Recent trends in the serologic diagnosis of syphilis

Improved efficiency using sequential automated immunoassays for syphilis screening in blood donors

Using sequential immunoassays for the screening of blood donors is well described for viral serology testing but not for the screening of syphilis. In this study, we report the evaluation results and 2-year sequential testing data using two highly sensitive automated serology assays, the Alinity s Syphilis chemiluminescent immunoassay for screening, with all repeatedly reactive samples then tested on the Elecsys Syphilis electrochemiluminescence immunoassay. We screened 1,767,782 blood donor samples between 7 July 2021 and 6 July 2023 and found the Alinity false-positive rate to be low at 0.08% (1,456/1,767,782). The common false-positive rate between the two assays was also low (3.83%, 58/1,514). Concordantly reactive samples were further tested using a Treponema pallidum particle agglutination test, a rapid plasma reagin test, and a fluorescent treponemal antibody absorption test. There were 262/1,376 concordantly reactive Alinity and Elecsys blood donor samples with reactivity on one or more of the confirmatory tests. A total of 26/1,376 donors had a current syphilis infection, 152/1,376 reported a past history of syphilis and had been treated, and 84/1,376 did not report a past history of syphilis. We suggest that future studies could explore the use of sequential immunoassays to aid in the serodiagnosis for syphilis.

IMPORTANCE

The serodiagnosis for syphilis usually follows two methodologies-a "traditional" algorithm using a non-treponemal test followed by confirmation using a treponemal test, or a "reverse" algorithm using a treponemal test followed by a non-treponemal test. There are limited reports in the literature of using a modified reverse algorithm (treponemal test followed by a second treponemal test), and to the best of knowledge, there are currently no published articles using two highly sensitive automated immunoassays to aid the serodiagnosis of syphilis. In addition, the Treponema pallidum particle agglutination (TPPA) assay is commonly used as a confirmatory test for the diagnosis of syphilis. With the withdrawal of the TPPA assay from Australia and presumably from the global market also, alternative testing algorithms are now required. This study provides proof of concept for using sequential immunoassays in the diagnosis of syphilis.

Performance Assessment of Treponemal and Nontreponemal Tests for the Diagnosis of Acquired Syphilis

There are a variety of nontreponemal test (NTT) and treponemal test (TT) kits for the serologic diagnosis of syphilis. Because of the complexity of the infection (multiple clinical stages) and the different antigens used in these kits, a systematic evaluation of the accuracy of the currently available commercial tests is warranted. Our objective was to evaluate the performance of commercially available tests for the diagnosis of syphilis infection. In this study, we analyzed one NTT (Venereal Disease Research Laboratory [VDRL] test, Wiener Laboratories, Rosario, Argentina) and two TTs (fluorescent treponemal antibody absorption [FTA-ABS] test, Euroimmun, Lübeck, Germany, and syphilis recombinant ELISA v. 4.0 test [ELISA], Wiener Laboratories, Rosario, Argentina) using a panel of 187 samples, including serum samples from 31 individuals with primary syphilis, 77 with secondary syphilis, and 79 with latent syphilis. An additional 192 samples from uninfected individuals and 323 serum samples from individuals with other diseases were included. The sensitivities of the VDRL, ELISA, and FTA-ABS tests were 97.9%, 100%, and 96.3%, respectively. The VDRL and ELISA tests showed a specificity of 100%, and the FTA-ABS test showed a specificity of 99.5%. Accuracy was 98.9% for the VDRL test, 100% for the ELISA, and 97.9% for the FTA-ABS test. For primary, secondary, and latent syphilis, the ELISA achieved a diagnostic performance of 100%, whereas the sensitivity for the VDRL and FTA-ABS tests ranged from 96.8% to 98.7% and 93.7% to 98.7%, respectively. No difference was observed when the tests were used as traditional or reverse algorithms. In general, all three tests are able to discriminate positive and negative samples for syphilis, regardless of the diagnostic algorithm.

Treponematosis in critically endangered Western chimpanzees (Pan troglodytes verus) in Senegal

Treponematoses encompass a group of chronic and debilitating bacterial diseases transmitted sexually or by direct contact and attributed to Treponema pallidum. Despite being documented since as far back as 1963, the epidemiology of treponematoses in wild primates has remained an uninvestigated territory due to the inherent challenges associated with conducting examinations and obtaining invasive biological samples from wild animals. The primary aim of this study was to investigate the presence of treponemal infections in the critically endangered Western chimpanzees in Senegal, utilizing an innovative non-invasive stool serology method. We provide compelling evidence of the existence of anti-Treponema-specific antibodies in 13 out of 29 individual chimpanzees. Our study also underscores the significant potential of stool serology as a valuable non-invasive tool for monitoring and surveilling crucial emerging diseases in wild animals. We recognize two major implications: (1) the imperative need to assess the risks of treponematosis in Western chimpanzee populations and (2) the necessity to monitor and manage this disease following a holistic One Health approach.

Seroconversion in syphilis screening without positive confirmatory tests points at early infection

INTRODUCTION

The chemiluminescence immunoassay (CLIA) is a widely used screening test for syphilis. A CLIA seroconversion in the absence of a positive line immunoassay (LIA) or rapid plasma reagin (RPR) could indicate either an early incubating syphilis or a false positive result. We aimed to evaluate the diagnostic value of such seroconversions.

METHODS

We retrospectively analysed data of clients visiting the Centre for Sexual Health Amsterdam between July 2013 and August 2021 with a positive CLIA and a negative RPR and negative or indeterminate LIA (at time To), and a preceding visit (T-1) with a negative CLIA <6 months of To ('unconfirmed CLIA seroconversion'). If available, data of follow-up visits (T1) <2 months of To were also included. A syphilis diagnosis was confirmed if darkfield microscopy or PCR for Treponema pallidum was positive at T0 or T1, or if RPR and/or LIA were positive at T1.

RESULTS

We included data of 107 clients with unconfirmed CLIA seroconversion. The value of CLIA seroconversion could not be established in 13 (12.1%) clients. In the remaining 94 clients, the unconfirmed CLIA seroconversion was confirmed as early syphilis in 72 (76.6%) clients and probable syphilis in 6 (6.4%) clients. In 16 (17.0%) clients, the unconfirmed CLIA seroconversion was regarded as a false positive reaction of whom 4 (5.3%) clients had a seroreversion of the CLIA at T1.

CONCLUSION

The majority of unconfirmed CLIA seroconversions represented early syphilis infections. Therefore, additional T. pallidum PCR, a follow-up consultation or early treatment is recommended.

Cerebrospinal fluid CXCL13 concentration for diagnosis and monitoring of neurosyphilis in people with HIV

OBJECTIVES

The study aimed to assess and compare cerebrospinal fluid (CSF)-CXCL13 levels in People with HIV (PWH) with suspected neurosyphilis (NS), those with syphilis but without NS, and patients without treponema infection. Additionally, it aimed to evaluate changes in CSF-CXCL13 concentrations before and after antibiotic treatment.

DESIGN

This was a prospective cohort study involving 93 PWH suspected of NS. All participants underwent lumbar puncture, with CSF-CXCL13 levels measured at baseline and during follow-up in patients diagnosed with NS.

METHODS

CSF-CXCL13 levels were quantified using ELISA. The Mann-Whitney U test was used to analyze differences between groups, while the Wilcoxon test assessed within subject changes. ROC curve analysis determined the diagnostic efficacy of CSF-CXCL13 for NS.

RESULTS

Significantly higher CSF-CXCL13 levels were observed in patients with NS compared to those with syphilis without NS and non-syphilis patients. Posttreatment, a decline in CSF-CXCL13 levels was noted in all NS cases. A CSF-CXCL13 threshold exceeding 60.0 pg/ml, in conjunction with reactive CSF-FTA-ABS, yielded a sensitivity of 88.9% and a specificity of 97.6% for NS diagnosis.

CONCLUSIONS

CSF-CXCL13 emerges as a valuable adjunctive biomarker for detecting NS in PWH, especially in cases with nonreactive CSF-VDRL. Monitoring CSF-CXCL13 levels also appears effective in evaluating therapeutic response in PWH undergoing NS treatment.

