Detection of Toxoplasma gondii, Epstein-Barr virus, and JC virus DNAs in the cerebrospinal fluid in acquired immunodeficiency syndrome patients with focal central nervous system complications

Disseminated toxoplasmosis infection 20 years post kidney transplant

Kidney transplant recipients are at increased risk of opportunistic infections and malignancy, including space-occupying intracranial lesions. Here, we present a case of a patient presenting with multiple intracranial lesions in the context of a distant history of transplantation. MRI findings were consistent with a large subcortical enhancing lesion. Leading differentials included posttransplant lymphoproliferative disorder and cerebral cryptococcoma. Brain biopsy was undertaken along with PCR testing on tissue detected Toxoplasma gondii and Epstein-Barr virus (EBV) DNA. Cerebral toxoplasmosis was diagnosed based on characteristic histology and negative EBV immunohistochemistry. This case demonstrates the difficulties and complexities in reaching a diagnosis in immunocompromised patients and the importance of brain biopsy.

Toxoplasmic encephalitis with high 201Tl uptake and retention mimicking malignant lymphoma in a patient with human immunodeficiency virus infection

Various opportunistic infections develop during immunodeficiency due to human immunodeficiency virus (HIV) infection. The treatment options for malignant lymphoma (ML) and toxoplasmic encephalitis (TE) are completely different; therefore, their discrimination is critical. A 25-year-old female of foreign nationality had been experiencing headaches for several weeks and suddenly developed convulsions. Brain computed tomography revealed multiple intracranial lesions; therefore, the patient was referred to the neurosurgery department. Brain magnetic resonance imaging (MRI) revealed multiple masses with surrounding edema, accompanied by enhanced contrast. The largest mass (2 cm) in the left occipital lobe exhibited ringed contrast enhancement. Her blood test results showed a CD4 count of 40/μL, positive HIV Ag/Ab, HIV-RNA level of 56 × 104 copies/mL, positive anti-Toxoplasma IgG (63 IU/mL), and negative anti-Toxoplasma IgM. 201Tl- single photon emission computed tomography (201Tl-SPECT) revealed abnormal accumulation only in the tumor in the left occipital lobe (early T/N ratio, 3.034; delayed T/N ratio, 2.738; retention index, 0.9), which was suspected to be a ML. Both tumors, with or without high accumulation of 201Tl, were subjected to craniotomy biopsy. Pathological examination revealed infiltration of small lymphocytes with a necrotic background. The patient was diagnosed with TE based on a positive result of a tissue polymerase chain reaction test for Toxoplasma gondii. Two weeks after sulfamethoxazole and trimethoprim combination therapy, MRI imaging showed dramatic improvement in multiple brain tumors. This case is atypical because ML was ruled out despite high 201Tl-SPECT uptake and retention. Careful diagnosis through pathological examination and DNA testing is important.

Molecular diagnostics of infectious disease: Detection and characterization of microbial agents in cytology samples

BACKGROUND

Cytology samples are widely used to diagnose various infectious diseases by detection and identification of causative infectious agents, including bacteria, fungi, and viruses. The role of cytopathology in infectious disease has expanded tremendously in the past decades with the advances in molecular techniques. Molecular diagnostic methods, compared to conventional methods, have shown improved patient outcome, reduction in cost, and shortened hospital stay times. The aim of this article is to review molecular testing in cytology samples for diagnosis of infectious diseases.

METHODS

The literature search for molecular testing in common cytology samples for diagnosis of infectious diseases was performed. The findings of the studies were summarized. The common cytology samples included in this article were gynecologic specimens, cerebrospinal fluid, bronchoalveolar lavage, and urine samples.

CONCLUSIONS

There are a number of molecular diagnostic tests that are available to be used in common cytology samples to detect infectious agents. Each test has its own advantages and limitations. It is our hope that upon reading this review article, the readers will have better understanding of molecular diagnostic testing of infectious diseases utilizing commonly sampled cytology specimens in daily practice.

