A systematic review and meta-analysis of the relative efficacy and safety of treatment regimens for HIV-associated cerebral toxoplasmosis: is trimethoprim-sulfamethoxazole a real option?

Guidelines for the management of Toxoplasma gondii infection and disease in patients with haematological malignancies and after haematopoietic stem-cell transplantation: guidelines from the 9th European Conference on Infections in Leukaemia, 2022

Patients with haematological malignancies might develop life-threatening toxoplasmosis, especially after allogeneic haematopoietic stem-cell transplantation (HSCT). Reactivation of latent cysts is the primary mechanism of toxoplasmosis following HSCT; hence, patients at high risk are those who were seropositive before transplantation. The lack of trimethoprim-sulfamethoxazole prophylaxis and various immune status parameters of the patient are other associated risk factors. The mortality of toxoplasma disease-eg, with organ involvement-can be particularly high in this setting. We have developed guidelines for managing toxoplasmosis in haematology patients, through a literature review and consultation with experts. In allogeneic HSCT recipients seropositive for Toxoplasma gondii before transplant, because T gondii infection mostly precedes toxoplasma disease, we propose weekly blood screening by use of quantitative PCR (qPCR) to identify infection early as a pre-emptive strategy. As trimethoprim-sulfamethoxazole prophylaxis might fail, prophylaxis and qPCR screening should be combined. However, PCR in blood can be negative even in toxoplasma disease. The duration of prophylaxis should be a least 6 months and extended during treatment-induced immunosuppression or severe CD4 lymphopenia. If a positive qPCR test occurs, treatment with trimethoprim-sulfamethoxazole, pyrimethamine-sulfadiazine, or pyrimethamine-clindamycin should be started, and a new sample taken. If the second qPCR test is negative, clinical judgement is recommended to either continue or stop therapy and restart prophylaxis. Therapy must be continued until a minimum of two negative PCRs for infection, or for at least 6 weeks for disease. The pre-emptive approach is not indicated in seronegative HSCT recipients, after autologous transplantation, or in non-transplant haematology patients, but PCR should be performed with a high level of clinical suspicion.

Omega-3 and omega-6 polyunsaturated fatty acids and their potential therapeutic role in protozoan infections

Protozoa exert a serious global threat of growing concern to human, and animal, and there is a need for the advancement of novel therapeutic strategies to effectively treat or mitigate the impact of associated diseases. Omega polyunsaturated fatty acids (ω-PUFAs), including Omega-3 (ω-3) and omega-6 (ω-6), are constituents derived from various natural sources, have gained significant attention for their therapeutic role in parasitic infections and a variety of essential structural and regulatory functions in animals and humans. Both ω-3 and ω-6 decrease the growth and survival rate of parasites through metabolized anti-inflammatory mediators, such as lipoxins, resolvins, and protectins, and have both in vivo and in vitro protective effects against various protozoan infections. The ω-PUFAs have been shown to modulate the host immune response by a commonly known mechanism such as (inhibition of arachidonic acid (AA) metabolic process, production of anti-inflammatory mediators, modification of intracellular lipids, and activation of the nuclear receptor), and promotion of a shift towards a more effective immune defense against parasitic invaders by regulation the inflammation like prostaglandins, leukotrienes, thromboxane, are involved in controlling the inflammatory reaction. The immune modulation may involve reducing inflammation, enhancing phagocytosis, and suppressing parasitic virulence factors. The unique properties of ω-PUFAs could prevent protozoan infections, representing an important area of study. This review explores the clinical impact of ω-PUFAs against some protozoan infections, elucidating possible mechanisms of action and supportive therapy for preventing various parasitic infections in humans and animals, such as toxoplasmosis, malaria, coccidiosis, and chagas disease. ω-PUFAs show promise as a therapeutic approach for parasitic infections due to their direct anti-parasitic effects and their ability to modulate the host immune response. Additionally, we discuss current treatment options and suggest perspectives for future studies. This could potentially provide an alternative or supplementary treatment option for these complex global health problems.

Calcified cerebral toxoplasmosis associated with recurrent perilesional edema causing neurological manifestations in an HIV-infected individual: case report with a decade-long follow-up

Four cases of people living with HIV/AIDS (PLWHA) with calcified cerebral toxoplasmosis associated with perilesional edema causing a single episode of neurological manifestations have recently been reported. Here, we describe the first detailed description of perilesional edema associated with calcified cerebral toxoplasmosis causing three episodes of neurological manifestations in a PLWHA, including seizures in two of them. These recurrences occurred over approximately a decade. Throughout this period, the patient showed immunological and virological control of the HIV infection, while using antiretroviral therapy regularly. This case broadens the spectrum of an emerging presentation of calcified cerebral toxoplasmosis, mimicking a well-described finding of neurocysticercosis in immunocompetent hosts.

Metagenomic Next-generation Sequencing May be a Tool for Timely Diagnosis of Seronegative and Primary Toxoplasma Infection After Allogeneic Hematopoietic Stem Cell Transplantation: A Case Report and Literature Review

We report a case of Toxoplasma gondii ( T. gondii ) antibody seronegativity in a 14-year-old boy with a primary infection of T. gondii after allogeneic hematopoietic stem cell transplantation for acute T-cell lymphoblastic leukemia who was rapidly diagnosed through metagenomic next-generation sequencing of peripheral blood as well as clinical manifestations. He was successfully cured with timely administration of trimethoprim-sulfamethoxazole due to early diagnosis.

Overview of management of infection-related movement disorders with focus on specific-infections

Infections are important treatable causes of secondary movement disorders (MD) that can have heterogeneous presentations. According to various studies, infection-related movement disorders (IRMD) account for around 10-20% of secondary MD. Certain infections have a predilection for causing various MD, and some MD phenomenologies, such as acute cerebellar ataxia and opsoclonus-myoclonus-ataxia syndromes (OMAS), suggest a strong possibility of an underlying infectious cause. The underlying pathophysiology is multifaceted, including direct neuronal damage due to neurotropism, granulomas, abscesses causing structural damage, and inflammatory and autoimmune responses triggered by infections. Understanding the prevalence, spectrum, and pattern of these IRMD and common infections that are responsible helps in early diagnosis, and instituting appropriate, timely treatment, thereby improving the overall prognosis and avoiding unnecessary investigations. In this review, we aim to provide a brief overview of common infections associated with MD, common clinical presentations of IRMD, their underlying pathophysiology, and overall approach to their treatment, with a focus on specific treatments of prevalent and treatable IRMD.