External quality assessment to support the WHO ProSPeRo study for the evaluation of two dual HIV/syphilis point-of-care tests in seven countries

BACKGROUND

Sexually transmitted infections (STIs) such as syphilis and HIV remain to be a significant public health issue worldwide. Dual rapid point-of-care tests (POCTs) have shown promise for detecting antibodies to HIV and syphilis but have not been fully evaluated in the field. Our study supported the WHO ProSPeRo study on Sexually Transmitted Infection Point-of-Care Testing (STI POCT) by providing external quality assessment (EQA) for HIV and syphilis testing in reference laboratories and their associated clinical sites in seven countries.

METHODS

HIV/syphilis serum liquid and dried tube specimen (DTS) panels were prepared by CDC. Liquid panels were distributed to the reference laboratories for three rounds of testing using commercially and locally available laboratory-based serological tests. DTS panels were sent to the clinical testing sites for 8 rounds of POC testing using the Abbott SD BIOLINE HIV/Syphilis Duo test (hereafter referred to as SD BIOLINE) and the Chembio Dual Path Platform (DPP) HIV-Syphilis assay. EQA panels were tested at CDC using the Rapid Plasma Reagin (RPR) test and the Treponema pallidum Particle Agglutination assay (TP-PA) for syphilis antibodies. Genetic Systems HIV-1/HIV-2 Plus O EIA, Geenius HIV Supplemental Assay and the Oraquick Advance HIV test were used to detect HIV antibodies in the EQA panels. Results from the reference laboratories and POCT sites were compared to those obtained at the CDC and a percentage agreement was calculated.

RESULTS

Qualitative RPR and TP-PA performed at the reference laboratories demonstrated 95.4-100% agreement with CDC results while quantitative RPR and TP-PA tests demonstrated 87.7% and 89.2% agreement, respectively. A 93.8% concordance rate was observed for qualitative HIV testing in laboratories. EQA testing at clinical sites using dual tests showed 98.7% and 99.1% agreement for detection of HIV antibodies and eight out of 10 sites had > 95.8% agreement for syphilis testing. However, two clinical sites showed only 65.0-66.7% agreement for SD BIOLINE and 84.0-86.7% for DPP, respectively, for syphilis testing.

CONCLUSIONS

Overall, laboratories demonstrated high EQA performance in this study. Both HIV/syphilis POCTs gave expected results in the clinic-based evaluations using DTS. However, testing errors were identified in a few testing sites suggesting the necessity for continuous training and monitoring the quality of POC testing.

A 4-fold or greater decrease in TPPA titers may indicate effective BPG treatment in primary syphilis

BACKGROUND

In the majority of clinical environments, the treponema pallidum particle agglutination (TPPA) test is known for its higher specificity compared to the rapid plasma reagin (RPR) test and is commonly employed for the diagnosis of syphilis, but their use for serological monitoring after syphilis therapy is controversial.

OBJECTIVES

We aim to evaluate whether the TPPA titers is suitable for monitoring syphilis treatment efficacy.

METHODS

At first, 232 patients with primary syphilis were recruited. Serological testing was performed at baseline (initial visit) and at 6 months (±1 month) after benzathine penicillin G (BPG) treatment. Second, New Zealand white male rabbits were infected with Treponema pallidum (T. pallidum) to evaluate the changes in TPPA titers after BPG therapy. Finally, we compared the TPPA titers in the culture supernatant of rabbit splenocytes stimulated with T. pallidum with or without BPG.

RESULTS

After 6 months of treatment, 150 (64.7%) of 232 primary syphilis patients achieved serological cure, and 82 (35.3%) had adverse outcomes. Among 110 patients with TPPA titers decreased by more than fourfold, 109 of them were serological cure patients (≥4-fold decrease in RPR titers) (P ＜ 0.0001). In the rabbit model of syphilis, the TPPA titers was significantly decreased in the treatment subgroup (P = 0.016) and remained constant (±2-fold) or increased (≥4-fold) in the nontreatment subgroup. In addition, T. pallidum resulted in a positive TPPA titers in the culture supernatant of splenocytes (median titers was 1: 80), while BPG could directly reduce the TPPA titers in the culture supernatant (median titers was 1: 40) (P = 0.032).

CONCLUSIONS

A 4-fold or greater decrease in TPPA titers may indicate effective treatment in primary syphilis. Combining TPPA titers with RPR titers results may potentially aid in the early diagnosis of syphilis.

Demystifying Ocular Syphilis - A Major Review

Syphilis, caused by the spirochaete, Treponema pallidum, continues to be a public health challenge globally with its rates steadily increasing in the past few years. The disease is transmitted through small breaks in the skin during sexual contact, or via congenital transmission in utero, either across the placenta or by contact with an active genital lesion during delivery. Estimated 5.7-6 million new cases are detected every year worldwide in the 15-49 years age group. An increased incidence has been reported in most populations with particular clusters in special groups like men who have sex with men, female sex workers, and their male clients. Ocular syphilis has a varied presentation and is considered a great mimicker in all cases of uveitis. The laboratory diagnosis of syphilis is predominantly based on serological tests including TPHA and VDRL. Parenteral penicillin is the cornerstone of treatment for all stages of ocular syphilis.

The Diagnostic Performance of Laboratory Tests of Neurosyphilis: A Systematic Review and Network Meta-Analysis

INTRODUCTION

The gold standard for diagnosing neurosyphilis (NS) is currently unavailable; various laboratory parameters in cerebrospinal fluid (CSF) and blood can assist in the diagnosis.

METHODS

PubMed, Embase, and the Cochrane Library were searched. Studies utilizing laboratory tests to assist in the diagnosis of NS were included. The pooled indicators for diagnostic performance and their respective 95% confidence intervals (CIs) were calculated. We used the superiority index to test the superiority of a diagnostic test.

RESULTS

Eleven citations were included in the study. Albumin quotient, CSF-TPHA, CSF-EIA, CSF-LDH, CSF-WBC, CSF-CXCL13, FTA-ABS, CSF-PCR, RPR, CSF-TPPA, TRUST, and CSF-venereal diseases research laboratory (VDRL) were assessed in the studies included. The pooled estimates of sensitivity, specificity, AUC of SROC and their respective 95% CIs for CSF-TPPA and CSF-VDRL were 0.97 (0.17, 1.00), 0.84 (0.62, 0.95), 0.93 (0.91, 0.95) and 0.74 (0.59, 0.85), 0.99 (0.93, 1.00), 0.94 (0.91, 0.96), respectively. CSF-TPHA demonstrated the highest relative sensitivity. CSF-VDRL manifested the highest specificity. CSF-TPHA, TRUST, CSF-VDRL, CSF-EIA, and RPR ranked in the top five laboratory tests with superiority index.

CONCLUSION

CSF-TPHA, TRUST, CSF-VDRL, CSF-EIA, and RPR indicate acceptable performance in detecting NS compared to other modalities. Comprehensive diagnostic strategies still play a significant role in the diagnosis of NS.

Advantages and limitations of current diagnostic laboratory approaches in syphilis and congenital syphilis

INTRODUCTION

The reemergence of syphilis, especially congenital syphilis, presents a significant public health threat. Accurate diagnosis of syphilis depends on recognition of a constellation of symptoms, review of medical and sexual history, and multiple laboratory tests. While reliable, current tests for syphilis can be difficult to interpret, which can lead to delays in treatment.

AREA COVERED

This review summarizes the major advantages and limitations of available diagnostic laboratory methods for syphilis, provides an update on recent advances in laboratory tools, and highlights the urgent need for coordinated efforts to create new tools to halt the resurgence of syphilis.

EXPERT OPINION

In syphilis, the wide variety of short-lived signs and symptoms followed by periods of latency create diagnostic challenges. Currently available laboratory tests, when positive, require additional information to interpret (prior testing, treatment, and sexual history). Point-of-care tests that can rapidly and accurately detect both treponemal and non-treponemal antibodies would be a huge step toward reducing test turnaround time and time to treatment. Incorporating biological insights and technology innovations to advance the development of direct detection assays is urgently needed. A comprehensive coordinated effort is critical to stem the tide of rising syphilis in the United States and globally.

