Association of Interleukin-10 promoter polymorphisms with neurosyphilis

The Significance of the Cell-Mediated Host Immune Response in Syphilis

Syphilis, caused by the highly invasive pathogen Treponema pallidum, remains one of the oldest and most significant public health challenges. According to the World Health Organization (WHO), the number of new syphilis cases among adults aged 15-49 years in 2022 was estimated at approximately 8 million, with notable increases observed in Europe, the Americas, and Africa. The cellular immune response plays a critical role in combating this infection, and its insufficient activity may contribute to chronic progression of the disease. T. pallidum effectively evades the host immune response, enabling its prolonged survival within the host and increasing the risk of late complications such as neurosyphilis and cardiovascular syphilis. This review article discusses the mechanisms of cellular immune responses in T. pallidum infection, including T lymphocyte activation, proinflammatory cytokine production, and the roles of macrophages and dendritic cells in pathogen recognition and elimination. Additionally, it examines the immune evasion strategies employed by T. pallidum, such as the low immunogenicity of its antigens and its ability to suppress the activation of effector cells. A comprehensive understanding of the current knowledge regarding cellular immune mechanisms may contribute to the development of more effective diagnostic and therapeutic approaches in syphilis management.

Elevated IL-10 serum levels are associated with slower serological response following syphilis treatment during pregnancy

BACKGROUND

Approximately 50% of pregnant individuals treated for syphilis do not achieve a decline in non-treponemal titers by delivery. The serological response in pregnant persons is significantly slower compared to non-pregnant individuals, with unclear pathogenesis and clinical significance. This study aimed to determine the association between the host immune response and serological outcome in pregnant individuals with syphilis.

METHODS

Twenty-four females with early syphilis, including 14 pregnant individuals, were included. Pro-inflammatory and regulatory cytokines (IFN-γ, TNF-α, IL-4, IL-1β, IL-10, TGF-β) were measured before treatment and 6 months after penicillin injection.

RESULTS

The median time to serological cure was 5 months for pregnant individuals and 2 months for non-pregnant females. Pregnant individuals had significantly higher serum levels of IL-10 and TGF-β at baseline and at 6 months post-treatment compared to non-pregnant individuals (p < .05).

CONCLUSIONS

A robust regulatory immune response to syphilis may be associated with a slower serological response to therapy during pregnancy.

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.

The association of host genes with specific sexually transmitted infections

Sexually transmitted infections (STIs) are hazardous to human health worldwide. STIs have a direct influence on sexual and reproductive health and can increase the chances of HIV. Globally, more than 1 million STIs are acquired every day and the majority are asymptomatic. Approximately, 374 million cases of STIs have been reported annually. The most prevalent STIs include chlamydia, gonorrhoea, syphilis, and trichomoniasis. These STIs are caused by Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum and Trichomonas vaginalis. The major factor that contributes to the susceptibility and prognosis of infectious diseases is genetic variation. Host genes play a huge role in STIs and immune response. The production of host factors is stimulated by a variety of bacteria, viruses and parasites and the host factors can play a role in increasing host vulnerability to infection and pathogen persistence. Genetic variation or polymorphisms within certain host genes can influence the course of pathogen infection and disease progression. Polymorphisms can contribute to changes in gene expression and or changes in the protein structure. which may either contribute to/or protect against infection. This review discusses the role of host genes in influencing the susceptibility of the most prevalent STIs caused by Chlamydia trachomatis, Trichomonas vaginalis, Treponema pallidum and Neisseria gonorrhoeae. We evaluate polymorphisms associated pathogen recognition signalling pathway of these diseases. These polymorphisms may be used as biomarkers to infer risk to specific STIs.

CARE-NS, a research strategy for neurosyphilis

Neurosyphilis is a major clinical manifestation of syphilis. In recent years, an increase in neurosyphilis cases has been reported in many countries. The overall incidence of neurosyphilis remains unknown, and there is a lack of understanding of the disease pathogenesis, which hampers clinical management, development of prevention strategies, and control. This article proposes the CARE-NS research strategy to enhance the clinical management of neurosyphilis, which consists of six key features: comprehensive management including multidisciplinary treatment (C), alleviating neurological impairment and sequelae (A), risk factors and clinical epidemiology (R), etiology and pathogenesis (E), new diagnostic indicators and strategies (N), and social impact and cost-effectiveness analysis (S).

An Updated Review of Recent Advances in Neurosyphilis

Neurosyphilis is caused by Treponema pallidum invading the central nervous system, of which the incidence is increasing worldwide. Due to its variable clinical manifestations, diagnosis of neurosyphilis remains challenging, especially the asymptomatic form. This review focuses on recent advances in neurosyphilis, including epidemiology, clinical manifestations, laboratory findings, comorbidities, diagnosis, treatment, prognosis, and basic research. The expansion of men who have sex with men and the infection of human immunodeficiency virus mainly accounted for the increasing incidence of neurosyphilis. The rate of some historically described forms of neurosyphilis in the pre-antibiotic era declined significantly; atypical features are more prevalent. Neurosyphilis, regarded as a great mimicker for neuro-ophthalmic, audio-vestibular, and psychiatric disorders, often presents concomitantly with other diseases, including metabolic disorders. Studies on long non-coding RNAs, miRNAs, chemokines, and metabolites in peripheral blood and cerebrospinal fluid may facilitate exploring the pathogenesis and identifying novel biomarkers of neurosyphilis. The drug resistance of Treponema pallidum to penicillin has not been reported; ceftriaxone was proposed to be more effective than penicillin, whereas few randomized controlled trials supported this view. This study may pave the way for further research, especially the diagnosis and treatment of neurosyphilis.