In vitro screening technologies for the discovery and development of novel drugs against Toxoplasma gondii

INTRODUCTION

Toxoplasmosis constitutes a challenge for public health, animal production and welfare. Since more than 60 years, only a limited panel of drugs has been in use for clinical applications.

AREAS COVERED

Herein, the authors describe the methodology and the results of library screening approaches to identify inhibitors of Toxoplasma gondii and related strains. The authors then provide the reader with their expert perspectives for the future.

EXPERT OPINION

Various library screening projects, in particular those using reporter strains, have led to the identification of numerous compounds with good efficacy and specificity in vitro. However, only few compounds are effective in suitable animal models such as rodents. Whereas no novel compound has cleared the hurdle to applications in humans, the few compounds with known indication and application profiles in human patients are of interest for further investigations. Taken together, drug repurposing as well as high-throughput screening of novel compound libraries may shorten the way to novel drugs against toxoplasmosis.

Single and combination treatment of Toxoplasma gondii infections with a bumped kinase inhibitor and artemisone in vitro and with artemiside in experimentally infected mice

In previous studies, the artemisinin derivatives artemisone, its pro-drug artemiside and the bumped-kinase inhibitor BKI-1748 were effective against T. gondii via different modes of action. This suggests that they may act synergistically resulting in improved efficacies in vitro and in vivo. To test this hypothesis, the compounds were applied alone and in combination to T. gondii infected human fibroblast host cells in order to determine their inhibition constants and effects on cellular ultrastructure. In addition, the efficacy of either single- or combined treatments were assessed in an acute TgShSp1-oocyst infection model based on CD1 outbred mice. Whereas the IC50 of the compounds in combination (42 nM) was close to the IC50 of BKI-1748 alone (46 nM) and half of the IC50 of artemisone alone (92 nM), the IC90 of the combination was half of the values found with the single compounds (138 nM vs. ca. 270 nM). Another indication for synergistic effects in vitro were distinct alterations of the cellular ultrastructure of tachyzoites observed in combination, but not with the single compounds. These promising results could not be reproduced in vivo. There was no decrease in number of T. gondii positive brains by either treatment. However, the levels of infection in these brains, i. e. the number of tachyzoites, was significantly decreased upon BKI-1748 treatment alone, and the combination with artemiside did not produce any further decrease. The treatment with artemiside alone had no significant effects. A vertical transmission model could not be established since artemiside strongly interfered with pregnancy and caused abortion. These results show that is difficult to extrapolate from promising in vitro results to the situation in vivo.

Sulfadiazine analogs: anti-Toxoplasma in vitro study of sulfonamide triazoles

Toxoplasmosis is an infection that prevails all over the world and is caused by the obligate intracellular protozoan parasite Toxoplasma gondii (T. gondii). Promising novel compounds for the treatment of T. gondii are introduced in the current investigation. In order to test their in vitro potency against T. gondii tachyzoites, six 1,2,3-triazoles-based sulfonamide scaffolds with terminal NH2 or OH group were prepared and investigated as sulfadiazine equivalents. When compared to sulfadiazine, which served as a positive control, hybrid molecules showed much more anti-Toxoplasma activity. The results showed that the IC50 of the examined compounds 3(a-f) were recoded as 0.07492 μM, 0.07455 μM, 0.0392 μM, 0.03124 μM, 0.0533 μM, and 0.01835 μM, respectively, while the sulfadiazine exhibited 0.1852 μM. The studied 1,2,3-triazole-sulfadrug molecular conjugates 3(a-f) revealed selectivity index of 10.4, 8.9, 25.4, 21, 8.3, and 29; respectively. The current study focused on the newly synthesized amino derivatives 3(d-f), as they contain the more potent amino groups which are recognized to be essential elements and promote better biological activity. Extracellular tachyzoites underwent striking morphological alterations after 2 h of treatment as seen by scanning electron microscopy (SEM). Additionally, the intracellular tachyzoite exposed to the newly synthesized amino derivatives 3(d-f) for a 24-h period of treatment revealed damaged and altered morphology by transmission electron microscopic (TEM) indicating cytopathic effects. Moreover, compound 3f underwent the most pronounced changes, indicating that it had the strongest activity against T. gondii.

An HIV-positive woman with massive brain lesion due to toxoplasmosis: A case report

Key Clinical Message

Toxoplasmosis-related huge brain lesions may require decompressive craniectomy and lesion excision to avoid brain damage. In this situation, injectable cotrimoxazole is a better choice for treatment.

Abstract

Toxoplasma gondii is a worldly distributed obligate intracellular protozoa. Toxoplasmosis is a prevalent opportunistic infection in HIV-infected people, but it was rarely recorded prior to the identification of HIV infection. Here, we report a toxoplasmosis brain lesion in an Iranian HIV-positive patient. A 45-year-old woman with a complaint of malaise was referred to the Valiasr Hospital in Arak city. In her past clinical history, the patient had a history of anemia, deep vein thrombosis (DVT), and positive HIV. The patient was informed of the diagnosis of massive brain toxoplasmosis as a definite diagnosis. The patient was then taken to the operating room for a left decompressive craniectomy, during which the ensuing brain lesion was excised. After a few days, she was discharged from the hospital in good condition and without any complications.

Toxoplasma gondii infection: novel emerging therapeutic targets

INTRODUCTION

Toxoplasmosis constitutes a challenge for public health, animal production, and welfare. So far, only a limited panel of drugs has been marketed for clinical applications. In addition to classical screening, the investigation of unique targets of the parasite may lead to the identification of novel drugs.

AREAS COVERED

Herein, the authors describe the methodology to identify novel drug targets in Toxoplasma gondii and review the literature with a focus on the last two decades.

EXPERT OPINION

Over the last two decades, the investigation of essential proteins of T. gondii as potential drug targets has fostered the hope of identifying novel compounds for the treatment of toxoplasmosis. Despite good efficacies in vitro, only a few classes of these compounds are effective in suitable rodent models, and none has cleared the hurdle to applications in humans. This shows that target-based drug discovery is in no way better than classical screening approaches. In both cases, off-target effects and adverse side effects in the hosts must be considered. Proteomics-driven analyses of parasite- and host-derived proteins that physically bind drug candidates may constitute a suitable tool to characterize drug targets, irrespectively of the drug discovery methods.

Revisiting the Evidence Base for Modern-Day Practice of the Treatment of Toxoplasmic Encephalitis: A Systematic Review and Meta-Analysis

BACKGROUND

Toxoplasmic encephalitis (TE) is an opportunistic infection of people with human immunodeficiency virus (HIV) or other causes of immunosuppression. Guideline-recommended treatments for TE are pyrimethamine and sulfadiazine (P-S) or pyrimethamine and clindamycin (P-C); however, a substantial price increase has limited access to pyrimethamine. Consequently, some centers have transitioned to trimethoprim-sulfamethoxazole (TMP-SMX), an inexpensive alternative treatment. We aimed to review the evidence on the efficacy and safety of pyrimethamine-containing therapies vs TMP-SMX.

