Clinical prediction and diagnosis of neurosyphilis in HIV-infected patients with early Syphilis

Loop-Mediated Isothermal Amplification Assay Using Gold Nanoparticles for Detecting Treponema pallidum subspp. pallidum

BACKGROUND

Venereal syphilis in humans is caused by Trepenoma pallidum subspp. pallidum. A study has shown that 30,302 individuals in Thailand had syphilis in 2020, with a male-to-female ratio of 1:0.8 and the highest incidence rate at ages between fifteen and twenty-four.

METHODS

This research aimed to develop a loop-mediated isothermal amplification assay using gold nanoparticles (LAMP-AuNPs). Analytical sensitivity, diagnostic specificity, accuracy, and predictive values for each technique are provided.

RESULTS

The diagnosis sensitivities of polymerase chain reaction using agarose gel electrophoresis (PCR-AGE), loop-mediated isothermal amplification assay using agarose gel electrophoresis (LAMP-AGE), and LAMP-AuNPs were 116 ng/µL, 11.6 ng/µL, and 11.6 ng/µL, respectively. We evaluated the analytical specificity using PCR and a LAMP-based assay, and there was no cross-reactivity to Leptospira interrogans, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, human immunodeficiency virus (HIV), and healthy humans. After analyzing 400 serum samples of patients suspected of syphilis, the LAMP-AGE and LAMP-AuNPs assays displayed 100% diagnostic sensitivity scores, 91% diagnostic specificity scores, 95.5% accuracy rates, 100% positive predictive values (PPVs), and 91% negative predictive values (NPVs), the positive likelihood ratio (LR+) was 11.11, while the negative likelihood ratio (LR-) was 0. Conversely, for PCR assays displayed 100% diagnostic sensitivity scores, 94.5% diagnostic specificity scores, 97.25% accuracy rates, 100% PPVs, and 94.5% NPVs, LR+ was 18.18, and LR- was 0.

CONCLUSIONS

The LAMP-AuNPs technique demonstrates rapidity, affordability, and convenience, rendering it well-suited for point-of-care applications in the diagnosis, prevention, and management of pathogenic infections.

Cerebrospinal Fluid Biomarkers of Symptomatic Neurosyphilis in People With HIV Compared with Uninfected Individuals

We evaluated the diagnostic clinical performance characteristics (DCPC) of cerebrospinal fluid (CSF) total protein (TP), white blood cell count (WBC), and lactate (LA) with different cutoff points as adjunct biomarkers of confirmed or presumptive symptomatic neurosyphilis (NS) and the impact of HIV infection. From 5,640 participants who underwent lumbar punctures, 236 participants were included, and classified as either people with HIV (PWH) or people without HIV (PWoH) according to the CDC criteria for confirmed NS (n = 42), presumptive NS (n = 74), systemic syphilis (SS) (n = 38), serological diagnosis of syphilis (n = 18), PWH without SS and NS (n = 10), and negative control (n = 72). In PWoH, for presumptive NS, the combination of CSF TP > 45 mg/dL and/or WBC > 5.0 cells/mm3 is valuable for screening, whereas in PWH, it is not recommended for either screening or case-finding NS, however the DCPC were better in the suppressed group. In PWoH, the value of CSF TP > 45 mg/dL is adequate for both screening and confirmation of presumptive NS, subject to prevalence. For WBC count > 20 cell/mm3, the positive predictive value (PPV) of the test is almost perfect, suggesting a confirmatory test. In PWH, CSF TP is an inadequate marker of NS. The WBC count, with cutoffs of > 10 or > 20 cells/mm3, was moderately applicable for screening.As conclusions: CSF WBC count and TP showed distinct DCPC in confirmed or presumptive NS, better in the former. These biomarkers could be included for presumptive NS diagnosis. DCPC of these biomarkers for the diagnosis of NS is greatly affected by HIV co-infection.

Clinical and laboratory features of neurosyphilis: A single-center, retrospective study of 402 patients

Neurosyphilis is a serious global health issue and a big challenge in developing countries, related risk factors should be taken seriously. Although there are a certain number of studies describing the clinical and laboratory features and risk factors for symptomatic neurosyphilis (SNS), but some risk factors are still controversial. The aim of this research is to investigate the association between asymptomatic neurosyphilis (ANS) and symptomatic neurosyphilis (SNS) and identify risk factors for SNS. This was a single-center retrospective study in a tertiary hospital in Hangzhou, China. The clinical and laboratory features of neurosyphilis patients from January 1, 2011 to July 31, 2020 were retrospectively reviewed. After detailed assessments based on diagnostic criteria, 402 patients with neurosyphilis were enrolled in this study. There were 299 male and 103 female patients. The median age was 53.5 (45, 61) years. Multivariable logistic regression displayed that SNS were correlated with the following factors: male, without anti-syphilis treatment, high pretreatment serum RPR titer and positive CSF RPR. Our findings suggest a potential association between SNS and specific factors, including male gender, elevated pretreatment serum and CSF RPR titers. Moreover, our observations indicate that individuals without anti-syphilis treatment may be at a higher likelihood of manifesting the symptomatic form. This underscores the importance of considering gender, RPR titers, and treatment status as significant contributors to the risk profile for SNS.

Characteristics of Hepatitis B Virus, Hepatitis C Virus, and Syphilis Coinfection in People With HIV/AIDS Contracted Through Different Sources: Retrospective Study

BACKGROUND

The burden of hepatitis B virus (HBV), hepatitis C virus (HCV), and syphilis coinfections remains disproportionately high among people living with HIV/AIDS. Hubei province is located in central China, where there are distinct regional characteristics of the distribution of people living with HIV/AIDS acquired via diverse transmission routes and the AIDS epidemic itself.

OBJECTIVE

We aimed to estimate the magnitude of HBV, HCV, or syphilis coinfections among people living with HIV/AIDS with blood-borne transmission, which includes former paid blood donors, contaminated blood recipients, and intravenous drug users, as well as among people with sex-borne HIV transmission (including heterosexual people and men who have sex with men) and people with mother-to-child HIV transmission.

METHODS

From January 2010 to December 2020, people living with HIV/AIDS were tested for hepatitis B surface antigen (HBsAg), HCV antibodies, and syphilis-specific antibodies. The positive patients were further tested for HBV markers, HBV DNA, and HCV RNA, and received a rapid plasma reagin circle card test. All people living with HIV/AIDS were first divided into transmission groups (blood, sex, and mother-to-child); then, people with blood-borne HIV transmission were divided into former paid blood donors, contaminated blood recipients, and intravenous drug users, while people with sex-borne HIV transmission were divided into heterosexual people and men who have sex with men.