Diagnostic value of EBV-DNA in CSF for PCNSL in AIDS patients with focal brain lesions: A meta-analysis of diagnostic test

BACKGROUND

Epstein-Barr virus (EBV) infection plays a crucial role in the progression of acquired immunodeficiency syndrome related primary central nervous system lymphoma (AR-PCNSL). This study aimed at evaluating the diagnostic value of cerebrospinal spinal fluid (CSF) EBV-deoxyribonucleic acid (DNA) for PCNSL in patients with infection of human immunodeficiency (HIV) virus through a meta-analysis of diagnostic test.

METHODS

A systematic search in PubMed, Embase, Web of Science, Wanfang, Chinese Biomedical Database and Chinese National Knowledge Infrastructure was conducted before May 10, 2022. Heterogeneity among the studies was assessed using Q test and I2 statistics. Publication bias was assessed using the Deek's funnel plot asymmetry test. Statistical analyses were performed using Stata 16.0 software. The pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratios (DOR) and 95% confidence intervals (CI) were caculated to evaluate the diagnostic value. A symmetric receiver operating characteristic (SROC) curve and the area under the SROC curve (AUC) were constructed to evaluate the test-performance.

RESULTS

Twelve studies were included in the final analyses, with a total of 141 patients with AR-PCNSL and 590 controls. The pooled diagnostic values were sensitivity of 0.83 (95% CI: 0.73-0.90), specificity of 0.95 (95%CI: 0.89-0.98), PLR of 17.8 (95%CI: 6.8-46.1), NLR of 0.17 (95%CI: 0.10-0.30), DOR of 102 (95%CI: 28-379), and AUC of 0.94 (95%CI: 0.91-0.96).

CONCLUSION

In summary the overall diagnostic value of CSF EBV-DNA is very high and it can be a reliable diagnostic biomarker for AR-PCNSL.

Management of Viral Central Nervous System Infections: A Primer for Clinicians

Viruses are a common cause of central nervous system (CNS) infections with many host, agent, and environmental factors influencing the expression of viral diseases. Viruses can be responsible for CNS disease through a variety of mechanisms including direct infection and replication within the CNS resulting in encephalitis, infection limited to the meninges, or immune-related processes such as acute disseminated encephalomyelitis. Common pathogens including herpes simplex virus, varicella zoster, and enterovirus are responsible for the greatest number of cases in immunocompetent hosts. Other herpes viruses (eg, cytomegalovirus, John Cunningham virus) are more common in immunocompromised hosts. Arboviruses such as Japanese encephalitis virus and Zika virus are important pathogens globally, but the prevalence varies significantly by geographic region and often season. Early diagnosis from radiographic evidence and molecular (eg, rapid) diagnostics is important for targeted therapy. Antivirals may be used effectively against some pathogens, although several viruses have no effective treatment. This article provides a review of epidemiology, diagnostics, and management of common viral pathogens in CNS disease.

Tissue is the issue: a solitary cerebral lesion 15 years after kidney transplantation

Primary toxoplasmosis and reactivation of latent infections occur in solid organ transplant recipients. However, solitary cerebral lesions due to toxoplasmosis are rare. In this case, a patient presented with a haemiparesis and a cerebral lesion. We expected to find cerebral post-transplant lymfoproliferative disorder because of positive Epstein–Barr virus by polymerase chain reaction in cerebrospinal fluid, but histological findings revealed Toxoplasma gondii bradyzoites and tachyzoites, illustrating the necessity of obtaining material for diagnostics in immunocompromised hosts.

Epstein-Barr viral load in cerebrospinal fluid as a diagnostic marker of central nervous system involvement of AIDS-related lymphoma

OBJECTIVE

AIDS-related lymphoma (ARL) often involves the central nervous system (CNS). Although the diagnostic value of Epstein-Barr virus (EBV)-DNA in cerebrospinal fluid (CSF) in detecting HIV-positive primary CNS lymphoma (PCNSL) has been established, its usefulness for identifying CNS involvement of systemic ARL remains elusive. In this study, we evaluated the utility of the EBV-DNA load in CSF in identifying CNS involvement in patients with systemic ARL.