METHODS

We searched for and included randomized controlled trials (RCTs) and observational studies of TE treatments, regardless of HIV status. Data for each therapy were pooled by meta-analysis to assess the proportions of patients who experienced clinical and radiologic responses to treatment, all-cause mortality, and discontinuation due to toxicity. Sensitivity analyses limited to RCTs directly compared therapies.

RESULTS

We identified 6 RCTs/dose-escalation studies and 26 single-arm/observational studies. Identified studies included only persons with HIV, and most predated modern antiretroviral treatment. Pooled proportions of clinical and radiologic response and mortality were not significantly different between TMP-SMX and pyrimethamine-containing regimens (P > .05). Treatment discontinuation due to toxicity was significantly lower in TMP-SMX (7.3%; 95% confidence interval [CI], 4.7-11.4; I2 = 0.0%) vs P-S (30.5%; 95% CI, 27.1-34.2; I2 = 0.0%; P < .01) or P-C (13.7%; 95% CI, 9.8-18.8; I2 = 32.0%; P = .031). These results were consistent in analyses restricted to RCT data.

CONCLUSIONS

TMP-SMX appears to be as effective and safer than pyrimethamine-containing regimens for TE. These findings support modern RCTs comparing TMP-SMX to pyrimethamine-based therapies and a revisiting of the guidelines.

Cerebral toxoplasmosis in HIV-infected patients: a review

Toxoplasma gondii infection in the central nervous system commonly occurs among immunodeficient patients. Its prevalence is high in countries with a high burden of HIV and low coverage of antiretroviral drugs. The brain is one of the predilections for T. gondii infection due to its low inflammatory reaction, and cerebral toxoplasmosis occurs solely due to the reactivation of a latent infection rather than a new infection. Several immune elements have recently been recognized to have an essential role in the immunopathogenesis of cerebral toxoplasmosis. Although real-time isothermal amplification, next-generation sequencing, and enzyme-linked aptamer assays from blood samples have been the recommended diagnostic tools in some in-vivo studies, a combination of clinical symptoms, serology examination, and neuroimaging are still the daily standard for the presumptive diagnosis of cerebral toxoplasmosis and early anti-toxoplasma administration. Clinical trials are needed to find a new therapy that is less likely to affect folate synthesis, have neuroprotective properties, or cure the latent phase of infection. The development of a vaccine is being extensively tested in animals, but its efficacy and safety for humans are still not proven.

Synergistic sulfonamides plus clindamycin as an alternative therapeutic regimen for HIV-associated Toxoplasma encephalitis: a randomized controlled trial

BACKGROUND

The preferred therapeutic regimen for Toxoplasma encephalitis (TE) is a combination of pyrimethamine and sulfadiazine, and trimethoprim-sulfamethoxazole (TMP-SMX) plus azithromycin is the widespread alternative therapeutic regimen. The synergistic sulfonamides tablet contains TMP, sulfadiazine, and SMX and hypothetically could be used for TE treatment. This study aimed to compare the efficacy and safety of synergistic sulfonamides plus clindamycin (regimen B) with TMP-SMX plus azithromycin (regimen A) for the treatment of human immunodeficiency virus (HIV) associated TE.

METHODS

This was an open-labeled, multi-center randomized controlled trial recruited from 11 centers. Each recruited patient was randomly assigned to receive regimen A or regimen B for at least 6 weeks. The overall response was evaluated by assessment of the clinical response of TE-associated clinical features and the radiological response of TE-associated radiological findings. The overall response rate, clinical response rate, radiological response rate, and adverse events were assessed at 2, 6, and 12 weeks. Death events were compared between the two regimens at 6, 12, and 24 weeks.

RESULTS

A total of 91 acquired immunodeficiency syndrome (AIDS)/TE patients were included in the final analysis (44 in regimen A vs . 47 in regimen B). The overall response rate, which refers to the combined clinical and radiological response, was 18.2% (8/44) for regimen A and 21.3% (10/47) for regimen B at week 6. The results of clinical response showed that, in comparison with regimen A, regimen B may perform better with regards to its effect on the relief of clinical manifestations (50.0% [22/44] vs . 70.2% [33/47], P = 0.049). However, no significant differences in radiological response, mortality events, and adverse events were found between the two regimens at week 6.

CONCLUSIONS

Synergistic sulfonamides plus clindamycin, as a novel treatment regimen, showed no significantly different efficacy and comparable safety in comparison with the TMP-SMX plus azithromycin regimen. In addition, the regimen containing synergistic sulfonamides may exhibit advantages in terms of clinical symptom alleviation.

TRIAL REGISTRATION

ChiCTR.org.cn, ChiCTR1900021195.

Brief Report: Financial Burden of Toxoplasmosis Encephalitis Treatment at a Safety Net Hospital

BACKGROUND

Although the price increase of pyrimethamine in 2015 received heavy media coverage, there are little data regarding specific implications to hospitals and the total costs of treating inpatients with toxoplasmosis encephalitis (TE).

METHODS

Using average drug wholesale costs, we estimated the inpatient drug costs of TE drugs 3 years prepyrimethamine and postpyrimethamine price increase in August 2015. The drug regimens and total doses were determined through retrospective chart review of patients living with HIV who received treatment for TE while inpatient during this period.

RESULTS

The 3-year pre-increase TE drug costs for 66 admissions were estimated at $50,310 compared with a total drug cost of $1,026,006 for 61 admissions postincrease. Pyrimethamine made up 98% of the drug costs postincrease, compared with 57% pre-increase. Pyrimethamine-based regimens were the most frequently used throughout the study period.

CONCLUSIONS

The price increase of pyrimethamine in 2015 led to a substantial and unnecessary financial burden to hospitals. This required health care systems to shift valuable resources to continue to provide medications to a vulnerable patient population. There has been more focus on providing high-value care in recent years. Our study highlights the need for further examination of pharmaceutical companies' arbitrary determination of medication costs and how they contribute to patient care.