RESULTS

Among 6623 people living with HIV/AIDS, rates of chronic HCV infection were 80.3% (590/735) in former paid blood donors, 73.3% (247/337) in intravenous drug users, 57.1% (444/777) in contaminated blood recipients, 19.4% (21/108) in people with mother-to-child HIV transmission, 8.1% (240/2975) in heterosexual people, and 1.2% (21/1691) in men who have sex with men. Chronic HBV infection rates were similar among all people with blood-borne HIV transmission. However, compared to heterosexual people, the chronic HBV infection rate was greater in men who have sex with men (213/1691, 12.6% vs 308/2975, 10.4%; χ21=5.469; P=.02), although HBV exposure was less common (827/1691, 48.9% vs 1662/2975, 55.9%; χ21=20.982; P<.001). Interestingly, the combination of HBsAg and hepatitis B e antigen (HBeAg) was found in 11 patients with sex-borne HIV transmission, but in 0 people with blood-borne HIV transmission (11/196, 5.6% vs 0/521, 0%; χ21=29.695, P<.001). In people with sex-borne HIV transmission, the proportions of patients with a syphilis titer ≥1:16 and neurosyphilis were 8.6% (105/1227) and 7.8% (37/473), respectively, whereas these values were 0 in people with blood-borne HIV transmission.

CONCLUSIONS

In people living with HIV/AIDS, HCV transmission intensity was significantly associated with specific exposure modes of blood or sexual contact. The rate of chronic HBV infection among men who have sex with men was higher than in any other population. Attention should be paid to the high prevalence of neurosyphilis in people living with HIV/AIDS who contract HIV by sexual intercourse.

Neurological manifestations of syphilis-HIV coinfection in South Africa

OBJECTIVE

Syphilis and HIV coinfection is highly prevalent in South Africa, and both can cause neurological complications. We describe the clinical presentation and outcome of neurosyphilis in patients with and without HIV coinfection diagnosed at a tertiary facility, Groote Schuur Hospital (GSH), in South Africa.

METHODS

We retrospectively analyzed folders of adults with positive cerebrospinal fluid (CSF) fluorescent treponemal antibody absorption test in 2018 and 2019, with follow-up data collected until 2022.

RESULTS

HIV-coinfection was identified in 35% of the 69 included patients. Patients with HIV-coinfection were more likely to be female (58% vs 25% female, p < 0.01), and present earlier (median age = 31 years vs. 40 years, p < 0.001). Neuropsychiatric manifestations (confusion, dementia, psychosis), and strokes were the commonest clinical presentations in both groups. Those with HIV-coinfection were significantly less likely to be diagnosed with neurosyphilis by the treating clinician (71% vs. 91%, p < 0.05), as were those with a negative CSF Venereal Disease Research Laboratory (74% vs. 94%, p < 0.05). Accurate diagnosis of neurosyphilis was associated with an increased 12-month survival (alive: N = 36 [63%]) relative to those who did not receive an accurate diagnosis (alive: N = 2 [17%], p < 0.05). Those who were optimally treated with antibiotics had significantly higher 12-month survival (alive: N = 33, 63%) compared to those with suboptimal treatment (alive: N = 5, 29%), p < 0.01.

CONCLUSION

Neurosyphilis presented similarly in those with and without HIV-coinfection. Accurate identification and optimal antibiotic treatment of neurosyphilis, particularly in CSF VDRL negative patients and those with HIV-coinfection, is necessary to improve patient survival.

Diagnosis of neurosyphilis in HIV-negative patients with syphilis: development, validation, and clinical utility of a suite of machine learning models

Background

The ability to accurately identify the absolute risk of neurosyphilis diagnosis for patients with syphilis would allow preventative and therapeutic interventions to be delivered to patients at high-risk, sparing patients at low-risk from unnecessary care. We aimed to develop, validate, and evaluate the clinical utility of simplified clinical diagnostic models for neurosyphilis diagnosis in HIV-negative patients with syphilis.

Methods

We searched PubMed, China National Knowledge Infrastructure and UpToDate for publications about neurosyphilis diagnostic guidelines in English or Chinese from database inception until March 15, 2023. We developed and validated machine learning models with a uniform set of predictors based on six authoritative diagnostic guidelines across four continents to predict neurosyphilis using routinely collected data from real-world clinical practice in China and the United States (through the Dermatology Hospital of Southern Medical University in Guangzhou [659 recruited between August 2012 and March 2022, treated as Development cohort], the Beijing Youan Hospital of Capital Medical University in Beijng [480 recruited between December 2013 and April 2021, treated as External cohort 1], the Zhongshan Hospital of Xiamen University in Xiamen [493 recruited between November 2005 and November 2021, treated as External cohort 2] from China, and University of Washington School of Medicine in Seattle [16 recruited between September 2002 and April 2014, treated as External cohort 3] from United States). We included all these patients with syphilis into our analysis, and no patients were further excluded. We trained eXtreme gradient boosting (XGBoost) models to predict the diagnostic outcome of neurosyphilis according to each diagnostic guideline in two scenarios, respectively. Model performance was measured through both internal and external validation in terms of discrimination and calibration, and clinical utility was evaluated using decision curve analysis.

Findings

The final simplified clinical diagnostic models included neurological symptoms, cerebrospinal fluid (CSF) protein, CSF white blood cell, and CSF venereal disease research laboratory test/rapid plasma reagin. The models showed good calibration with rescaled Brier score of 0.99 (95% CI 0.98-1.00) and excellent discrimination (the minimum value of area under the receiver operating characteristic curve, 0.84; 95% CI 0.81-0.88) when externally validated. Decision curve analysis demonstrated that the models were useful across a range of neurosyphilis probability thresholds between 0.33 and 0.66 compared to the alternatives of managing all patients with syphilis as if they do or do not have neurosyphilis.

Interpretation

The simplified clinical diagnostic models comprised of readily available data show good performance, are generalisable across clinical settings, and have clinical utility over a broad range of probability thresholds. The models with a uniform set of predictors can simplify the sophisticated clinical diagnosis of neurosyphilis, and guide decisions on delivery of neurosyphilis health-care, ultimately, support accurate diagnosis and necessary treatment.

Funding

The Natural Science Foundation of China General Program, Health Appropriate Technology Promotion Project of Guangdong Medical Research Foundation, Department of Science and technology of Guangdong Province Xinjiang Rural Science and Technology（Special Commissioner）Project, Southern Medical University Clinical Research Nursery Garden Project, Beijing Municipal Administration of Hospitals Incubating Program.

Performance of the nontreponemal tests and treponemal tests on cerebrospinal fluid for the diagnosis of neurosyphilis: A meta-analysis

Background

Nontreponemal and treponemal tests for analyzing cerebrospinal fluid to confirm the existence of neurosyphilis have been widely used, so we aim to evaluate and compare their performance on the cerebrospinal fluid in the diagnosis of neurosyphilis.

Methods

We conducted a systematic literature search on five databases and utilized a bivariate random-effects model to perform the quantitative synthesis.