Point-of-Care Testing for Sexually Transmitted Infections

Point-of-care testing for sexually transmitted infections is essential for controlling transmission and preventing sequelae in high-risk populations. Since the World Health Organization published the ASSURED criteria, point-of-care testing has improved for use in large population screening and rapid testing that prevents loss of clinical follow-up. Recent advancements have been advantageous for low-resource areas allowing testing at a minimal cost without reliable electricity or refrigeration. Point-of-care nucleic acid detection and amplification techniques are recommended, but are often inaccessible in low-resource areas. Future advancements in point-of-care diagnostic testing should focus on improving antibody-based assays, monitoring viral loads, and detecting antimicrobial resistance.

Diagnostic performance of two rapid tests for syphilis screening in people living with HIV in Cali, Colombia

INTRODUCTION

There is insufficient evidence supporting the use of rapid diagnostic tests (RDTs) for syphilis in people living with HIV (PLWH). We evaluated the diagnostic performance of two commercially available RDTs (Bioline and Determine) in PLWH in Cali, Colombia.

METHODS

A cross-sectional field validation study on consecutive adults with confirmed HIV diagnosis attending three outpatient clinics. Both RDTs were performed on capillary blood (CB), obtained by finger prick, and sera, by venipuncture. A combination of treponemal enzyme linked immunosorbent assay (ELISA) and Treponema pallidum haemagglutination assay (TPHA) on serum samples was the reference standard. Rapid plasma reagin (RPR) and clinical criteria were added to define active syphilis. Sensitivity and specificity, predictive values and likelihood ratios (LR) of RDTs were estimated with their corresponding 95% confidence interval (95% CI). Stratified analyses by sample type, patient characteristics, non-treponemal titers, operator and re-training were performed.

RESULTS

244 PLWH were enrolled, of whom 112 (46%) had positive treponemal reference tests and 26/234 (11.1%) had active syphilis. The sensitivities of Bioline on CB and sera were similar (96.4% vs 94.6%, p = 0.6). In contrast, Determine had a lower sensitivity on CB than sera (87.5% vs 99.1%, p<0.001). Sensitivities were lower in PLWH not receiving ART (Bioline 87.1% and Determine 64.5%, p<0.001) and for one of the operators (Bioline 85% and Determine 60%, p<0.001). Specificities of the RDTs were > 95% in most analyses. Predictive values were 90% or higher. For active syphilis, the RDTs showed a similar performance pattern but with decreased specificities.

CONCLUSION

The studied RDTs have an excellent performance in PLWH to screen for syphilis and potentially for active syphilis, yet Determine performs better on sera than CB. Patient characteristics and potential difficulties operators may face in acquiring enough blood volume from finger pricks should be considered for the implementation and the interpretation of RDTs.

The role of pyroptosis in endothelial dysfunction induced by diseases

Most organs in the body rely on blood flow, and vesicular damage is the leading cause of injury in multiple organs. The endothelium, as the barriers of vessels, play a critical role in ensuring vascular homeostasis and angiogenesis. The rapid development of risk factors in endothelial injuries has been seen in the past decade, such as smoking, infectious, and diabetes mellites. Pyroptotic endothelium is an inflammatory mode of governed endothelial cell death that depend on the metabolic disorder and severe infectious such as atherosclerosis, and sepsis-related acute lung injury, respectively. Pyroptotic endothelial cells need GSDMD cleaved into N- and C-terminal by caspase1, and the cytokines are released by a pore constructed by the N-terminal of GSDMD in the membrane of ECs, finally resulting in severe inflammation and pyroptotic cell death. This review will focus on the patho-physiological and pharmacological pathways of pyroptotic endothelial metabolism in diseases. Overall, this review indicates that pyroptosis is a significant risk factor in diseases and a potential drug target in related diseases.

The role of pyroptosis in endothelial dysfunction induced by diseases

Most organs in the body rely on blood flow, and vesicular damage is the leading cause of injury in multiple organs. The endothelium, as the barriers of vessels, play a critical role in ensuring vascular homeostasis and angiogenesis. The rapid development of risk factors in endothelial injuries has been seen in the past decade, such as smoking, infectious, and diabetes mellites. Pyroptotic endothelium is an inflammatory mode of governed endothelial cell death that depend on the metabolic disorder and severe infectious such as atherosclerosis, and sepsis-related acute lung injury, respectively. Pyroptotic endothelial cells need GSDMD cleaved into N- and C-terminal by caspase1, and the cytokines are released by a pore constructed by the N-terminal of GSDMD in the membrane of ECs, finally resulting in severe inflammation and pyroptotic cell death. This review will focus on the patho-physiological and pharmacological pathways of pyroptotic endothelial metabolism in diseases. Overall, this review indicates that pyroptosis is a significant risk factor in diseases and a potential drug target in related diseases.

Syphilis in Dermatology: Recognition and Management

The incidence of syphilis has been increasing in the USA since 2000. Notably, the coronavirus disease 2019 pandemic negatively impacted the public health efforts to contain the spread of sexually transmitted diseases including syphilis and congenital syphilis. Clinical manifestations of syphilis are predominantly mucocutaneous lesions, thus dermatologists are primed to recognize the myriad presentations of this disease. Primary syphilis is classically characterized by a painless transient chancre most often located in the genital area. Secondary syphilis typically manifests clinically as systemic symptoms in addition to a mucocutaneous eruption of which a variety of forms exist. Although less common in the era of effective penicillin treatment, late clinical manifestations of syphilis are described as well. In addition to recognition of syphilis on physical examination, several diagnostic tools may be used to confirm infection. Treponema pallidum spirochetes may be detected directly using histopathologic staining, darkfield microscopy, direct fluorescent antibody, and polymerase chain reaction assays. A table detailing the histopathologic features of syphilis is included in this article. Serologic testing, non-treponemal and treponemal tests, is the preferred method for screening and diagnosing syphilis infections. Two serologic testing algorithms exist to aid clinicians in diagnosing positive syphilis infection. Determining the correct stage of syphilis infection combines results of serologic tests, patient history, and physical examination findings. Using the current Centers for Disease Control and Prevention case definitions and treatment guidelines, a management algorithm is proposed here. Penicillin remains the pharmacological treatment of choice although specific clinical situations allow for alternative therapies. Syphilis is a reportable disease in every state and should be reported by stage according to individual state requirements. Screening recommendations are largely based upon risks encountered through sexual exposures. Likewise, sexual partner management includes evaluating and treating persons exposed to someone diagnosed with an infective stage of syphilis. Close clinical follow-up and repeat testing are recommended to ensure appropriate response to treatment. This guide will discuss the current epidemiology of syphilis and focus on practice aspects of diagnosis and management, including public health reporting.

Screening for maternal and congenital syphilis with a chemiluminescence immunoassay in a South African private specialist healthcare sector setting

Background. Syphilis is a sexually transmitted infection that is most frequently found in lower socio-economic groups globally and is associated with significant maternal and fetal complications. In South Africa (SA), the last two to three decades have seen a rise in the number of people in the low and middle economic social groups seeking private specialist healthcare services.Objective. To evaluate the prevalence rates of maternal and congenital syphilis in a private specialist healthcare setting. Methods. The laboratory case records of women who had antenatal maternal syphilis (MS) screening using the automated chemiluminescence immunoassay (Architect Syphilis TP) in a private laboratory facility in Durban were reviewed.Results. A total of 9 740 individual maternal serum samples were analysed and 256 were Architect Syphilis TP positive, resulting in a MS prevalence rate of 2.7%. Of the less than three-quarters of exposed neonates tested (71.1%; n=182/256), 38.5% (n=70/182) were Architect syphilis TP positive. Less than a tenth of exposed neonates (2.43%; n=6) had only rapid plasma reagin (RPR) titers test whereas 26.6% (n=68/256) did not have a syphilis screen test. Based on the 182 exposed neonates tested, the congenital syphilis (CS) prevalence from the laboratory records was 7.7%. The highest rate of MS was in the ≥35 years age group. Conclusion. The prevalence of MS in the private specialist healthcare sector in SA is relatively high and warrants continued maternal antenatal screening during early pregnancy across all socio-economic groups. The high rate of MS in the age group over 35 years warrants further investigations and explanation.