METHODS

We retrospectively reviewed the clinical and pathological data of consecutive ARL patients managed at our clinic between January 1998 and June 2012. Sixty-two patients with ARL, including eight PCNSL patients and 52 systemic ARL patients, and 63 controls underwent CSF EBV-DNA load evaluations before receiving chemotherapy. ARL-related CNS involvement was defined as any lesion diagnosed histologically or radiologically as a lymphoma in the brain, meninges, spine, cranial nerves or oculus.

RESULTS

A cut off value of 200 copies/mL predicted the presence of CNS lesions with a sensitivity of 70% and a specificity of 85% in both the PCNSL and systemic ARL patients, while a sensitivity of 75% and a specificity of 93% were obtained for systemic ARL. A cut off value of 2,000 (3.30 log) copies/mL provided the best specificity (100%), with a sensitivity of 50%.

CONCLUSION

Our results support the clinical utility of evaluating the quantitative EBV-DNA load in the CSF for the diagnosis of CNS involvement of systemic ARL as well as PCNSL.

Importance of nonenteric protozoan infections in immunocompromised people

There are many neglected nonenteric protozoa able to cause serious morbidity and mortality in humans, particularly in the developing world. Diseases caused by certain protozoa are often more severe in the presence of HIV. While information regarding neglected tropical diseases caused by trypanosomatids and Plasmodium is abundant, these protozoa are often not a first consideration in Western countries where they are not endemic. As such, diagnostics may not be available in these regions. Due to global travel and immigration, this has become an increasing problem. Inversely, in certain parts of the world (particularly sub-Saharan Africa), the HIV problem is so severe that diseases like microsporidiosis and toxoplasmosis are common. In Western countries, due to the availability of highly active antiretroviral therapy (HAART), these diseases are infrequently encountered. While free-living amoebae are rarely encountered in a clinical setting, when infections do occur, they are often fatal. Rapid diagnosis and treatment are essential to the survival of patients infected with these organisms. This paper reviews information on the diagnosis and treatment of nonenteric protozoal diseases in immunocompromised people, with a focus on patients infected with HIV. The nonenteric microsporidia, some trypanosomatids, Toxoplasma spp., Neospora spp., some free-living amoebae, Plasmodium spp., and Babesia spp. are discussed.

Diagnosis of systemic toxoplasmosis with HIV infection using DNA extracted from paraffin-embedded tissue for polymerase chain reaction: a case report

Introduction

Toxoplasmosis can be a life-threatening disease when it occurs in patients with HIV infection. In particular, meningioencephalitis has been regarded as the most common toxoplasmic complication in such patients. However, toxoplasmic meningitis in a patient with HIV infection is extremely rare and purulent or tuberculous meningitis should be considered initially as a disease for differential diagnosis in Japan.

Case presentation

Toxoplasmic meningitis in a patient with HIV infection is reported. A 36-year-old Japanese man presented with fever, pulsating headache, lumbago, nausea, and vomiting. No examinations suggested toxoplasmosis including cerebrospinal fluid examinations, images, and serological tests. The result of a polymerase chain reaction assay using paraffin-embedded section was regarded as the conclusive evidence for the diagnosis.

Conclusions

We wish to emphasize the usefulness of polymerase chain reaction assays with nucleic acid extracted from paraffin-embedded tissue sections processed for routine histopathological examination, if the section shows the infectious agents or findings suggesting some infectious diseases.

The significance of Epstein-Barr virus detected in the cerebrospinal fluid of people with HIV infection

INTRODUCTION

Epstein-Barr virus (EBV) is detected in the cerebrospinal fluid (CSF) in people with HIV infection who develop primary cerebral lymphoma (PCL). However, EBV may also be detected in the CSF of patients without PCL, and here the significance is uncertain.

METHODS

Ninety-eight HIV-positive patients had lumbar punctures performed and polymerase chain reaction (PCR) for EBV was undertaken on the CSF. Thirty-eight patients had non-Hodgkin's lymphoma (NHL), including four with PCL. Sixty patients had a CSF examination for other indications. The clinicopathological details, symptoms, diagnosis, CSF and neuroimaging findings and therapy at time of CSF were recorded and correlated with CSF EBV PCR results.

