Persistent infection with human polyomavirus revealed by urinary cytology in a patient with heart transplantation. A case report

Polyomavirus Nephropathy in Kidney Transplantation

Polyomavirus nephropathy has become an important complication in kidney transplantation, with a prevalence of 1% to 8%. Unfortunately, the risk factors for polyomavirus nephropathy and renal allograft loss are not well defined. The definitive diagnosis is made through assessment of a kidney transplant biopsy. Recently, noninvasive urine and serum markers have been used to assist in polyomavirus nephropathy diagnosis and monitoring. Primary treatment is immunosuppression reduction, but must be balanced with the risks of rejection. No antiviral treatments for polyomavirus nephropathy have been approved by the Food and Drug Administration. Although cidofovir has shown in vitro activity against murine polyomaviruses, and has been effective in some patients, it is associated with significant nephrotoxicity. Graft loss due to polyomavirus nephropathy should not be a contraindication to retransplantation; however, experience is limited. This review presents potential risk factors, screening, diagnostic and monitoring methods, therapeutic management, and retransplantation experience for polyomavirus nephropathy.

BK nephropathy in the native kidneys of patients with organ transplants: Clinical spectrum of BK infection

Nephropathy secondary to BK virus, a member of the Papoviridae family of viruses, has been recognized for some time as an important cause of allograft dysfunction in renal transplant recipients. In recent times, BK nephropathy (BKN) of the native kidneys has being increasingly recognized as a cause of chronic kidney disease in patients with solid organ transplants, bone marrow transplants and in patients with other clinical entities associated with immunosuppression. In such patients renal dysfunction is often attributed to other factors including nephrotoxicity of medications used to prevent rejection of the transplanted organs. Renal biopsy is required for the diagnosis of BKN. Quantitation of the BK viral load in blood and urine are surrogate diagnostic methods. The treatment of BKN is based on reduction of the immunosuppressive medications. Several compounds have shown antiviral activity, but have not consistently shown to have beneficial effects in BKN. In addition to BKN, BK viral infection can cause severe urinary bladder cystitis, ureteritis and urinary tract obstruction as well as manifestations in other organ systems including the central nervous system, the respiratory system, the gastrointestinal system and the hematopoietic system. BK viral infection has also been implicated in tumorigenesis. The spectrum of clinical manifestations from BK infection and infection from other members of the Papoviridae family is widening. Prevention and treatment of BK infection and infections from other Papovaviruses are subjects of intense research.

European perspective on human polyomavirus infection, replication and disease in solid organ transplantation

Human polyomaviruses (HPyVs) are a growing challenge in immunocompromised patients in view of the increasing number of now 12 HPyV species and their diverse disease potential. Currently, histological evidence of disease is available for BKPyV causing nephropathy and haemorrhagic cystitis, JCPyV causing progressive multifocal leukoencephalopathy and occasionally nephropathy, MCPyV causing Merkel cell carcinoma and TSPyV causing trichodysplasia spinulosa, the last two being proliferative skin diseases. Here, the current role of HPyV in solid organ transplantation (SOT) was reviewed and recommendations regarding screening, monitoring and intervention were made. Pre-transplant screening of SOT donor or recipient for serostatus or active replication is currently not recommended for any HPyV. Post-transplant, however, regular clinical search for skin lesions, including those associated with MCPyV or TSPyV, is recommended in all SOT recipients. Also, regular screening for BKPyV replication (e.g. by plasma viral load) is recommended in kidney transplant recipients. For SOT patients with probable or proven HPyV disease, reducing immunosuppression should be considered to permit regaining of immune control. Antivirals would be desirable for treating proven HPyV disease, but are solely considered as adjunct local treatment of trichodysplasia spinulosa, whereas surgical resection and chemotherapy are key in Merkel cell carcinoma. Overall, the quality of the clinical evidence and the strength of most recommendations are presently limited, but are expected to improve in the coming years.