Impact of Plant-Based Foods and Nutraceuticals on Toxoplasma gondii Cysts: Nutritional Therapy as a Viable Approach for Managing Chronic Brain Toxoplasmosis

Toxoplasma gondii is an obligate intracellular parasite that mainly infects warm-blooded animals including humans. T. gondii can encyst and persist chronically in the brain, leading to a broad spectrum of neurological sequelae. Despite the associated health threats, no clinical drug is currently available to eliminate T. gondii cysts. In a continuous effort to uncover novel therapeutic agents for these cysts, the potential of nutritional products has been explored. Herein, we describe findings from in vitro and in vivo studies that support the efficacy of plant-based foods and nutraceuticals against brain cyst burden and cerebral pathologies associated with chronic toxoplasmosis. Finally, we discuss strategies to increase the translatability of preclinical studies and nutritional products to address whether nutritional therapy can be beneficial for coping with chronic T. gondii infections in humans.

Epigenetic Manipulation of Psychiatric Behavioral Disorders Induced by Toxoplasma gondii

Toxoplasma gondii is known to have a complex life cycle and infect almost all kinds of warm-blooded animals around the world. The brain of the host could be persistently infected by cerebral cysts, and a variety of psychiatric disorders such as schizophrenia and suicide have been reported to be related with latent toxoplasmosis. The infected animals showed fear reduction and a tendency to be preyed upon. However, the mechanism of this “parasites manipulation” effects have not been elucidated. Here, we reviewed the recent infection prevalence of toxoplasmosis and the evidence of mental and behavioral disorders induced by T. gondii and discussed the related physiological basis including dopamine dysregulation and gamma-aminobutyric acid (GABA) pathway and the controversial opinion of the necessity for cerebral cysts existence. Based on the recent advances, we speculated that the neuroendocrine programs and neurotransmitter imbalance may play a key role in this process. Simultaneously, studies in the evaluation of the expression pattern of related genes, long noncoding RNAs (lncRNAs), and mRNAs of the host provides a new point for understanding the mechanism of neurotransmitter dysfunction induced by parasite manipulation. Therefore, we summarized the animal models, T. gondii strains, and behavioral tests used in the related epigenetic studies and the responsible epigenetic processes; pinpointed opportunities and challenges in future research including the causality evidence of human psychiatric disorders, the statistical analysis for rodent-infected host to be more vulnerable preyed upon; and identified responsible genes and drug targets through epigenetics.

Characterization of murine extracellular vesicles and Toxoplasma gondii infection

This study characterized extracellular vesicles (EVs) of sera from mice infected with Toxoplasma gondii or immunized with EVs derived T gondii. EVs were purified of sera from four groups (5 A/Sn mice/group). EV-IM: Mice immunized with T gondii-released EVs; ACT: mice in acute infection; CHR: mice in chronic infection; and NI: normal mice. EVs were purified by ultracentrifugation. Concentration of serum-derived EVs from NI group was smaller than EV-IM, ACT and CHR groups. Most of the EVs from ACT and CHR groups were microvesicles, and they were bigger than the NI group. The same results were shown by Transmission Electron Microscopy. The presence of exosomes was shown in immunoblotting by tetraspanin (CD63 and CD9) evidence. Splenocytes of EV-IM, CHR and NI groups were stimulated with T. gondii derived EVs. EV-IM and CHR groups up-expressed IFN-γ; TNF-α and IL-17, when compared with the NI group. IL-10 was up-expressed only in the EV-IM group. EV-IM, ACT and CHR groups expressed more miR-155-5p, miR-29c-3p and miR-125b-5p than the NI group. Host-T gondii interaction can occur, also, via EVs. miRNAs participate in the modulation of cellular immune response against T gondii. These data give subsidies to propose the differentiation between infect or noninfect hosts by concentration of EVs.

4-Arylthiosemicarbazide derivatives as a new class of tyrosinase inhibitors and anti-Toxoplasma gondii agents

We report herein anti-proliferation effects of 4-arylthiosemicarbazides, with a cyclopentane substitution at N1 position, on highly virulent RH strain of Toxoplasma gondii. Among them, the highest in vitro anti-Toxoplasma activity was found with the meta-iodo derivative. Further experiments demonstrated inhibitory effects of thiosemicarbazides on tyrosinase (Tyr) activity, and good correlation was found between percentage of Tyr inhibition and IC_50Tg. To confirm the concept that thiosemicarbazides are able to disrupt tyrosine metabolism in Toxoplasma tachyzoites, the most potent Tyr inhibitors were tested for their efficacy of T. gondii growth inhibition. All of them significantly reduced the number of tachyzoites in the parasitophorous vacuoles (PVs) compared to untreated cells, as well as inhibited tachyzoites growth by impeding cell division. Collectively, these results indicate that compounds with the thiosemicarbazide scaffold are able to disrupt tyrosine metabolism in Toxoplasma tachyzoites by deregulation of their crucial enzyme tyrosine hydroxylase (TyrH).

Treatment of toxoplasmic encephalitis with the combination of clindamycin plus azithromycin in an HIV-infected patient: A case report

The existence of alternative oral therapies could help clinicians to treat toxoplasmic encephalitis (TE) in the HIV patients. The combination of azithromycin and clindamycin may serve as an effective treatment for TE in HIV-infected patients.

Immunization with extracellular vesicles excreted by Toxoplasma gondii confers protection in murine infection, activating cellular and humoral responses

The study aim was to analyze whether microvesicles and exosomes, named extracellular vesicles (EVs), purified from Toxoplasma gondii are able to stimulate the protective immunity of experimental mice when administered, as challenge, a highly virulent strain. EVs excreted from T. gondii tachyzoites (RH strain) were purified by chromatography and used for immunization assays in inbred mouse groups (EV-IM). Chronic infected (CHR) and naive (NI) mice were used as control groups, since the immune response is well known. After immunizations, experimental groups were challenged with 100 tachyzoites. Next, parasitemias were determined by real-time PCR (qPCR), and survival levels were evaluated daily. The humoral response was analyzed by detection of IgM, IgG, IgG1 and IgG2a, and opsonization experiments. The cellular response was evaluated in situ by immunohistochemistry on IFN-γ, IL-10, TNF-α and IL-17 expression in cells of five organs (brain, heart, liver, spleen and skeletal muscles). EV immunization reduced parasitemia and increased the survival index in two mouse lineages (A/Sn and BALB/c) infected with a lethal T. gondii strain. EV-IM mice had higher IgG1 levels than IgM or IgG2a. IgGs purified from sera of EV-IM mice were able to opsonize tachyzoites (RH strain), and mice that received these parasites had lower parasitemias, and mortality was delayed 48 h, compared with the same results from those receiving parasites opsonized with IgG purified from NI mice. Brain and spleen cells from EV-IM mice more highly expressed IFN-γ, IL-10 and TNF-α. In conclusion, EV-immunization was capable of inducing immune protection, eliciting high production of IgG1, IFN-γ, IL-10 and TNF-α.

