Syphilitic infection impairs immunity by inducing both apoptosis and pyroptosis of CD4+ and CD8+ T lymphocytes

Comparative analysis of T-cell immunity between Streptococcus agalactiae susceptible and resistant tilapia (Oreochromis niloticus)

Nile tilapia (Oreochromis niloticus) is one of the important economic fish species cultured worldwide. However, Streptococcus agalactiae has emerged as a significant bacterial threat, severely impacting the economy of tilapia industry. The immune response underlying the resistance of tilapia to S. agalactiae are not well understood, hindering the reasonable evaluation of breeding and the formulation of effective strategies. In this study, we investigated the differences in T-cell immunity between S. agalactiae-resistant and -susceptible tilapia. Compared with susceptible tilapia, resistant tilapia exhibited a higher percentage of T cells and BrdU+ T cells during infection, indicating a superior proliferative capacity. Whether infected or not, T cells from resistant fish demonstrated a greater ability to resist apoptosis. Additionally, T cell effector genes, including interleukin (IL)-2, interferon (IFN)-γ, perforin A, and granzyme B were expressed at higher levels in resistant tilapia after infection. Along with these T-cell immune responses, resistant fish showed more effective clearance of infection. Our study elucidates the T-cell immune responses in resistant tilapia, which may contribute to the high resistance of tilapia to S. agalactiae, and provide valuable theoretical references for the selection and evaluation of disease-resistant fish strains in the future.

Coinfection of cerebral toxoplasmosis and neurosyphilis as the first manifestation of AIDS

A male in his 30s with a medical history of newly diagnosed HIV with a CD4 count of 292 cells/mm3 presented with a bilateral frontal headache and left upper and lower extremity weakness and paraesthesias. A few months prior, the patient experienced a desquamating rash on his scalp and a pruritic, papular genital rash, which both self-resolved. CT head without contrast revealed extensive vasogenic oedema involving the right basal ganglia, thalamus, temporal and occipital lobes. MRI of the brain with and without contrast revealed two enhancing masses in the right lentiform nucleus and right temporal-occipital junction with associated vasogenic oedema. Cerebrospinal fluid (CSF) studies confirmed cerebral toxoplasmosis with positive CSF Toxoplasma gondii PCR and neurosyphilis with positive serum rapid plasma reagin and CSF venereal disease research laboratory test. He was treated with trimethoprim/sulfamethoxazole and intravenous penicillin G with the resolution of his symptoms.

LC-MS metabolomics and lipidomics in cerebrospinal fluid from viral and bacterial CNS infections: a review

There is compelling evidence that a dysregulated immune inflammatory response in neuroinfectious diseases results in modifications in metabolic processes and altered metabolites, directly or indirectly influencing lipid metabolism within the central nervous system (CNS). The challenges in differential diagnosis and the provision of effective treatment in many neuroinfectious diseases are, in part, due to limited understanding of the pathophysiology underlying the disease. Although there are numerous metabolomics studies, there remains a deficit in neurolipidomics research to provide a comprehensive understanding of the connection between altered metabolites and changes in lipid metabolism. The brain is an inherently high-lipid organ; hence, understanding neurolipidomics is the key to future breakthroughs. This review aims to provide an integrative summary of altered cerebrospinal fluid (CSF) metabolites associated with neurolipid metabolism in bacterial and viral CNS infections, with a particular focus on studies that used liquid chromatography-mass spectrometry (LC-MS). Lipid components (phospholipids) and metabolites (carnitine and tryptophan) appear to be the most significant indicators in both bacterial and viral infections. On the basis of our analysis of the literature, we recommend employing neurolipidomics in conjunction with existing neurometabolomics data as a prospective method to enhance our understanding of the cross link between dysregulated metabolites and lipid metabolism in neuroinfectious diseases.

Novel and characteristic radiological features of neurosyphilis: a case series

BACKGROUND

Treponema pallidum can invade the central nervous system (CNS) early in its infection, causing neurosyphilis. Neurosyphilis typically presents with meningovasculitis in the acute or subacute phase, while tabes dorsalis and dementia paralytica are classical conditions in the later stages. However, syphilis is often misdiagnosed as other conditions such as tumors or autoimmune diseases including vasculitis and encephalitis, which is why the condition is known as "The Great Mimicker." The increasing incidence of syphilis in recent years emphasizes the importance of early diagnosis and treatment; however, its multiple clinical manifestations impose diagnostic challenges for clinicians because it resembles other diseases. In this case series, we present the impressive manifestations of neurosyphilis through three unique radiological presentations.