Combination of the neutrophil to lymphocyte ratio and serum toluidine red unheated serum test titer as a predictor of neurosyphilis in HIV-negative patients

The present study explored the associations of the neutrophil to lymphocyte ratio (NLR) and the serum toluidine red unheated serum test (TRUST) titer with neurosyphilis (NS). The present retrospective study examined 87 NS patients and 80 Non-NS patients from an HIV-negative cohort and 1:1 age- and gender-matched healthy controls. The results demonstrated that the NLR was increased in both NS and Non-NS groups compared with that in the healthy controls (P<0.001 and P=0.01, respectively). The NLR and serum TRUST titer in the NS group were significantly higher than those in the Non-NS group (P=0.004 and P<0.001, respectively). The NLR was positively correlated with the serum TRUST titer (r=0.298, P<0.001). Age, elevated NLR and serum TRUST titer were distinctly associated with NS by binomial logistic regression analysis [odds ratio (OR)=1.10, P<0.001; OR=1.36, P=0.028; OR=3.07, P<0.001; respectively]. The cut-off values for the NLR and serum TRUST titer were 1.97 and 1:8, respectively. A significantly higher sensitivity of 90.8% was obtained for screening out NS with a combination of the NLR and serum TRUST titer compared with each test alone. Age, elevated NLR and serum TRUST titer were associated with NS. The combination of NLR and serum TRUST titer is a potential predictor for NS, and the reduced NLR and serum TRUST titer at the 6-month follow up suggested that the NLR and serum TRUST titer were biomarkers for monitoring the disease course.

CXCL13 concentration in latent syphilis patients with treatment failure

We aimed to investigate the CXCL13 concentration of the serum and cerebral spinal fluid (CSF) in human immunodeficiency virus (HIV)-negative latent syphilis patients with treatment failure and explore the change in CXCL13 after treatment. Sixty-eight latent syphilis patients with treatment failure (failure group), 68 syphilis patients with successful treatment (seroconversion group) and 18 patients with non-inflammatory diseases of the nervous system (control group) were included and serum and CSF were collected. Enzyme-linked immunosorbent assay was employed to detect the CXCL13 in the serum and CSF. Results showed that the serum CXCL13 concentration was comparable among three groups, and the CSF leukocyte count, IgG index and CXCL13 concentration in the failure group were significantly higher than those in the seroconversion group and control group (P < 0.05, P < 0.01). CSF CXCL13 concentration in the failure group was positively related to the CSF leukocyte count (r = 0.3594, P < 0.001). Of the 68 patients in the treatment failure group, neurosyphilis was found in 17 (25.0%). In conclusion, involvement of nervous system is one of the reasons for the treatment failure in patients with latent syphilis. Detection of CSF CXCL13 concentration is helpful for the diagnosis and therapeutic evaluation of HIV-negative latent syphilis patients with treatment failure and neurosyphilis.

Cerebrospinal Fluid Cytokines in Patients with Neurosyphilis: The Significance of Interleukin-10 for the Disease

The aim of this study was to examine the cerebrospinal fluid (CSF) concentrations of proinflammatory and anti-inflammatory cytokines in neurosyphilis (NS), analyze the differences between asymptomatic NS (ANS) and symptomatic NS (SNS), and explore the diagnostic value of these cytokines. We enrolled 45 patients with a diagnosis of NS, including 18 patients with ANS and 27 patients with SNS, whose cerebrospinal fluid (CSF) samples were collected before penicillin therapy. Twelve patients with syphilis but non-NS (NNS) were also included. We measured the CSF levels of interleukin- (IL-) 1β, IL-4, IL-6, IL-10, IL-17A, IL-21, and tumor necrosis factor- (TNF-) α; the CSF levels of the microglial activation marker soluble triggering receptor expressed on myeloid cells 2 (sTREM2); and the CSF levels of the neuronal injury marker neurofilament light proteins (NFL) using the human cytokine multiplex assay or ELISA. Of the measured cytokines in the CSF, only IL-10 levels were significantly increased in NS patients compared to NNS patients (p < 0.001). In a subgroup analysis, the CSF levels of IL-10 were significantly elevated in SNS patients compared to ANS and NNS patients (p = 0.024 and p < 0.001, respectively). The CSF IL-10 levels had a significant correlation with the markers of microglial activation and neuronal injury, and they also correlated with CSF rapid plasma reagin (RPR) titer, CSF white blood cell (WBC) count, and CSF protein concentration. The areas under the ROC curve (AUC) of CSF IL-10 in the diagnosis of NS and ANS were 0.920 and 0.891, respectively. The corresponding sensitivities/specificities were 86.7%/91.7% and 83.3%/91.7%, respectively. Therefore, the excessive production of IL-10 might facilitate bacterial persistent infection, play an important role in the pathogenesis of NS, and associate with the progression of the disease. CSF IL-10 concentration had a useful value in the diagnosis of NS, especially in ANS.

