Measurement of viral sequences in cerebrospinal fluid of AIDS patients with cerebral white-matter lesions using polymerase chain reaction

Biomarkers for progressive multifocal leukoencephalopathy: emerging data for use of JC virus DNA copy number in clinical trials

Progressive multifocal leukoencephalopathy is a rare but devastating demyelinating disease caused by the JC virus (JCV), for which no therapeutics are approved. To make progress towards addressing this unmet medical need, innovations in clinical trial design are needed. Quantitative JCV DNA in CSF has the potential to serve as a valuable biomarker of progressive multifocal leukoencephalopathy disease and treatment response in clinical trials to expedite therapeutic development, as do neuroimaging and other fluid biomarkers such as neurofilament light chain. Specifically, JCV DNA in CSF could be used in clinical trials as an entry criterion, stratification factor, or predictor of clinical outcomes. Insights from the investigation of candidate biomarkers for progressive multifocal leukoencephalopathy might inform approaches to biomarker development for other rare diseases.

HIV-RNA decay in paired blood and semen samples of subjects receiving their first dolutegravir-based ART regimen

BACKGROUND AND OBJECTIVES

We aimed to investigate to what extent a first-line DTG-based ART regimen reduces HIV-RNA in semen compared to plasma.

STUDY DESIGN

In this prospective, observational study, ART-naïve, HIV-infected males starting their first ART regimen with DTG plus TDF/FTC or ABC/3TC were enrolled. Paired blood (BP) and seminal plasma (SP) samples were collected at baseline (T0) and at week-2/4/12/24 after ART initiation. Sexually transmitted infections (STI) were ruled out before enrolment.

RESULTS

Median baseline HIV-RNA levels were lower in SP compared to BP (657 versus 38.200 copies/ml, p < 0.001), three subjects had undetectable semen HIV-RNA. After 12 weeks of treatment, HIV-RNA was below the quantification limit in both BP and SP of 11 pts (61.1%). Discordant results were obtained in 6 subjects (33.3%), showing quantifiable HIV-RNA in blood only (2 cases) and in semen only (4 cases). Finally, one subject had a positive HIV-RNA in SP/BP. At W24, only in 2/16 subjects (12.5%) HIV-RNA was detectable in semen, while in the others it was negative on SP/BP. No concurrent STI was found in subjects with detectable VL in semen.

CONCLUSIONS

DTG demonstrated effectiveness in reducing VL with different kinetics in blood and semen, despite seminal viral suppression after 6 months of ART was not obtained in the totality of subjects.

Progressive multifocal leukoencephalopathy: what's new?

Progressive multifocal leukoencephalopathy (PML), a severe demyelinating disease that is caused by human JC polyomavirus, was first described as a complication of immune suppression 50 years ago and emerged as a major complication of HIV infection in the 1980s. The prognosis has remained dismal since then, with discouraging results from clinical trials of various therapeutic approaches, including immunomodulation and/or inhibition of viral replication. PML is caused by reactivation of latent JC virus, and serotonergic 5-HT(2a) receptors have been identified as being critical for viral infection of glial cells. In recent years, immunosuppressive therapeutic antibodies have been associated with an increased incidence rate of PML. Here, the authors review findings on the pathogenesis of PML and the encouraging case reports of novel treatments.

Severe, demyelinating leukoencephalopathy in AIDS patients on antiretroviral therapy

OBJECTIVES

To describe a severe form of demyelinating HIV-associated leukoencephalopathy in AIDS patients failing highly active antiretroviral therapy (HAART), its relationship to clinical and neuroimaging findings, and suggest hypotheses regarding pathogenesis.

DESIGN AND METHODS

AIDS patients who failed HAART and displayed severe leukoencephalopathy were included. All cases had detailed neuromedical, neuropsychological, neuroimaging and postmortem neuropathological examination. Immunocytochemical and PCR analyses were performed to determine brain HIV levels and to exclude other viruses.

RESULTS

Seven recent autopsy cases of leukoencephalopathy in antiretroviral-experienced patients with AIDS were identified. Clinically, all were severely immunosuppressed, six (86%) had poorly controlled HIV replication despite combination antiretroviral therapy, and five (71%) had HIV-associated dementia. Neuropathologically, all seven had intense perivascular infiltration by HIV-gp41 immunoreactive monocytes/macrophages and lymphocytes, widespread myelin loss, axonal injury, microgliosis and astrogliosis. The extent of damage exceeds that described prior to the use of HAART. Brain tissue demonstrated high levels of HIV RNA but evidence of other pathogens, such as JC virus, Epstein-Barr virus, cytomegalovirus, human herpes virus type-8, and herpes simplex virus types 1 and 2, was absent. Comparison of the stages of pathology suggests a temporal sequence of events. In this model, white matter damage begins with perivascular infiltration by HIV-infected monocytes, which may occur as a consequence of antiretroviral-associated immune restoration. Intense infiltration by immune cells injures brain endothelial cells and is followed by myelin loss, axonal damage, and finally, astrogliosis.