RESULTS

EBV was detected in the CSF in three of four patients (75%) with PCL, one of three (33%) with systemic lymphoma and meningeal involvement, and four of 31 (13%) with systemic lymphoma and no meningeal disease. Seven of 60 patients (12%) without lymphoma were CSF EBV-positive. There were no differences in immunological, clinical, biochemical or radiological parameters between patients with and without EBV in the CSF. After a median follow-up time of 30 weeks (maximum 102 weeks), none of the seven CSF EBV-positive patients has developed PCL.

CONCLUSION

EBV was detected in up to 12% of patients with neurological symptoms but without lymphoma. A positive result did not correlate with more advanced immunosuppression or a particular neurological diagnosis. Patients with EBV in their CSF did not appear to be at increased risk of developing PCL in the short term.

Results of diagnostic accuracy studies are not always validated

BACKGROUND AND OBJECTIVE

Internal validation of a diagnostic test estimates the degree of random error, using the original data of a diagnostic accuracy study. External validation requires a new study in an independent but similar population. Here we describe whether diagnostic research is validated, which technique is used, and to what extent the validation study results differ from the original.

STUDY DESIGN AND SETTING

All original diagnostic accuracy studies published in 1993 in a predefined set of journals were selected. Validation of these studies was assessed in the original article and in articles published within a period of 10 years, through a literature search and contacting the authors.

RESULTS

None of the original studies reported any form of validation. Validation studies published later could be identified for 7 of the 11 original studies. Test characteristics were difficult to compare. Despite what was generally believed, not every validation study showed results inferior to the original. We found more studies that evaluated the test in a different population than in a similar one.

CONCLUSION

Not every diagnostic accuracy study is validated. Diagnostic tests are more often repeated in different populations.

Frequent detection of Epstein-Barr Virus and cytomegalovirus but not JC virus DNA in cerebrospinal fluid samples from human immunodeficiency virus-infected patients in northern Thailand

Applying nested-PCRs, we frequently detected DNA of Epstein-Barr virus and cytomegalovirus but not JC virus in cerebrospinal fluid samples from 140 human immunodeficiency virus-infected patients with central nervous system symptoms in northern Thailand. Despite the low incidence of primary central nervous system lymphoma or cytomegalovirus encephalitis among Thai AIDS patients, Epstein-Barr virus and cytomegalovirus infections in the central nervous system are common.

Molecular methods for diagnosis of viral encephalitis

Hundreds of viruses cause central nervous system (CNS) disease, including meningoencephalitis and postinfectious encephalomyelitis, in humans. The cerebrospinal fluid (CSF) is abnormal in >90% of cases; however, routine CSF studies only rarely lead to identification of a specific etiologic agent. Diagnosis of viral infections of the CNS has been revolutionized by the advent of new molecular diagnostic technologies to amplify viral nucleic acid from CSF, including PCR, nucleic acid sequence-based amplification, and branched-DNA assay. PCR is ideally suited for identifying fastidious organisms that may be difficult or impossible to culture and has been widely applied for detection of both DNA and RNA viruses in CSF. The technique can be performed rapidly and inexpensively and has become an integral component of diagnostic medical practice in the United States and other developed countries. In addition to its use for identification of etiologic agents of CNS disease in the clinical setting, PCR has also been used to quantitate viral load and monitor duration and adequacy of antiviral drug therapy. PCR has also been applied in the research setting to help discriminate active versus postinfectious immune-mediate disease, identify determinants of drug resistance, and investigate the etiology of neurologic disease of uncertain cause. This review discusses general principles of PCR and reverse transcription-PCR, including qualitative, quantitative, and multiplex techniques, with comment on issues of sensitivity, specificity, and positive and negative predictive values. The application of molecular diagnostic methods for diagnosis of specific infectious entities is reviewed in detail, including viruses for which PCR is of proven efficacy and is widely available, viruses for which PCR is less widely available or for which PCR has unproven sensitivity and specificity, and nonviral entities which can mimic viral CNS disease.

