Immune profiling of pregnant Toxoplasma-infected US and Colombia patients reveals surprising impacts of infection on peripheral blood cytokines

Beyond schistosomiasis: unraveling co-infections and altered immunity

Schistosomiasis is a neglected tropical disease caused by the helminth Schistosoma spp. and has the second highest global impact of all parasites. Schistosoma are transmitted through contact with contaminated fresh water predominantly in Africa, Asia, the Middle East, and South America. Due to the widespread prevalence of Schistosoma, co-infection with other infectious agents is common but often poorly described. Herein, we review recent literature describing the impact of Schistosoma co-infection between species and Schistosoma co-infection with blood-borne protozoa, soil-transmitted helminths, various intestinal protozoa, Mycobacterium, Salmonella, various urinary tract infection-causing agents, and viral pathogens. In each case, disease severity and, of particular interest, the immune landscape, are altered as a consequence of co-infection. Understanding the impact of schistosomiasis co-infections will be important when considering treatment strategies and vaccine development moving forward.

Sleeping monsters: chronic infections in COVID-19 pathogenesis

We each harbor several chronic infections that can reactivate in response to various stressors and cause serious disease. In this forum article, we consider the reactivation of chronic microbial infections in the context of COVID-19.

Tryptophan metabolism and immune alterations in pregnant Hispanic women with chronic Toxoplasma gondii infection

PROBLEM

Pregnancy markedly modifies women's metabolism and immune functions. We hypothesized that pregnancy might alter the immune and metabolic responses to chronic Toxoplasma gondii infection in pregnancy.

METHOD OF STUDY

A population of 690 pregnant Hispanic women were screened for antibodies to T. gondii and 158 women were positive (23% positivity) with 83% showing high avidity indices. These seropositive women were followed through their pregnancies with four data collection time points and a postpartum collection at two clinics in Tampa, Florida. A T. gondii seronegative group (N = 128) was randomly selected to serve as a control group and measured along pregnancy in the same way. Serum levels of tryptophan, kynurenine, and their ratio, phenylalanine, tyrosine and their ratio, neopterin, and nitrite were measured through pregnancy and the postpartum. A plasma cytokine panel (IFN-γ, TNFα, IL-2, IL-10, IL-12, IL-6, IL-17) was analyzed in parallel.

RESULTS

The major findings suggest that indoleamine 2,3-dioxygenase (IDO-1) was less activated in T. gondii seropositive pregnant Hispanic women with chronic infection. Evidence for IDO-1 suppression was that tryptophan catabolism was less pronounced and there were lower levels of multiple inflammatory cytokines including IFN-γ, which is the major inducer of IDO-1, and higher nitrite concentration, a surrogate marker for nitric oxide, an inhibitor of IDO.

CONCLUSIONS

Latent T. gondii infection was associated with higher plasma tryptophan levels, and lower inflammatory cytokines across pregnancy, suggesting suppression of the IDO-1 enzyme, and possible T cell exhaustion during pregnancy.

Adverse pregnancy outcomes in Toxoplasma gondii seropositive Hispanic women

AIMS

Chronic Toxoplasma gondii infection is not thought to affect pregnancy or birth outcomes, but there are few prospective studies. The study aims were T. gondii immunoglobulin G measurement and relationship of chronic T. gondii infection with gestational age at birth and adverse pregnancy outcomes in 690 Hispanic women in Tampa, Florida.

METHODS

Hispanic women, born either in the United States or in Latin America or the Caribbean had a venous blood sample drawn to measure T. gondii IgG and T. gondii serotype at the first prenatal visit, along with collection of demographic and health-related measures. Seropositive and seronegative women were followed throughout their pregnancy. Gestational age, infant weights, and adverse pregnancy outcomes (miscarriages, preterm births) were compared in the two groups.

RESULTS

There were 740 women of self-reported Hispanic ethnicity screened and enrolled in Tampa, Florida, with 690 having birth data extracted from the electronic health record (538 T. gondii negative and 152 T. gondii seropositive). T. gondii seropositivity was 22.4% and the majority (83%) had high avidity titers, indicating chronic infection. Compared to T. gondii seronegative Hispanic women, seroseropositive women had more smaller for gestational age infants and higher prevalences of miscarriages and preterm birth.

