Effect of immunosuppression on the urinary excretion of BK and JC polyomaviruses in renal allograft recipients

JC Polyomavirus and Transplantation: Implications for Virus Reactivation after Immunosuppression in Transplant Patients and the Occurrence of PML Disease

The JC polyomavirus (JCPyV/JCV) is a member of the Polyomaviridae family and is ubiquitious in the general population, infecting 50–80% of individuals globally. A primary infection with JCV usally results in an asymptomatic, persistent infection that establishes latency in the renourinary tract. Reactivation from latency via iatrogenic immununosuppression for allograft transplantation may result in organ pathology and a potential life-threatening neuropathological disease in the form of progressive multifocal leukoencephalopathy (PML). Currently, no treatment exists for PML, a rare complication that occurs after transplantation, with an incidence of 1.24 per 1000 persons a year among solid organ transplant patients. PML is also observed in HIV patients who are immununosuppressed and are not receiving antiretroviral therapy, as well as individuals treated with biologics to suppress chronic inflammatory responses due to multiple sclerosis, Crohn’s disease, non-Hodgkin’s lymphoma, rheumatoid arthritis, and other autoimmune-mediated hematological disorders. Here, we describe the proposed mechanisms of JCV reactivation as it relates to iatrogenic immunosuppression for graft survival and the treatment of proinflammatory disease, such as biologics, proposed trafficking of JCV from the renourinary tract, JCV central nervous system dissemination and the pathology of PML in immunosuppressed patients, and potential novel therapeutics for PML disease.

John Cunningham (JC) virus genotypes in kidney transplant recipients, rheumatoid arthritis patients and healthy individuals in Isfahan, Iran

In healthy individuals John Cunningham virus is latent without any clinical signs, but in the cases of the use of immunosuppressive drugs in graft recipients, autoimmune diseases and also increasing of age, that the immune system is suppressed it may cause disease in reactivation. Progressive multifocal leukoencephalopathy (PML) is the well-known disease caused by the virus. It has also been associated with nephropathy and tumorogensis. At present, based on vp1 capsid gene 7 genotypes have been detected. Genetic variations of JC virus in different geographical areas and the presence of different subtypes is a useful tool for reconstructing of the genetic information of JC virus and understanding of its evolution. The aim of this study was to investigate different genotypes of the JC virus in the urine of 100 kidney transplant recipients, 43 rheumatoid arthritis patients, and 100 healthy individuals as control group in Isfahan. DNA was extracted by phenol-chloroform method and subjected to a nested PCR using specific primer for vp1 capsid gene designed by Oligo 7 software. Fisher's exact test was used for statistical analyses. Using MEGA 6 software the sequences were aligned using Clustal W tool and phylogenetic trees were constructed by neighbor joining method. Thirty-one positive samples were sequenced. Genotypes 1, 3, and 4 of the virus were detected for the first time in Iran. For the first time genotype 3 was reported as the dominant genotype in Iran. For the first time in the world, genotype 4 was detected in rheumatoid arthritis patients. J. Med. Virol. 89:337-344, 2017. © 2016 Wiley Periodicals, Inc.

A review on JC virus infection in kidney transplant recipients

The polyomavirus (PyV), JC virus (JCV), is a small nonenveloped DNA virus that asymptomatically infects about 80% of healthy adults and establishes latency in the kidney tissue. In case of immunodeficient hosts, JCV can lytically infect the oligodendrocytes, causing a fatal demyelinating disease, known as progressive multifocal leukoencephalopathy (PML). Although the reactivation of another human PyV, BK virus (BKV), is relatively common and its association with the polyomavirus associated nephropathy (PyVAN) following renal transplantation is proven, JCV replication and its impact on graft function and survival are less well studied. Here we describe the biology of JCV and its pathological features and we review the literature regarding the JCV infection analyzed in the setting of transplantations.

Prospective monitoring of BK virus reactivation in renal transplant recipients in North India

BACKGROUND

BK nephropathy (BKN) is an important complication of renal transplantation with a reported incidence between 1% and 10% in different parts of the world. Early diagnosis is important to plan early therapeutic strategies. The epidemiology and evolution of BKN is relatively unknown in India and hence, the present study has been designed to prospectively monitor the activation of BK virus (BKV) in renal transplant recipients in India.

PATIENTS AND METHODS

In this study, 32 renal allograft recipients were prospectively monitored with protocol biopsies of allografts, BKV DNA load in plasma, and viral particles in urine by electron microscopy (EM) on day 1, and at 1, 3, and 6 months. Additionally, the baseline BKV DNA load in plasma was quantitated in 21 corresponding donors.