CASE PRESENTATION

Case 1 details optic nerve involvement in an HIV-positive male, where MRI and fundoscopic findings confirmed syphilitic optic neuritis. Case 2 describes a patient in her pregnancy initially suspected of acoustic neuroma on MRI, later diagnosed with syphilitic gumma affecting the inner ear canal. Case 3 is a young male with clinical features mimicking temporal arteritis, ultimately identified as skull osteomyelitis secondarily causing inflammation of the musculus temporalis and meningitis.

CONCLUSIONS

These cases underscore the necessity of considering syphilis in differential diagnoses, given the diversity of its clinical presentations. Radiology plays an important role in avoiding unnecessary interventions. The increasing prevalence of recurrent syphilis imposes diagnostic challenges, emphasizing the importance of the early diagnosis and treatment of neurosyphilis by clinicians.

Immunophenotypic variations in syphilis: insights from Mendelian randomization analysis

Background

Infection with Treponema pallidum instigates complex immune responses. Prior research has suggested that persistent Treponema pallidum infection can manipulate host immune responses and circumvent host defenses. However, the precise role of immune cells in Treponema pallidum infection across different stages remains a contentious issue.

Methods

Utilizing summary data from genome-wide association studies, we employed a two-sample Mendelian randomization method to investigate the association between 731 immunophenotypes and syphilis. Syphilis was categorized into early and late stages in this study to establish a more robust correlation and minimize bias in database sources.

Results

Our findings revealed that 33, 36, and 27 immunophenotypes of peripheral blood were associated with syphilis (regardless of disease stage), early syphilis and late syphilis, respectively. Subsequent analysis demonstrated significant variations between early and late syphilis in terms of immunophenotypes. Specifically, early syphilis showcased activated, secreting, and resting regulatory T cells, whereas late syphilis was characterized by resting Treg cells. More B cells subtypes emerged in late syphilis. Monocytes in early syphilis exhibited an intermediate and non-classical phenotype, transitioning to classical in late syphilis. Early syphilis featured naive T cells, effector memory T cells, and terminally differentiated T cells, while late syphilis predominantly presented terminally differentiated T cells. Immature myeloid-derived suppressor cells were evident in early syphilis, whereas the dendritic cell immunophenotype was exclusive to late syphilis.

Conclusion

Multiple immunophenotypes demonstrated associations with syphilis, showcasing substantial disparities between the early and late stages of the disease. These findings hold promise for informing immunologically oriented treatment strategies, paving the way for more effective and efficient syphilis interventions.

Neurosyphilis: insights into its pathogenesis, susceptibility, diagnosis, treatment, and prevention

Background and aim

Invasion of the central nervous system by Treponema pallidum can occur at any stage of syphilis. In the event that T. pallidum is not cleared promptly, certain individuals may experience progression to neurosyphilis, which manifests as cognitive and behavioral abnormalities, limb paralysis, and potentially fatal outcomes. Early identification or prevention of neurosyphilis is therefore crucial. The aim of this paper is to conduct a critical and narrative review of the latest information focusing exclusively to the pathogenesis and clinical management of neurosyphilis.

Methodology

To compile this review, we have conducted electronic literature searches from the PubMed database relating to neurosyphilis. Priority was given to studies published from the past 10 years (from 2013 to 2023) and other studies if they were of significant importance (from 1985 to 2012), including whole genome sequencing results, cell structure of T. pallidum, history of genotyping, and other related topics. These studies are classic or reflect a developmental process.

Results

Neurosyphilis has garnered global attention, yet susceptibility to and the pathogenesis of this condition remain under investigation. Cerebrospinal fluid examination plays an important role in the diagnosis of neurosyphilis, but lacks the gold standard. Intravenous aqueous crystalline penicillin G continues to be the recommended therapeutic approach for neurosyphilis. Considering its sustained prominence, it is imperative to develop novel public health tactics in order to manage the resurgence of neurosyphilis.

Conclusion

This review gives an updated narrative description of neurosyphilis with special emphasis on its pathogenesis, susceptibility, diagnosis, treatment, and prevention.

