Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us

THERMO FISHER SCIENTIFIC

Thermo Fisher Scientific provides analytical instruments, lab equipment, specialty diagnostics, reagents and integrat... read more Featured Products: More products

Download Mobile App




Toxoplasmic Encephalitis in HIV Patients Detected in Urine

By LabMedica International staff writers
Posted on 25 Mar 2021
Toxoplasma encephalitis (TE) is the most commonly reported neurological opportunistic infection in human immunodeficiency virus (HIV)-infected patients since the introduction of combination ART (cART). More...
Diagnosis of TE is challenging under the best clinical circumstances.

The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) for Toxoplasma gondii in blood and cerebrospinal fluid (CSF) and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment.

An international team of scientists led by the University of Illinois Chicago (Chicago, IL, USA) recruited in a study 164 HIV positive patients from Peru and Bolivia and 51 ambulatory HIV/T. gondii positive patients for controls. Blood and urine specimens were taken at enrollment, which for most hospitalized patients was shortly after admission; remnant CSF was collected if the subject underwent lumbar puncture as part of their medical care. CD4 and CD8 cell counts and viral loads were abstracted from participants’ charts.

The investigators have described a proof of concept for novel urine diagnostics for TE using Poly-N-isoproplyacrylamide nanoparticles dyed with Reactive Blue-221 to concentrate antigens, substantially increasing the limit of detection. After nanoparticle-concentration, a standard western blotting technique with a monoclonal antibody was used for antigen detection. Toxoplasma gondii IgG serological status was determined with an in-house enzyme linked immunosorbent assay (ELISA). For qPCR, target sequences were amplified using a Light Cycler (Applied Biosciences, Foster City, CA, USA). Digested samples were analyzed by parallel-reaction-monitoring (PRM) on an Orbitrap Fusion mass spectrometer with a nanospray EASY-nLC 1200 HPLC (Thermo Fisher Scientific, Waltham, MA, USA).

The team reported that the limit of detection (LoD) of T. gondii antigens GRA1 and SAG1 was 7.8pg/mL and 31.3pg/mL, respectively. To characterize this diagnostic approach, 164 hospitalized HIV-infected patients with neurological symptoms compatible with TE were tested for 1) T. gondii serology (121/147, positive samples/total samples tested), 2) qPCR in cerebrospinal fluid (11/41), 3) qPCR in blood (10/112), and 4) urinary GRA1 (30/164) and SAG1 (12/164). GRA1 appears to be superior to SAG1 for detection of TE antigens in urine. Fifty-one HIV-infected, T. gondii seropositive but asymptomatic persons all tested negative by nanoparticle western blot and blood qPCR, suggesting the test has good specificity for TE for both GRA1 and SAG1. In a subgroup of 44 patients, urine samples were assayed with mass spectrometry PRM for the presence of T. gondii antigens. PRM identified antigens in eight samples, six of which were concordant with the urine diagnostic.

The authors concluded that their results demonstrate nanoparticle technology’s potential for a noninvasive diagnostic test for TE and that GRA1 is a promising target for antigen based diagnostics for TE. The study was published on March 2, 2021 in the journal PLOS Neglected Tropical Diseases.

Related Links:
University of Illinois Chicago
Applied Biosciences
Thermo Fisher Scientific



Gold Member
Quality Control Material
iPLEX Pro Exome QC Panel
Collection and Transport System
PurSafe Plus®
New
Automated Chemiluminescence Immunoassay Analyzer
MS-i3080
New
Gold Member
Cardiovascular Risk Test
Metabolic Syndrome Array I & II
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Molecular Diagnostics

view channel
Image: Colorectal cancer under the microscope (Photo courtesy of Adobe Stock)

Unique Microbial Fingerprint to Improve Diagnosis of Colorectal Cancer

Colorectal cancer is the fourth most common cancer in the UK and the second deadliest. New research has revealed that it carries a unique microbial fingerprint, which could help doctors better understand... Read more

Hematology

view channel
Image: New research points to protecting blood during radiation therapy (Photo courtesy of 123RF)

Pioneering Model Measures Radiation Exposure in Blood for Precise Cancer Treatments

Scientists have long focused on protecting organs near tumors during radiotherapy, but blood — a vital, circulating tissue — has largely been excluded from dose calculations. Each blood cell passing through... Read more

Immunology

view channel
Image: The VENTANA HER2 (4B5) test is now CE-IVDR approved (Photo courtesy of Roche)

Companion Diagnostic Test Identifies HER2-Ultralow Breast Cancer and Biliary Tract Cancer Patients

Breast cancer is the most common cancer in Europe, with more than 564,000 new cases and 145,000 deaths annually. Metastatic breast cancer is rising in younger populations and remains the leading cause... Read more

Technology

view channel
Image: Conceptual design of the CORAL capsule for microbial sampling in the small intestine (H. Mohammed et al., Device (2025). DOI: 10.1016/j.device.2025.100904)

Coral-Inspired Capsule Samples Hidden Bacteria from Small Intestine

The gut microbiome has been linked to conditions ranging from immune disorders to mental health, yet conventional stool tests often fail to capture bacterial populations in the small intestine.... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.