CONCLUSION

This is one of the largest longitudinal cohort studies of women with chronic T. gondii infection followed through pregnancy. There was a higher percentages of adverse pregnancy outcomes in this group compared to T. gondii seronegative controls. The mechanism for this is unknown and warrants reexamination of the dogma that chronic T. gondii infection in pregnant women has no significant clinical consequences.

The imbalance in the relationship between inflammatory and regulatory cytokines during gestational toxoplasmosis can be harmful to fetuses: A systematic review

Objective

To evaluate the available information on inflammatory and regulatory plasma mediators in pregnant women (PW) diagnosed with toxoplasmosis. Source: The PubMed, Embase, Scopus, and Lilacs databases were evaluated until October 2022. Study eligibility criteria: This review was carried out following the PRISMA and registered on the PROSPERO platform (CRD42020203951). Studies that reported inflammatory mediators in PW with toxoplasmosis were considered.

Evaluation methods

After excluding duplicate articles, two authors independently carried out the process of title and abstract exclusion, and a third resolved disagreements when necessary. The full text was evaluated to detect related articles. The extraction table was built from the following data: Author, year of publication, journal name and impact factors, country, study design, number of gestations and maternal age (years), gestational period, diagnosis of toxoplasmosis, levels of inflammatory markers, laboratory tests, and clinical significance. Methodological quality was assessed using Joanna Briggs Institute tools.

Results

Of the 1,024 studies reported, only eight were included. Of the 868 PW included in this review, 20.2% were IgM+/IgG- and 50.8% were IgM-/IgG+ to T. gondii, and 29.0% uninfected. Infected PW presented higher plasma levels ofIL-5, IL-6, IL-8, IL-17, CCL5, and IL-10. Regarding the methodological quality, four studies obtained high quality. Data from this review pointed out the maintenance of the inflammatory pattern during pregnancy with a closely related to the parasite.

Conclusion

Immune status in PW defined the course of the T. gondii infection, where the equilibrium between inflammatory and regulatory cytokines mitigated the harmful placenta and fetus effects.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD420203951.

The Impact of Latent Toxoplasma gondii Infection on Spontaneous Abortion History and Pregnancy Outcomes: A Large-Scale Study

BACKGROUND

Toxoplasma gondii (TG), a zoonotic protozoan parasite, belongs to a group of TORCH infectious agents, which can cause severe damage to the fetus if a primary infection occurs during pregnancy. After primary infection, TG rests lifelong in human organisms causing a latent infection. Most studies have analyzed the consequences of acute, but not latent, TG infection. This study analyzed the impact of latent toxoplasmosis on spontaneous abortion history, pregnancy complication rate and neonatal outcome.

METHODS

IgG and IgM anti-TG antibodies were tested in 806 pregnant women who were consulted at the Timisoara Clinical Emergency Hospital between 2008 and 2010. Demographic data, obstetrical history, and data about the pregnancy complications, birth and neonate were collected for each woman and comparisons between the groups, with and without latent TG infection, were made.

RESULTS

This study did not show differences between groups regarding the history of spontaneous abortion (OR = 1.288, p = 0.333), cesarean section (OR = 1.021, p = 0.884), placental abruption (OR 0.995, p = 0.266), pregnancy-induced hypertension rate (OR 1.083, p = 0.846), secondary sex ratio (1.043, p = 0.776), 1' APGAR score at birth (p = 0.544), gestational age at birth (p = 0.491) or birth weight (p = 0.257).

CONCLUSIONS

The observed differences between the rate of pregnancy complications in the two groups of pregnant women with and without latent infection with TG, did not reach a statistical significance.

Dynamic immune profile in French toxoplasmosis patients

BACKGROUND

Toxoplasma gondii infection is usually benign in Europe due to the strong predominance of type II strains. Few studies have been conducted to examine the immunological course of infection in humans and have yielded conflicting results, maybe influenced by heterogeneous parasite strains.