Efficacy of Guanabenz Combination Therapy against Chronic Toxoplasmosis across Multiple Mouse Strains

Toxoplasma gondii, an obligate intracellular parasite that can cause life-threatening acute disease, differentiates into a quiescent cyst stage to establish lifelong chronic infections in animal hosts, including humans. This tissue cyst reservoir, which can reactivate into an acute infection, is currently refractory to clinically available therapeutics. Recently, we and others have discovered drugs capable of significantly reducing the brain cyst burden in latently infected mice, but not to undetectable levels. In this study, we examined the use of novel combination therapies possessing multiple mechanisms of action in mouse models of latent toxoplasmosis. Our drug regimens included combinations of pyrimethamine, clindamycin, guanabenz, and endochin-like quinolones (ELQs) and were administered to two different mouse strains in an attempt to eradicate brain tissue cysts. We observed mouse strain-dependent effects with these drug treatments: pyrimethamine-guanabenz showed synergistic efficacy in C57BL/6 mice yet did not improve upon guanabenz monotherapy in BALB/c mice. Contrary to promising in vitro results demonstrating toxicity to bradyzoites, we observed an antagonistic effect between guanabenz and ELQ-334 in vivo While we were unable to completely eliminate the brain cyst burden, we found that a combination treatment with ELQ-334 and pyrimethamine impressively reduced the brain cyst burden by 95% in C57BL/6 mice, which approached the limit of detection. These analyses highlight the importance of evaluating anti-infective drugs in multiple mouse strains and will help inform further preclinical studies of cocktail therapies designed to treat chronic toxoplasmosis.

Approach to an Intracranial Mass in Patients With HIV

PURPOSE OF REVIEW

Space-occupying lesions represent a diagnostic challenge among people with the human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS). To determine the best diagnostic approach to the wide array of possible etiologies and provide a thorough interpretation of neuroimaging in order to narrow a hierarchical differential diagnosis among these patients. Given that there is no pathognomonic neuroimaging pattern in this clinical setting, we searched results from brain biopsies to best determine the etiology of commonly found lesions.

RECENT FINDINGS

Multimodal brain MRI and MRI spectroscopy (MRS) often provide the most valuable information in the study of focal masses among people with HIV/AIDS. Brain biopsy appears safe and provides high diagnostic yields in these patients. Among patients with HIV/AIDS who present with space-occupying intracranial lesions, brain MRI and MRS are useful tests. However, in cases of diagnostic uncertainty, brain biopsy is a safe procedure and should be performed. The role of metabolic studies like ²⁰¹Th-SPECT or PET is useful in the detection of primary central nervous system lymphoma.

Congenital toxoplasmosis: What is the evidence for chemoprophylaxis to prevent fetal infection?

Although prenatal diagnosis and prenatal and neonatal therapy of congenital toxoplasmosis are available, there is controversy concerning the effectiveness of prophylaxis to prevent placental transmission. Experimental, parasitological, and clinical data suggest a "window of opportunity" following maternal infection. Among medications active against Toxoplasma gondii, mainly spiramycin (Spy) and pyrimethamine + sulfonamide combinations (P-S) have been evaluated. Results from observational studies suffered treatment bias, since prescriptions differed according to the gestational age at seroconversion, which is the major risk factor for transmission, and many lacked precise timing. Some large retrospective studies found no difference in transmission according to prophylactic treatment, but transmission was lower when treatment started promptly after maternal seroconversion. A few recent studies adjusting for timing of infection observed lower transmission in case of P-S than other or no prophylaxis. In the only randomized controlled trial, transmission was lower with P-S than S (18.5% vs 30%, P = .147); this association was strengthened when the treatment was started within 3 weeks of seroconversion, and the incidence of fetal cerebral ultrasound signs was significantly reduced in the P-S group. Rapid initiation of prophylactic therapy following maternal infection, which is usually asymptomatic, requires systematic screening for maternal seroconversion during pregnancy.

Acute toxoplasmosis complicated with myopericarditis and possible encephalitis in an immunocompetent patient

We document a case of a 34-year-old man with no medical previous history, presenting with lymphoproliferative syndrome associated to Toxoplasma gondii infection complicated with myopericarditis and possible encephalitis, whose diagnosis was made with lymph node biopsy, cardiac imaging, serology compatible with acute toxoplasmosis and clinical response after treatment.

Human extracellular vesicles and correlation with two clinical forms of toxoplasmosis

Aim

This study analyzed microvesicles and exosomes, called as extracellular vesicles (EVs) excreted in serum and cerebrospinal fluid (CSF) from patients with cerebral or gestational toxoplasmosis.

Methods

Clinical samples from 83 individuals were divided into four groups. Group I, 20 sera from healthy individuals and pregnant women (seronegative for toxoplasmosis); group II, 21 sera from seropositive patients for toxoplasmosis (cerebral or gestational forms); group III, 26 CSF samples from patients with cerebral toxoplasmosis/HIV co-infection (CT/HIV) (seropositive for toxoplasmosis); and group IV, 16 CSF samples from seronegative patients for toxoplasmosis, but with HIV infection and other opportunistic infections (OI/HIV). Serum and CSF samples were ultracentrifuged to recover EVs. Next, vesicle size and concentration were characterized by Nanoparticle Tracking Analysis (NTA).

Results

Concentrations of serum-derived EVs from toxoplasmosis patients (mean: 2.4 x 10¹⁰ EVs/mL) were statically higher than of non-infected individuals (mean: 5.9 x 10⁹ EVs/mL). Concentrations of CSF-derived EVs were almost similar in both groups. CT/HIV (mean: 2.9 x 10⁹ EVs/mL) and OI/HIV (mean: 4.8 x 10⁹ EVs/mL). Analyses by NTA confirmed that CSF-derived EVs and serum-derived EVs had size and shape similar to microvesicles and exosomes. The mean size of EVs was similar in serum and CSF. Thus, the concentration, and not size was able distinguish patients with toxoplasmosis than healthy individuals. Presence of exosomes was also confirmed by transmission electron microscopy and evidence of tetraspanins CD63 and CD9 in immunoblotting. Relative expressions of miR-146a-5p, miR-155-5p, miR-21-5p, miR-29c-3p and miR-125b-5p were estimated in exosomal miRNA extracted of EVs.

Serum-derived EVs from group II (cerebral and gestational toxoplasmosis) up-expressed miR-125b-5p and miR-146a-5p. CSF-derived EVs from CT/HIV patients) up-expressed miR-155-5p and miR-21-5p and were unable to express miR-29c-3p.