Comparison of 17 serological treponemal and nontreponemal assays for syphilis: A retrospective cohort study

Objectives

Rapid plasma reagin (RPR) and Treponema pallidum (TP) antibody test kits are often used to diagnose syphilis, although the relationship between their measured values is unclear. We aimed to reveal the relevance of these kits’ results.

Design and methods

In all, 143 sera from 110 patients were tested using 12 TP kits and 5 RPR kits and the results compared.

Results

The specificity and sensitivity of RPR kits were 81–96% and 95–100%, respectively. The correlation coefficients (0.849–0.934) considerably differed between the manual RPR card test and latex agglutination (LA) assay kits. The following sensitivities were obtained: 82–91% for TP fluorescent treponemal antibody absorption assay (FTA-ABS), TP hemagglutination assay (HA), and TP particle agglutination assay (PA); 94–95% for TP LAs; and 92–100% for chemiluminescent immunoassay (CLIA), chemiluminescent enzyme immunoassay (CLEIA), and immunochromatography assay (IC). Correlation coefficients between TP kits were 0.753–0.974, and the measured values varied. Changes in RPR and quantifiable TP kits were the same for patients with reinfected syphilis and with syphilis under treatment.

Conclusions

RPR tests had lower specificity than TP antibody tests. RPR card test and RPR LAs had similar specificity and sensitivity, but their measured values were different. RPR should be measured using automatic RPR LA without setting the upper limit of the reported value. RPR LA should also be standardized. The sensitivity of TP antibody was better in CLIA, CLEIA, and IC than in FTA-ABS, HA, PA, and LA. Therefore, TP antibody kits should be standardized and quantified.

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RPR CT and four RPR LAs have similar specificity and sensitivity.

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RPR CT and four RPR LAs have different measured values.

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CLIA, CLEIA, and IC have more sensitive TP antibodies than other tests.

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The measured values of 12 TP antibody kits vary.

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Quantitative TP antibodies are similar to RPR in the clinical course of syphilis.

Clinical Protocols and Treatment Guidelines for the Management of Maternal and Congenital Syphilis in Brazil and Portugal: Analysis and Comparisons: A Narrative Review

(1) Background: Maternal syphilis (MS) and congenital syphilis (CS) are serious public health problems worldwide due to their high morbidity and mortality rates. (2) Objective: Evaluating the applicability of Clinical Protocols and Treatment Guidelines on case incidence trends in Brazil and Portugal. (3) Methods: The review was done through bibliographic research in two public databases and government websites from both countries, published between 2007 and 2022. All guidelines that contained CS and MS were selected. (4) Results and discussion: After evaluation, we found that Brazil and Portugal have adequate protocols for screening and treating congenital and maternal syphilis. (5) Conclusion: The results suggest that CS and MS incidence are notably higher in Brazil than in Portugal due to economic, cultural, and social disparities and the differences in territory size. Therefore, these demographic and socioeconomic factors could strongly influence efforts to fight against syphilis and thus control the infection.

Assessment of recombinant antigens Tp0100 and Tp1016 of Treponema pallidum for serological diagnosis of syphilis

Objective

To discover novel serodiagnostic candidates for the serological diagnosis of syphilis.

Methods

Two recombinant Treponema pallidum proteins Tp0100 and Tp1016 were expressed, purified, and identified by Western Blotting. A total of 600 clinical serum samples were tested with the Tp0100‐based ELISA, the Tp1016‐based ELISA, and the commercial LICA Syphilis TP kit (ChIVD, Beijing, China). The sensitivities were determined by testing 340 samples from individuals with clinically diagnosed primary, secondary, latent, and tertiary syphilis. The specificities were determined by screening 260 samples from healthy controls and individuals with potentially cross‐reactive infections, including leptospirosis, Lyme disease, hepatitis B, tuberculosis, rheumatoid arthritis, systemic lupus erythematosus. Kappa (κ) values were applied to compare the agreement between clinical syphilis diagnosis and the Tp0100‐based ELISA, the Tp1016‐based ELISA, or the LICA Syphilis TP test.

Results

Using clinical syphilis diagnosis as the gold standard, Tp0100 exhibited an overall sensitivity of 95.6% and specificity of 98.1% for testing IgG antibody while Tp1016 demonstrated only an overall sensitivity of 75.0% and specificity of 79.6%. In contrast, the LICA Syphilis TP test revealed an overall sensitivity of 97.6% and specificity of 96.2%. In addition, the overall percent agreement and corresponding κ values were 96.7% (95% CI 95.6%–97.8%) and 0.93 for the Tp0100‐based ELISA, 77.0% (95% CI 74.3%–79.7%) and 0.54 for the Tp1016‐based ELISA, and 97.0% (95% CI 96.0%–98.0%) and 0.94 for the LICA Syphilis TP test, respectively.

Conclusion

The recombinant T. pallidum protein Tp0100 shows promise as a novel diagnostic antigen in the serological tests for syphilis.

Treponema pallidum delays the apoptosis of human polymorphonuclear neutrophils through the intrinsic and extrinsic pathways

Treponema pallidum is a "stealth pathogen" responsible for infectious sexually transmitted diseases. Although neutrophils are usually present in skin lesions of early syphilis, the role of these cells in T. pallidum infection has barely been investigated. Neutrophils are short-lived cells that undergo constitutive apoptosis, and phagocytosis usually accelerates this process. Here, we demonstrated that human polymorphonuclear neutrophils (hPMNs) could phagocytose T. pallidum in vitro. An unexpected discovery was that T. pallidum inhibited hPMNs apoptosis markedly in an opsonin-independent manner. Furthermore, this phenomenon was not affected by bacterial viability, as detected by annexin V, morphology studies, and TUNEL staining. Exploration of the underlying mechanism showed that expression of the cleaved forms of caspase-3, -8, and -9 and effector caspase activity were diminished significantly in T. pallidum-infected hPMNs. T. pallidum also impaired staurosporine- and anti-Fas-induced signaling for neutrophil apoptosis. Of note, these effects were accompanied by inducing the autocrine production of the anti-apoptotic cytokine IL-8. Taken together, our data revealed that T. pallidum could inhibit the apoptosis of hPMNs through intrinsic and extrinsic pathways and provide new insights for understanding the pathogenicity mechanisms of T. pallidum.

Evaluation of The Diagnostic Algorithms for Serodiagnosis of Syphilis

We analyzed the performance parameters of the traditional and the reverse algorithms to find out which one is more convenient for serodiagnosis of syphilis. In total, 4789 serum samples were obtained in a cross-sectional study. Venereal Disease Research Laboratory (VDRL), Treponema pallidum Haemagglutination Assay (TPHA) and Chemiluminescent Microparticle Immunoassay (CMIA) tests were performed for every serum sample. In case of discordance between results, the TPHA was applied as a second treponemal test. Overall, 207 patients were serodiagnosed with syphilis. Among 4789 subjects tested, 125 (2.6%) and 206 (4.3%) were positive using the traditional algorithm and the reverse algorithm, respectively. The missed diagnosis rate of the traditional algorithm was 42.5%. The reverse algorithm had higher sensitivity than the traditional algorithm. Sensitivity levels of the traditional and the reverse algorithms were 57.49% and 99.85% respectively. The false positivity of the reverse algorithms was 0.02%.

Brazilian Protocol for Sexually Transmitted Infections 2020: syphilis diagnostic tests

The recommendations for diagnostic tests for investigating syphilis are part of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections and the Technical Manual for Syphilis Diagnosis, published by the Brazilian Ministry of Health. These recommendations were developed based on scientific evidence and discussions with a panel of experts. This article presents direct tests to detect Treponema pallidum in lesions and algorithms that combine treponemal and non-treponemal antibody tests to assist in syphilis diagnosis, with the aim of contributing to the efforts of health service managers and health professionals in qualifying health care. The article also covers the use of non-treponemal tests to investigate neurosyphilis and guidelines for interpreting non-treponemal antibody titers in monitoring the treatment and diagnosis of congenital syphilis, as well as prospects for innovations in diagnosis. The critical role of rapid immunochromatographic treponemal tests for public health and for addressing syphilis is also highlighted.