METHODS

We measured 23 immune mediators in 39, 40, and 29 sera of French non-infected, acutely infected, and chronically infected immunocompetent pregnant women, respectively.

RESULTS

Four different cytokine patterns were identified regarding their dynamics through infection phases. For eleven of the cytokines, IFN-β, IFN-γ, IL-4, IL5, IL-6, IL-10, IL-12, IL-15, CXCL9, CCL2 and CSF2, the serum levels were significantly elevated during acute infection. The inflammatory mediators IL-1β, IL-17A, IL-18, TNF-α and CSF3 remained unchanged during acute infection, while they were significantly lower in chronically infected compared to non-infected patients. As for the anti-inflammatory cytokines TGF-β and CCL5, their levels remained significantly elevated during chronic infection. We also observed a significant negative correlation of several cytokine concentrations with IgG levels, indicating a rapid decline of serum concentrations during the acute phase.

DISCUSSION

These results indicate an anti-inflammatory pattern in chronically infected patients in a type II dominated setting and demonstrate the highly dynamic immune situation during acute infection.

TNFα rs1799964 TT genotype may be a susceptibility factor for vertical transmission of Toxoplasma gondii and clinical signs in newborns from pregnant women with acute toxoplasmosis

BACKGROUND

One of the main impacts of Toxoplasma gondii infection occurs during pregnancy and is related to the vertical transmission of the parasite (congenital toxoplasmosis), which can cause severe clinical outcomes and fetal death. During acute infection, in order to control the rapid replication of tachyzoites, different host immune response genes are activated, and these include cytokine-encoding genes. Considering that polymorphisms in cytokine genes may increase susceptibility to vertical transmission of T. gondii by determining the immune status of the pregnant woman, this study evaluated the influence of polymorphisms of tumor necrosis factor alpha (TNFα) rs1799964 (- 1031) and interleukin 1 beta (IL1β) rs16944 (- 511) genes on gestational toxoplasmosis and on the vertical transmission of the parasite and verified the allele and genotype frequency of these polymorphisms in pregnant patients whose respective newborn did or did not present clinical abnormalities suggestive of congenital toxoplasmosis.

METHODS AND RESULTS

A total of 204 pregnant patients with (n = 114) or without (n = 90) infection by T. gondii were enrolled. No associations were found involving the polymorphisms rs1799964 (- 1031) of the TNFα gene and rs16944 (- 511) of the IL1β gene with the increased chance of T. gondii infection during pregnancy. However, it was observed that the maternal TT genotype referring to the polymorphism of the TNFα gene seems to influence the vertical transmission of the parasite (P = 0.01; χ² = 6.05) and the presence of clinical manifestation in newborns from pregnancies with acute toxoplasmosis (P = 0.007; χ² = 9.68).

CONCLUSION

The TNFα rs1799964 TT genotype may act as a susceptibility factor for the vertical transmission of parasite and for the presence of clinical signs in newborns from pregnant women with acute toxoplasmosis.

Immune response against toxoplasmosis-some recent updates RH: Toxoplasma gondii immune response

AIMS

Cytokines, soluble mediators of immunity, are key factors of the innate and adaptive immune system. They are secreted from and interact with various types of immune cells to manipulate host body's immune cell physiology for a counter-attack on the foreign body. A study was designed to explore the mechanism of Toxoplasma gondii (T. gondii) resistance from host immune response.

METHODS AND RESULTS

The published data on aspect of host (murine and human) immune response against T. gondii was taken from Google scholar and PubMed. Most relevant literature was included in this study. The basic mechanism of immune response starts from the interactions of antigens with host immune cells to trigger the production of cytokines (pro-inflammatory and anti-inflammatory) which then act by forming a cytokinome (network of cytokine). Their secretory equilibrium is essential for endowing resistance to the host against infectious diseases, particularly toxoplasmosis. A narrow balance lying between Th1, Th2, and Th17 cytokines (as demonstrated until now) is essential for the development of resistance against T. gondii as well as for the survival of host. Excessive production of pro-inflammatory cytokines leads to tissue damage resulting in the production of anti-inflammatory cytokines which enhances the proliferation of Toxoplasma. Stress and other infectious diseases (human immunodeficiency virus (HIV)) that weaken the host immunity particularly the cellular component, make the host susceptible to toxoplasmosis especially in pregnant women.