Conclusion

These data suggest the participation of EVs and exosomal miRNAs in unbalance of immune response as elevation of TNF-α, IL-6; and downregulation of IFN-γ in cerebral and gestational forms of toxoplasmosis.

Fulminant and Diffuse Cerebral Toxoplasmosis as the First Manifestation of HIV Infection: A Case Presentation and Review of the Literature

Patient: Male, 9-year-old

Final Diagnosis: Fulminant and diffuse cerebral toxoplasmosis

Symptoms: Decreased level of consciousness • fever • generalized tonic-clonic seizures • hemiplegia

Medication: —

Clinical Procedure: Decompressive hemicraniectomy

Specialty: Neurosurgery

Combination of Clindamycin and Azithromycin as Alternative Treatment for Toxoplasma gondii Encephalitis

Current standard therapies for toxoplasmic encephalitis often cause severe adverse events. A 57-year-old HIV-positive man in Japan who had toxoplasmic encephalitis but was intolerant to trimethoprim/sulfamethoxazole, pyrimethamine, sulfadiazine, and atovaquone was successfully treated with the combination of clindamycin and azithromycin. This drug combination can be an alternative treatment for this condition.

Folic Acid Antagonists: Antimicrobial and Immunomodulating Mechanisms and Applications

: Bacterial, protozoan and other microbial infections share an accelerated metabolic rate. In order to ensure a proper functioning of cell replication and proteins and nucleic acids synthesis processes, folate metabolism rate is also increased in these cases. For this reason, folic acid antagonists have been used since their discovery to treat different kinds of microbial infections, taking advantage of this metabolic difference when compared with human cells. However, resistances to these compounds have emerged since then and only combined therapies are currently used in clinic. In addition, some of these compounds have been found to have an immunomodulatory behavior that allows clinicians using them as anti-inflammatory or immunosuppressive drugs. Therefore, the aim of this review is to provide an updated state-of-the-art on the use of antifolates as antibacterial and immunomodulating agents in the clinical setting, as well as to present their action mechanisms and currently investigated biomedical applications.

Efficacy and safety of trimethoprim-sulfamethoxazole in HIV-infected patients with cerebral toxoplasmosis in Brazil: a single-arm open-label clinical trial

Cerebral toxoplasmosis continues to cause high morbidity and mortality in developing countries. The association of sulfadiazine and pyrimethamine is considered the standard therapy; however, it has potential disadvantages. This single-arm open-label clinical trial was carried out in a tertiary hospital in São Paulo, Brazil. We included patients of at least 18 years of age, whose HIV infection was confirmed, and clinical and brain computed tomography (CT) findings were compatible with cerebral toxoplasmosis upon admission. Patients received trimethoprim (TMP) 10 mg/kg/day sulfamethoxazole (SMX) 50 mg/kg/day, in two divided doses. Brain CT was performed at study entry and after two weeks. The endpoints of the study were: (i) the proportion of patients with clinical and radiological response after two weeks of TMP-SMX and (ii) the proportion of patients who discontinued TMP-SMX due to adverse events. Forty-six patients were included (23 males, median age 35 years). The main clinical manifestations were headache, hemiparesis and altered mental status. The proportion of patients who obtained clinical and radiological response after two weeks of anti-toxoplasma treatment was 85% (n = 39). Overall, TMP-SMX was safe, with only 2 (4%) discontinuations due to adverse events. In this study, TMP-SMX was effective and safe in the treatment of HIV-related cerebral toxoplasmosis.

Treatment of toxoplasmosis: Current options and future perspectives

Toxoplasmosis is a worldwide parasitic disease infecting about one third of humans, with possible severe outcomes in neonates and immunocompromised patients. Despite continuous and successful efforts to improve diagnosis, therapeutic schemes have barely evolved since many years. This article aims at reviewing the main clinical trials and current treatment practices, and at addressing future perspectives in the light of ongoing researches.

Discovery of Potent and Selective Halogen-Substituted Imidazole-Thiosemicarbazides for Inhibition of Toxoplasma gondii Growth In Vitro via Structure-Based Design

Employing a simple synthetic protocol, a series of highly effective halogen-substituted imidazole-thiosemicarbazides with anti-Toxoplasma gondii effects against the RH tachyzoites, much better than sulfadiazine, were obtained (IC_50s 10.30—113.45 µg/mL vs. ~2721.45 µg/mL). The most potent of them, 12, 13, and 15, blocked the in vitro proliferation of T. gondii more potently than trimethoprim (IC₅₀ 12.13 µg/mL), as well. The results of lipophilicity studies collectively suggest that logP would be a rate-limiting factor for the anti-Toxoplasma activity of this class of compounds.

Systematic Identification of Thiosemicarbazides for Inhibition of Toxoplasma gondii Growth In Vitro

One of the key stages in the development of new therapies in the treatment of toxoplasmosis is the identification of new non-toxic small molecules with high specificity to Toxoplasma gondii. In the search for such structures, thiosemicarbazide-based compounds have emerged as a novel and promising leads. Here, a series of imidazole-thiosemicarbazides with suitable properties for CNS penetration was evaluated to determine the structural requirements needed for potent anti-Toxoplasma gondii activity. The best 4-arylthiosemicarbazides 3 and 4 showed much higher potency when compared to sulfadiazine at concentrations that are non-toxic to the host cells, indicating a high selectivity of their anti-toxoplasma activity.

HIV-Related Cerebral Toxoplasmosis Revisited: Current Concepts and Controversies of an Old Disease

Cerebral toxoplasmosis is the most common cause of expansive brain lesions in people living with HIV/AIDS (PLWHA) and continues to cause high morbidity and mortality. The most frequent characteristics are focal subacute neurological deficits and ring-enhancing brain lesions in the basal ganglia, but the spectrum of clinical and neuroradiological manifestations is broad. Early initiation of antitoxoplasma therapy is an important feature of the diagnostic approach of expansive brain lesions in PLWHA. Pyrimethamine-based regimens and trimethoprim-sulfamethoxazole (TMP-SMX) seem to present similar efficacy, but TMP-SMX shows potential practical advantages. The immune reconstitution inflammatory syndrome is uncommon in cerebral toxoplasmosis, and we now have more effective, safe, and friendly combined antiretroviral therapy (cART) options. As a consequence of these 2 variables, the initiation of cART can be performed within 2 weeks after initiation of antitoxoplasma therapy. Herein, we will review historical and current concepts of epidemiology, diagnosis, and treatment of HIV-related cerebral toxoplasmosis.