Renal failure five years after lung transplantation due to polyomavirus BK-associated nephropathy

Polyomavirus-associated nephropathy (PyVAN) is rare in nonrenal solid organ transplantation and only limited information is available from single cases. We describe a 67-year-old female presenting with hypertension and progressive kidney failure due to PyVAN 60 months after lung transplantation. Plasma BK virus (BKV) loads were 4.85 log¹⁰ copies/mL at diagnosis and cleared slowly over 14 months after switching from tacrolimus, mycophenolate and prednisone to low-dose tacrolimus, sirolimus and leflunomide, the latter being discontinued for anemia and diarrhea. BKV- and JC virus-specific immunoglobulins were detectable prior to transplantation. Only BKV-specific IgG and IgM increased during follow-up. BKV-specific T cells were detectable in blood following in vitro expansion, but cleared with reincreased sirolimus, yet BKV viremia remained undetectable. We identified eight other cases of PyVAN in nonrenal solid organ transplantation including lung (n = 1), heart (n = 6) and pancreas (n = 1). Overall, diagnosis was later than commonly seen in kidney transplants (median 18 months, interquartile range 10-29). Seven patients were male, five received triple immunosuppression consisting of tacrolimus, mycophenolate, prednisone. Immunosuppression was reduced in four cases and cidofovir and/or leflunomide administered in five and two cases, respectively. Renal function deteriorated in five requiring hemodialysis in four. We discuss mTOR inhibitors versus cidofovir and leflunomide as potential PyVAN rescue therapy.

Native BK viral nephropathy in a pediatric heart transplant recipient

BK viral nephropathy is a well-documented clinical entity in kidney transplant recipients and a significant cause of morbidity and allograft loss in affected patients. BK viral nephropathy in native kidneys of non-kidney transplant recipients is relatively uncommon, but has been reported in adult patients. We report the occurrence of BK viral nephropathy in a pediatric heart transplant recipient. A 10-yr-old boy with past history of Ewing's sarcoma underwent heart transplantation for dilated cardiomyopathy induced by previous chemotherapy with doxorubicin. Post-transplant course was complicated by grade 3A rejection and CMV colitis. He was diagnosed with native BK viral nephropathy approximately 18 months post-transplant due to mild, but persistent, elevation in serum creatinine associated with proteinuria. BK viral nephropathy affects non-kidney transplant recipients, and a high index of suspicion is necessary for early diagnosis and management of this condition.

BK virus infection after non-renal transplantation

Infection with BK virus (BKV), a member of the Polyomavirus (PV) family, is ubiquitous, with the virus remaining in a latent form in the kidney and urinary tract. This infection is usually asymptomatic, but with impairment of the cellular immune system the virus can reactivate and lead to tissue damage. In recipients of bone marrow and solid organ transplants, PV reactivation can be associated with disease in urinary tract and kidneys. BKV was first discovered in 1971 from the urine of a kidney transplant recipient who had developed ureteral stenosis 4 months after transplantation. While much of the subsequent research focuses on patients after renal transplantation, we will review PV impact in patients after bone marrow transplant (BMT) and those with non-renal solid organ transplants.

Urine cytology findings of polyomavirus infections

Polyomaviruses of the BK- and JC-strains often remain latent within the transitional cell layer of the bladder, ureters and the renal pelvis as well as in tubular epithelial cells of the kidney. Slight changes in the immune status and/or an immunocompromised condition can lead to the (re)activation of latent polyomaviruses, especially along the transitional cell layer, resulting in the shedding of viral particles and infected cells into the urine. A morphologic sign of the (re)activation of polyomaviruses is the detection of typical intranuclear viral inclusion bearing epithelial cells, so-called "decoy cells", in the urine. Decoy cells often contain polyoma-BK-viruses. The inclusion bearing cells are easily identified and quantifiable in routine Papanicolaou stained urine cytology specimens. With some experience, decoy cells can also be detected in the unstained urinary sediment by phase contrast microscopy. Different morphologic variants of decoy cells (types 1 through 4) are described and ancillary techniques (immunohistochemistry, electron microscopy (EM), and fluorescence-in-situ-hybridization (FISH)) for proper identification and characterization are discussed. Special emphasis is placed on the clinical significance of the detection of decoy cells as a parameter to assess the risk for disease, i.e., polyoma-BK-virus nephropathy (BKN) in kidney transplant recipients. The sensitivity and specificity of decoy cells for diagnosing BKN is 99% and 95%, respectively, the positive predictive value varies between 27% and more than 90%, and the negative predictive value is 99%. The detection of decoy cells is compared to other techniques applicable to assess the activation of polyomaviruses in the urine (polymerase chain reaction (PCR) and EM).