CONCLUSION

The current review findings state that in vitro harvesting of IL12 from DCs, Np and MΦ upon exposure with T. gondii might be a source for therapeutic use in toxoplasmosis. Current review also suggests that therapeutic interventions leading to up-regulation/supplementation of SOCS-3, IL12, and IFNγ to the infected host could be a solution to sterile immunity against T. gondii infection. This would be of interest particularly in patients passing through immunosuppression owing to any reason like the ones receiving anti-cancer therapy, the ones undergoing immunosuppressive therapy for graft/transplantation, the ones suffering from immunodeficiency virus (HIV) or having AIDS. Another imortant suggestion is to launch the efforts for a vaccine based on GRA6Nt or other similar antigens of T. gondii as a probable tool to destroy tissue cysts.

Congenital Toxoplasmosis: The State of the Art

Infection with the protozoan parasite Toxoplasma gondii occurs worldwide and usually causes no symptoms. However, a primary infection of pregnant women, may infect the fetus by transplacental transmission. The risk of mother-to-child transmission depends on week of pregnancy at the time of maternal infection: it is low in the first trimester, may reach 90% in the last days of pregnancy. Inversely, however, fetal disease is more severe when infection occurs early in pregnancy than later. Systematic serologic testing in pregnant women who have no antibodies at the beginning of pregnancy, can accurately reveal active maternal infection. Therefore, the risk of fetal infection should be assessed and preventive treatment with spiramycin must be introduced as soon as possible to reduce the risk of mother-to-child transmission, and the severity of fetal infection. When maternal infection is confirmed, prenatal diagnosis with Polymerase Chain Reaction (PCR) on amniotic fluid is recommended. If fetal infection is certain, the maternal treatment is changed to a combination of pyrimethamine-sulfonamide and folinic acid. Congenitally infected newborns are usually asymptomatic at birth, but at risk for tardive sequelae, such as blindness. When congenital infection is evident, disease include retinochoroiditis, cerebral calcifications, hydrocephalus, neurocognitive impairment. The diagnosis of congenital infection must be confirmed at birth and management, specific therapy, and follow-up with multidisciplinary counseling, must be guaranteed.

Increased levels of IL-17A in serum and amniotic fluid of pregnant women with acute toxoplasmosis

This study detected and compared the levels of Il-17A, IFN-gamma and IL-10 in the amniotic fluid (AF) and serum of pregnant women with acute toxoplasmosis in southern Brazil. It also compared the serum levels of these mediators in pregnant women with acute or chronic toxoplasmosis and with uninfected women. The serological investigations of anti-T. gondii IgM and IgG from the 60 pregnant women were determined by chemiluminescence microparticle immunoassay (CMIA). Twenty patients were uninfected, twenty were in the chronic phase and twenty were in the acute phase of toxoplasmosis. The 20 pregnant women in acute phase all agreed with amniocentesis. Serum and AF cytokines were evaluated by sandwich enzyme-linked immunosorbent assay. The analyzed cytokines showed no significant difference in blood versus amniotic fluid levels of pregnant women in the acute toxoplasmosis. Furthermore, we observed that serum IL-17A was significantly higher in pregnant women in the acute phase of infection compared to pregnant women with chronic toxoplasmosis and seronegative pregnant women. T. gondii DNA was not amplified in any of the samples of amniotic fluid by the nested-PCR reaction. Serum IL-10 levels were also higher in negative pregnant women than in infected pregnant women. Our findings indicate the activation of an inflammatory response to infection by T. gondii and suggest that increased production of IL-17A may be a protective factor against infection of the fetus.

