Diagnostic Issues of Asymptomatic Neurosyphilis in HIV-Positive Patients: A Retrospective Study

Refining a non-invasive prediction model for neurosyphilis diagnosis by using immunoassay to detect serum anti-TP0435 (TP17) and TP0574 (TP47) IgG antibodies: two-centre cross-sectional retrospective study in China

OBJECTIVES

Invasive lumbar puncture is the conventional method for diagnosing neurosyphilis (NS). We investigated a non-invasive alternative method to detect serum Treponema pallidum-specific antibodies against highly immunogenic antigens TP0171 (TP15), TP0435 (TP17), and TP0574 (TP47) by using luciferase immunosorbent assay.

METHODS

A total of 816 HIV-negative patients suspected of NS from the Beijing and Guangzhou cohorts were retrospectively selected and tested for serum anti-TP15, TP17, and TP47 IgG antibodies. Two diagnostic prediction models were developed using stepwise logistic regression in the Beijing cohort, and evaluated in the Guangzhou cohort for external validation.

RESULTS

Serum antibodies against TP15, TP17, and TP47 showed moderate capability for NS diagnosis in the Beijing cohort and the corresponding area under the receiver operating characteristic curves (AUCs) were 0.722 [95% confidence interval (CI): 0.680-0.762)], 0.780 (95% CI: 0.741-0.817), and 0.774 (95% CI: 0.734-0.811), respectively. An expanded NS prediction model integrated with anti-TP17 and anti-TP47 antibodies showed better performance than the base NS diagnostic model without anti-TP17 and anti-TP47 antibodies with the AUC of 0.874 (95% CI: 0.841-0.906) vs. 0.845 (95% CI: 0.809-0.881) (p = 0.007) in the development cohort, and 0.934 (95% CI: 0.909-0.960) vs. 0.877 (95% CI: 0.840-0.914) (p < 0.001) in validation cohort, respectively. Decision curve analysis revealed that the net benefit of the expanded model exceeded that of the base model when the threshold probability was between 0.10 and 0.95 in both the development and external validation cohorts.

DISCUSSION

Serum antibodies against TP17 and TP47 exhibited promising diagnostic capability for NS and significantly enhanced the predictive accuracy of model for NS diagnosis. Our study highlights the potential of serum treponemal antibody detection as a non-invasive method for NS diagnosis to substitute invasive lumbar puncture in NS diagnosis.

Response to Ceftriaxone in Asymptomatic Neurosyphilis Refractory to Doxycycline and Benzathine Penicillin

An asymptomatic male in his mid-30s presented with a positive Venereal Disease Research Laboratory (VDRL) test report. He was investigated and detected to be reactive for human immunodeficiency virus (HIV)-1 antibodies. A lumbar puncture revealed cerebrospinal fluid (CSF) VDRL to be reactive at a titer of 1:160 which led to a diagnosis of asymptomatic neurosyphilis. The unavailability of first-line antibiotics necessitated the search for alternative regimens. The patient was administered oral doxycycline 200 mg twice daily for 28 days along with intramuscular benzathine penicillin 2.4 million units once weekly for three weeks. A repeat CSF-VDRL performed six months later with raised titers of 1:320 indicated treatment failure. The patient was then administered ceftriaxone 1 g intramuscularly for 14 consecutive days. A final CSF-VDRL examination performed six months later showed non-reactive titers.

Development of a Cyclic Voltammetry-Based Method for the Detection of Antigens and Antibodies as a Novel Strategy for Syphilis Diagnosis

The improvement of laboratory diagnosis is a critical step for the reduction of syphilis cases around the world. In this paper, we present the development of an impedance-based method for detecting T. pallidum antigens and antibodies as an auxiliary tool for syphilis laboratory diagnosis. We evaluate the voltammetric signal obtained after incubation in carbon or gold nanoparticle-modified carbon electrodes in the presence or absence of Poly-L-Lysine. Our results indicate that the signal obtained from the electrodes was sufficient to distinguish between infected and non-infected samples immediately (T0') or 15 min (T15') after incubation, indicating its potential use as a point-of-care method as a screening strategy.

Comparing Noninvasive Predictors of Neurosyphilis Among Syphilis Patients With and Without HIV Co-Infection Based on the Real-World Diagnostic Criteria: A Single-Center, Retrospective Cohort Study in China

Diagnosis of neurosyphilis is currently based on the cerebrospinal fluid (CSF) assessments and CSF-Venereal Disease Research Laboratory (CSF-VDRL) is the traditional "gold standard." In the real world, CSF assessments and CSF-VDRL are not always available. This study aimed to identify noninvasive predictors of neurosyphilis based on real-world clinical parameters and diagnostic criteria in populations with different HIV status. In this retrospective cohort study, syphilis patients with different HIV statuses hospitalized for neurosyphilis screening were retrospectively recruited at an infectious disease hospital. Neurosyphilis was defined by real-world diagnostic criteria. Logistic regression and receiver operating characteristic curve analysis were used to investigate and evaluate predictors of neurosyphilis. In total, 528 patients were enrolled, including 143 syphilis patients without HIV infection and 385 HIV/syphilis-co-infected patients. One hundred twelve and 304 neurosyphilis patients were identified in the HIV-negative and HIV-positive groups, respectively. A high serum toluidine red unheated serum test (TRUST) titer was a robust predictor of neurosyphilis in all participants. An age ≥50 years old [adjusted odds ratio (aOR) = 5.062, 95% confidence interval (CI), 1.449-17.680] in the HIV-negative group and CD4⁺ T cell count <330/μL (<300 as reference, aOR = 0.552, 95% CI, 0.315-0.966) in the HIV-positive group were predictors of asymptomatic neurosyphilis. In real-world situations, for asymptomatic syphilis patients, relatively old age and a high serum TRUST titer in HIV-negative populations, and CD4⁺ T cells <330/μL and/or serum TRUST titer >1:64 in HIV-positive populations might predict neurosyphilis.