Highlighted excerpt: During the natural evolution of syphilis, activity periods with distinct clinical, immunological, and histopathological characteristics are interspersed with latent periods when there are no signs or symptoms, making access to tests critical for early diagnosis.

Brazilian Protocol for Sexually Transmitted Infections, 2020: congenital syphilis and child exposed to syphilis

The topics of congenital syphilis and children exposed to syphilis compose the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health in 2020. Such document was elaborated based on scientific evidence and validated in discussions with specialists. This article provides guidelines for syphilis in pregnant women and congenital syphilis clinical management, emphasizing the vertical transmission of Treponema pallidum prevention. Epidemiological and clinical aspects of these infections are presented and recommendations for managers in the programmatic and operational management of syphilis. The article also includes guidelines for health professionals in screening, diagnosing, and treating people with sexually transmitted infections and their sex partners, in addition to strategies for surveillance actions, prevention, and control of the disease.

Most congenital syphilis cases arise from test failures in prenatal care or inadequate or no treatment of maternal syphilis.

Immunological tests and their interpretation in uveitis

Uveitis is a complex disorder including both infectious and non-infectious etiologies. Clinical diagnosis is a challenge because many diseases share common clinical signs. Laboratory support is crucial for confirming the clinical diagnosis. Laboratory diagnosis includes direct tests and indirect tests. For example smear, culture, and molecular diagnostics demonstrate the pathogens, hence they are direct tests. Immunologic tests employ an antigen to detect presence of antibodies to a pathogen, or an antibody to detect the presence of an antigen, of the pathogen in the specimens. The immunological tests used in laboratories are made by producing artificial antibodies that exactly “match” the pathogen in question. When these antibodies come into contact with a sample they bind to the matching pathogen if found in the sample. Hence they are grouped under indirect evidence. There are several investigations in uveitis to reach the confirmed diagnosis including microbiological, immunological, imaging and molecular diagnostic testing. In this section we will discuss immunological investigations of infectious and non-infectious uveitis.

The laboratory diagnosis of Syphilis

Syphilis is a multisystem infection caused by the spirochaete Treponema pallidum Currently, cases of possible syphilis are commonly investigated using the treponemal serological tests T. pallidum IgG chemiluminescence immunoassay (CLIA) and the T. pallidum particle agglutination (TPPA). The non-treponemal rapid plasma reagin (RPR) flocculation test is used to assess disease activity. There has been a resurgence of syphilis diagnoses in Australia. Large foci of infection have been identified in isolated communities. The remoteness of these locations, in conjunction with the particular socio-cultural characteristics of the population, pose unique challenges to the traditional diagnostic and treatment paradigms for syphilis. As a consequence of this increased incidence of syphilis, there has been interest in the utility of point of care tests (POCT), nucleic acid amplification tests (NAAT), the role of IgM testing in suspected congenital syphilis, and the laboratory investigation of possible neurosyphilis. This review looks at the current status of traditional serological assays and provides an update on more recent methods. It assesses the published literature in this area and makes recommendations for the rational use of pathology testing to aid in the diagnosis of the many facets of syphilis.

The impact of antenatal syphilis point of care testing on pregnancy outcomes: A systematic review

Background

Mother-to-child transmission of syphilis remains a leading cause of neonatal death and stillbirth, disproportionally affecting women in low-resource settings where syphilis prevalence rates are high and testing rates low. Recently developed syphilis point-of-care tests (POCTs) are promising alternatives to conventional laboratory screening in low-resource settings as they do not require a laboratory setting, intensive technical training and yield results in 10–15 minutes thereby enabling both diagnosis and treatment in a single visit. Aim of this review was to provide clarity on the benefits of different POCTs and assess whether the implementation of syphilis POCTs is associated with decreased numbers of syphilis-related adverse pregnancy outcomes.

Methods

Following the PRISMA guidelines, three electronic databases (PubMed, Medline (Ovid), Cochrane) were systematically searched for intervention studies and cost-effectiveness analyses investigating the association between antenatal syphilis POCT and pregnancy outcomes such as congenital syphilis, low birth weight, prematurity, miscarriage, stillbirth as well as perinatal, fetal or infant death.

Results

Nine out of 278 initially identified articles were included, consisting of two clinical studies and seven modelling studies. Studies compared the effect on pregnancy outcomes of treponemal POCT, non-treponemal POCT and dual POCT to laboratory screening and no screening program. Based on the clinical studies, significantly higher testing and treatment rates, as well as a significant reduction (93%) in adverse pregnancy outcomes was reported for treponemal POCT compared to laboratory screening. Compared to no screening and laboratory screening, modelling studies assumed higher treatment rates for POCT and predicted the most prevented adverse pregnancy outcomes for treponemal POCT, followed by a dual treponemal and non-treponemal POCT strategy.

Conclusion

Implementation of treponemal POCT in low-resource settings increases syphilis testing and treatment rates and prevents the most syphilis-related adverse pregnancy outcomes compared to no screening, laboratory screening, non-treponemal POCT and dual POCT. Regarding the benefits of dual POCT, more research is needed. Overall, this review provides evidence on the contribution of treponemal POCT to healthier pregnancies and contributes greater clarity on the impact of diverse diagnostic methods available for the detection of syphilis.

[Brazilian Protocol for Sexually Transmitted Infections 2020: congenital syphilis and child exposed to syphilis]

The topics of congenital syphilis and children exposed to syphilis are part of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health in 2020. The Protocol and Guidelines have been developed based on scientific evidence and validated in discussions with specialists. This article provides guidelines for clinical management of both syphilis in pregnant women and also congenital syphilis, emphasizing prevention of vertical transmission of Treponema pallidum. Epidemiological and clinical aspects of these infections are presented, as well as recommendations for health service managers regarding the programmatic and operational management of syphilis. The article also includes guidelines for health professionals on screening, diagnosing and treating people with sexually transmitted infections and their sex partners, in addition to strategies for syphilis surveillance, prevention and control actions.

[Brazilian Protocol for Sexually Transmitted Infections 2020: syphilis diagnostic tests]

The recommendations for diagnostic tests for investigating syphilis are part of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections and the Technical Manual for Syphilis Diagnosis, published by the Brazilian Ministry of Health. These recommendations were developed based on scientific evidence and discussions with a panel of experts. Aiming to contribute to the efforts of health service managers and health professionals in qualifying health care, this article presents the use of direct tests to detect Treponema pallidum in lesions, as well as algorithms that combine treponemal and non-treponemal antibody tests to assist in the diagnosis of syphilis. The article also covers use of non-treponemal tests to investigate neurosyphilis and guidelines for interpreting non-treponemal antibody titers in monitoring treatment and diagnosis of congenital syphilis, as well as prospects for innovations in diagnosis. The important role of rapid immunochromatographic treponemal tests for public health and for addressing syphilis is also highlighted.

Syphilis Diagnosis and Treatment: State of The Art

The present review summarises the current knowledge in the field of syphilis diagnosis and treatment, along with epidemiologic and historical data. A literature search was conducted in PubMed and Google Scholar, using the search terms “syphilis”, “diagnosis”, “dermoscopy”, “management AND treatment”, “laboratory tests AND syphilis”, and “primary OR secondary OR tertiary OR congenital syphilis”. A total of 55 out of 100 papers were included in this review. An overview of the different clinical presentation of primary, secondary, tertiary, and congenital syphilis, with particular attention to dermatologic signs and dermoscopic examination, is provided. The panorama diagnostic procedures are illustrated, along with their accuracy and recommendation. Treatment and management options of patients at different syphilis stages are provided and discussed according to the referring guidelines. The dermatologist can play a key role in providing the early and correct diagnosis and setting up in the proper management of patients with syphilis infection.