BK viral reactivation in cardiac transplant patients: evidence for a double-hit hypothesis

BACKGROUND

BK nephropathy is a significant cause of renal dysfunction in renal allograft recipients. The question of whether BK viral infection plays a role in renal dysfunction in cardiac transplantation patients remains to be answered.

METHODS

We prospectively examined the prevalence of BK viral reactivation in the setting of cardiac transplantation and performed a cross-sectional analysis of 111 cardiac transplantation patients. We also assessed the prevalence of viremia in a cohort of 29 renal transplant recipients.

RESULTS

We found urinary decoy cells in 28 cardiac transplantation patients. Of these, 14 patients had evidence of BK viral DNA in the urine. None, however, had evidence of BK viremia. Mean age, gender, levels of pre- and post-transplant serum creatinine, cardiopulmonary bypass time, and ischemic time were not significantly different between the groups. We found that 7 of 29 renal transplant recipients studied had BK viral DNA in their urine.

CONCLUSION

These findings are evidence of BK virus reactivation in the setting of cardiac transplantation at a percentage similar to that seen in renal allograft recipients. In contrast to renal allograft recipients, none had evidence of viremia. Thus, even in the setting of established BK virus reactivation, immunosuppression in combination with renal allograft dysfunction and renal ischemic injury is usually insufficient to cause BK viremia and nephropathy, and it appears that a second, organ-specific hit is necessary, such as kidney inflammation, kidney ischemia, or donor-recipient human leukocyte antigen mismatch.

BK virus nephropathy in a heart transplant recipient: case report and review of the literature

The human polyomavirus BK virus (BKV) remains latent in the urinary tract and may be reactivated in immunocompromised states. BKV is noted to be the etiologic agent of polyomavirus-associated nephropathy (PVAN), which is a significant cause of allograft failure in renal transplant patients. Renal dysfunction following non-renal solid organ transplantation is common and is typically attributed to drug toxicity or patient comorbidities. In this article we describe a case of PVAN in the native kidneys of a heart transplant recipient and review the literature. Although this is only the fourth case reported, BKV nephropathy should be considered in the differential diagnosis of new renal failure following non-kidney solid organ transplantation, as early diagnosis of PVAN is necessary to prevent irreversible renal damage.

Prevalence of BK virus replication among recipients of solid organ transplants

BACKGROUND

BK virus (BKV) has been implicated as a cause of nephritis and graft loss in 2%-9% of kidney transplant recipients, but the prevalence among recipients of other solid organ transplants (SOTs) has not been well established. Our objective was to determine the prevalence of BKV infection for all types of SOT recipients at our medical center.

METHODS

A total of 156 consecutive SOT recipients were studied, of whom 49 received kidney transplants, 43 received heart transplants, and 64 received liver transplants. Samples were obtained a median of 559 days (range, 1-9481 days) after transplantation. Nested polymerase chain reaction was performed for detection of BKV DNA in urine and plasma specimens.

RESULTS

BKV was found in 19% of urine specimens and 6% of plasma specimens. The prevalence of viruria after kidney, heart, and liver transplantation was 26.5%, 25.5%, and 7.8%, respectively. BKV viremia was detected in 12.2% of kidney transplant recipients and 7% of heart transplant recipients. Mean creatinine levels were higher in patients with BKV viruria or viremia (1.9 and 3.5 mg/dL, respectively) than in patients with no BKV replication (1.3 mg/dL). Independent factors related to impaired renal function were renal transplantation (odds ratio [OR], 14.4); BKV replication, including viruria or viremia (OR, 3.3); and mycophenolate use (OR, 2.6).