Predictive Value of Polymerase Chain Reaction of Cerebrospinal Fluid for Detection of Epstein-Barr Virus to Establish the Diagnosis of HIV-Related Primary Central Nervous System Lymphoma

Polymerase chain reaction (PCR) of cerebrospinal fluid (CSF) for detection of Epstein-Barr virus (EBV) DNA has been proposed as a minimally invasive method for establishing the diagnosis of human immunodeficiency virus-related primary central nervous system lymphoma (PCNSL). In a review of the operational characteristics of this test in our clinical practice, the positive predictive value of CSF PCR for EBV for establishing the diagnosis of PCNSL was only 29%. Of 7 patients with CSF PCR positive for EBV, 2 had PCNSL, and 5 received alternative diagnoses (specificity, 79.1%).

Development of a rapid polymerase chain reaction-ELISA assay using polystyrene beads for the detection of Toxoplasma gondii DNA

AIMS

To develop a rapid colourimetric assay for the detection of Toxoplasma gondii DNA using polystyrene beads as solid support.

METHODS AND RESULTS

A nested-polymerase chain reaction (PCR)-ELISA assay for the detection of T. gondii DNA was standardized by optimizing the hybridization time and probe concentration. Its detection threshold was then determined and compared with Southern blotting hybridization. These were found to be equivalent, but the PCR-ELISA-beads test is easier to perform and the turnaround time is much shorter than with Southern blot.

CONCLUSIONS

The PCR-ELISA-beads assay is a valuable tool for the detection of T. gondii DNA.

SIGNIFICANCE AND THE IMPACT OF THE STUDY

Our results demonstrate that this PCR-ELISA assay, using polystyrene beads, can be used as a routine diagnostic test for the detection of T. gondii in clinical laboratories.

Molecular diagnosis of toxoplasmosis

Toxoplasmosis is an anthropozoonotic disease endemic world-wide, caused by the apicomplexan Toxoplasma gondii. Although the course of infection is generally benign, it can cause significant morbidity and mortality in the developing fetus and in immunocompromised individuals. Biological diagnosis classically relies upon serology and direct detection of the parasite by inoculation to laboratory animals. In the past decade, the use of the polymerase chain reaction (PCR) has made a significant improvement in both the prenatal diagnosis of congenital toxoplasmosis and the detection of acute disease in the immunocompromised patient. Nevertheless, like many 'in-house' PCR assays, the PCR-Toxoplasma suffers from lack of standardization and variable performance according to the laboratory. A wide variety of primers has been used in different assays, but few comparative tests have been performed. Moreover, in contrast to other parasitic diseases, PCR-Toxoplasma has not yet attained a sufficient level of sensitivity, regardless of the clinical condition considered. These drawbacks are discussed, together with the undoubted gain that PCR has brought to this difficult diagnosis.

[Detection by nested-PCR of Toxoplasma gondii in patients infected with human immunodeficiency virus]

BACKGROUND

Our purpose was to evaluate the effectiveness of the nested polymerase chain reaction (nested-PCR) for the laboratory diagnosis of active toxoplasmosis in patients infected with human immunodeficiency virus (HIV).

PATIENTS AND METHOD

The study was carried out in 157 HIV-infected patients. We determined IgG, IgM and IgA antibodies against Toxoplasma gondii as well as parasite DNA by nested-PCR in blood samples.

RESULTS

IgG antibodies were detected in 56 patients, IgM in 1 and IgA in 5 patients. Eleven patients were found to have DNA of the parasite.

CONCLUSIONS

The polymerase chain reaction is a rapid, sensitive and effective technique in the early diagnosis of toxoplasmosis in HIV-infected patients. Its positivity may also point to the beginning of treatment in asymptomatic individuals.