The Application of Cytokine Expression Assays to Differentiate Active From Previously Treated Syphilis

To investigate the role of serum cytokine assays to distinguish between active from treated syphilis among serofast patients, we recruited individuals into a prospective cohort study. Participants underwent routine syphilis screening. We selected specimens from a majority cohort of serofast participants with treated and active syphilis. We analyzed specimens with a 62-cytokine multiplex bead-based enzyme-linked immunosorbent assay. Cytokines, brain-derived neurotrophic factor and tumor necrosis factor β, were most predictive. We built a decision tree that was 82.4% accurate, 100% (95% confidence interval, 82%-100%) sensitive, and 45% (18%-75%) specific. Our decision tree differentiated between serum specimens from serofast participants with treated syphilis versus active syphilis.

Laboratory Diagnostic Tools for Syphilis: Current Status and Future Prospects

With the increasing number of patients infected with syphilis in the past 20 years, early diagnosis and early treatment are essential to decline syphilis prevalence. Owing to its diverse manifestations, which may occur in other infections, the disease often makes clinicians confused. Therefore, a sensitive method for detecting T. pallidum is fundamental for the prompt diagnosis of syphilis. Morphological observation, immunohistochemical assay, rabbit infectivity test, serologic tests, and nucleic acid amplification assays have been applied to the diagnosis of syphilis. Morphological observation, including dark-field microscopy, silver-staining, and direct fluorescent antibody staining for T. pallidum, can be used as a direct detection method for chancre specimens in primary syphilis. Immunohistochemistry is a highly sensitive and specific assay, especially in the lesion biopsies from secondary syphilis. Rabbit infectivity test is considered as a sensitive and reliable method for detecting T. pallidum in clinical samples and used as a historical standard for the diagnosis of syphilis. Serologic tests for syphilis are widely adopted using non-treponemal or treponemal tests by either the traditional or reverse algorithm and remain the gold standard in the diagnosis of syphilis patients. In addition, nucleic acid amplification assay is capable of detecting T. pallidum DNA in the samples from patients with syphilis. Notably, PCR is probably a promising method but remains to be further improved. All of the methods mentioned above play important roles in various stages of syphilis. This review aims to provide a summary of the performance characteristics of detection methods for syphilis.

The many faces of ocular syphilis: case-based update on recognition, diagnosis, and treatment

In recent years, syphilis (Treponema pallidum) has become increasingly prevalent in Canada, and as a result, rates of ocular syphilis are also rising. Classically, syphilis was seen primarily in men who have sex with men; now, it is increasingly seen in people of all age groups, sexes, and sexual orientations. We present a series of 26 cases of ocular syphilis from London, Ontario, 5 of which are discussed in detail to illustrate the varied presentations and diagnostic challenges of ocular syphilis. The presentations include uveitis, iris granuloma (gumma), retinitis (acute syphilitic posterior placoid chorioretinitis), vasculitis, optic neuritis, and serous retinal detachment. The 5 cases are mostly middle-aged heterosexual men and women without the typical risk factors that would alert the examiner to suspect syphilis. We emphasize the importance of testing for syphilis when assessing and treating inflammatory eye disease, regardless of demographics and known risk factors, given the increasing prevalence of this disease. Diagnosis of syphilis relies on serologic testing, which is complex and has undergone significant changes from historical reliance on the Venereal Disease Research Laboratory test. We provide an overview of the strategy and rationale for modern serologic testing. The mainstay of treatment remains intravenous penicillin G, with alternative antibiotics (e.g., ceftriaxone) being less effective.

Acceptability of dual HIV/syphilis rapid test in community- and home-based testing strategy among transgender women in Buenos Aires, Argentina

BACKGROUND

Little is known of acceptability and feasibility of dual HIV and syphilis rapid tests in community- and home-based provider-initiated strategies among transgender women (TGW), in Latin America. Objectives were (1) to assess the acceptability of this strategy and, (2) to determine the percentage of positive results of HIV and syphilis, analyze the correlates of HIV or syphilis positive results, and measure the rates of effective referral and treatment completion among TGW.

METHODS

A multidisciplinary team tested 89 TGW in Buenos Aires. An acceptability survey was administered after the HIV/syphilis Duo test was used. All confirmed cases were referred for treatment initiation.

RESULTS

We found high levels of acceptability (98.8%) of this strategy among TGW. However, only 60.7% preferred simultaneous HIV and syphilis diagnosis test. Moreover, we found 9% of positive results of HIV, 51.7% of syphilis, and 3.4% of positive results for both infections. Only not being tested before was associated with an HIV positive result, and only low level of education was associated with a positive syphilis result. Among 8 TGW who tested positive for HIV, 37.5% (n = 3) started antiretroviral therapy. Of 46 who tested positive for syphilis, only 73.9% (n = 34) were effectively referred and from 23 who started treatment, only 39.1% completed it.

CONCLUSIONS

Community- and home-based dual HIV and syphilis rapid test is a feasible and highly acceptable approach for this hard-to-reach population. Implementing similar strategies could improve screening uptake and accessibility. However, these results highlight the need to improve strategies for treatment uptake, in order to reduce morbidity and risk of onward transmission.

Serologic false-positive reactions for syphilis in children of adenoidal hypertrophy:2 case reports and review of the literature

Adenoid hypertrophy (AH) is a common disease in children. We describe two cases of AH in children with syphilis enzyme-linked immunosorbent assay (EIA) for false-positive. To our knowledge, there are few reports of false-positive in syphilis EIA in children with AH. Two cases of AH children with syphilis EIA positive samples were confirmed by TPPA and LIA, both showed negative reaction. Therefore, the occurrence of syphilis EIA positive reactions in such diseases should dramatically arouse the attention of docimasters and doctors so as to avoid misdiagnosis caused by false-positive in children with AH.

Diagnostic role of CXCL13 and CSF serology in patients with neurosyphilis

BACKGROUND

Considering the unknown prevalence of neurosyphilis in West China, and the confusing diagnosis of neurosyphilis, the role of CSF_CXCL13 and syphilis serology was studied to provide a more accurate reference for the clinical detection and diagnosis of neurosyphilis.

METHODS

A retrospective data set I was used to investigate the prevalence of neurosyphilis, as well as the laboratory characteristics of 244 patients. Besides, to explore the diagnostic value of CSF_CXCL13 and syphilis serology for neurosyphilis, another 116 CSF_serum paired samples (data set II) were collected from 44 neurosyphilis and 72 non-neurosyphilis/syphilis patients.

RESULTS

About 6.25% (156 out of 2494) syphilis was neurosyphilis. When Treponema pallidum infection occurs, syphilis serology (sero_TRUST ≥1:16 and sero_TPPA titre ≥1:10240) can be good predictors of neurosyphilis, as well as syphilis CSF serology (CSF_TPPA ≥1:320, CSF_TRUST and venereal disease research laboratory). The sensitivity of serology in neurosyphilis can be complemented by CSF_CXCL13, which could be the therapy monitor of neurosyphilis.

CONCLUSION

Due to the lack of ideal biomarkers for neurosyphilis, the importance of syphilis serology cannot be ignored, and their combination with CSF_CXCL13 or other biomarkers should be further investigated.

Relationship between DiaSorin Liaison Treponema pallidum antibody indices and confirmatory assay results in the reverse syphilis testing algorithm

Published studies show that >99% of sera reactive in the reverse syphilis testing algorithm (RSTA) screening assay with an index above an assay-specific threshold confirm as reactive, with either a rapid plasma reagin-reactive (RPR^R) or RPR-nonreactive/Treponema pallidum particle agglutination-reactive (TPPA^R) result. However, the relationship between screen indices and confirmatory patterns has not been characterized. We thus assessed confirmatory testing results for 577 sera submitted for RSTA testing and a screen-reactive result in the DiaSorin Liaison assay. The median screen index was significantly higher for RPR^R samples than TPPA^R samples (55.6 versus 10.4), and the proportion with indices >28.3 (median for all 577 samples) was significantly higher for RPR^R versus TPPA^R samples (82% versus 26%). However, RPR^R titers did not significantly correlate with screen indices (R² = 0.02). These findings demonstrate a significant relationship between RSTA screen indices and confirmatory assay results. The clinical utility of this relationship requires further study.

Repeat screening for syphilis in pregnancy as an alternative screening strategy in the UK: a cost-effectiveness analysis

OBJECTIVES

To assess the cost-effectiveness of universal repeat screening for syphilis in late pregnancy, compared with the current strategy of single screening in early pregnancy with repeat screening offered only to high-risk women.