Results

Nontreponemal tests demonstrated a pooled sensitivity of 0.77 (95% CI: 0.68-0.83), a pooled specificity of 0.99 (95% CI: 0.97-1.00), and a summary AUC of 0.97 (95% CI: 0.95-0.98). The pooled sensitivity, pooled specificity, and summary AUC of treponemal tests were 0.95 (95% CI: 0.90-0.98), 0.85 (95% CI: 0.67-0.94), and 0.97 (95% CI: 0.95-0.98), respectively. The pooled specificity of all nontreponemal tests varied minimally (ranging from 0.97 to 0.99), with TRUST (0.83) having a higher pooled sensitivity than VDRL (0.77) and RPR (0.73). Among all treponemal tests, EIA has outstanding diagnostic performance with a pooled sensitivity of 0.99 and a pooled specificity of 0.98.

Conclusion

Nontreponemal tests exhibited a higher pooled specificity, and treponemal tests exhibited a higher pooled sensitivity in diagnosing neurosyphilis on cerebrospinal fluid. TRUST may be a satisfactory substitute for VDRL. EIA is a prospective diagnostic tool that deserves further study in the future. Our study may be useful to clinical laboratories in selecting appropriate serological tests on the cerebrospinal fluid for the diagnosis of neurosyphilis.

Neurosyphilis in China: A Systematic Review of Cases From 2009-2021

Considered the increased threaten of neurosyphilis in China, a review on cases reported in the literature to describe the clinical epidemiological characteristics of neurosyphilis cases, may be beneficial to the early detection and management strategies of neurosyphilis for clinicians. We searched the literature on Chinese neurosyphilis cases published from January 1, 2009 to December 31, 2021, described their clinical epidemiological characteristics and calculated the prevalence of neurosyphilis amongst other associated diseases, according to the individual study criteria. A total of 284 studies including 7,486 neurosyphilis cases were included. No meta-analysis was performed due to the heterogeneity of the data. Among 149 case reports and 93 retrospective case series studies, the main clinical manifestation of 3,507 neurosyphilis cases was cerebral parenchymal syphilis (57.3%), followed by asymptomatic neurosyphilis (16.7%), meningovascular syphilis (13.6%), meningitis syphilis (7.7%) and ocular syphilis (2.8%), etc. In addition, the initial diagnosis was incorrect in 53.2% patients, and the most frequent misdiagnoses were mental disorders (31.0%), stroke (15.9%), cognitive impairment (9.0%), etc. The positive or abnormal rates of cerebrospinal fluid non-treponemal and treponemal tests, white blood cell counts and protein concentrations were 74.2%, 96.2%, 61.5%, and 60.9%, respectively. Aqueous penicillin was the first choice for treatment in 88.3% cases, and 81.7% and 50.0% patients had response in the improvement of symptoms and serological effective in CSF, respectively. Among 26 studies on neurosyphilis patients amongst other associated diseases, the prevalence of neurosyphilis amongst central nervous system infectious diseases, syphilis-associated neurological symptoms, serofast status, coinfected with human immunodeficiency virus were 10.6%-30.1%, 23.2%-35.5%, 9.8%-56.1%, and 8.9%, respectively. In summary, the lack of early detection of neurosyphilis cases remains a clinical challenge. The high rate of misdiagnosis and high prevalence of neurosyphilis amongst associated diseases strongly remind clinicians to focus on the early detection among suspected cases. Besides, the standard treatment regimen and long-term follow-up, which complied with guideline should be provided. Further prospective studies are urgent to better delineate the clinical epidemiological characteristics of neurosyphilis in China.

Management of Adult Syphilis: Key Questions to Inform the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines

A panel of experts generated 5 "key questions" in the management of adult syphilis. A systematic literature review was conducted and tables of evidence were constructed to answer these questions. Available data suggest no clinical benefit to >1 dose of benzathine penicillin G for early syphilis in human immunodeficiency virus (HIV)-infected patients. While penicillin remains the drug of choice to treat syphilis, doxycycline to treat early and late latent syphilis is an acceptable alternate option if penicillin cannot be used. There are very limited data regarding the impact of additional antibiotic doses on serologic responses in serofast patients and no data on the impact of additional antibiotic courses on long-term clinical outcomes. In patients with isolated ocular or otic signs and symptoms, reactive syphilis serologic results, and confirmed ocular/otic abnormalities at examination, a diagnostic cerebrospinal fluid (CSF) examination is not necessary, because up to 40% and 90% of patients, respectively, would have no CSF abnormalities. Based on the results of 2 studies, repeated CSF examinations are not necessary for HIV-uninfected patients or HIV-infected patients on antiretroviral therapy who exhibit appropriate serologic and clinical responses after treatment for neurosyphilis. Finally, several important gaps were identified and should be a priority for future research.

Development and external validation of a nomogram for neurosyphilis diagnosis among non-HIV patients: a cross-sectional study

Background

The diagnosis of neurosyphilis is challenging due to the requirement of a lumbar puncture and cerebrospinal fluid (CSF) laboratory tests. Therefore, a convenient diagnostic nomogram for neurosyphilis is warranted. This study aimed to construct diagnostic models for diagnosing neurosyphilis.

Methods

This cross-sectional study included data of two patient cohorts from Western China Hospital of Sichuan University between September 2015 and April 2021 and Shangjin Hospital between September 2019 and April 2021 as the development cohort and the external validation cohort, respectively. A diagnostic model using logistic regression analysis was constructed to readily provide the probability of diagnosis at point of care and presented as a nomogram. The clinical usefulness of the diagnostic models was assessed using a receiver operating characteristic (ROC) and Harrell concordance (Harrell C) index for discrimination and calibration plots for accuracy, which adopted bootstrap resampling 500 times.

Results

One hundred forty-eight and 67 patients were included in the development and validation cohorts, respectively. Of those, 131 were diagnosed as having reactive neurosyphilis under the criteria of positive results in both CSF treponemal and non-treponemal tests. In the development cohort, male, psychiatric behaviour disorders, and serum toluidine red unheated serum test were selected as diagnostic indicators applying a stepwise procedure in multivariable logistic model. The model reached 80% specificity, 79% sensitivity, and 0·85 area under the curves (AUC) (95% confidence interval, 0·76–0·91). In the validation cohorts, the Harrell C index for the diagnostic possibility of reactive neurosyphilis was 0·71.

Conclusions

A convenient model using gender, presence of psychiatric behaviour disorders, and serum TRUST titre was developed and validated to indicate diagnostic results in patients suspected of neurosyphilis. Checking the model value of factors on nomogram is a feasible way to assist clinicians and primary health servers in updating patients’ medical charts and making a quantitatively informed decision on neurosyphilis diagnosis.