Community-acquired acute meningitis and encephalitis: a narrative review

Meningitis and encephalitis are medical emergencies. Patients need prompt evaluation and immediate empiric therapy to reduce the likelihood of fatal outcomes and chronic neurological sequelae. Conjugate bacterial vaccines have significantly reduced the incidence of bacterial meningitis, especially in children. As the results of changes in patterns of bacterial drug sensitivity, ceftriaxone is now part of the recommended empiric treatment for bacterial meningitis and should be administered as early as possible. Neuroimaging delays the treatment of meningitis and is not needed in most cases. Adjunctive corticosteroid therapy is of benefit for many patients with meningitis and should be initiated in most adults before antibiotic therapy. Molecular testing can assist the specific diagnosis of encephalitis and should be based on the exposure history and geographic risk factors relevant to the patient, but non-infectious causes of encephalitis are also common. Empiric therapy for encephalitis should be directed at the most frequently identified infectious pathogen, herpes simplex virus type 1 (ie, intravenous aciclovir). Vaccines can protect against the major pathogens of childhood infections (measles, mumps, rubella, polio, varicella viruses), influenza viruses, and exotic pathogens that cause meningitis and encephalitis (rabies, Japanese encephalitis, dengue, yellow fever, tick-borne encephalitis viruses, Mycobacterium tuberculosis).

Treatment of Toxoplasmosis: Historical Perspective, Animal Models, and Current Clinical Practice

Primary Toxoplasma gondii infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for Toxoplasma infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.

Evaluation of Current and Emerging Antimalarial Medicines for Inhibition of Toxoplasma gondii Growth in Vitro

Toxoplasma gondii is a common zoonotic infection of humans, and estimates indicate that 1-2 billion people are chronically infected. Although largely asymptomatic, chronic infection poses risk of serious disease due to reactivation should immunity decline. Current therapies for toxoplasmosis only control acute infection caused by actively proliferating tachyzoites but do not eradicate the chronic tissue cyst stages. As well, there are considerable adverse side effects of the most commonly used therapy of combined sulfadiazine and pyrimethamine. Targeting the folate pathway is also an effective treatment for malaria, caused by the related parasites Plasmodium spp., suggesting common agents might be used to treat both infections. Here, we evaluated currently approved and newly emerging medicines for malaria to determine if such compounds might also prove useful for treating toxoplasmosis. Surprisingly, the majority of antimalarial compounds being used currently or in development for treatment of malaria were only modestly effective at inhibiting in vitro growth of T. gondii tachyzoites. These findings suggest that many essential processes in P. falciparum that are targeted by antimalarial compounds are either divergent or nonessential in T. gondii, thus limiting options for repurposing of current antimalarial medicines for toxoplasmosis.

Adverse Event Profile of Pyrimethamine-Based Therapy in Toxoplasmosis: A Systematic Review

Introduction

Approximately a third of the population worldwide is chronically infected with Toxoplasma gondii. Pyrimethamine-based regimens are recommended for the treatment of toxoplasmosis.

Objective

The aim was to evaluate the safety profile of pyrimethamine-based treatment for the three main Toxoplasma manifestations: toxoplasmic encephalitis (TE), ocular toxoplasmosis, and congenital toxoplasmosis.

Methods

PubMed, Cochrane Library, and Google Scholar databases were searched through August 1, 2016. Randomized, observational, prospective/retrospective, and cohort studies were eligible. Thirty-one studies were included with a total of 2975 patients. Of these, 13 were in congenital toxoplasmosis (n = 929), 11 in ocular toxoplasmosis (n = 1284), and seven in TE (n = 687). Across manifestations, adverse event (AE)-related treatment discontinuation and/or change in therapy involved ≤37% of patients and occurred in >55% of studies: 100% for ocular toxoplasmosis, 57.1% for TE, and 61.5% for congenital toxoplasmosis. The most commonly observed AEs were bone marrow suppression, dermatologic, and gastrointestinal (GI). The prevalence of bone marrow suppression-related AEs was ≤50% in congenital toxoplasmosis, ≤42.7% in TE, and ≤9.0% in ocular toxoplasmosis. The frequency of GI and dermatologic AEs were ≤100 and ≤11.1%, respectively, for ocular toxoplasmosis, ≤10.7 and ≤17.9% for TE, and ≤10.8 and ≤2.1% for congenital toxoplasmosis. Steven–Johnson syndrome was reported in two patients with ocular toxoplasmosis and one with TE.

Conclusion

The AE profile associated with pyrimethamine-based treatments differed by each manifestation of toxoplasmosis and within a given manifestation. Hematologic AEs occurred across all manifestations indicating the importance of monitoring the blood of patients administered pyrimethamine-based regimens.

Systematic review and meta-analysis of secondary prophylaxis for prevention of HIV-related toxoplasmic encephalitis relapse using trimethoprim-sulfamethoxazole

A recent systematic literature and meta-analysis reported relative efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment of toxoplasmic encephalitis (TE) in HIV-infected adults. Here, we estimated relapse rates during secondary prophylaxis with TMP-SMX, and further explored differences in relapse rates prior to introduction of highly active antiretroviral therapy (HAART) and the widespread adoption of HAART. A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials yielded 707 studies whereby 663 were excluded after abstract screening, and 38 were excluded after full review leaving 6 studies for extraction. We performed double data extraction with a third-party adjudicator. Study designs varied with only one randomized study, four prospective cohorts and one retrospective cohort. Relapse rates were transformed using the Freeman-Tukey method and pooled using both fixed-effect and random-effects meta-analysis models. The TMP-SMX relapse rate was 16.4% (95% CI = 6.2% to 30.3%) based on random-effects models. When the disaggregated pre-HAART studies (n = 4) were included, the relapse rate was 14.9% (random effects; 95% CI = 3.7% to 31.9%). Analysis of two post-HAART studies indicated a relapse rate of 19.2% (random effects; 95% CI = 2.8% to 45.6%). Comparing the relapse rates between pre- and post-HAART studies were contrary to what might be expected based on known benefits of HAART therapy in this population. Nevertheless, cautious interpretation is necessary considering the heterogeneity of the included studies and a limited number of subjects receiving TMP-SMX reported in the post-HAART era.

Symptomatic Acute Toxoplasmosis in Returning Travelers

We report a family who acquired acute toxoplasmosis after a trip to Central America. One member developed severe clinical manifestations including bilateral chorioretinitis, hepatitis, and myocarditis requiring therapy. Symptomatic acute toxoplasmosis is unusual and possesses a diagnostic challenge. We discuss the clinical and epidemiological implications, laboratory diagnosis, and treatment plan.