Clinical outcomes of HIV-syphilis coinfection among patients with no neurological symptoms: a retrospective cohort study

OBJECTIVE

Our objective was to describe and compare the occurrence of neurological outcomes and neurosyphilis in people living with HIV with incident syphilis and no neurological symptoms who underwent early screening for asymptomatic neurosyphilis (ANS) or regular clinical management without a lumbar puncture.

METHODS

This was a retrospective cohort study in a single referral centre of Sao Paulo, Brazil. Patients with incident syphilis diagnosed between January 2000 and August 2016 and meeting the adapted criteria for ANS investigation suggested by Marra et al. (CD4⁺ T-cell counts ≤350 cells/mm³ and/or venereal disease research laboratory test results ≥1:16) were identified. Those with no neurological symptoms and immediately referred for lumbar puncture were categorized as group 1, and those not referred for cerebrospinal fluid collection were categorized as group 2. We compared the occurrence of neurological symptoms and neurosyphilis diagnoses between the groups using incidence rates and Kaplan-Meier curves.

RESULTS

We included 425 participants with a median follow-up of 6 years. The incidence rate of neurological symptoms was 36.5/1000 person-years in group 1 and 40.6/1000 person-years in group 2 (incidence rate ratio [IRR] 0.90; 95% confidence interval [CI] 0.57-1.39; p = 0.62). The incidence rate of neurosyphilis was 15.0 cases/1000 person-years in group 1 and 6.7 cases/1000 person-years in group 2 (IRR 2.26; 95% CI 0.93-5.68; p = 0.05).

CONCLUSIONS

We found no statistically significant differences between groups in the incidence rates of neurological symptoms and neurosyphilis. Our findings support the current guidelines, which suggest a less invasive approach regarding ANS investigation among people living with HIV with incident syphilis.

Diagnostic tools for neurosyphilis: a systematic review

Purpose

Increasing incidences of syphilis highlight the preoccupation with the occurrence of neurosyphilis. This study aimed to understand the current diagnostic tools and their performance to detect neurosyphilis, including new technologies and the variety of existing methods.

Methods

We searched databases to select articles that reported neurosyphilis diagnostic methods and assessed their accuracy, presenting sensitivity and specificity values. Information was synthesized in tables. The risk of bias was examined using the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy recommendations.

Results

Fourteen studies were included. The main finding was a remarkable diversity of tests, which had varied purposes, techniques, and evaluation methodologies. There was no uniform criterion or gold standard to define neurosyphilis. The current basis for its diagnosis is clinical suspicion and cerebrospinal fluid analysis. There are new promising tests such as PCR tests and chemokine measurement assays.

Conclusions

The diagnosis of neurosyphilis is still a challenge, despite the variety of existing and developing tests. We believe that the multiplicity of reference standards adopted as criteria for diagnosis reveals the imprecision of the current definitions of neurosyphilis. An important next step for the scientific community is to create a universally accepted diagnostic definition for this disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06264-8.

Socio-Demographic Characteristics and Sexual Behavioral Factors of Patients with Sexually Transmitted Infections Attending a Hospital in Southern Italy

Sexually transmitted infections (STIs) are a serious global health problem. In Italy, data describing the vulnerability to STIs of specific sexual minorities and the influence of sociodemographic and behavioral determinants are limited, as most infections are not subject to mandatory notification. This retrospective study describes the sociodemographic profile and main sexual behaviors of patients attending a hospital in Palermo (Sicily, Italy) from January 2018 to March 2019 as predictors of STI risk. Patients were divided in subgroups: men-who-have-sex-with-men (MSM), men-who-have-sex-with-women (MSW), bisexual men and females. Data were obtained through an anonymous questionnaire. Patients were tested for chlamydia, syphilis, Mycoplasma genitalium infection, genital herpes and HPV infection. A total of 294 subjects with STIs (male/female ratio about 2:1) were screened. Of the total sample, 79.6% of patients were Italian. MSM accounted for 34.3%, MSW for 29.6%, bisexual men for 5.8% and females for 30.3%. A total of 44.5% of patients had a high education level, 42.5% reported irregular use of condoms, 20.7% reported having had 5-10 partners in the six months prior to the visit and 32.9% were HIV-positive. HPV infection and syphilis were the most prevalent STIs. Conclusions: The most common profile of patients attending our clinic was that of an adult, Italian man with a high level of education, poor use of condoms and a high number of partners. MSM had the highest sex-behavior-related risk for STIs. In addition, our results suggest that all STD teams need to implement counselling topics and recommendations to share with patients, as well as tips on how to approach sexual health education/counselling, thereby promoting patient-centered approaches and educational programs.

Neurosyphilis and the Jarisch-Herxheimer reaction: A therapy concern with HIV disease

Jarisch-Herxheimer reaction (JHR) should be anticipated in treating neurosyphilis with coexistent human immunodeficiency virus (HIV) encephalitis. In that context we have devised a staging classification for JHR. In addition, an illustrative case is provided to emphasize the need to consider the diagnosis of neurosyphilis in HIV patients, and if delineated, to be prepared for a severe JHR.