CXCL8, CXCL9, and CXCL10 serum levels increase in syphilitic patients with seroresistance

The serological dilemma: rethinking syphilis treatment evaluation

INTRODUCTION

Nontreponemal tests (NTT) constitute a significant method in syphilis detection, playing a crucial role in screening, diagnosing, and monitoring disease activity. However, recent discussions have cast doubt on the traditional belief that NTT are suitable for evaluating treatment efficacy, as inconsistencies between NTT results and syphilis treatment outcomes have been observed with some frequency.

AREAS COVERED

We have delineated the current status of serological methods for evaluating the therapeutic efficacy of syphilis treatment and summarized and discussed the exploration of biomarkers for syphilis therapy. A literature search was conducted in PubMed over all available dates for relevant published papers and conference abstracts with the search terms, 'Syphilis,' 'Treponema pallidum,' 'Serofast,' 'Treatment efficacy evaluation,' 'Nontreponemal,' 'RPR,' 'TRUST,' 'VDRL,' 'Neurosyphilis,' 'Pregnant syphilis,' 'Congenital syphilis,' 'Reinfection,' 'Cardiolipin,' 'Serology.'

EXPERT OPINION

Currently, the assessment of treatment efficacy through serological methods is limited to the use of the NTT. Therefore, it is imperative for clinicians to gain a deeper understanding of the significance and limitations of the NTT, as well as a focus on exploring more potential indicators for evaluating treatment efficacy.

Serofast status in syphilis: Pathogenesis to therapeutics

Syphilis, a sexually transmitted infection caused by Treponema pallidum, has been experiencing a rise in prevalence in recent years. "Syphilis serofast" describes a unique serological reaction in patients with syphilis whose clinical symptoms have resolved following consistent anti-syphilitic therapy, but the non-Treponema pallidum antigen serologic test is still positive. Syphilis serofast is a risk factor for syphilis recurrence, neurosyphilis, and multisystem involvement. Considering the current lack of comprehensive knowledge about the epidemiological characteristics, pathogenesis, and therapies of syphilis serofast, we conducted an online search of research relating to syphilis serofast over the last twenty years. Previous research has shown that the pathogenesis of syphilis serofast is mainly related to clinical factors, immune factors, syphilis subtypes, and T.pallidum membrane protein repeat gene antigen. There are two distinct viewpoints on the treatment of serofast: no excessive treatment and active treatment. In addition, serofast patients also showed two clinical outcomes: syphilis recurrence and persistent serofast status. This article systematically reviews the related factors, treatment, and clinical outcomes of syphilis serofast, provides a theoretical basis for its research, diagnosis, and treatment, and helps clinicians develop a follow-up treatment management plan for syphilis serofast.

Can alpha‐linolenic acid be a modulator of “cytokine storm,” oxidative stress and immune response in SARS‐CoV‐2 infection?

Alpha‐linolenic acid (ALA) is a long‐chain polyunsaturated essential fatty acid of the Ω3 series found mainly in vegetables, especially in the fatty part of oilseeds, dried fruit, berries, and legumes. It is very popular for its preventive use in several diseases: It seems to reduce the risk of the onset or decrease some phenomena related to inflammation, oxidative stress, and conditions of dysregulation of the immune response. Recent studies have confirmed these unhealthy situations also in patients with severe coronavirus disease 2019 (COVID‐19). Different findings (in vitro, in vivo, and clinical ones), summarized and analyzed in this review, have showed an important role of ALA in other various non‐COVID physiological and pathological situations against “cytokines storm,” chemokines secretion, oxidative stress, and dysregulation of immune cells that are also involved in the infection of the 2019 novel coronavirus. According to the effects of ALA against all the aforementioned situations (also present in patients with a severe clinical picture of severe acute respiratory syndrome‐(CoV‐2) infection), there may be the biologic plausibility of a prophylactic effect of this compound against COVID‐19 symptoms and fatality.