The neuropathology of the adult cerebellum

This chapter summarizes the neuropathologic features of nonneoplastic disorders of the adult cerebellum. Gait ataxia and extremity dysmetria are clinical manifestations of diseases that interrupt the complex cerebellar circuitry between the neurons of the cerebellar cortex, the cerebellar nuclei (especially the dentate nuclei), and the inferior olivary nuclei. The cerebellum is a prominent target of several sporadic and hereditary neurodegenerative diseases, including multiple system atrophy, spinocerebellar ataxia, and Friedreich ataxia. Purkinje cells display selective vulnerability to hypoxia but a surprising resistance to hypoglycemia. A classic toxin that damages the cerebellar cortex is methylmercury, but the most common injurious agent to Purkinje cells is ethanol. Many drugs cause ataxia, but doubts continue about phenytoin. Ischemic lesions of the cerebellum due to arterial thrombosis or embolism cause a spectrum of symptoms and signs, depending on the territory involved. Large hemorrhages have an unfavorable prognosis because they displace critical brainstem structures or penetrate into the fourth ventricle. Fungal infections and toxoplasmosis of the cerebellum, and cerebellar progressive multifocal leukoencephalopathy, have become rarer because of improved control of the acquired immunodeficiency syndrome. Ataxia is a prominent feature of prion disease. Adult-onset Niemann-Pick type C1 disease and Kufs disease may have a predominantly ataxic clinical phenotype. The adult cerebellum is also vulnerable to several leukodystrophies. A rare but widely recognized complication of cancer is paraneoplastic cerebellar degeneration.

Molecular diagnosis of symptomatic toxoplasmosis: a 9-year retrospective and prospective study in a referral laboratory in São Paulo, Brazil

Symptomatic forms of toxoplasmosis are a serious public health problem and occur in around 10–20% of the infected people. Aiming to improve the molecular diagnosis of symptomatic toxoplasmosis in Brazilian patients, this study evaluated the performance of real time PCR testing two primer sets (B1 and REP-529) in detecting Toxoplasma gondii DNA. The methodology was assayed in 807 clinical samples with known clinical diagnosis, ELISA, and conventional PCR results in a 9-year period. All samples were from patients with clinical suspicion of several features of toxoplasmosis. According to the minimum detection limit curve (in C_T), REP-529 had greater sensitivity to detect T. gondii DNA than B1. Both primer sets were retrospectively evaluated using 515 DNA from different clinical samples. The 122 patients without toxoplasmosis provided high specificity (REP-529, 99.2% and B1, 100%). From the 393 samples with positive ELISA, 146 had clinical diagnosis of toxoplasmosis and positive conventional PCR. REP-529 and B1 sensitivities were 95.9% and 83.6%, respectively. Comparison of REP-529 and B1 performances was further analyzed prospectively in 292 samples. Thus, from a total of 807 DNA analyzed, 217 (26.89%) had positive PCR with, at least one primer set and symptomatic toxoplasmosis confirmed by clinical diagnosis. REP-529 was positive in 97.23%, whereas B1 amplified only 78.80%. After comparing several samples in a Brazilian referral laboratory, this study concluded that REP-529 primer set had better performance than B1 one. These observations were based after using cases with defined clinical diagnosis, ELISA, and conventional PCR.

Hepatic expression profiles in retroviral infection: relevance to drug hypersensitivity risk

HIV‐infected patients show a markedly increased risk of delayed hypersensitivity (HS) reactions to potentiated sulfonamide antibiotics (trimethoprim/sulfamethoxazole or TMP/SMX). Some studies have suggested altered SMX biotransformation in HIV infection, but hepatic biotransformation pathways have not been evaluated directly. Systemic lupus erythematosus (SLE) is another chronic inflammatory disease with a higher incidence of sulfonamide HS, but it is unclear whether retroviral infection and SLE share risk factors for drug HS. We hypothesized that retroviral infection would lead to dysregulation of hepatic pathways of SMX biotransformation, as well as pathway alterations in common with SLE that could contribute to drug HS risk. We characterized hepatic expression profiles and enzymatic activities in an SIV‐infected macaque model of retroviral infection, and found no evidence for dysregulation of sulfonamide drug biotransformation pathways. Specifically, NAT1,NAT2,CYP2C8,CYP2C9,CYB5R3,MARC1/2, and glutathione‐related genes (GCLC,GCLM,GSS,GSTM1, and GSTP1) were not differentially expressed in drug naïve SIVmac239‐infected male macaques compared to age‐matched controls, and activities for SMX N‐acetylation and SMX hydroxylamine reduction were not different. However, multiple genes that are reportedly over‐expressed in SLE patients were also up‐regulated in retroviral infection, to include enhanced immunoproteasomal processing and presentation of antigens as well as up‐regulation of gene clusters that may be permissive to autoimmunity. These findings support the hypothesis that pathways downstream from drug biotransformation may be primarily important in drug HS risk in HIV infection.

Toxoplasmic encephalitis relapse rates with pyrimethamine-based therapy: systematic review and meta-analysis

Toxoplasmic encephalitis (TE) is caused by Toxoplasma gondii infection and can be a life-threatening disease in immunocompromised patients. This study evaluated the rate of relapse associated with pyrimethamine-based maintenance therapy (i.e. secondary prophylaxis) in patients with human immunodeficiency virus (HIV) or AIDs treated prior to and after the common use (i.e. 1996) of highly active antiretroviral therapy (HAART) (pre-HAART and post-HAART, respectively). PubMed, Google Scholar, and Cochrane databases were searched to 6 June 2016 using search terms: pyrimethamine, Daraprim, Fansidar, Metakelfin, Fansimef, 5-(4-chlorophenyl)-6-ethyl-2,4-pyrimidinediamine, encephalitis, cerebral, toxoplasmosis, toxoplasmic, and gondii. Single-arm cohort, retrospective, and randomized studies were included. Twenty-six studies with 1,596 patients were included in the analysis; twenty pre-HAART (n = 1,228) studies and six post-HAART (n = 368) were performed. Pooled proportions test for pyrimethamine-based therapy from pre-HAART studies indicated a relapse rate of 19.2% and 18.9% from the fixed-effects and random-effects models, respectively. The relapse rate in the post-HAART studies was 11.1% (fixed and random effects). Continuous therapy was suggestive of lower incidence of relapse compared with intermittent therapy in the pre-HAART era (range, 18.7 to 17.3% vs. 20.9 to 25.6%, respectively). These findings indicate that the likelihood of relapse associated with pyrimethamine-based therepy in patients with HIV and TE decreased after the introduction of HAART to approximately 11%. The findings have important implications as relapse may affect a patient’s disease severity and prognosis, increase utilization of health care resources, and result in additional health care expenditure.