Trial registration

This research was retrospectively registered in the Ethics committee on biomedical research, West China Hospital of Sichuan University. The research registration and committee’s reference number was 1163 in 2020 approval.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02454-8.

Ocular and neurosyphilis: epidemiology and approach to management

PURPOSE OF REVIEW

In the context of a resurgence of syphilis worldwide, it can be anticipated that a rise in cases of ocular, otic, and neurosyphilis will also be seen. This article reviews the current epidemiology, manifestations, and approach to management and treatment.

RECENT FINDINGS

Although studies continue investigating alternate approaches and new diagnostic tests for ocular and neurosyphilis, few data exist to change current diagnostic algorithms and approaches to diagnosis, management, or follow up.

SUMMARY

The diagnosis of neurologic and eye/ear involvement with syphilis may be delayed because of a lack of specificity of findings, low suspicion for syphilis, fluctuation in symptoms, and/or similarities in presentation to other diseases. A high index of suspicion for syphilis and re-education about the protean manifestations of syphilis by all clinicians is required provide timely diagnosis and management of ocular, otic, and neurosyphilis.

Prevalence of syphilis, neurosyphilis and associated factors in a cross-sectional analysis of HIV infected patients attending Bugando Medical Centre, Mwanza, Tanzania

Background

HIV-syphilis co-infection can enhance the rapid progression of early or late latent syphilis to neurosyphilis and can cause catastrophic neurological complications. In studies in Mwanza, syphilis affects ~ 8% of healthy outpatients and studies done in the 1990s have suggested that up to 23.5% of HIV-syphilis co-infected patients also have neurosyphilis.

Methodology

This was a cross sectional study in which adult HIV infected patients who were hospitalized or attending the outpatient Care and Treatment Clinic (CTC) were interviewed using a structured questionnaire and screened for syphilis using serum Treponema Pallidum Hemagglutination Assay (TPHA). Blood was also taken for CD4+ T cells and viral load. Those who were found to have syphilis underwent neurological examination for any neurologic deficit and were offered a lumbar puncture.

Results

The prevalence of syphilis in HIV infected patients was found to be 9.6%. The majority of patients were female (72.5%) and median age was 42 years [interquartile range, 32–50]. Most patients were on ART (99.4%). In the study population of 1748 participants, 9.6% were TPHA positive; the majority (89.2%) reported not knowing their syphilis status and not previously been treated. One hundred and forty-one participants with syphilis had neurological examinations performed. Four of these had abnormal findings that necessitated a lumbar puncture. Neurosyphilis was confirmed in one patient (0.7%).

Conclusion

The high prevalence of syphilis in HIV infected patients indicates that there is a need to increase efforts in targeting this population to reduce sexually transmitted infections. Screening for syphilis should be done for all HIV patients given the high prevalence of the infection and the risk that aggressive forms of neurosyphilis can occur despite recovery of CD4+ T cell counts in untreated syphilis.

Decomplexifying Serum and Cerebrospinal Fluid (CSF) Serologic Testing of Neurosyphilis: A Case Report of Ocular Syphilis and Highlights of the Principles of Serologic Testing

Serologic tests for syphilis can be quite complex. The screening and confirmatory tests, which number at least eight, are mathematically interpreted as a total of 16 possible combinations, if we choose one test from each of two sets of four. However, this bewildering complexity is simplified if we apply certain principles. We reiterate and propose four axioms. First, we distinguish between treponemal versus non-treponemal tests. The former, the treponemal test, is specific for the spirochete, treponema pallidum, and is used as a confirmatory test. It rarely declines over time. The latter, the non-treponemal test, is a screening test and reflects treponemal or tissue damage, is reported as a titer, and is used to monitor disease activity. We usually need both for screening and confirmatory diagnostic testing. Secondly, for rapid plasma reagin (RPR) tests, a non-treponemal serology test titer of at least 1:8 is suggestive of syphilis, but not necessarily neurosyphilis. A false-negative test usually registers below this dilution level and may be due to the "prozone phenomenon". Serum RPR titers are usually greater than 1:32. Thirdly, a negative treponemal test in the cerebrospinal fluid excludes neurosyphilis and a positive test is highly sensitive but lacks specificity, usually due to blood contamination. Most patients with neurosyphilis will have a positive non-treponemal test in the cerebrospinal fluid (CSF) with elevated protein and pleocytosis. Fourthly, a serological cure is defined as at least a four-fold decline in a non-treponemal test titer at three and six months, or a persistently low titer after treatment. Patients who do not fulfill these criteria are known as "serofast". We describe the case of a 38-year-old man with human immunodeficiency virus-type 1 who developed bilateral optic disc edema with photopsias and transient visual obscurations.

Clinical prediction and diagnosis of neurosyphilis in HIV-negative patients: a case-control study

BACKGROUND

Early diagnosis and treatment of neurosyphilis is of great significance for regression. There is no gold standard for the diagnosis of neurosyphilis. We did this study to explore the factors associated with the clinical diagnosis of neurosyphilis and assess their accuracy for the diagnosis of neurosyphilis.

METHODS

We retrospectively reviewed 100 cases of syphilis patients who underwent lumbar puncture at a major dermatology hospital in Guangzhou, China between April 2013 and November 2016. Fifty patients who were clinically diagnosed with neurosyphilis were selected as case group. Control group consisted of 50 general syphilis patients who were matched with age and gender. The records of patients were reviewed to collect data of socio-demographic information, clinical symptom, and laboratory indicators. Multivariable logistic regression was used to explore diagnostic indictors, and ROC analysis was used to assess diagnostic accuracy.

RESULTS

Neurological symptoms (odds ratio (OR) = 59.281, 95% CI:5.215-662.910, P = 0.001), cerebrospinal fluid (CSF) Treponema pallidum particle agglutination (TPPA) titer (OR = 1.004, 95% CI:1.002-1.006, P < 0.001), CSF protein (OR = 1.005, 95% CI:1.000-1.009, P = 0.041), and CSF white blood cell (WBC) (OR = 1.120, 95% CI:1.017-1.233, P = 0.021) were found to be statistically associated with neurosyphilis. In ROC analysis, CSF TPPA titer had a sensitivity of 90%, a specificity of 84%, and an area under curve (AUC) of 0.941.

CONCLUSION

CSF TPPA can potentially be considered as an alternative test for diagnosis of neurosyphilis. Combining with neurological symptoms, CSF protein, CSF WBC, the diagnosis would have a higher sensitivity.

The development of an online risk calculator for the prediction of future syphilis among a high-risk cohort of men who have sex with men and transgender women in Lima, Peru

Background Syphilis incidence worldwide has rebounded since 2000, particularly among men who have sex with men (MSM). A predictive model for syphilis infection may inform prevention counselling and use of chemoprophylaxis.