Resurgence of syphilis: focusing on emerging clinical strategies and preclinical models

Syphilis, a sexually transmitted disease (STD) caused by Treponema pallidum (T. pallidum), has had a worldwide resurgence in recent years and remains a public health threat. As such, there has been a great deal of research into clinical strategies for the disease, including diagnostic biomarkers and possible strategies for treatment and prevention. Although serological testing remains the predominant laboratory diagnostic method for syphilis, it is worth noting that investigations pertaining to the DNA of T. pallidum, non-coding RNAs (ncRNAs), chemokines, and metabolites in peripheral blood, cerebrospinal fluid, and other bodily fluids have the potential to offer novel perspectives on the diagnosis of syphilis. In addition, the global spread of antibiotic resistance, such as macrolides and tetracyclines, has posed significant challenges for the treatment of syphilis. Fortunately, there is still no evidence of penicillin resistance. Hence, penicillin is the recommended course of treatment for syphilis, whereas doxycycline, tetracycline, ceftriaxone, and amoxicillin are viable alternative options. In recent years, efforts to discover a vaccine for syphilis have been reignited with better knowledge of the repertoire of T. pallidum outer membrane proteins (OMPs), which are the most probable syphilis vaccine candidates. However, research on therapeutic interventions and vaccine development for human subjects is limited due to practical and ethical considerations. Thus, the preclinical model is ideal for conducting research, and it plays an important role in clinical transformation. Different preclinical models have recently emerged, such as in vitro culture and mouse models, which will lay a solid foundation for clinical treatment and prevention of syphilis. This review aims to provide a comprehensive summary of the most recent syphilis tactics, including detection, drug resistance treatments, vaccine development, and preclinical models in clinical practice.

Serum Interleukin-26 is a Potential Biomarker for the Differential Diagnosis of Neurosyphilis and Syphilis at Other Stages

Background

Interleukin-26 (IL-26) is an atypical proinflammatory cytokine due to its binding to circulating double-stranded DNA and direct antibacterial activity. Although IL-26 has been confirmed to be involved in the pathophysiology of cancer, chronic inflammatory diseases and infections, the diagnostic and prognostic values of IL-26 levels in syphilis patients are not clear. This study aimed to investigate IL-26 levels in different stages of syphilis progression.

Methods

A total of 30 healthy controls and 166 patients with syphilis at different stages of disease progression were enrolled. Serum IL-26 levels were quantified in accordance with the protocols of RayBio^® Human Interleukin-26 Enzyme Linked Immunosorbent Assay (ELISA) kits. Clinical laboratory diagnostic parameters and blood analysis data were detected and collected according to clinical medical laboratory standards.

Results

The levels of serum IL-26 were significantly higher in neurosyphilis patients than in healthy subjects (6.87 (4.36, 12.14) and 1.67 (0.09, 4.89) pg/μL, respectively; ****p < 0.0001), latent syphilis (1.48 (0.40, 2.05) pg/μL, ****p < 0.0001), seroresistant syphilis (0.81 (0.20, 2.91) pg/μL, ****p < 0.0001) and secondary syphilis (1.66 (0.41, 4.25) pg/μL, ****p < 0.0001) with data presented as the median with interquartile range. The concentration of serum IL-26 was most sensitive to serum low-density lipoprotein concentration (r = -0.438, **p = 0.004) in latent syphilis, urine epithelial cells (r = 0.459, **p = 0.003) in seroresistant syphilis, and serum creatinine levels (r = 0.463, **p = 0.004) and urea creatinine ratio levels (r = 0.500, **p = 0.008) in secondary syphilis patients. There was no significant correlation with the concentration of IL-26 and toluidine red unheated serum test (TRUST) titers in each type of syphilis patient.

Conclusion

Circulating IL-26 in serum displays diagnostic potential in the progression of neurosyphilis and warrants further evaluation in clinical trials.

CXCL8, CXCL9, and CXCL10 serum levels increase in syphilitic patients with seroresistance

Background

Recently, the rise of syphilitic seroresistance brings great confusion to the clinical diagnosis and treatment of syphilis, and no clear diagnostic marker has been found to distinguish syphilitic seroresistance from other progression of syphilis. This study evaluated the serum chemokines levels of CCL2, CXCL8, CXCL9, and CXCL10 and its correlation with blood routine, coagulation, and biochemical indexes in seroresistant syphilitic patients.

Method

Serum levels of chemokines were quantitatively determined by Flow Cytometric Bead Array (CBA). The results expressed in pg/ml. Clinical parameters were detected and analyzed according to the clinical laboratory standards. A correlation analysis was subsequently performed.

Results

The seroresistant syphilitic patients increased significantly serum chemokines levels of CXCL8 (***p < 0.001), CXCL9 (***p < 0.001), and CXCL10 (**p < 0.01) when compared to noninfected individuals, but the CCL2 was not statistically significant, and serum CXCL8 shows a strong association with platelets (r = 0.51, **p = 0.004) and serum CXCL10 was significantly positively related to INR levels (r = 0.49, **p = 0.007).

Conclusion

Increasing serum abnormalities in CXCL8, CXCL9, and CXCL10 level combining with platelets of peripheral blood and plasmatic INR in syphilis patients may be helpful for the diagnosis of serofast state.