BK virus-associated progressive multifocal leukoencephalopathy

In silico design and evaluation of a novel mRNA vaccine against BK virus: a reverse vaccinology approach

Human polyomavirus type 1, or BK virus (BKV), is a ubiquitous pathogen belonging to the polyomaviridae family mostly known for causing BKV-associated nephropathy (BKVN) and allograft rejection in kidney transplant recipients (KTRs) following the immunosuppression regimens recommended in these patients. Reduction of the immunosuppression level and anti-viral agents are the usual approaches for BKV clearance, which have not met a desired outcome yet. There are also debating matters such as the effect of this pathogen on emerging various comorbidities and the related malignancies in the human population. In this study, a reverse vaccinology approach was implemented to design a mRNA vaccine against BKV by identifying the most antigenic proteins of this pathogen. Potential immunogenic T and B lymphocyte epitopes were predicted through various immunoinformatic tools. The final epitopes were selected according to antigenicity, toxicity, allergenicity, and cytokine inducibility scores. According to the obtained results, the designed vaccine was antigenic, neutral at the physiological pH, non-toxic, and non-allergenic with a world population coverage of 93.77%. Since the mRNA codon optimization ensures the efficient expression of the vaccine in a host cell, evaluation of different parameters showed our designed mRNA vaccine has a stable structure. Moreover, it had strong interactions with toll-like receptor 4 (TLR4) according to the molecular dynamic simulation studies. The in silico immune simulation analyses revealed an overall increase in the immune responses following repeated exposure to the designed vaccine. Based on our findings, the vaccine candidate is ready to be tested as a promising novel mRNA therapeutic vaccine against BKV.

BK polyomavirus associated progressive multifocal leukoencephalopathy in a person living with HIV

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the white matter central nervous system occurring in immunocompromised patients particularly those with T cell deficiency such as in HIV, haematological and solid organ malignancies and those taking immunomodulatory medications. PML is caused by JC virus however in rare cases BK virus has been isolated in the cerebral spinal fluid of patients presenting with PML.

In this case we describe a 49 year old man who presented to the emergency department with a 2 week history of progressive right sided weakness and dysarthria. His background history included HIV diagnosed in 2005, he had not engaged with care in the past 2 years and had not been taking anti-retroviral therapy (ART). Other past medical history included untreated hepatitis C. His CD4 count was 90 (11%) cells/mm³ on admission and his HIV viral load VL) was 141,000 copies/ml. Magnetic resonance imaging(MRI) showed a hypointense lesion on T1, hyperintense on T2 and FLAIR without diffusion restriction and without mass effect. A lumbar puncture was performed which confirmed JC virus was positive (PCR <50 copies/ml) and also revealed BK virus was positive (PCR 46,511 copies/ml). The patient was commenced on tenofovir alafenamide fumarate/emtricitabine/darunavir/cobicistat in combination with dolutegravir 50mg twice daily. On day 40 post commencement of ART the patient was readmitted with worsening of his right arm weakness and dysarthria. A repeat MRI was performed which showed the hyperdense lesion on T2 and FLAIR appeared slightly larger with some slight enhancement with gadolinium contrast but no other features suggesting PML immune reconstitution inflammatory syndrome (IRIS). The CD4 count had increased to 141(17%) and HIV VL had decreased to 85 copies/ml. A clinical diagnosis of PML IRIS was made and the patient was commenced on prednisolone 30mg BD which lead to an initial improvement in symptoms.

Interestingly in this case, both JC virus and BK virus were detected in the CSF of this patient with the level of JC virus being too low to quantify. BK virus was not detectable on peripheral serum sampling suggesting that BK virus is replicating in the CNS independent of other body sites. There have been 5 case reports in the literature of BK virus as the cause of PML.

Testing for BK virus should be considered in patients presenting with signs and symptoms of PML and encephalitis particularly when no other cause is found.

Progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a relatively common complication of HIV disease. In this chapter changes to the epidemiology are discussed along with an update in its pathogenesis and treatment. Immune reconstitution inflammatory syndrome is increasingly frequent in PML; accordingly management strategies and prognosis are detailed.

BK Polyomavirus: Clinical Aspects, Immune Regulation, and Emerging Therapies

BK polyomavirus (BKV) causes frequent infections during childhood and establishes persistent infections within renal tubular cells and the uroepithelium, with minimal clinical implications. However, reactivation of BKV in immunocompromised individuals following renal or hematopoietic stem cell transplantation may cause serious complications, including BKV-associated nephropathy (BKVAN), ureteric stenosis, or hemorrhagic cystitis. Implementation of more potent immunosuppression and increased posttransplant surveillance has resulted in a higher incidence of BKVAN. Antiviral immunity plays a crucial role in controlling BKV replication, and our increasing knowledge about host-virus interactions has led to the development of improved diagnostic tools and clinical management strategies. Currently, there are no effective antiviral agents for BKV infection, and the mainstay of managing reactivation is reduction of immunosuppression. Development of immune-based therapies to combat BKV may provide new and exciting opportunities for the successful treatment of BKV-associated complications.

Demyelinating syndrome in SLE encompasses different subtypes: Do we need new classification criteria? Pooled results from systematic literature review and monocentric cohort analysis

OBJECTIVE

To describe features of demyelinating syndrome (DS) in systemic lupus erythematosus (SLE).