IL-1R Regulates Disease Tolerance and Cachexia in Toxoplasma gondii Infection

Toxoplasma gondii is an obligate intracellular parasite that establishes life-long infection in a wide range of hosts, including humans and rodents. To establish a chronic infection, pathogens often exploit the trade-off between resistance mechanisms, which promote inflammation and kill microbes, and tolerance mechanisms, which mitigate inflammatory stress. Signaling through the type I IL-1R has recently been shown to control disease tolerance pathways in endotoxemia and Salmonella infection. However, the role of the IL-1 axis in T. gondii infection is unclear. In this study we show that IL-1R-/- mice can control T. gondii burden throughout infection. Compared with wild-type mice, IL-1R-/- mice have more severe liver and adipose tissue pathology during acute infection, consistent with a role in acute disease tolerance. Surprisingly, IL-1R-/- mice had better long-term survival than wild-type mice during chronic infection. This was due to the ability of IL-1R-/- mice to recover from cachexia, an immune-metabolic disease of muscle wasting that impairs fitness of wild-type mice. Together, our data indicate a role for IL-1R as a regulator of host homeostasis and point to cachexia as a cost of long-term reliance on IL-1-mediated tolerance mechanisms.

A Proinflammatory Immune Response Might Determine Toxoplasma gondii Vertical Transmission and Severity of Clinical Features in Congenitally Infected Newborns

Toxoplasma gondii is the etiological agent of toxoplasmosis. Mother-to-child transmission of this parasite can occur during pregnancy. Newborns with congenital toxoplasmosis may develop central nervous system impairment, with severity ranging from subclinical manifestations to death. A proinflammatory/regulated specific immune profile is crucial in the defense against the parasite; nevertheless, its role in the infected pregnant women and the congenitally infected offspring has been poorly explored, and there is still no consensus about its relation to parasite vertical transmission or to severity and dissemination in the congenitally infected newborns. This work aimed to characterize these relations by means of principal component and principal factor analyses. For this purpose, we determined the specific production of the four immunoglobulin G antibody subclasses, cytokines, and lymphocyte proliferation in the T. gondii–infected pregnant women−10 who transmitted the infection to their offspring and seven who did not—as well as in 11 newborns congenitally infected and grouped according to disease severity (five mild and six moderate/severe) and dissemination (four local and seven disseminated). We found that the immune response of nontransmitter women differed from that of the transmitters, the latter having a stronger proinflammatory response, supporting a previous report. We also found that newborns who developed moderate/severe disease presented higher levels of lymphocyte proliferation, particularly of CD8⁺ and CD19⁺ cells, a high proportion of tumor necrosis factor α producers, and reduced expression of the immune modulator transforming growth factor β, as opposed to children who developed mild clinical complications. Our results suggest that a distinctive, not regulated, proinflammatory immune response might favor T. gondii vertical transmission and the development of severe clinical manifestations in congenitally infected newborns.

Seroprevalencia y detección molecular de Toxoplasma gondii en donantes de un banco de sangre de Cúcuta, Colombia

Introducción. La infección por Toxoplasma gondii puede presentarse en los humanos con un amplio rango de manifestaciones que van desde el estado asintomático hasta la enfermedad grave, según el estado inmunológico del individuo. Los mecanismos de transmisión incluyen la transfusión sanguínea, pero poco se sabe sobre la frecuencia del parásito en los bancos de sangre de Colombia.Objetivo. Determinar la prevalencia de la infección con T. gondii en donantes de un banco de sangre de Cúcuta mediante técnicas de diagnóstico serológico y molecular.Materiales y métodos. Se determinaron los anticuerpos IgG e IgM contra T. gondii mediante un inmunoensayo en suero en 348 donantes. Se determinó la frecuencia de ADN de T. gondii utilizando la reacción en cadena de la polimerasa (PCR) en sangre total de donantes seropositivos y se analizaron las variables de interés con base en la información obtenida durante la selección de donantes.Resultados. De los 348 donantes participantes, 134 (38,5 %) presentaron anticuerpos IgG contra T. gondii; dos (0,6 %) de ellos presentaron tanto IgG como IgM y, en dos (1,5 %), se detectó ADN del parásito en la sangre. Un análisis bivariado evidenció una asociación entre la seropositividad para T. gondii y tener más de 26 años de edad (p=0,020).Conclusiones. La prevalencia de la infección con T. gondii encontrada en los donantes de sangre sugiere una exposición significativa al agente, la cual adquiere relevancia al detectarse la parasitemia.