RESULTS

On follow-up in 32 recipients, 9.7%, 23.8%, 19.2%, and 13.3% of patients showed viral profiles by EM at day 1, 1 month, 3 months, and 6 months, respectively. BKV DNA positivity in plasma was 25.8%, 42.9%, 15.4%, and 20% at day 1, 1 month, 3 months, and 6 months, respectively, with mean BKV copy number/mL plasma of 1796, 1029, 2611, and 3318, respectively. A total of 15.7% (17/108) urine samples of 32 renal recipients were positive by urine EM. Out of 100 protocol biopsies, none developed histologically demonstrable cytopathic effects of BKN, although 8% biopsies were SV-40 large T antigen (SV-40 T Ag) positive. By quantitative real-time polymerase chain reaction assay, 27/108 (25%) of recipients' plasma samples were positive for BKV. Peak viremia and viruria occurred at 1-3 months post transplantation. The baseline viremia in donors was predictive of viremia positivity in the post-transplantation period at 1 month. Twenty-four episodes of graft dysfunction were attributed mainly to rejection.

CONCLUSION

The study shows a total of 15.7% and 25% urine and plasma samples were positive for BKV at any time during a 6-month follow-up. The highest incidence of BK viruria and viremia occurred at 1 month. In protocol biopsies, focal positivity of SV-40 T Ag was seen in 8% biopsies.

Polyomavirus BK versus JC replication and nephropathy in renal transplant recipients: a prospective evaluation

BACKGROUND

JC virus (JCV) viruria is more common than BK virus (BKV) viruria in healthy individuals but in kidney transplants (KT), polyomavirus nephropathy (PVAN) is primarily caused by BKV. Few cases of PVAN have been attributed to JCV. Systematic studies on JCV replication in KT are lacking.

METHODS

Out of a cohort of KT patients screened with urine cytology, patients shedding decoy cells were studied (n=103). Molecular studies demonstrated BKV, JCV, or BKV+JCV shedding in 58 (56.3%), 28 (27.2%), and 17 (16.5%), respectively. Biopsy was performed when decoy cells persisted 2 months or serum creatinine increased >20%.

RESULTS

BKV viruria was strongly associated with BKV viremia (93%), PVAN (48%, P=0.01) and graft loss (P=0.03). Higher BKV viremia correlated with graft dysfunction (P=0.01), more advanced histological pattern of PVAN (P<0.0001), and more infected cells in biopsy (P=0.0001). BKV viremia of > or =10,000 copies/mL was significantly associated with histologically confirmed PVAN (P=0.0001). Reduction of immunosuppression lead to disappearance of decoy cells in patients shedding BK (>93%). JCV viruria, was more often asymptomatic (P=0.002) and affected older patients (P=0.02). JCV PVAN was less common (21.4%) and was characterized by sparse cytopathic changes but significant inflammation and fibrosis. JCV viremia was rare (14.2%), transient, and low (mean 2.0E+03/mL). After reduction of immunosuppression decoy cells persisted in >50% of patients with JCV (P=0.0001), but no graft loss occurred. During the period of the current study, the incidence of BKV-PVAN was 5.5% and the incidence of JCV-PVAN was 0.9%.

CONCLUSIONS

The data point to significant differences of BKV and JCV biology regarding replication and disease in KT patients, with important implications for screening and management.

Discovery and epidemiology of the human polyomaviruses BK virus (BKV) and JC virus (JCV)

Although discovered over thirty years ago, many aspects of the epidemiology of BKV and JCV in the general population, such as the source of infectious virus and the mode of transmission, are still unknown. Primary infection with both BKV and JCV is usually asymptomatic, and so age seroprevalence studies have been used to indicate infection. BKV commonly infects young children in all parts of the world, with the exception of a few very isolated communities, adult seroprevalence rates of 65-90% being reached by the age of ten years. In contrast, the pattern of JCV infection appears to vary between populations; in some anti-JCV antibody is acquired early as for BKV, but in others anti-JCV antibody prevalence continues to rise throughout life. This indicates that the two viruses are probably transmitted independently and by different routes. Whilst BKV DNA is found infrequently in the urine of healthy adults, JCV viruria occurs universally, increasing with age, with adult prevalence rates often between 20% and 60%. Four antigenic subtypes have been described for BKV and eight genotypes are currently recognized for JCV. The latter have been used to trace population movements and to reconstruct the population history in various communities.

