Dataset Information

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles.

ABSTRACT:

Background

Diagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) for Toxoplasma in blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment.

Methology/principle findings

Here we describe proof of concept for a novel urine diagnostics for TE using Poly-N-Isopropylacrylamide 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. Limit of detection was 7.8pg/ml and 31.3pg/ml of T. gondii antigens GRA1 and SAG1, 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 parallel-reaction-monitoring (PRM) for the presence of T. gondii antigens. PRM identified antigens in 8 samples, 6 of which were concordant with the urine diagnostic.

Conclusion/significances

Our results demonstrate nanoparticle technology's potential for a noninvasive diagnostic test for TE. Moving forward, GRA1 is a promising target for antigen based diagnostics for TE.

SUBMITTER: Steinberg HE

PROVIDER: S-EPMC7954332 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Publications

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles.

Steinberg Hannah E HE Bowman Natalie M NM Diestra Andrea A Ferradas Cusi C Russo Paul P Clark Daniel E DE Zhu Deanna D Magni Ruben R Malaga Edith E Diaz Monica M Pinedo-Cancino Viviana V Ramal Asayag Cesar C Calderón Maritza M Carruthers Vern B VB Liotta Lance A LA Gilman Robert H RH Luchini Alessandra A

PLoS neglected tropical diseases 20210302 3

<h4>Background</h4>Diagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) for Toxoplasma in blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment.<h4>Methology/principle findings</h4>Here we describe proof of concept for a novel urine diagnostics fo ...[more]

PMID: 33651824

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Project description:Reactivation of a latent infection by the protozoan parasite Toxoplasma gondii can result in severe neurologic outcomes and even death. T. gondii reactivation cases have been strongly associated with acquired immunodeficiency syndrome, but other immunosuppressive situations are also associated. Anti-TNF-α therapy reliably triggers the reactivation of T. gondii latent cysts in mice models. Reactivation of T. gondii by TNF-a blockade is rare in humans though despite widespread use of TNF-a blockers. Serologic evidence of a possible latent T. gondii infection in humans is common worldwide, so why anti-TNF-α reactivation isn't more common is unknown. Here we present a 74-year-old woman who developed fatal cerebral toxoplasmosis after anti-tumor necrosis factor-α (TNF-α). After presenting to a local urgent care with confusion, a worsening cognitive status led to an emergency room visit. Computed tomography resulted in suspicion of metastatic disease leading to treatment with steroids. Lumbar puncture ruled out bacterial or viral meningitis. With continued cognitive decline, magnetic resonance imaging of the head revealed an increased number of lesions with T. gondii-associated ring-enhancing lesions. A brain biopsy confirmed the presence of T. gondii parasites. Despite standard treatment for toxoplasmosis, the patient expired. At least two possible factors may have contributed to this unfortunate outcome. First, in addition to her rheumatoid arthritis pathology, there is evidence of loss of immune resilience and abnormal T cell subsets. Second, some strains of T. gondii are more virulent than others. Post-mortem mass spectrometry and proteomic analysis of her cerebrospinal fluid show several T. gondii peptides. A literature review suggests that risks associated with anti-TNF-α therapy for patients who are seropositive for T. gondii have not been adequately recognized. We advise T. gondii seropositivity testing be considered before and after initiation of anti-TNF-α therapy as is done for other infections such as tuberculosis.

Project description:Toxoplasma gondii is a ubiquitous intracellular protozoan parasite that establishes a life-long chronic infection largely restricted to the central nervous system (CNS). Constant immune pressure, notably IFN-γ-STAT1 signaling, is required for preventing fatal pathology during T. gondii infection. Here, we report that abrogation of STAT1 signaling in microglia, the resident immune cells of the CNS, is sufficient to induce a loss of parasite control in the CNS and susceptibility to toxoplasmic encephalitis during the early stages of chronic infection. Using a microglia-specific genetic labeling and targeting system that discriminates microglia from blood-derived myeloid cells that infiltrate the brain during infection, we find that, contrary to previous in vitro reports, microglia do not express inducible nitric-oxide synthase (iNOS) during T. gondii infection in vivo. Instead, transcriptomic analyses of microglia reveal that STAT1 regulates both (i) a transcriptional shift from homeostatic to "disease-associated microglia" (DAM) phenotype conserved across several neuroinflammatory models, including T. gondii infection, and (ii) the expression of anti-parasitic cytosolic molecules that are required for eliminating T. gondii in a cell-intrinsic manner. Further, genetic deletion of Stat1 from microglia during T. gondii challenge leads to fatal pathology despite largely equivalent or enhanced immune effector functions displayed by brain-infiltrating immune populations. Finally, we show that microglial STAT1-deficiency results in the overrepresentation of the highly replicative, lytic tachyzoite form of T. gondii, relative to its quiescent, semi-dormant bradyzoite form typical of chronic CNS infection. Our data suggest an overall protective role of CNS-resident microglia against T. gondii infection, illuminating (i) general mechanisms of CNS-specific immunity to infection (ii) and a clear role for IFN-STAT1 signaling in regulating a microglial activation phenotype observed across diverse neuroinflammatory disease states.

Dataset Information

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles.

Background

Methology/principle findings

Conclusion/significances

Publications

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles.

Similar Datasets

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