METHODS

A systematic review using a combination of Mesh terms in PubMed and a retrospective analysis of 343 adult patients with SLE were carried out to identify patients with DS. Retrieved cases were classified as affected with DS according to 1999 ACR nomenclature and attributed to SLE by applying the 2015 algorithm. DS defined according to the clinical but not temporal 1999 ACR criteria was classified as clinically isolated syndrome (CIS).

RESULTS

Estimated prevalence of DS (including CIS) in the SLE cohort was 1.3% and incidence rate was 1.5 cases per 1000 patient-years. Overall, 100 cases from literature review and 4 from SLE cohort were identified and are presented as a whole: 49 (47.1%) were classified as neuromyelitis optica spectrum disorders (NMOSD), 29 (27.9%) as CIS, 14 (13.5%) as NMO, 7 (6.7%) as DS prominently involving the brainstem and 5 (4.8%) as DS prominently involving the brain. DS was the SLE onset manifestation in 41 (39.4%) patients. Longitudinally extensive transverse myelitis was the most frequent manifestations being present in 73 (70.2%) patients (37 NMOSD, 21 CIS, 14 NMO, 1 DSB). Methylprednisolone (79.8%) and cyclophosphamide (55.8%) pulses, but also plasma-exchange (16.3%) and rituximab (7.6%) in relapsing-refractory cases, were mostly prescribed. Complete recovery rate ranged between 62% in CIS to 7% in NMO.

CONCLUSION

DS in SLE is rare (1%) and encompasses different subtypes including CIS. Timely diagnosis and early treatment are recommended to minimize complications.

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.

BK virus encephalopathy and sclerosing vasculopathy in a patient with hypohidrotic ectodermal dysplasia and immunodeficiency

Human BK polyomavirus (BKV) is reactivated under conditions of immunosuppression leading most commonly to nephropathy or cystitis; its tropism for the brain is rare and poorly understood. We present a unique case of BKV-associated encephalopathy in a man with hypohidrotic ectodermal dysplasia and immunodeficiency (HED-ID) due to IKK-gamma (NEMO) mutation, who developed progressive neurological symptoms. Brain biopsy demonstrated polyomavirus infection of gray and white matter, with predominant involvement of cortex and distinct neuronal tropism, in addition to limited demyelination and oligodendroglial inclusions. Immunohistochemistry demonstrated polyoma T-antigen in neurons and glia, but expression of VP1 capsid protein only in glia. PCR analysis on both brain biopsy tissue and cerebrospinal fluid detected high levels of BKV DNA. Sequencing studies further identified novel BKV variant and disclosed unique rearrangements in the noncoding control region of the viral DNA (BKVN NCCR). Neuropathological analysis also demonstrated an unusual form of obliterative fibrosing vasculopathy in the subcortical white matter with abnormal lysosomal accumulations, possibly related to the patient's underlying ectodermal dysplasia. Our report provides the first neuropathological description of HED-ID due to NEMO mutation, and expands the diversity of neurological presentations of BKV infection in brain, underscoring the importance of its consideration in immunodeficient patients with unexplained encephalopathy. We also document novel BKVN NCCR rearrangements that may be associated with the unique neuronal tropism in this patient.

BK virus nephropathy complicated with meningoencephalitis after kidney transplantation

BK disease is an opportunistic infection in organ transplant recipients and patients with other cellular immunodeficiencies. To the best of our knowledge, we report the second case of BK meningoencephalitis associated with nephropathy in a kidney transplant recipient. A 15-yr-old boy underwent a cadaveric kidney transplant without complications; however, 11 wk after the transplantation, he was admitted to the hospital for graft dysfunction and cytopenia, which were confirmed by BK nephropathy (plasma viral replication and histological evidence). Four days after his hospital admission, he developed a high-grade fever and headache. CSF analysis revealed pleocytosis with a positive PCR for BK virus. Reduction in immunosuppression and supportive care conducting cycles of immunoglobulin and cidofovir were successful in treating the patient. BK meningoencephalitis should be considered in kidney transplant recipients who present with signs and symptoms of meningoencephalitis.

The human polyomavirus BK (BKPyV): virological background and clinical implications

Polyomavirus BK (BKPyV) infects most people subclinically during childhood and establishes a lifelong infection in the renourinary tract. In most immunocompetent individuals, the infection is completely asymptomatic, despite frequent episodes of viral reactivation with shedding into the urine. In immunocompromised patients, reactivation followed by high-level viral replication can lead to severe disease: 1-10% of kidney transplant patients develop polyomavirus-associated nephropathy (PyVAN) and 5-15% of allogenic hematopoietic stem cell transplant patients develop polyomavirus-associated haemorrhagic cystitis (PyVHC). Other conditions such as ureteric stenosis, encephalitis, meningoencephalitis, pneumonia and vasculopathy have also been associated with BKPyV infection in immunocompromised individuals. Although BKPyV has been associated with cancer development, especially in the bladder, definitive evidence of a role in human malignancy is lacking. Diagnosis of PyVAN and PyVHC is mainly achieved by quantitative PCR of urine and plasma, but also by cytology, immunohistology and electron microscopy. Despite more than 40 years of research on BKPyV, there is still no effective antiviral therapy. The current treatment strategy for PyVAN is to allow reconstitution of immune function by reducing or changing the immunosuppressive medication. For PyVHC, treatment is purely supportive. Here, we present a summary of the accrued knowledge regarding BKPyV.