Management of infections by the human polyomavirus JC: past, present and future

Progressive multifocal leukoencephalopathy is a fatal demyelinating disease caused by infection of oligodendrocytes by the human polyomavirus known as JC virus. Over the past 10 years, the disease has been documented almost exclusively in AIDS patients, who constitute a rapidly growing population of immunosuppressed individuals. More recently, progressive multifocal leukoencephalopathy has also been described in patients undergoing solid organ or cell transplant, as a result of immunosuppressive therapy to avoid graft rejection. Although there are several reports of successful treatment of progressive multifocal leukoencephalopathy, large-scale prospective trials have been few, and with mixed results. As more is discovered about the biology of JC virus infection and advances are made in targeted parenchymal delivery of therapeutic agents, there is hope for the development of an effective therapy for progressive multifocal leukoencephalopathy.

Renal transplantation and polyomavirus infection: recent clinical facts and controversies

Although many articles have been published on polyomavirus-induced pathologies in transplant recipients, our knowledge regarding their clinical aspects remains relatively limited. In fact, the number of questions and controversies on the subject seems even to be increasing as new publications continue to appear. This article presents some of these controversies through a brief review of recent clinical facts about the three polyomaviruses that infect humans--JC virus, simian virus 40, and BK virus--as they relate to renal transplantation.

A regulatory region rearranged BK virus is associated with tubulointerstitial nephritis in a rejected renal allograft

A renal allograft transplant patient with high serum creatinine presented clinical symptoms of rejection. Sections of renal biopsy tissue showed mononuclear leukocyte infiltration in the tubulointerstitium and nuclear enlargement with inclusions in the tubular epithelium. The morphological characteristics resembled polyomavirus-induced interstitial nephritis. Electron microscopy of the nuclear inclusions showed paracrystalline arrays of naked viral particles with a diameter of 45 nm. Molecular studies revealed that a new variant of BK virus (BKV) with rearrangement at the regulatory region was involved in the nephritis. The BKV regulatory region contained a tandem repeat from the P-block to the Q-block causing duplication of several important transcriptional elements or transcriptional factor binding motifs. This is the first report to show a naturally occurring BKV variant with regulatory region rearrangement associated with tubulointerstitial nephritis.

Treatment with cytotoxic immunosuppression agents increases urinary excretion of JCV in patients with autoimmune disease

Human JC virus is ubiquitous in human populations and is reactivated frequently in immunosuppressed patients. Fifty-one patients with autoimmune disease receiving immunomodulating therapy were evaluated to study the possible relationship between immunosuppression and JCV viruria. Patients were divided into cytotoxic and noncytotoxic treatment groups based on their prescription. The incidence of JCV viruria in the cytotoxic treatment group was significantly higher than that in the noncytotoxic group (67% vs. 28%; P < 0.05). Most patients with JCV viruria were receiving corticosteroid (P = 0.03 for any dose and P < 0.001 for higher-dose treatments) and cytotoxic agents (P = 0.02). Age, disease duration, and medication duration appeared not to be the precipitating factors of JCV viruria in this study. The results of clinical evaluation indicate that cytotoxic immunosuppression may play an important role in JC virus reactivation.

Transmission of the human polyomavirus JC virus occurs both within the family and outside the family

JC polyomavirus (JCV) is a ubiquitous symbiote in the human population, infecting children asymptomatically and then persisting in renal tissue. We reevaluated the urinary excretion of JCV in subjects in various age groups using PCR. The detection rate for urinary JCV DNA was 9 to 17% until the age of 20 years; this rate increased dramatically to about 46% at the ages of 20 to 29 years and then increased gradually with age. Therefore, it appears that in most people excretion of JCV begins at the age of 20 to 29 years, which is earlier than suggested previously. Next, we studied the way in which JCV is spread in the human population. We selected eight Japanese families in which both parents and children excreted JCV in their urine. Their JCV subtypes were determined by PCR amplification of a JCV DNA fragment; this was followed by restriction enzyme analysis. JCV species in all JCV-positive family members were classified into either of the two subtypes, subtypes CY and MY, which are prevalent in the Japanese population. The following features of JCV subtype distribution were seen in the families: (i) both subtypes were detected in children of five of the eight families, and (ii) of 21 children who excreted JCV, 14 children excreted the same subtypes excreted by their mothers or fathers, while the remainder (7 children) excreted subtypes different from those excreted by their parents. These features suggest that JCV is transmitted both within the family and outside the family. The data also indicate that vertical transmission is not common in the spread of JCV.