Point-of-care testing for <i>Toxoplasma gondii</i> IgG/IgM using <i>Toxoplasma</i> ICT IgG-IgM test with sera from the United States and implications for developing countries

Background: Congenital toxoplasmosis is a serious but preventable and treatable disease. Gestational screening facilitates early detection and treatment of primary acquisition. Thus, fetal infection can be promptly diagnosed and treated and outcomes can be improved. Methods: We tested 180 sera with the Toxoplasma ICT IgG-IgM point-of-care (POC) test. Sera were from 116 chronically infected persons (48 serotype II; 14 serotype I-III; 25 serotype I-IIIa; 28 serotype Atypical, haplogroup 12; 1 not typed). These represent strains of parasites infecting mothers of congenitally infected children in the U.S. 51 seronegative samples and 13 samples from recently infected persons known to be IgG/IgM positive within the prior 2.7 months also were tested. Interpretation was confirmed by two blinded observers. A comparison of costs for POC vs. commercial laboratory testing methods was performed. Results: We found that this new Toxoplasma ICT IgG-IgM POC test was highly sensitive (100%) and specific (100%) for distinguishing IgG/IgM-positive from negative sera. Use of such reliable POC tests can be cost-saving and benefit patients. Conclusions: Our work demonstrates that the Toxoplasma ICT IgG-IgM test can function reliably as a point-of-care test to diagnose Toxoplasma gondii infection in the U.S. This provides an opportunity to improve maternal-fetal care by using approaches, diagnostic tools, and medicines already available. This infection has serious, lifelong consequences for infected persons and their families. From the present study, it appears a simple, low-cost POC test is now available to help prevent morbidity/disability, decrease cost, and make gestational screening feasible. It also offers new options for improved prenatal care in low- and middle-income countries.</p

Point-of-Care Testing for Toxoplasma Gondii IgG/IgM Using Toxoplasma ICT IgG-IgM Test with Sera from the United States and Implications for Developing Countries

Background Congenital toxoplasmosis is a serious but preventable and treatable disease. Gestational screening facilitates early detection and treatment of primary acquisition. Thus, fetal infection can be promptly diagnosed and treated and outcomes can be improved. Methods We tested 180 sera with the Toxoplasma ICT IgG-IgM point-of-care (POC) test. Sera were from 116 chronically infected persons (48 serotype II; 14 serotype I-III; 25 serotype I-IIIa; 28 serotype Atypical, haplogroup 12; 1 not typed). These represent strains of parasites infecting mothers of congenitally infected children in the U.S. 51 seronegative samples and 13 samples from recently infected persons known to be IgG/IgM positive within the prior 2.7 months also were tested. Interpretation was confirmed by two blinded observers. A comparison of costs for POC vs. commercial laboratory testing methods was performed. Results We found that this new Toxoplasma ICT IgG-IgM POC test was highly sensitive (100%) and specific (100%) for distinguishing IgG/IgM-positive from negative sera. Use of such reliable POC tests can be cost-saving and benefit patients. Conclusions Our work demonstrates that the Toxoplasma ICT IgG-IgM test can function reliably as a point-of-care test to diagnose Toxoplasma gondii infection in the U.S. This provides an opportunity to improve maternal-fetal care by using approaches, diagnostic tools, and medicines already available. This infection has serious, lifelong consequences for infected persons and their families. From the present study, it appears a simple, low-cost POC test is now available to help prevent morbidity/disability, decrease cost, and make gestational screening feasible. It also offers new options for improved prenatal care in low- and middle-income countries