CONCLUSION

BKV is common in all types of SOT recipients, particularly those who have received heart or kidney transplants.

BK virus associated nephropathy in native kidneys of a heart allograft recipient

Polyomavirus-mediated nephropathy is an increasingly recognized complication in renal transplant recipients, but data on the status of viral activity in the native kidneys of non-renal solid organ recipients are limited. Thirteen native kidney biopsies of heart transplant recipients with significant renal impairment were evaluated for the evidence of polyomavirus reactivation by immunohistochemistry and PCR. One case of BK virus-mediated nephropathy in a cardiac transplant recipient exposed to high levels of immunosuppressive drugs was identified. Clinical and histopathological findings of this patient progressing to terminal renal failure are discussed in detail. In conclusion, polyomavirus reactivation in native kidneys of heart transplant recipients can cause significant renal impairment and should be considered in the differential diagnosis in this patient cohort.

Polyomavirus nephropathy in kidney transplantation

Polyomavirus nephropathy has become an important complication in kidney transplantation, with a prevalence of 1% to 8%. Unfortunately, the risk factors for polyomavirus nephropathy and renal allograft loss are not well defined. The definitive diagnosis is made through assessment of a kidney transplant biopsy. Recently, noninvasive urine and serum markers have been used to assist in polyomavirus nephropathy diagnosis and monitoring. Primary treatment is immunosuppression reduction, but must be balanced with the risks of rejection. No antiviral treatments for polyomavirus nephropathy have been approved by the Food and Drug Administration. Although cidofovir has shown in vitro activity against murine polyomaviruses, and has been effective in some patients, it is associated with significant nephrotoxicity. Graft loss due to polyomavirus nephropathy should not be a contraindication to retransplantation; however, experience is limited. This review presents potential risk factors, screening, diagnostic and monitoring methods, therapeutic management, and retransplantation experience for polyomavirus nephropathy.

BK virus-associated renal problems--clinical implications

BK virus (BKV), a human polyomavirus, infects most of the human population, but clinically relevant infections are usually limited to individuals who are immunosuppressed. After primary infection, BKV remains latent in the kidneys and can be reactivated in immune deficiency conditions, including transplantation. As primary infection occurs in childhood, BKV may be particularly important in the pediatric transplant population. BKV is associated with tubulointerstitial nephritis and ureteric stenosis in renal transplant recipients and hemorrhagic cystitis in bone marrow transplant recipients. There are increasing reports of BKV causing nephropathy and cystitis in non-renal solid organ transplant recipients and other immunodeficiency diseases. This might be related to the use of more potent immunosuppressive regimens or increasing awareness of BKV as an important pathogen. Diagnosis of BKV disease is by biopsy. Histopathological changes in renal biopsy specimens may mimic rejection or drug toxicity, but BKV nuclear inclusions can be seen. Treatment is by reduction of immunosuppression. Antiviral agents such as cidofovir are showing promise. BKV DNA polymerase chain reaction in blood or biopsy may be helpful in monitoring therapy. The impact of BKV disease in children is not well understood and prospective studies are needed to elucidate this further. This article reviews the current understanding of BKV-associated renal problems.

Polyomavirus reactivation in native kidneys of pancreas alone allograft recipients

BACKGROUND

Polyomavirus infection is common in childhood, with a seroprevalence of 60% to 100%. These viruses remain latent mostly in the kidney. Impairment in cellular immunity can allow reactivation of the virus. Reactivation can occur in 10% to 45% of renal allografts. A higher intensity of immunosuppression and the allogeneic microenvironment of the graft have been suggested to predispose to reactivation. There are limited data on the status of viral activity in the native kidneys of non-renal solid organ recipients.