DESIGN

A decision tree model was developed to assess the incremental costs and health benefits of the two screening strategies. The base case analysis considered short-term costs during the pregnancy and the initial weeks after delivery. Deterministic and probabilistic sensitivity analyses and scenario analyses were conducted to assess the robustness of the results.

SETTING

UK antenatal screening programme.

POPULATION

Hypothetical cohort of pregnant women who access antenatal care and receive a syphilis screen in 1 year.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the cost to avoid one case of congenital syphilis (CS). Secondary outcomes were the cost to avoid one case of intrauterine fetal demise (IUFD) or neonatal death and the number of women needing to be screened/treated to avoid one case of CS, IUFD or neonatal death. The cost per quality-adjusted life year gained was assessed in scenario analyses.

RESULTS

Base case results indicated that for pregnant women in the UK (n=725 891), the repeat screening strategy would result in 5.5 fewer cases of CS (from 8.8 to 3.3), 0.1 fewer cases of neonatal death and 0.3 fewer cases of IUFD annually compared with the single screening strategy. This equates to an additional £1.8 million per case of CS prevented. When lifetime horizon was considered, the incremental cost-effectiveness ratio for the repeat screening strategy was £120 494.

CONCLUSIONS

Universal repeat screening for syphilis in pregnancy is unlikely to be cost-effective in the current UK setting where syphilis prevalence is low. Repeat screening may be cost-effective in countries with a higher syphilis incidence in pregnancy, particularly if the cost per screen is low.

MiR-223-3p inhibits rTp17-induced inflammasome activation and pyroptosis by targeting NLRP3

The incidence of syphilis caused by Treponema pallidum subsp pallidum (T pallidum) infection is accompanied by inflammatory injuries of vascular endothelial cells. Studies have revealed that T pallidum infection could induce inflammasome activation and pyroptosis in macrophages. MicroRNA‐223‐3p (miR‐223‐3p) was reported to be a negative regulator in inflammatory diseases. The present study aimed to explore whether miR‐223‐3p regulates T pallidum‐induced inflammasome activation and pyroptosis in vascular endothelial cells, and determine the mechanisms which underlie this process. MiR‐223‐3p levels in syphilis and control samples were determined. The biological function of miR‐223‐3p in the NLRP3 inflammasome and pyroptosis was evaluated in T pallidum‐infected human umbilical vein endothelial cells (HUVECs). We observed a dramatic decrease in miR‐223‐3p levels in syphilis patients (n = 20) when compared to healthy controls (n = 20). Moreover, miR‐223‐3p showed a notable inhibitory effect on recombinant Tp17 (rTP17)‐induced caspase‐1 activation, resulting in decrease in IL‐1β production and pyroptosis, which was accompanied by the release of lactate dehydrogenase (LDH) in HUVECs. Additionally, the dual‐luciferase assay confirmed that NLRP3 is a direct target of miR‐223‐3p. Moreover, NLRP3 overexpression or knockdown largely blocked the effects of miR‐223‐3p on T pallidum‐induced inflammasome activation and pyroptosis in HUVECs. Most importantly, a notable negative correlation was observed between miR‐223‐3p and NLRP3, caspase‐1, and IL‐1β, respectively, in the serum of syphilis patients and healthy controls. Taken together, our results reveal that miR‐223‐3p targets NLRP3 to suppress inflammasome activation and pyroptosis in T pallidum‐infected endothelial cells, implying that miR‐223‐3p could be a potential target for syphilis patients.

Application of Metagenomic Sequencing in the Diagnosis of Infectious Uveitis

Purpose: to summarize the origin and very recent history of the use of metagenomic sequencing for the diagnosis of infectious uveitis, convey the technique as described by one of the primary institutions experimenting with the technology, and present recent successful applications of the technology as well as potential advantages and pitfalls compared to other current diagnostic tools.Methods: review of peer-reviewed literature concerning metagenomic sequencing for the diagnosis of infectious uveitis.Conclusion: compared to existing diagnostic methods, metagenomic deep sequencing is a sensitive, unbiased, and comprehensive technique with great potential for diagnosing the causative pathogens of cases of infectious uveitis. However, many issues remain to be addressed in the process of developing this technology, including but not limited to the potentially overwhelming amount of information generated, definition of diagnostic thresholds, demonstration of validity, contamination, and cost.

Human immunodeficiency virus and intraocular inflammation in the era of highly active anti retroviral therapy - An update

Intraocular inflammation in patients with human immunodeficiency virus (HIV) infection is commonly due to infectious uveitis. Ocular lesions due to opportunistic infections (OI) are the most common and have been described extensively in the pre highly active antiretroviral therapy (HAART) era. Many eye lesions were classified as acquired immunodeficiency syndrome (AIDS) defining illnesses. HAART-associated improvement in immunity of the individual has changed the pattern of incidence of these hitherto reported known lesions leading to a marked reduction in the occurrence of ocular OI. Newer ocular lesions and newer ocular manifestations of known agents have been noted. Immune recovery uveitis (IRU), the new menace, which occurs as part of immune recovery inflammatory syndrome (IRIS) in the eye, can present with significant ocular inflammation and can pose a diagnostic and therapeutic challenge. Balancing the treatment of inflammation with the risk of reactivation of OI is a task by itself. Ocular involvement in the HAART era can be due to the adverse effects of some systemic drugs used in the management of HIV/AIDS. Drug-associated retinal toxicity and other ocular side effects are being increasingly reported. In this review, we discuss the ocular manifestations in HIV patients and its varied presentations following the introduction of HAART, drug-associated lesions, and the current treatment guidelines.

More than meets the eye: Papilledema from syphilis posing as idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a diagnosis of exclusion. Elevated intracranial pressure (ICP) can result from a variety of inflammatory and structural causes affecting cerebrospinal fluid production and absorption. First described in 1935, syphilis is a well-established cause of elevated ICP, referred to as syphilitic hydrocephalus. We report a case of a 49-year-old man presenting with vision changes and headache who was treated for IIH without resolution of symptoms, and eventually diagnosed with syphilitic hydrocephalus. Syphilis should be considered as a cause of elevated ICP prior to a diagnosis of IIH.

Health screening results of Cubans settling in Texas, USA, 2010-2015: A cross-sectional analysis

BACKGROUND

Protecting the health of refugees and other migrant populations in the United States is key to ensuring successful resettlement. Therefore, to identify and address health concerns early, the US Centers for Disease Control and Prevention (CDC) recommends a domestic medical examination (screening for infectious and noninfectious diseases/conditions) shortly after arrival in the US. However, because refugee/migrant populations often have differing health patterns from one another and the US population, the collection and analysis of health information is key to developing population-specific clinical guidelines to guide the care of resettled individuals. Yet little is known regarding the health status of Cubans resettling in the US. Among the tens of thousands of Cuban migrants who have resettled in the US, some applied as refugees in Cuba, some applied for parole (a term used to indicate temporary US admission status for urgent humanitarian reasons or reasons of public benefit under US immigration law) in Cuba, and others applied for parole status after crossing the border. These groups were eligible for US government benefits to help them resettle, including a domestic medical examination. We reviewed health differences found in these examinations of those who were determined to be refugees or parolees in Cuba and those who were given parole status after arrival.

METHODS AND FINDINGS

We conducted a retrospective cross-sectional analysis of the Texas Department of State Health Services database. Cubans who arrived from 2010 to 2015 and received a domestic medical examination in Texas were included. Those granted refugee/parolee status in Cuba were listed in federal databases for US-bound refugees/parolees; those who were paroled after arrival were not listed. Overall, 2,189 (20%) obtained either refugee or parolee status in Cuba, and 8,709 (80%) received parolee status after arrival. Approximately 62% of those who received parolee status after arrival at the border were male, compared with 49% of those who obtained prior refugee/parolee status in Cuba. Approximately one-half (45%) of those paroled after arrival were 19-34 years old (versus 26% among those who obtained refugee/parolee status in Cuba). Separate models were created for each screening indicator as the outcome, with entry route as the main exposure variable. Crude and adjusted prevalence ratios were estimated using PROC GENMOD procedures in SAS 9.4. Individuals paroled after arrival were less likely to screen positive for parasitic infections (9.6% versus 12.2%; adjusted prevalence ratio: 0.79, 0.71-0.88) and elevated blood lead levels (children ≤16 years old, 5.2% versus 12.3%; adjusted prevalence ratio: 0.42, 0.28-0.63). Limitations include potential disease misclassification, missing clinical information, and cross-sectional nature.