METHODS

Data from a longitudinal cohort study of MSM and transgender women meeting high-risk criteria for syphilis who were followed quarterly for 2 years were analysed. Incidence was defined as a four-fold increase in rapid plasma reagin (RPR) titres or new RPR reactivity if two prior titres were non-reactive. Generalised estimating equations were used to calculate rate ratios (RR) and develop a predictive model for 70% of the dataset, which was then validated in the remaining 30%. An online risk calculator for the prediction of future syphilis was also developed.

RESULTS

Among 361 participants, 22.0% were transgender women and 34.6% were HIV-infected at baseline. Syphilis incidence was 19.9 cases per 100-person years (95% confidence interval (CI) 16.3-24.3). HIV infection (RR 2.22; 95% CI 1.54-3.21) and history of syphilis infection (RR 2.23; 95% 1.62-3.64) were significantly associated with incident infection. The final predictive model for syphilis incidence in the next 3 months included HIV infection, history of syphilis, number of male sex partners and sex role for anal sex in the past 3 months, and had an area under the curve of 69%. The online syphilis risk calculator based on those results is available at: www.syphrisk.net.

CONCLUSIONS

Using data from a longitudinal cohort study among a population at high risk for syphilis infection in Peru, we developed a predictive model and online risk calculator for future syphilis infection. The predictive model for future syphilis developed in this study has a moderate predictive accuracy and may serve as the foundation for future studies.

Clinical and Laboratory Characteristics of Symptomatic and Asymptomatic Neurosyphilis in HIV-Negative Patients: A Retrospective Study of 264 Cases

A retrospective study was performed to compare the differences in clinical and laboratory features of asymptomatic neurosyphilis (ANS) and symptomatic neurosyphilis (SNS). A total of 264 HIV-negative inpatients with neurosyphilis were enrolled from Beijing Ditan Hospital and Beijing Tiantan Hospital between January 2014 and May 2018, including 110 SNS and 154 ANS. The SNS group had more patients in males, older median age and without antisyphilis treatment than ANS group (P<0.001, P<0.001, and P<0.001, respectively). The laboratory findings showed that the SNS group had higher pretreatment serum rapid plasma regain (RPR) titer, current serum RPR titer, cerebrospinal fluid (CSF) white blood cell (WBC) counts, CSF protein concentrations, and higher positive CSF RPR rate than those in the ANS group (P=0.011, P<0.001, P<0.001, P<0.001, and P<0.001, respectively). The multivariate logistic regression analysis revealed that male (OR=2.833, P=0.009), age≥45 years (OR=3.611, P=0.001), without antisyphilis treatment (OR=0.247, P<0.001), higher current serum RPR titer (OR=1.373, P=0.022), positive CSF RPR (OR=4.616, P<0.001), and higher CSF protein concentration (OR=1.017, P=0.026) were independent risk predictors for SNS. Therefore, clinical and laboratory features between SNS and ANS are quietly different. Male gender, age≥45 years, and lack of antisyphilis treatment are risk factors for SNS. The elevated level of serum RPR titer, CSF protein concentration, and CSF RPR titer may indicate the development of neurosyphilis and the aggravation of neurological symptoms.

PCR detection for syphilis diagnosis: Status and prospects

Syphilis, a re‐emerging public health problem worldwide caused by Treponema pallidum subsp pallidum (T. pallidum), usually induces systemic and chronic inflammation in hosts who do not receive timely therapy after exposing to high‐risk factors such as leprous sexual contact. Before the treatment, rapid and accurate detection of syphilis is essential. However, the existing detection methods, which focus on the treponemal or non‐treponemal antibody test, both have inherent limitations. For instance, both of them cannot distinguish the stage and severity of syphilis. Non‐treponemal test such as RPR, which is generally deemed to be used for assessing treatment response, is influenced by biological false positives. Therefore, it is imperative to seek out a new and effective diagnostic test. With recent advancements in molecular biology and whole‐genome sequencing, the molecular diagnosis has increased in popularity, especially the use of polymerase chain reaction (PCR). Here, we firstly present a mini‐review on the research of PCR detection methods used for syphilis diagnosis over the past decade, and we then compare these methodologies to assess their potential and the challenges faced. This information can provide a fresh perspective to help researchers address the current challenges.

Urea-mediated dissociation alleviate the false-positive Treponema pallidum-specific antibodies detected by ELISA

The serological detection of antibodies to Treponema pallidum is essential to the diagnosis of syphilis. However, for the presence of cross-reaction, the specific antibody tests [e.g., enzyme-linked immunosorbent assay (ELISA)] always have false-positive results. In this study, we derived and validated the dissociation of urea in an attempt to alleviate the situation of false-positive antibodies to T. pallidum detected by ELISA. Six serum samples that were false-positive antibodies to T. pallidum detected by ELISA, and 16 control serum samples (8 sera positive for both specific IgG and IgM, and 8 IgG-positive and IgM-negative sera) were collected to select the appropriate dissociated concentration and time of urea. Our goal was to establish improved an ELISA method based on the original detection system of ELISA. The sensitivity of the improved ELISA was evaluated by 275 serum samples with class IgM-positive antibodies to T. pallidum. At 6 mol/L with 10 minutes dissociation of urea, 6 samples with false-positive antibodies to T. pallidum were converted to negative, and compared with true-positive antibodies to T. pallidum. The sensitivity of the improved ELISA was 100% by detecting the class IgM-positive antibodies to T. pallidum in sera of patients with syphilis. Considering the importance at the diagnosis of syphilis, antibodies to T. pallidum in serum samples should be retested by the improved ELISA method to avoid false-positive results.

Looking at the positives: proactive management of STIs in people with HIV

Patients who are HIV-positive and co-infected with other sexually transmitted infections (STIs) are at risk of increased morbidity and mortality. This is of clinical significance. There has been a dramatic increase in the incidence of STIs, particularly syphilis, gonorrhoea, Mycoplasma genitalium and hepatitis C virus (HCV) in HIV-positive patients. The reasons for this are multifactorial, but contributing factors may include effective treatment for HIV, increased STI testing, use of HIV pre-exposure prophylaxis and use of social media to meet sexual partners. The rate of syphilis-HIV co-infection is increasing, with a corresponding increase in its incidence in the wider community. HIV-positive patients infected with syphilis are more likely to have neurological invasion, causing syndromes of neurosyphilis and ocular syphilis. HIV infection accelerates HCV disease progression in co-infected patients, and liver disease is a leading cause of non-AIDS-related mortality among patients who are HIV-positive. Since several direct-acting antivirals have become subsidised in Australia, there has been an increase in treatment uptake and a decrease in HCV viraemia in HIV-positive patients. The incidence of other sexually transmitted bacterial infections such as Neisseria gonorrhoeae and M. genitalium is increasing in HIV patients, causing urethritis, proctitis and other syndromes. Increasing antimicrobial resistance has also become a major concern, making treatment of these infections challenging. Increased appropriate testing and vigilant management of these STIs with data acquisition on antimicrobial sensitivities and antimicrobial stewardship are essential to prevent ongoing epidemics and emergence of resistance. Although efforts to prevent, treat and reduce epidemics of STIs in patients living with HIV are underway, further advances are needed to reduce the significant morbidity associated with co-infection in this patient setting.