METHODS

Thirty-eight recipients of pancreas transplant alone were evaluated for evidence of polyomavirus reactivation by urine cytology. All had received induction therapy and were maintained on tacrolimus, mycophenolate mofetil, and prednisone. The renal function and degree of exposure to immunosuppressive agents of patients shedding polyomavirus-infected renal tubular cells were compared with those of patients with negative urine cytology.

RESULTS

Screening cytology was performed 16 months (mean) after transplantation. Four subjects (11%) had polyomaviruria. The renal function at baseline and time of screening was comparable between the two groups. The 12-hour trough levels of tacrolimus were significantly higher in patients with positive cytology compared with those without viruria. The doses of mycophenolate mofetil and prednisone were not different between the two groups.

CONCLUSION

This study shows that polyomavirus reactivation in native kidneys and urinary tract of pancreas transplant alone patients is not uncommon. In these recipients, viral reactivation was not associated with significant renal functional impairment. The results also suggest that patients who are exposed to higher blood levels of tacrolimus are at higher risk of viral reactivation.

Polyomavirus nephropathy in native kidneys of a solitary pancreas transplant recipient

BACKGROUND

Latent polyomavirus (PV) infection of the urinary tract can be reactivated by immunosuppression. When this occurs in the renal allograft, permanent loss of allograft function can occur. Polyomavirus reactivation could potentially affect the native kidneys of nonrenal transplant recipients and cause renal dysfunction.

METHODS

This article describes a case of PV nephropathy in the native kidneys of a solitary-pancreas transplant recipient. This patient had a progressive increase in serum creatinine. Screening urine cytology showed numerous cells with cytopathic changes suggestive of polyomavirus infection.

RESULTS

Biopsy of the native kidneys of this patient showed renal tubular cells with intranuclear inclusions characteristic of PV infection, which was confirmed by immunohistochemistry. Electron microscopy showed intranuclear viral particles. Patchy inflammation and fibrosis also were noted.

CONCLUSION

Polyomavirus reactivation can occur in the native kidneys of nonrenal solid organ transplant recipients. This should be considered in the differential diagnosis of renal impairment in these patients. The effects of PV reactivation on long-term native kidney function are not known.

Diagnosis and management of BK polyomavirus interstitial nephritis in renal transplant recipients

BACKGROUND

Interstitial nephritis caused by BK polyomavirus is a recognized complication of renal transplantation. A study of renal transplant recipients at Duke University Medical Center was undertaken to evaluate diagnostic modalities and assess clinical outcomes in transplant polyomavirus infections.

METHODS

Polyomavirus nephritis was identified in 6 of 240 patients who received renal transplants between January 1996 and June 1998 and an additional patient who underwent transplantation in 1995. The clinical records of these seven patients were reviewed, as were all renal biopsy and nephrectomy specimens. Electron microscopy (EM) was performed on negatively stained urine samples from 6 patients with polyomavirus infection and 23 patients with other diagnoses.

RESULTS

Patients with polyomavirus infection shared several clinical features, including ureteral obstruction (5/7 patients), lymphocele (3/7), bacterial urinary tract infection (3/7), hematuria (3/7), cytomegalovirus infection (3/7), and immunosuppression with mycophenolate mofetil (6/7). All patients experienced elevations in serum creatinine, which stabilized or decreased in four patients with altered or decreased immunosuppression. The diagnosis of polyomavirus infection was established by renal biopsy and EM of urine in five patients, by biopsy alone in one, and by EM alone in one. Sequential examinations of urine by EM were used to monitor the course of infection in six patients.

CONCLUSIONS

Interstitial nephritis due to BK polyomavirus occurred in 2.5% of patients receiving renal transplants at our center since 1996. Polyomavirus infection can cause transplant dysfunction and graft loss, but progression of the infection can frequently be abrogated with alterations in immunosuppressive therapy. Both renal biopsy and EM of urine samples are useful in the diagnosis and monitoring of polyomavirus infections.