CONCLUSIONS

Within-country variations in health status are often not examined in refugee populations, yet they are critical to understand granular health trends. Results suggests that the health profiles of Cuban Americans in Texas differed by entry route. This information could assist in developing targeted screenings and health interventions.

Improving the coverage and accuracy of syphilis testing: The development of a novel rapid, point-of-care test for confirmatory testing of active syphilis infection and its early evaluation in China and South Africa

BACKGROUND

Current point-of-care tests (POCT) for syphilis, based on the detection of Treponema pallidum (TP) total antibodies, have limited capacity in distinguishing between active and past/treated syphilis. We report the development and early evaluation of a new prototype POCT based on the detection of TP-IgA antibodies, a novel biomarker for active syphilis.

METHODS

The TP-IgA POCT (index test) was developed in response to the World Health Organisation (WHO) target product profile (TPP) for a POCT for confirmatory syphilis testing. Two sub-studies were conducted consecutively using 458 pre-characterised stored plasma samples in China (sub-study one, addressing the criteria for the WHO TPP), and 503 venous blood samples collected from pregnant/postpartum women in South Africa (sub-study two, addressing potential clinical utility). Performance of the index test was assessed against standard laboratory-based serology using a combination of treponemal (TPHA) and non-treponemal (rapid plasma reagin [RPR]) tests.

FINDINGS

In sub-study one, the index test demonstrated 96·1% (95%CI=91·7%-98·5%) sensitivity and 84·7% (95%CI=80·15-88·6%) specificity for identification of active syphilis (TPHA positive, RPR positive). It correctly identified 71% (107/150) samples of past-treated syphilis (TPHA positive, RPR negative). In sub-study two, the index test achieved 100% (95%CI=59%-100%) sensitivity for active syphilis and correctly identified all nine women with past syphilis.

INTERPRETATION

The TP-IgA POCT has met the WHO TPP for a POCT for diagnosis of active syphilis and demonstrated its potential utility in a clinical setting. Future studies are warranted to evaluate field performance of the final manufactured test.

FUNDING

Saving Lives at Birth: Grand Challenge for Development, Thrasher Research Fund, and the Victorian Government Operational Infrastructure Scheme.

Congenital syphilis, the great imitator-case report and review

Syphilis is caused by a spirochaete bacterium called Treponema pallidum. Vertical transmission of spirochaetes can lead to congenital infection of the fetus in pregnant women who are inadequately treated or not treated at all, causing various clinical manifestations including stillbirth and neonatal death, cutaneous and visceral manifestations, or asymptomatic infection. We present a severe case of syphilis in a 3-month-old boy with skin lesions, portal hypertension, and anaemia. Because the mother was tested negative for syphilis antibodies at 16 weeks of gestation, a diagnosis of congenital syphilis was initially not considered. This case shows that transmission of T pallidum can still occur in high-income countries with a high rate of antenatal screening. Early recognition might be hampered if physicians do not consider congenital syphilis as a possible diagnosis. Congenital syphilis should be considered in any severe and diagnostically challenging infectious disease case, even in the context of negative antenatal screening.

Comparison of coronary artery bypass grafting and percutaneous coronary intervention for syphilitic coronary artery ostial lesions: A 4-year retrospective study

This study investigated the efficacy of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in treatment of patients with syphilitic coronary artery ostial lesions (SCAOL).Sixty SCAOL patients were divided into two groups according to the different treatments: the CABG group (n = 32) and the PCI group (n = 28). We determined serum levels of β-type natriuretic peptide (BNP) and cardiac function, and evaluated treatment efficacy such as the rates of restenosis, patency, and major adverse cardiovascular events (MACEs) during hospital stay and the effects of antisyphilis and different types of CABG on restenosis during the 6-month follow-up period.There were no statistical differences in demographic or baseline clinical characteristics, BNP levels, left ventricular end-diastolic diameter (LVDd), or ejection fraction (EF) between the CABG and PCI groups at 1 week after surgery, However, after 6-month of follow-up, the CABG group had a significantly lower rate of coronary artery restenosis, lower incidence of MACEs, and better cardiac function than the PCI group. Within the CABG group, the left internal mammary artery (LIMA) subgroup had a lower restenosis rate than the saphenous vein graft (SVG) subgroup. In addition, patients who had received anti-syphilis therapy had a significantly lower restenosis rate than those without anti-syphilis therapy at 6-month post-surgery.Compared with patients who received PCI, patients who received CABG had better prognoses. LIMA has a better therapeutic efficacy than SVG in terms of the restenosis rate, and anti-syphilis treatment significantly reduces the restenosis rate, compared with non-anti-syphilis treatment.

Evaluation of the fully automated AIX1000 rapid plasma reagin system compared to a manual plasma reagin testing method for the diagnosis of syphilis

The analytical performance of the FDA-cleared AIX1000 automated RPR testing platform was evaluated in comparison to manual RPR card testing. Eight hundred thirty-three patient serum samples were analyzed, 87 samples were positive by the AIX1000, 108 were positive by the manual test method; overall agreement between methods was 96.5% (κ = 0.83). Cases were further classified by clinical and laboratory-based confirmation of disease, to which reactivity rates were compared, yielding sensitivities of 96.4% and 100%, and specificities of 99.2% and 96.8% for the automated and manual RPR methods, respectively. The difference in specificity between methods was statistically significant (P < 0.001). Twenty-five of 29 samples with discordant results were reactive by manual testing (titers of 1:1 or 1:2); 21 of 25 patients with negative AIX100 results were identified to have histories of remote, treated syphilis. Overall, the AIX1000 platform demonstrated excellent agreement with the manual RPR method; discrepancies occurred with specimens at the threshold of reactivity.

Development of a novel magnetic particle-based agglutination immunoassay for anticardiolipin antibody detection in syphilis

Objectives

Serological tests of non-treponemal and treponemal types are the most frequently used for syphilis diagnosis. Treponemal tests are available in wide variety of assay formats; however, limited advances have been made for the improvement of conventional non-treponemal tests. The objective of this work was to develop a novel non-treponemal magnetic particle-based agglutination assay (NT-MAA) and evaluate its feasibility for syphilis testing.

Methods

Cardiolipin was modified and coupled to magnetic microbeads. Serum diluted in phosphate-buffered saline was mixed with cardiolipin-coupled beads and incubated in a round bottom microplate for 90–120 min followed by visual inspection. A panel of reported syphilis (n=127) and non-reactive (n=244) specimens was prepared to evaluate the NT-MAA performance in comparison to conventional rapid plasma reagin (RPR). Treponema pallidum particle agglutination (TP-PA) assay and enzyme immunoassay (EIA) were included. Analytical sensitivity and reproducibility of NT-MAA were also determined.

Results

The non-treponemal NT-MAA and RPR showed sensitivity of 90.6% and 88.2% and specificity of 96.7% and 100%, respectively. The treponemal TP-PA and EIA yielded sensitivity of 100% and 99.2%, respectively, and 100% specificity by both assays. The per cent agreement between NT-MAA and RPR was 97% (kappa=0.931, 95% CI 0.891 to 0.971). Analytical sensitivity determined with IgM anticardiolipin antibody (ACA) was 2.6 µg/mL for both NT-MAA and RPR, while IgG ACA yielded 0.9 µg/mL and 1.7 µg/mL for NT-MAA and RPR, respectively. Qualitative results of intra-assay and interassay reproducibility revealed 100% consistency for NT-MAA.

Conclusion

Preliminary evaluation of the novel NT-MAA validated proof of concept using laboratory-characterised syphilis sera and demonstrated performance comparable to RPR. Further validation of NT-MAA using additional specimens with better clinical staging may broaden the scope of developed test for syphilis diagnosis.