Immune Mediators against Toxoplasma Gondii during Reactivation of Toxoplasmic Retinochoroiditis

Purpose: The purpose of this article is to analyze possible associations between systemic and ocular cytokine levels and specific clinical ophthalmologic signs from patients with a reactivation of toxoplasmic retinochoroiditis (RTR). Methods: A total of 18 patients with an active RTR episode, 8 patients with inactive scars, and 14 control patients were included in the study. Serum samples and aqueous humor (AH) samples were analyzed for IFN (interferon)-γ, interleukin (IL)-10, and IL-6 levels by ELISA. Inflammation grade, location, and size of the retinochoroidal active lesion, sampling time, and time to resolution were recorded. Results: A significantly negative correlation between AH and serum levels of IFN-γ was detected (p < 0.05). Patients with an AH IFN-γ/IL-10 ratio lower than 1 were associated with the longest time to resolution and/or severe complications. Conclusion: Serum IFN-γ levels may be used as a prognostic marker for both time to resolution and the development of possible severe complications during a given RTR episode.

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.

Cytokine signature associated with disease severity in chronic fatigue syndrome patients

Although some signs of inflammation have been reported previously in patients with myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), the data are limited and contradictory. High-throughput methods now allow us to interrogate the human immune system for multiple markers of inflammation at a scale that was not previously possible. To determine whether a signature of serum cytokines could be associated with ME/CFS and correlated with disease severity and fatigue duration, cytokines of 192 ME/CFS patients and 392 healthy controls were measured using a 51-multiplex array on a Luminex system. Each cytokine's preprocessed data were regressed on ME/CFS severity plus covariates for age, sex, race, and an assay property of newly discovered importance: nonspecific binding. On average, TGF-β was elevated (P = 0.0052) and resistin was lower (P = 0.0052) in patients compared with controls. Seventeen cytokines had a statistically significant upward linear trend that correlated with ME/CFS severity: CCL11 (Eotaxin-1), CXCL1 (GROα), CXCL10 (IP-10), IFN-γ, IL-4, IL-5, IL-7, IL-12p70, IL-13, IL-17F, leptin, G-CSF, GM-CSF, LIF, NGF, SCF, and TGF-α. Of the 17 cytokines that correlated with severity, 13 are proinflammatory, likely contributing to many of the symptoms experienced by patients and establishing a strong immune system component of the disease. Only CXCL9 (MIG) inversely correlated with fatigue duration.

T cell immunoregulation in active ocular toxoplasmosis

Toxoplasma gondii infection is an important cause of infectious ocular disease. The physiopathology of retinochoroidal lesions associated with this infection is not completely understood. The present study was undertaken to investigate cytokine production by T cells from individuals with active toxoplasmic retinochoroiditis (TR) comparing with controls. Eighteen patients with active TR and 15 healthy controls (6 controls IgG⁺ to Toxoplasma and 9 negative controls) were included in the study. Peripheral blood mononuclear cells were incubated in the presence or absence of T. gondii antigen (STAg), and stained against CD4, CD8, TNF, IL-10 and IFN-γ. Baseline expression of cytokines was higher in TR/IgG⁺ patients in comparison with controls. Cytokine expression was not increased by STAg in vitro stimulation in controls. After stimulation, TR/IgG⁺ patients' lymphocytes increased cytokine as compared to cultures from both controls. While T cells were the main source of IL-10, but also IFN-γ and TNF, other lymphocyte populations were relevant source of inflammatory cytokines. Interestingly, it was observed a negative correlation between ocular lesion size and IL-10 expression by CD4⁺ lymphocytes. This study showed that T cells are the main lymphocyte populations expressing IL-10 in patients with TR. Moreover, expression of IL-10 plays a protective role in active TR.

Cytokine profiles in patients with toxoplasmic lymphadenitis in the setting of pregnancy

INTRODUCTION

Majority of Toxoplasma gondii infections are benign and asymptomatic; however, some patients experience toxoplasmic lymphadenitis (TL). Factors associated as to whether infection will be symptomatic or not are unknown.