Lack of antiretroviral therapy is associated with higher risk of neurosyphilis among HIV-infected patients who remain serofast after therapy for early syphilis

Resolution of clinical symptoms and at least 4-fold decline in nontreponemal antibody titers after treatment of syphilis is regarded as "proof of cure." However, a substantial proportion of patients demonstrates <4-fold reduction of titers after recommended therapy (serofast state). It remains unclear whether the serofast state is indicative of persistence of bacteria or only a residual immune response.The aim of the present study was to determine the association between the serofast state and the risk of neurosyphilis in human immunodeficiency virus (HIV)-infected individuals and to identify potential predictors of neurosyphilis.Thirty-three patients with early syphilis and HIV co-infection were included. One year after the recommended treatment of syphilis, all patients who did not achieve proper serologic response underwent lumbar puncture and cerebrospinal fluid (CSF) examination.Twelve months after completing therapy for syphilis, the proportion of patients with serofast state after syphilis therapy was 36.4% (n = 12). Among them, 5 (41.7%) had neurosyphilis. Individuals who remained serofast and had neurosyphilis (n = 5) when compared to those without neurosyphilis (n = 7) were characterized by significantly lower CD4+ cell count and higher HIV RNA levels (P < .05). Moreover, a significantly higher proportion of patients with neurosyphilis was not receiving antiretroviral therapy (ART). The nonreceipt of ART independently increased the risk of neurosyphilis in the analyzed group of serofast HIV-infected patients (odds ratio = 4.5; 95% confidence interval 1.5-13.59, P = .003).Patients co-infected with HIV require careful serologic and clinical follow-up after therapy for syphilis. In all of the patients who do not respond serologically after treatment for syphilis, especially in those who are not receiving ART, lumbar puncture and CSF examination should be considered.

Consider Syphilis in Case of Lymphopenia in HIV-Infected Men Who Have Sex with Men (MSM): A Single-center, Retrospective Study

Introduction

The way syphilis affects the immunologic and virologic parameters of a human immunodeficiency virus (HIV) infection remains controversial. The aim of this study was to investigate the impact of syphilis infection on lymphocyte and lymphocyte subset counts as well as viral load in HIV-infected patients.

Methods

All HIV-infected patients attending the outpatient clinic for infectious diseases of Hannover Medical University Hospital diagnosed with syphilis between 2009 and 2016 were retrospectively evaluated for changes in total lymphocyte, B cell, CD3⁺ T cell, CD4⁺ and CD8⁺ T cell counts as well as in HIV viral load. These parameters were assessed at three different time points, i.e., 3–6 months before, at diagnosis and 3–6 months after treatment of syphilis.

Results

Eighty-four HIV-infected patients, all with early syphilis, were identified. The vast majority were men who have sex with men (MSM), and 80% were receiving antiretroviral therapy (ART). Syphilis was associated with a significant reduction in the total lymphocyte count and counts of all studied lymphocyte subsets, including CD4⁺ T cells, whose percentage among lymphocytes did not change. No significant changes in HIV viral load were observed at any of the studied time points. Further, antibiotic treatment of syphilis restored lymphocyte counts back to pretreatment levels.

Conclusion

Syphilis induces a relative non-CD4⁺ T cell-specific lymphopenia in HIV-infected patients. Our data suggest that serologic testing for syphilis should be considered in HIV-infected MSM in case of an otherwise unexplained drop in total lymphocyte count.

Electronic supplementary material

The online version of this article (10.1007/s40121-018-0219-9) contains supplementary material, which is available to authorized users.

Diagnostic performance of PCR assays for the diagnosis of neurosyphilis: a systematic review

INTRODUCTION

Syphilis continues to be a major public health problem and the recent resurgence in syphilis in high-income settings has seen an accompanying increase in cases of neurosyphilis. While the introduction of PCR has had a significant impact on the diagnosis of early syphilis, cerebrospinal fluid (CSF) serological assays remain the most commonly used tests to diagnosis neurosyphilis. We reviewed data on the performance of CSF-PCR for the diagnosis of neurosyphilis.

METHODS

We searched Pubmed, Medline, EMBASE and the grey literature for references on PCR in neurosyphilis. We calculated the sensitivity and specificity of PCR compared with reference testing for the diagnosis of neurosyphilis.

RESULTS

We identified 66 articles of which seven met the study inclusion criteria. The sensitivity of PCR for definite neurosyphilis varied between 40% and 70% and specificity between 60% and 100% across the studies. The most commonly used PCR assay targeted Tp47 which had an overall sensitivity of 68% and a specificity of 91.9%.

DISCUSSION

The sensitivity of PCR was low compared with CSF-serological assays but the challenges of evaluating a diagnostic test in the absence of a clear gold standard make definitive interpretation challenging. Most studies were small and not adequately powered highlighting the need for multicentre, multicountry trials to provide adequate statistical power in evaluations of new tests the diagnosis of neurosyphilis.

Neurosyphilis Increases Human Immunodeficiency Virus (HIV)-associated Central Nervous System Inflammation but Does Not Explain Cognitive Impairment in HIV-infected Individuals With Syphilis

Background

Individuals infected with human immunodeficiency virus (HIV) who have previously had syphilis may have cognitive impairment. We tested the hypothesis that neurosyphilis causes cognitive impairment in HIV by amplifying HIV-related central nervous system (CNS) inflammation.

Methods

HIV-infected participants enrolled in a study of cerebrospinal fluid (CSF) abnormalities in syphilis underwent the mental alternation test (MAT), venipuncture, and lumbar puncture. CSF concentrations of chemokine (C-X-C motif) ligand 10 (CXCL10), chemokine (C-C motif) ligand 2 (CCL2), and neurofilament light (NFL) were determined by commercial assays. The proportion of peripheral blood mononuclear cells (PBMCs) and of CSF white blood cells (WBCs) that were activated monocytes (CD14+CD16+) was determined by flow cytometry. Neurosyphilis was defined as detection of Treponema pallidum 16S RNA in CSF or CSF white blood cells (WBCs) >20/uL or a reactive CSF-Venereal Disease Research Laboratory (VDRL) test; uncomplicated syphilis was defined as undetectable CSF T. pallidum, CSF WBCs ≤5/uL and nonreactive CSF-VDRL. MAT <18 was considered low.