Publisher Correction: Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper

Auditory brain-stem responses in hydrocephalic patients

Auditory brain-stem response (ABR) was measured in 40 patients (80 ears) with confirmed hydrocephalus. Eighty-eight percent of these patients showed some form of ABR abnormality. Responses indicative of brain-stem dysfunction consisted of prolonged I–V interwave latency (38%), reduced V/I amplitude ratio (33%), and abnormalities in wave-shape of components III (27%) and V (53%). In addition, 70% of the patients had elevated ABR thresholds; 45% had responses in excess of 20 dB HL and the remaining 25% had no ABR activity. The etiology of the hydrocephalus, head circumference and brain-stem symptoms were not associated with particular ABR abnormalities. Communicating hydrocephalus correlated significantly with both prolonged I–V conduction time and absence of ABR activity, compared with non-communicating hydrocephalus. Four of the 9 patients retested showed ABR improvement on follow-up; one patient showed deterioration. The results were compared to our prior studies of ABR in 60 post-meningitic patients and in 100 severely neurologically impaired institutionalized children in whom the incidence of intrinsic brain-stem abnormalities was one-third and two-thirds that of the hydrocephalic group, respectively. The results of this study suggest that ABR can be used to document clinically unsuspected brain-stem pathology that may accompany hydrocephalus. Auditory brain-stem dysfunction is likely to complicate the assessment of hearing sensitivity in hydrocephalic patients. La réponse auditive du tronc cérébral (RATC) a été enregistrée chez 40 patients (80 oreilles) hydrocéphales confirmés. Quatre-vingt-huit pourcent de ces patients ont présenté des anomalies de ces réponses. Celles-ci, indiquant un dysfunctionement du tronc cérébral présentaient: une augmenatation de la latence interondes I–V (38%), une diminution du rapport des amplitudes V/I (33%), des anomalies de la forme d'onde des composantes III (27%) et V (53%). De plus, 70% des patients ont présenté un seuil élevé pour ces réponses; 45% avaient des réponses à des valeurs supérieures de 20 dB HL et les autres 25% n'avaient pas d'activité RATC. L'étiologie de l'hydrocéphalie, le périmétre crânien, et les symptm̂es du tronc cérébral n'étaient pas associés à des anomalies particuliéres de la RATC. L'hydrocéphalie communicate était corrélée de façon significative avec à la fois l'augmentation sence d'activité RATC, contrairement à l'hydrocéphalie non communicante. Quatres des 9 patients testés à nouveau ont présenté une amélioration subséquente de leur RATC; un patient en revanche a présenté une détérioration. Les résultats ont été comparés avec nos études précédentes sur la RATC chez 60 patients ayant été atteints d'une méningite et chez 100 enfants sévèrement atteints neurologiquement et hospitalisés, chez lesquels l'indicidence des anomalies intrinséques du tronc cérébral étaient respectivement de 1 3 et 2 3 de celle du groupe des hydrocéphales. Les résultats de cette étude suggérent que la RATC peut être utilisée pour déceler cliniquement une pathologie du tronc cérébral non suspectée qui peut accompagner l'hydrocéphalie. Le dysfonctionnement des structures auditives du tronc cérébral pourrait compliquer l'évaluation de la sensibilité auditive chez les patients hydrocépahales

Toxoplasma modulates signature pathways of human epilepsy, neurodegeneration & cancer

One third of humans are infected lifelong with the brain-dwelling, protozoan parasite, Toxoplasma gondii. Approximately fifteen million of these have congenital toxoplasmosis. Although neurobehavioral disease is associated with seropositivity, causality is unproven. To better understand what this parasite does to human brains, we performed a comprehensive systems analysis of the infected brain: We identified susceptibility genes for congenital toxoplasmosis in our cohort of infected humans and found these genes are expressed in human brain. Transcriptomic and quantitative proteomic analyses of infected human, primary, neuronal stem and monocytic cells revealed effects on neurodevelopment and plasticity in neural, immune, and endocrine networks. These findings were supported by identification of protein and miRNA biomarkers in sera of ill children reflecting brain damage and T. gondii infection. These data were deconvoluted using three systems biology approaches: "Orbital-deconvolution" elucidated upstream, regulatory pathways interconnecting human susceptibility genes, biomarkers, proteomes, and transcriptomes. "Cluster-deconvolution" revealed visual protein-protein interaction clusters involved in processes affecting brain functions and circuitry, including lipid metabolism, leukocyte migration and olfaction. Finally, "disease-deconvolution" identified associations between the parasite-brain interactions and epilepsy, movement disorders, Alzheimer's disease, and cancer. This "reconstruction-deconvolution" logic provides templates of progenitor cells' potentiating effects, and components affecting human brain parasitism and diseases

ALOX12 In Human Toxoplasmosis.