Multiple SARS-CoV-2 immunizations of an unvaccinated population lead to complex immunity. A T cell reactivity study of blood donors in Antananarivo

BACKGROUND

Madagascar has undergone multiple and robust COVID-19 waves. The resulting immune background developed by its poorly vaccinated population has however not been described.

METHODS

In this study, serological analysis and specific T cell response descriptions were used to describe the history of exposures of the capital's blood donors to SARS-CoV-2 and its VOCs. Samples were collected early 2022, and pools of multiple immunogenic peptides of SARS-CoV-2 were used in an IFN-γ secretion ELISPOT assay to characterize the specific T-cell immunity developed against these potential epitopes.

RESULTS

Multiple epidemic waves have led to 92.1% of donors having detectable antibodies, and 94.8% having developed T-cells against SARS-CoV-2. Heterogeneous reactivities to different strain-derived peptides suggested multiple immunological backgrounds in the population including 16.1% of individuals exposed at least once to a unique strain, 27.1% to two strains, 28.5% to three strains, and 23.1% to four distinct strains.

CONCLUSIONS

Cross-reactivity increased with multiple exposures but did not decrease the risk of re-infection. These results describe the extremely complex immunological background developed following multiple natural immunizations.

Effects of syphilis infection among HIV-1-positive individuals on suppressive antiretroviral therapy

INTRODUCTION

Incident syphilis leads to changes in plasma HIV-1 RNA and CD4 + T-cell level in people with HIV (PWH) with viraemia. Its effect in PWH on suppressive antiretroviral therapy (ART) is less clear.

METHODS

PWH on suppressive ART (plasma HIV-1 RNA < 50copies/mL) followed at the Queen Elizabeth Hospital, Hong Kong, China were regularly screened for syphilis. Their plasma HIV-1 RNA, CD4 + and CD8 + T-cell, and total lymphocyte levels before syphilis, during syphilis, and after successful treatment were compared.

RESULTS

Between 2005 and 2020, 288 syphilis episodes from 180 individuals were identified; 287 episodes were related to male, with a median age of 41 at diagnosis; 221 (77%) were syphilis re-infection. The rates of plasma HIV-1 suppression were statistically unchanged across the time-points (97% pre-syphilis, 98% during syphilis, and 99% post-treatment). Total lymphocyte, CD4+ and CD8+ T-cell levels decreased during incident syphilis (p<0.01), and rebounded post-treatment (p<0.01). VDRL titre was associated with declines in CD4+ T-cell (p=0.045), CD8+ T-cell (p=0.004), and total lymphocyte levels (p=0.021). Pre-syphilis CD4/CD8 ratio was associated with increases in CD8+ T-cell (p=0.001) and total lymphocyte levels (p=0.046) during syphilis. Syphilis re-infection was associated with an increase in total lymphocyte level (p=0.037). In the multivariable analysis, only pre-syphilis CD4/CD8 ratio was independently associated with increases in CD8+ T-cell (p=0.014) and total lymphocyte levels (p=0.039) during syphilis.

CONCLUSIONS

Among virally-suppressed PWH, total lymphocyte, CD4+, and CD8+ T-cell levels declined during incident syphilis but rebounded post-treatment. The status of plasma HIV suppression was unaffected by syphilis.

Fascinating Molecular and Immune Escape Mechanisms in the Treatment of STIs (Syphilis, Gonorrhea, Chlamydia, and Herpes Simplex)

The incidence of syphilis, gonorrhea, chlamydia, and herpes simplex has increased over the last decade, despite the numerous prevention strategies. Worldwide scientists report a surge in drug-resistant infections, particularly in immunocompromised patients. Antigenic variations in syphilis enable long-term infection, but benzathine penicillin G maintains its efficiency, whereas macrolides should be recommended with caution. Mupirocin and zoliflodacin were recently introduced as therapies against ceftriaxone-resistant gonococcus, which poses a larger global threat. The gastrointestinal and prostatic potential reservoirs of Chlamydia trachomatis may represent the key towards complete eradication. Similar to syphilis, macrolides resistance has to be considered in genital chlamydiosis. Acyclovir-resistant HSV may respond to the novel helicase-primase inhibitors and topical imiquimod, particularly in HIV-positive patients. Novel drugs can overcome these challenges while nanocarriers enhance their potency, particularly in mucosal areas. This review summarizes the most recent and valuable discoveries regarding the immunopathogenic mechanisms of these sexually transmitted infections and discusses the challenges and opportunities of the novel molecules and nanomaterials.