Association of interleukin-10 promoter polymorphisms with serofast state after syphilis treatment

OBJECTIVES

Recent studies suggested that upregulation of anti-inflammatory immune response during early syphilis may be associated with persistence of Treponema pallidum infection despite adequate treatment, resulting in a serofast state. The objective of this study was to determine whether enhanced interleukin (IL)-10-related response during early T. pallidum infection increased the risk of serofast syphilis.

METHODS

Two IL10 gene promoter polymorphisms affecting IL-10 production (-1082A>G [rs1800896], -592C>A [rs1800872]) and serum levels of IL-10 were measured in 80 patients with early syphilis before and 6 months after penicillin treatment and in 24 healthy volunteers (control group).

RESULTS

After 6 months, patients were stratified based on serological response into two groups: (1) serofast state (n = 28) and (2) serologically cured (n = 52). Pretreatment and post-treatment serum IL-10 levels were significantly higher in patients who remained serofast compared with those who had a serological cure (p<0.001). The GG genotype of the -1082A>G (rs1800896) polymorphism and the CC genotype of the -592C>A (rs1800872) polymorphism were significantly correlated with higher serum IL-10 levels. Moreover, the OR for remaining serofast for carriers of these genotypes was 16.2 (95% CI: 4.1 to 65.0, p<0.0001) and 2.9 (95% CI: 1.4 to 5.9, p=0.002), respectively.

CONCLUSIONS

We showed that a pronounced anti-inflammatory immune response may be an important predictor for the serofast state. Additionally, host-related factors such as polymorphisms of immune regulatory genes may influence the risk of remaining serofast after syphilis therapy.

The immunological response to syphilis differs by HIV status; a prospective observational cohort study

Background

It is not known if there is a difference in the immune response to syphilis between HIV-infected and uninfected individuals.

Methods

We prospectively recruited all patients with a new diagnosis of syphilis and tested their plasma for IFNα, IFNγ, IL-1β, IL-12p40, IL-12p70, IP-10, MCP-1, MIP-1α, MIP-1β, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10 and IL-17A at baseline pre-treatment and 6 months following therapy.

Results

A total of 79 HIV-infected [44 primary/secondary syphilis (PSS) and 35 latent syphilis (LS)] and 12 HIV-uninfected (10 PSS and 2 LS) cases of syphilis and 30 HIV-infected controls were included in the study. At the baseline visit, compared to the control group, concentrations of IL-10 were significantly elevated in the HIV-infected and uninfected groups. The level of IL-10 was significantly higher in the HIV-infected compared to the HIV-uninfected PSS group (25.3 pg/mL (IQR, 4.56–41.76) vs 2.73 pg/mL (IQR, 1.55–9.02), P = 0.0192). In the HIV-infected PSS group (but not the HIV-infected LS or HIV-uninfected PSS groups) the IP-10, MIP-1b, IL-6 and IL-8 were raised compared to the controls. IL-10 levels decreased but did not return to control baseline values by 6 months in HIV infected PSS and LS and HIV uninfected PSS.

Conclusion

PSS and LS in HIV-infected individuals is characterized by an increase in inflammatory and anti-inflammatory cytokines such as IL-10. The increase of IL-10 is greater in HIV-infected than uninfected individuals. Further work is required to ascertain if this is part of an immunological profile that correlates with adverse outcomes such as serofast syphilis and neurosyphilis, in HIV-infected individuals.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2201-7) contains supplementary material, which is available to authorized users.

Robust pro-inflammatory immune response is associated with serological cure in patients with syphilis: an observational study

OBJECTIVES

Approximately 15% of adequately treated patients with early syphilis remain serofast. Pathogenesis and clinical significance of this phenomenon is unclear. The objective of this study was to determine whether there is any association between host immune response and treatment outcome (serofast state or proper serological response).

METHODS

Forty-four patients with secondary syphilis were enrolled to this study. Levels of pro-inflammatory cytokines such as interferon-γ, tumour necrosis factor-α and interleukin-6 were measured before treatment and 8 hours after injection of antibiotic.

RESULTS

After 1 year, based on the serological response patients were stratified into two groups: (1) proper serological response (n=31) and (2) serofast state (n=9). The serological cure rate was 77.5% at 12 months after treatment. Patients with proper serological response had significantly higher levels of analysed cytokines (at baseline and 8 hours after treatment) compared with the serofast state group (p<0.05).

CONCLUSIONS

We showed that robust host pro-inflammatory immune response to infection may be the predictive factor of serological cure. The treatment outcome may be also associated with the magnitude of immune reaction occurring during the treatment.