CONCLUSIONS

Taken together, our findings provide evidence for the emergence of a severe form of HIV-associated leukoencephalopathy. This condition warrants further study and increased vigilance among those who provide care for HIV-infected individuals.

Clinical course of cardiomyopathy in HIV-infected patients with or without encephalopathy related to the myocardial expression of tumour necrosis factor-alpha and nitric oxide synthase

OBJECTIVE

To define whether the development of encephalopathy influences the clinical course of HIV-associated cardiomyopathy (HIV-DCM) in relation to the myocardial expression of tumour necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthase (iNOS).

DESIGN

Prospective study.

SETTING

University hospitals and AIDS centres.

METHODS

115 HIV-infected patients with echocardiographic diagnosis of HIV-associated cardiomyopathy (34 with encephalopathy and 81 without encephalopathy) were followed for a mean of 24 +/- 3.2 months. All patients underwent endomyocardial biopsy for determination of myocardial immunostaining intensity of TNF-alpha and iNOS. Cerebrospinal fluid (CSF) from patients with encephalopathy was examined for the presence of viruses. Patients underwent clinical examination every 3 months and echocardiographic examination every 6 months. The intensity of TNF-alpha and iNOS immunostaining was also evaluated on postmortem cerebral tissue of patients who died of congestive heart failure (CHF).

RESULTS

A greater impairment of echocardiographic parameters was observed in patients with HIV-associated cardiomyopathy after development of encephalopathy. These parameters tended to worsen progressively during the follow-up period and were inversely correlated with HIV-1 viral load, CD4 cell count, mini mental status score and the intensity of myocardial and cerebral TNF-alpha and iNOS staining. CSF specimens were available in 29 patients with encephalopathy. HIV-1 sequences were detected in CSF of all these patients with cytomegalovirus sequences in two. The mortality rate for CHF was greater among patients with encephalopathy (73% versus 12%).

CONCLUSIONS

The development of encephalopathy has an adverse effect on the clinical course of HIV-associated cardiomyopathy. In the relationship between cardiomyopathy and encephalopathy, the activation of iNOS by TNF-alpha may have a significant pathogenetic role in HIV disease.

Quantification of human polyomavirus JC in brain tissue and cerebrospinal fluid of patients with progressive multifocal leukoencephalopathy by competitive PCR

Activation of human polyomavirus JC (JCV) infection is the cause of the central nervous system (CNS) disease progressive multifocal leukoencephalopathy (PML). Previous studies with uncontrolled quantification systems suggested that the virus load in the CNS correlates with the state of disease and might reflect therapeutic effects. Therefore the aim of this study was the development of a competitive system with standard PCR techniques that allowed rapid detection of JCV subtypes, simultaneous differentiation of the two human polyomaviruses JCV and BKV and absolute quantification of the virus burden in initial diagnosis and progressive disease states. Subtype- and species-specificity of the PCR was achieved with the development of a degenerative PCR primer pair that detected JCV DNA in a range regularly found in PML samples, but did not amplify BKV DNA. The accuracy of the system was evaluated by quantification of known amounts of cloned JCV DNA with a competitive JCV-specific template that exhibited a comparable amplification rate to that of the native product. The calibration study demonstrated a linear correlation over a wide range of DNA concentrations on the background of buffer or JCV-negative diagnostic samples. The reliability of the system for PML diagnosis was analysed by calibration and determination of the virus burden in tissue and cerebrospinal fluid (CSF) of 11 PML patients confirming the accuracy in both types of samples under diagnostic conditions. Comparison of the JCV DNA concentration in tissue and CSF by a tightly controlled quantification technique revealed for the first time differences in a range of about four orders of magnitude and a variable virus load in CSF samples taken at comparable states of disease. This pointed to an individual course of virus shedding and demonstrates that a controlled competitive PCR system of high accuracy is essential for reliable quantification of virus DNA either in initial diagnosis, in progressive disease or for the evaluation of therapeutic effects.