Results

Median proportion of PBMCs that were activated monocytes (16.6 vs. 5.3), and median CSF CXCL10 (10658 vs. 2530 units), CCL2 (519 vs. 337 units) and HIV RNA (727 vs. 50 c/mL) were higher in neurosyphilis than in uncomplicated syphilis (P ≤ .001 for all comparisons). Neurosyphilis was not related to low MAT scores. Participants with low MAT scores had higher median CSF CXCL10 (10299 vs. 3650 units, P = .008) and CCL2 (519 vs. 365 units, P = .04) concentrations than those with high MAT scores.

Conclusions

Neurosyphilis may augment HIV-associated CNS inflammation, but it does not explain cognitive impairment in HIV-infected individuals with syphilis.

Other central nervous system infections: cytomegalovirus, Mycobacterium tuberculosis, and Treponema pallidum

Human immunodeficiency virus (HIV)-infected individuals are particularly susceptible to several central nervous system infections: human cytomegalovirus, which may cause encephalitis, ventriculitis, polyradiculitis, or polyradiculomyelitis; Mycobacterium tuberculosis, which can cause meningitis or space-occupying lesions; and Treponema pallidum subspecies pallidum (T. pallidum), which affects the meninges, cerebrospinal fluid, cranial nerves, and vasculature in early neurosyphilis, and additionally the brain and spinal cord parenchyma in late neurosyphilis. Central nervous system cytomegalovirus infection is seen in HIV-infected individuals with very advanced immunosuppression. Its prognosis is poor and optimal therapy has not been determined. Tuberculous meningitis has a high mortality in those also infected with HIV, especially in the developing world, and better therapies are urgently needed. As the rates of syphilis increase in the developed world, neurosyphilis and in particular ocular syphilis are increasingly reported. The likelihood of all three of these central nervous system infections is decreased in individuals who receive potent antiretroviral therapy.

Novel predictors of neurosyphilis among HIV-negative syphilis patients with neurological symptoms: an observational study

Background

Known predictors of neurosyphilis were mainly drawn from human immunodeficiency virus (HIV)-infected syphilis patients, which may not be applicable to HIV-negative populations as they have different characteristics, particularly those with neurological symptoms. This study aimed to identify novel predictors of HIV-negative symptomatic neurosyphilis (S-NS).

Methods

From June 2005 to June 2015, 370 HIV-negative syphilis patients with neurological symptoms were recruited, consisting of 191 S-NS patients (including 123 confirmed neurosyphilis and 68 probable neurosyphilis patients) and 179 syphilis/non-neurosyphilis (N-NS) patients. Clinical and laboratory characteristics of S-NS were compared with N-NS to identify factors predictive of S-NS. Serum rapid plasma reagin (RPR), Treponema pallidum particle agglutination (TPPA), and their parallel testing format for screening S-NS were evaluated.

Results

The likelihood of S-NS was positively associated with the serum RPR and TPPA titers. The serum TPPA titers performed better than the serum RPR titers in screening S-NS. The optimal cut-off points to recognize S-NS were serum RPR titer ≥1:4 and serum TPPA titer ≥1:2560 respectively. A parallel testing format of a serum RPR titer ≥1:2 and serum TPPA titer ≥1:1280 screened out 95.8% of S-NS and all confirmed cases of neurosyphilis. S-NS was independently associated with male sex, serum RPR titer ≥1:4, serum TPPA titer ≥1:2560, and elevated serum creatine kinase. Concurrence of these factors increased the likelihood of S-NS.

Conclusions

Quantitation of serum TPPA is worthwhile and performs better than serum RPR in screening S-NS. Serum RPR, serum TPPA, male sex, and serum creatine kinase can predict S-NS. Moreover, patients with both a serum RPR titer <1:2 and a serum TPPA titer <1:1280 have a low probability of S-NS, suggesting that it is reasonable to reduce lumbar punctures in such individuals.

Late Neurosyphilis and Tertiary Syphilis in Guangdong Province, China: Results from a Cross-sectional Study

Due to challenges in diagnosis and the need for complex laboratory tests, misdiagnosis of neurosyphilis and tertiary syphilis is common in China. We validated the diagnosis and examined the treatment of late neurosyphilis and tertiary syphilis in Guangdong Province, China. A cross-sectional study was conducted to collect data from late neurosyphilis and tertiary syphilis cases reported between 2009 and 2014 in Guangdong, China. Descriptive analysis, bivariate analyses and multiple logistic regressions were performed to determine the structural factors associated with correct diagnosis and standard treatment of late neurosyphilis and tertiary syphilis. Among the 3805 respondents (3805/3936, 96.7%), 1,837 (48.3%) met the misdiagnosed criteria. The misdiagnosis rate decreased over the study period (54.2% in 2009 and 41.8% in 2014). Only 27.1% and 24.9% of the correctly diagnosed late neurosyphilis and tertiary syphilis cases received standard treatment, respectively. Multiple logistic regression revealed that departments of dermatology or STDs [aOR = 3.24, 95% CI: 2.66-3.95], county or township level hospitals [aOR = 2.89, 95% CI: 2.14-3.89], and hospitals situated outside of Pearl River Delta area [aOR = 1.70, 95% CI: 1.46-1.97] had higher likelihood in misdiagnosis of neurosyphilis, compared to the reference groups. Targeted trainings for physicians and expanded syphilis screening services are urgently needed.

Screening for asymptomatic neurosyphilis in HIV patients after treatment of early syphilis: an observational study

OBJECTIVE

To determine the prevalence of asymptomatic neurosyphilis (ANS) in HIV-positive individuals after treatment of early syphilis with single-dose benzathine penicillin G (BPG) or oral antibiotic alternatives.

METHODS

Patients at high risk of neurosyphilis (defined by serum rapid plasma reagin (RPR) titre ≥1:32 and/or peripheral blood CD4 lymphocyte count ≤350/μL) underwent lumbar puncture (LP) at a median time of 8.2 months post treatment. ANS was diagnosed by a reactive cerebrospinal fluid (CSF) RPR test or CSF white blood cells (WBC) >20/μL plus a reactive CSF Treponema pallidum particle agglutination (TPPA) ≥1:640.

RESULTS

Of 133 eligible patients, all were men who have sex with men. Of these, 64 consented to LP. Full CSF results were available for 59 patients. Inclusion criteria were serum RPR (21/59), CD4 count (22/59) and combined RPR and CD4 (16/59). The LP patients were white British (82%), median age 40. Syphilis stages were primary (17%) secondary (43%) and early latent (41%). Syphilis was treated with BPG (47/59), doxycycline 100 mg two times per day for 14 days (10/59) and for 21 days (1/59). Azithromycin 500 mg one time per day for 10 days was given to 1/59. At the time of LP, 100% of patients had achieved serological cure, and 66% were taking antiretroviral treatment. Only 1/59 was diagnosed with ANS. The CSF showed: RPR non-reactive (59/59); TPPA non-reactive in 54/59; WBC ≤5/μL in 51/59.

