the specific immunologic mechanisms involved may have a role.

Screening for latent BK virus infection in a renal transplant population for the first time in Romania: a single-center experience

The BK virus nephropathy (BKVN) is one of the most important infectious complications in renal transplant recipients. As BKVN lacks any effective antiviral treatment, early diagnosis is required in order to try to limit viral replication and subsequent damage to the renal allograft, by reducing the immunosuppressive therapy. Our study, the first of its kind in Romania, aimed to assess the prevalence of BKVN among renal transplant patients in our center. In this cross-sectional study, we included 143 renal transplant patients from our center who had received their renal allograft between 2005 and 2010. We searched for latent BK virus infection by detection of serum anti-BK virus antibodies, using an in-house developed enzyme-linked immunosorbent assay (ELISA) technique. Serology was considered positive if results were >0.33 optical density units. In patients with positive serology, we searched for BKVN with qualitative (polymerase chain reaction, PCR) and quantitative (TaqMan real-time PCR) molecular techniques. Additionally, we searched for other viral infections, including hepatitis B (with HBsAg test), hepatitis C (with anti-HCV Abs test), and cytomegalovirus (CMV, with pp65Ag test). All patients screened with ELISA were found to have positive BK virus serology and two of these were diagnosed with BKVN. Both patients with BKVN presented with acute impairment of the renal graft function, and one of them also developed a ureteral graft stenosis. In both cases, BKVN resolved after reduction of immunosuppressive doses. We also diagnosed hepatitis B in 18.18%, hepatitis C in 7.0%, and CMV in 27.97% of patients. Our study demonstrates for the first time the existence of BK virus in Romania, and we believe it opens the prospective of diagnosing BKVN in high-risk patients in our country in the future. In renal transplant patients from our center, we found the prevalence of BK virus infection to be as high as 100%. The prevalence of hepatitis B and CMV was also remarkably high. In patients with BKVN, the reduction of immunosuppression enables the spontaneous resolution of the disease.

BK Virus Nephritis after Renal Transplantation

BK virus nephritis is an increasing problem and is posing a threat to improving renal transplant graft survival. The pathogenesis of this condition remains to be investigated. Higher prevalence of BK virus infection in recent years has been correlated with declining acute rejection rates and the use of potent immunosuppressive agents. Patients with this infection usually have asymptomatic viremia and/or nephritis with or without worsening of renal function. The diagnosis of this disease is based on detecting the virus or its effects in urine, blood, and renal tissue. In the past, approximately 30 to 60% of patients with BK virus nephritis developed graft failure. In recent years, the combination of early detection, prompt diagnosis, and therapies including preventive measures have resulted in better outcomes.

Prevalence of human polyoma virus (BK virus and JC virus) infection in patients with chronic renal disease

Polyoma virus infection in renal transplant patients is sometimes critical in graft survival. But, to date, polyoma virus infection or reactivation has not been checked before renal transplantation. The prevalence of polyoma viruses (BK virus and JC virus) was investigated in 45 patients with renal disease who were future candidates as renal graft recipients. Because these viruses are excreted in urine, the urine of these 45 patients was analyzed by polymerase chain reaction (PCR). The urine of 37 age-matched normal subjects (control group) was also investigated. In the control group, 13.5% of the normal subjects were positive for BK virus and 24.3% were positive for JC virus. In the patients with renal disease, 33.3% were positive for BK virus and 33.3% were positive for JC virus; the prevalence of BK virus infection was significantly higher than that in the normal subjects. Patients with renal disease with corticosteroid therapy revealed an especially high prevalence of BK virus infection (55.6%), indicating the possibility of viral reactivation by corticosteroid therapy. More attention should be paid to polyoma virus infection in candidates for renal transplantation with a previous therapeutic history of corticosteroid administration.