Reduced concentrations of HIV-RNA and TNF-alpha coexist in CSF of AIDS patients with progressive multifocal leukoencephalopathy

OBJECTIVES

To confirm reduced human immunodeficiency virus type-1 (HIV-1) burden in the CSF of patients with progressive multifocal leukoencephalopathy (PML) and to verify whether this viral load coincides with the absence of inflammatory changes in the CSF.

METHODS

Paired CSF and plasma samples from 17 patients with PML, 26 with non-PML cerebral opportunistic infections, nine with HIV-1 leukoencephalopathy (HIVE), and 12 neurologically asymptomatic AIDS patients were subjected to HIV-RNA titration. Tumour necrosis factor (TNF)-alpha was also measured and the CSF albumin: serum albumin ratio (Q(Alb)) was calculated.

RESULTS

The CSF HIV-1 burden of patients with PML did not differ from that of neurologically asymptomatic patients (p=0.21), but was significantly lower than CSF burden of the remaining patients (non-PML opportunistic infections, p<0.001; HIVE, p<0.001). Q(Alb) was normal for all neurologically asymptomatic patients, for 86.6% patients with PML, and 62.5% patients with HIVE (p=0.09). Q(Alb) was altered in 91.6% patients with non-PML opportunistic infections. TNF-alpha in CSF was higher in patients with non-PML opportunistic infections (p<0.001) and those with HIVE (p<0.001) than in patients with PML who consistently had TNF-alpha concentrations<10 pg/ml.

CONCLUSIONS

These results, while indicating a reduced HIV replication in CSF of patients with PML which might serve as a disease marker, emphasise the increased CSF HIV-RNA concentration in patients with HIVE and patients with non-PML opportunistic infections. Low concentrations of HIV-RNA in CSF coincide with reduced TNF-alpha concentrations, possibly due to particular features of PML compared with other opportunistic infections as it develops without detectable inflammatory changes in the CSF.

HIV-1-related central nervous system diseases

The frequency of HIV-1-related central nervous system diseases has been reduced by new combinations of antiviral agents, in part through the reduction of both viral load in blood and continuous penetration of virus into brain. This will probably not be sufficient to abolish any neurological risk. HIV-1-related dementia also depends on the intensity of glial cell activation in the central nervous system, which induces reactivation of latent infection in these cells with possible reinfection of the periphery, and on secretion of soluble inflammatory mediators acting on nearby neurones. The fact that only a small subgroup of patients suffers from neurological diseases also suggests a genetic component, at the level either of viral receptors or of the immune response.

New Thoughts on Pathogenesis and Diagnosis of Encephalitis

Knowledge regarding the pathogenesis of viral encephalitis, defined as inflammation and destruction of the central nervous system (CNS) from viral infection and the resulting immune response, has improved with advances in molecular biology techniques and recent advances in immunology and neuroscience research. An increasingly complex understanding has developed with regard to viral CNS infection. In addition to advances in viral genetics exploring increased viral spread and neurovirulence, improved understanding from research on neurochemistry, neurodevelopment, and cytokine expression in the CNS has led to new hypotheses regarding the mechanism of CNS damage during viral CNS infection. This review explores three advances in the understanding of viral encephalitis in the past few years: 1) the relationship between viral load and extent of viral CNS disease, 2) chemokines and their role in the CNS inflammatory response as well as in the pathogenesis of encephalitis, and 3) secondary damage from the release of neurotoxins during encephalitis. By examining this research, the reviewers intend to introduce novel therapeutic modalities that are developing for the management of patients with viral encephalitis beyond the timely use of antiviral therapy.

Herpesviruses--a rationale for antiviral treatment in multiple sclerosis

In multiple sclerosis (MS), the extensive and long lasting search for viruses or other pathogens has hitherto failed to identify a common etiological agent. However, the beneficial effects by interferon-beta treatment in MS, although suggested to depend mainly on immunomodulation, might lend support to a viral involvement in the pathogenesis. The human herpesviruses have attracted interest since their recurrent modes of infection share some similarity with the relapsing-remitting course of MS, most members are readily detected within the brain, and several of these viruses may induce demyelination within the central nervous system in human hosts as well as in animal models. Accumulated diagnostic and epidemiological data are compatible with a role for the herpesviruses as possible cofactors rather than etiological agents, and recent studies showing early neuronal damage in MS patients focus attention on the neurotropic alpha-herpesviruses. Antiviral treatment trials with safe and effective drugs such as valaciclovir offer a possibility of testing the hypotheses concerning herpesviral involvement in MS.