METHODS

Dye test titers of patients with acute toxoplasmosis (pregnant and not pregnant) with TL (TL+) were compared with those in patients with asymptomatic acute infection (TL-). Additionally, mean levels of 62 serum cytokines were compared between TL+ and TL- pregnant women and between TL+ pregnant and non-pregnant women.

RESULTS

During acute infection, mean dye test titer was higher in TL+ than in TL- patients (p=0.021). In addition, out of 62 cytokines, CXCL9andCXCL10 levels were higher (p<0.05) and resistin mean levels were lower (p<0.05) in pregnant women with TL+ compared to TL-. Among patients with TL+, levels of VCAM1andCCL2 were lower (p<0.05) in pregnant women than in non-pregnant women.

CONCLUSION

Here we report differences in dye test titers in patients with acute infection. Cytokine responses vary according to the presence of TL+ and to the pregnancy status. Factors underlying these differences are presently unknown and require further studies to define individual and combined roles of cytokines in TL+.

New paradigms for understanding and step changes in treating active and chronic, persistent apicomplexan infections

Toxoplasma gondii, the most common parasitic infection of human brain and eye, persists across lifetimes, can progressively damage sight, and is currently incurable. New, curative medicines are needed urgently. Herein, we develop novel models to facilitate drug development: EGS strain T. gondii forms cysts in vitro that induce oocysts in cats, the gold standard criterion for cysts. These cysts highly express cytochrome b. Using these models, we envisioned, and then created, novel 4-(1H)-quinolone scaffolds that target the cytochrome bc1 complex Qi site, of which, a substituted 5,6,7,8-tetrahydroquinolin-4-one inhibits active infection (IC50, 30 nM) and cysts (IC50, 4 μM) in vitro, and in vivo (25 mg/kg), and drug resistant Plasmodium falciparum (IC50, <30 nM), with clinically relevant synergy. Mutant yeast and co-crystallographic studies demonstrate binding to the bc1 complex Qi site. Our results have direct impact on improving outcomes for those with toxoplasmosis, malaria, and ~2 billion persons chronically infected with encysted bradyzoites.

CD8(+) T cells remove cysts of Toxoplasma gondii from the brain mostly by recognizing epitopes commonly expressed by or cross-reactive between type II and type III strains of the parasite

Our previous study demonstrated that CD8(+) T cells remove cysts of Toxoplasma gondii from the brain through perforin-mediated mechanisms. We here show that a transfer of CD8(+) immune T cells primed with a type II or a type III strain of T. gondii both efficiently removed cysts of a type II strain from infected SCID mice, although the former tended to be slightly more efficient than the latter. Similarly, a transfer of type II-primed CD8(+) T cells removed cysts of a type III strain. Therefore, CD8(+) T cells are capable of removing T. gondii cysts by recognizing epitopes commonly expressed in types II and III strains or cross-reactive between these two genotypes.

Strain hypothesis of Toxoplasma gondii infection on the outcome of human diseases

The intracellular protozoan Toxoplasma gondii is an exceptionally successful food and waterborne parasite that infects approximately 1 billion people worldwide. Genotyping of T. gondii isolates from all continents revealed a complex population structure. Recent research supports the notion that T. gondii genotype may be associated with disease severity. Here, we (1) discuss molecular and serological approaches for designation of T. gondii strain type, (2) overview the literatures on the association of T. gondii strain type and the outcome of human disease and (3) explore possible mechanisms underlying these strain-specific pathology and severity of human toxoplasmosis. Although no final conclusions can be drawn, it is clear that virulent strains (e.g. strains containing type I or atypical alleles) are significantly more often associated with increased frequency and severity of human toxoplasmosis. The significance of highly virulent strains can cause severe diseases in immunocompetent patients and might implicated in brain disorders such as schizophrenia should led to reconsideration of toxoplasmosis. Further studies that combine parasite strain typing and human factor analysis (e.g. immune status and genetic background) are required for better understanding of human susceptibility or resistance to toxoplasmosis.