Detection of Toxoplasma gondii DNA in primary intraocular B-cell lymphoma

Primary intraocular lymphoma, a variant of primary central nervous system lymphoma with ocular involvement, is a large B-cell non-Hodgkin's lymphoma. Some cases of primary intraocular lymphoma have been reported to be associated with microorganisms including Epstein-Barr virus (EBV) and human herpes virus-8 (HHV-8), but not parasites. We analyzed 10 cases of primary intraocular lymphoma using microdissection and PCR. Tumor and normal cells were microdissected from ocular tissue on slides and subjected to PCR for genes from Toxoplasma gondii, EBV, and HHV-8. We detected Toxoplasma gondii, not HHV-8 or EBV, DNA in the lymphoma but not in normal cells of two cases that resembled ocular toxoplasmosis clinically. We speculate that Toxoplasma gondii may play a role in some forms of primary intraocular B-cell lymphoma.

Toxoplasmosis, a severe complication in allogeneic hematopoietic stem cell transplantation: successful treatment strategies during a 5-year single-center experience

Toxoplasmosis is a rare but often fatal complication that occurs after patients undergo allogeneic hematopoietic stem cell transplant. At our institution, toxoplasmosis was diagnosed in 8 of 301 patients who received stem cell transplants. Disseminated toxoplasmosis with a rapid fatal course was observed in 2 patients. Six patients had cerebral toxoplasmosis diagnosed on the basis of neurological signs and observation of the patients' mental confusion, seizures, and typical lesions (which were assessed by computed tomography, magnetic resonance imaging, or both). Seroconversion of antitoxoplasma immunoglobulin and a discovery of toxoplasma deoxyribonucleic acid in the cerebrospinal fluid (confirmed by use of polymerase chain reaction) were documented in all patients. Treatment consisted of clindamycin therapy (for 2 patients) and of pyrimethamine-clindamycin therapy, sulfadiazine therapy, or both (for 5 patients). Patients showed improvement after therapy, as assessed by clinical and radiological means. Three of 8 patients survive-1 without any residual neurological symptoms and 2 with minimal neurological symptoms.

Molecular methods in the diagnosis of infections in the immunocompromised host

Despite recent developments, infection remains a major obstacle to a successful outcome in transplantation. Molecular methods have allowed for earlier diagnosis and have proven to be powerful tools for analysing the epidemiology of infectious diseases. More recently, some of these molecular methods have been commercialized, enabling standardized diagnostic techniques to be used in multicentre trials.

Progressive Multifocal Leukoencephalopathy

Before embarking on experimental therapies for progressive multifocal leukoencephalopathy (PML), the diagnosis needs to be unequivocally established. Improving the underlying immunodeficiency state is the best initial approach to the management of PML. Immunosuppressive therapies should be discontinued when feasible. In the patient with AIDS, highly active antiretroviral therapy should be administered; this appears to prolong survival. At present, no therapy has been demonstrated to be effective in a well-designed prospective trial. Cytosine arabinoside, which has demonstrated efficacy in vitro against JC virus, has not been effective when administered intravenously or intrathecally to patients with AIDS and PML. The failure of regimens employing cytosine arabinoside in PML may have been the consequence of inadequate penetration of the drug to sites of infection in the brain. Other drugs with established in vitro activity against JC virus, such as topoisomerase and camptothecin, are poorly tolerated. The use of cidofovir in patients with AIDS and PML remains anecdotal, although it is currently under investigation. Interferon alfa may improve survival in patients with AIDS and PML and may have general applicability to PML regardless of the cause of the underlying immunodeficient state. Approximately 7% to 9% of patients with PML demonstrate prolonged survival (>12 months) and associated improvement in clinical and radiographic abnormalities in the absence of specific therapy. In patients with AIDS-related PML, prolonged survival correlates with PML as the presenting manifestation of AIDS, higher CD4 T-lymphocyte counts, and contrast enhancement of PML lesions on radiographic imaging. A brisk inflammatory response may also be associated with improved survival. The increased understanding of the pathophysiology of JC virus provides hope for the development of curative strategies. The growing number of persons affected with PML has allowed the organization of carefully designed therapeutic trials to address this issue.