International audience: ALOX12 is a gene encoding arachidonate 12-lipoxygenase (12-LOX), a member of a non-heme lipoxygenase family of dioxygenases. ALOX12 catalyzes the addition of oxygen onto arachidonic acid producing 12-hydroperoxyeicosatetraenoic acid, 12-HPETE, which can be reduced to eicosanoid, 12-HETE. 12-HETE acts in diverse cellular processes including catecholamine synthesis, vasoconstriction, neuronal function and inflammation. Consistent with effects on these fundamental mechanisms, allelic variants of ALOX12 are associated with diseases including schizophrenia, atherosclerosis and cancers without definition of mechanisms. Toxoplasma gondii is an apicomplexan parasite that causes morbidity and mortality and stimulates an innate and adaptive immune inflammatory reaction. Recently, it has been shown that a gene region known as Toxo1 is critical for susceptibility or resistance to T. gondii infection in rats. An orthologous gene region with ALOX12 centromeric is also present in humans. Herein, we report that the human ALOX12 gene has susceptibility alleles for human congenital toxoplasmosis (rs6502997 [P<0.000309], rs312462 [P<0.028499], rs6502998 [P<0.029794], rs434473 [P<0.038516]). A human monocytic cell line was genetically engineered using lentivirus RNA interference to knockdown ALOX12. In ALOX12 knockdown cells, ALOX12 RNA expression decreased and ALOX12 substrate, arachidonic acid, increased. ALOX12 knockdown attenuated progression of T. gondii infection and resulted in greater parasite burden, but decreased consequent late cell death of the human monocytic cell line. These findings suggest that, ALOX12 influences host responses to T. gondii infection in human cells. ALOX12 has been shown in other studies to be important in numerous diseases. Herein, we now demonstrate the critical role ALOX12 plays in T. gondii infection in humans

Distribution of hand function by age in individuals with Rett syndrome

Abstract: Objective: We aimed to determine the longitudinal distribution of hand function skills in individuals with classic Rett syndrome (RTT), an X‐linked dominant neurodevelopmental disorder, and correlate with MECP2 variants. Method: We conducted a longitudinal study of 946 girls and young women with typical RTT seen between 2006 and 2021 in the US Natural History Study (NHS) featuring a structured clinical evaluation to assess the level of hand function skills. The specific focus of&nbsp;this study was to assess longitudinal variation of hand skills from age 2 through age 18 years in relation to specific MECP2 variant groups. Results: Following the initial regression period, hand function continues to decline across the age spectrum in individuals with RTT. Specific differences are noted with steeper declines in hand function among those with milder variants (Group A: R133C, R294X, R306C, and C‐terminal truncations) compared with groups composed of individuals with more severe variants. Conclusions: These temporal variations in hand use represent specific considerations that&nbsp;could influence the design of clinical trials that test therapies aiming to ameliorate specific functional limitations in individuals with RTT. Furthermore, the distinct impact of specific MECP2 variants on clinical severity, especially related to hand use, should be considered in such interventional trials

Implementation of <i>Toxoplasma</i> ICT IgG-IgM POC testing with separation of serum at point of care and representative <i>Toxoplasma</i> ICT IgG-IgM test negative and positive test results for sera.

<p>This involves a lancet to obtain the sample with fingerprick ($0.13 for the lancet and a very low cost for alcohol wipes), a small centrifuge tube to separate the serum, a small Class II biosafety cabinet ($6546) for safe handling of samples, and a small centrifuge for separating serum (228), from which serum can be removed easily and be tested. The following methodology is described in Chapey [17]: Briefly: the Toxoplasma ICT IgG-IgM assay is based on a lateral flow chromatographic immunoassay (LFCI) technology that allows the simultaneous detection of T. gondii IgG or IgM antibodies in human serum/plasma [17]. A minimum sample volume of 30–50 μL of serum/plasma is required [17]. Each cassette contains: a) a nitrocellulose strip on which there are two reactive bands, one with the Toxoplasma gondii antigen (from whole cell lysate) called the “test” band (T band) and one with the rabbit gamma globulins called the “control” band (C band); b) a fiberglass support (conjugate pad) which is impregnated with red latex particles coupled with Toxoplasma antigens (“test” latex = T latex) and blue latex particles coupled with goat anti-rabbit IgG (“control” latex = C latex) [17]. The test is run by dispensing the serum/plasma and an eluting solution (eluent) in the “sample well” of the cassette [17]. With the addition of the eluent, starts the concomitant migration (chromatography) of the serum/plasma and the latex particles [17]. If anti-Toxoplasma antibodies (IgG or IgM or both) are present in the sample, a complex is formed between the T latex and the patient’s antibodies, which is then captured by the T band, and it results in the appearance of a red line (positive test) [17]. The direct capture of the C latex by the C band results in the appearance of a control blue line which indicates that the chromatography performed well [17]. The results are read 20–30 minutes after the eluent solution has been dispensed into the well [17]. Representative example of U.S. sera, negative (left) and positive (right) results. This is the new simple POC test, based on lateral-flow-chromatographic-immunoassay method, already commercially available in France, that detects simultaneously both Toxoplasma IgG and IgM antibodies and costs only 4 (the cost we were charged) per test, as opposed to a $650 cost for testing at a commercial laboratory in the U.S.</p