CONCLUSIONS

Although the number of patients in our study is modest, single-dose BPG appears to be highly effective even in patients at high risk of neurosyphilis.

Factors associated with syphilis incidence in the HIV-infected in the era of highly active antiretrovirals

After several years of steady decline, syphilis is reemerging globally as a public health hazard, especially among people living with human immunodeficiency virus (HIV). Syphilis resurgence is observed mainly in men who have sex with men (MSM), yet other transmission groups are affected too. In this manuscript, we study the factors associated with syphilis incidence in the Swiss HIV cohort study in the era of highly effective antiretrovirals. Using parametric interval censored models with fixed and time-varying covariates, we studied the immunological, behavioral, and treatment-related elements associated with syphilis incidence in 3 transmission groups: MSM, heterosexuals, and intravenous drug users. Syphilis incidence has been increasing annually since 2005, with up to 74 incident cases per 1000 person-years in 2013, with MSM being the population with the highest burden (92% of cases). While antiretroviral treatment (ART) in general did not affect syphilis incidence, nevirapine (NVP) was associated with a lower hazard of syphilis incidence (multivariable hazard ratio 0.5, 95% confidence interval 0.2-1.0). We observed that condomless sex and younger age were associated with higher syphilis incidence. Moreover, time-updated CD4, nadir CD4, and CD8 cell counts were not associated with syphilis incidence. Finally, testing frequency higher than the recommended once a year routine testing was associated with a 2-fold higher risk of acquiring syphilis. Condomless sex is the main driver of syphilis resurgence in the Swiss HIV Cohort study; ART and immune reconstitution provide no protection against syphilis. This entails targeted interventions and frequent screening of high-risk populations. There is no known effect of NVP on syphilis; therefore, further clinical, epidemiological, and microbiological investigation is necessary to validate our observation.

Global challenges in human immunodeficiency virus and syphilis coinfection among men who have sex with men

INTRODUCTION

Syphilis and human immunodeficiency virus (HIV) coinfection disproportionately affects men who have sex with men (MSM), and the rate of coinfection has been increasing over the last decade. HIV and syphilis coinfection is particularly challenging because the infections interact synergistically thereby increasing the risk of acquisition and transmission as well as accelerating disease progression. Areas covered: This paper reviews and summarizes the epidemiology, pathogenesis, diagnosis, clinical management and prevention of HIV and syphilis coinfection among MSM. Expert commentary: Research does not support a different syphilis treatment for coinfected individuals; however, coinfection may warrant a recommendation for antiretroviral therapy. In order to reverse the epidemic of syphilis and HIV coinfection, there needs to be greater awareness, improved cultural sensitivity among health care providers, improved access to preventative services and increased screening for syphilis and HIV.

Reduced Treponema pallidum-Specific Opsonic Antibody Activity in HIV-Infected Patients With Syphilis

BACKGROUND

Human immunodeficiency virus (HIV)-infected individuals may have poorer serological responses to syphilis treatment and may be more likely to experience neurosyphilis. Treponema pallidum is cleared from sites of infection by opsonization, ingestion, and killing by macrophages.

METHODS

Serum samples from 235 individuals with syphilis were tested for T. pallidum-specific opsonic activity. Blood T. pallidum concentrations were determined by real-time polymerase chain reaction amplification of the tp0574 gene, and T. pallidum was detected in cerebrospinal fluid (CSF) by reverse-transcriptase polymerase chain reaction of 16S ribosomal RNA.

RESULTS

Opsonic activity was higher with higher serum rapid plasma reagin titers (P < .001), and in those treated for uncomplicated syphilis before serum collection (P < .001). Opsonic activity was lower in HIV-infected than in HIV-uninfected individuals even after the above factors were taken into account (P = .006). In participants in whom blood T. pallidum was detectable, those with the highest opsonic activity had lower blood T. pallidum concentrations. In multivariable analyses, there was not a significant relationship between opsonic activity and detection of T. pallidum in CSF or CSF-VDRL reactivity.

CONCLUSIONS

Serum T. pallidum-specific opsonic activity is significantly lower in HIV-infected individuals. Impaired T. pallidum-specific immune responses could contribute to differences in the course of disease or treatment response.

Serum TRSUT Titer ≥1: 16 Is a Predictor for Neurosyphilis Among HIV-Infected Patients With Concurrent Syphilis and No Neurological Symptoms

Investigating the predictors for lumbar puncture to diagnose the asymptomatic neurosyphilis among HIV and syphilis co-infected patients in Shanghai, China. Respectively, screening the medical records from August 1, 2009 to June 30, 2015. Those HIV-infected patients with concurrent syphilis who had received lumbar puncture were selected and their clinical and demographic data were recorded. Participants comprised symptomatic and asymptomatic patients. The latter ones could be further divided into 3 groups: late syphilis, early syphilis with anti-syphilis treatment failure, and early syphilis with serum toludine red unheated serum test (TRUST) ≥1:32. Both syphilis stage and anti-syphilis treatment effect were defined by common criteria, and syphilis of unknown duration was considered as late syphilis. Asymptomatic neurosyphilis was defined as neurosyphilis without neurological symptoms such as headache, cognitive dysfunction, motor deficits, auditory or ophthalmic abnormalities, and stroke. Neurosyphilis was defined as reactive cerebrospinal fluid (CSF) TRUST and/or CSF white blood cell >20 cells/μL without other reasons. Mann-Whitney test and Fisher's exact test were used for analyzing the difference between neurosyphilis and non-neurosyphilis group. Logistic regression test was performed to analyze the risk factors for neurosyphilis. In total, 170 participants were collected, and the rate of neurosyphilis was 32.35%. Among all the 105 participants without neurological symptoms, 80 patients were with late syphilis and 25 were with early syphilis. Among the early syphilis patients, 23 had a TRUST ≥1:32 and the other 2 experienced an anti-syphilis treatment failure. The differences of clinical and demographic variables between neurosyphilis and non-neurosyphilis group were not statistically significant except the serum TRUST titer (P < 0.01). From HIV/syphilis co-infected patients with or without neurological symptom, those who had neurological symptoms, CD4 <350 per μL and serological TRUST titer ≥1:16 were 4.9-fold (95% confidence interval [CI]: 2.37-10.31), 4.3-fold (95% CI: 1.17-15.78), and 4.1-fold (95% CI: 1.58-10.76), respectively, more likely to be diagnosed with neurosyphilis. Asymptomatic patients whose serum TRUST titer ≥1:16 were 8.48-fold (95% CI: 1.08-66.63) more likely to have asymptomatic neurosyphilis. Among asymptomatic HIV-infected patients with late syphilis or early syphilis experienced an anti-syphilis treatment failure, those who have a serum TRUST titer ≥1:16 are suggested to perform lumbar puncture in order to avoid delayed diagnosis and the occurrence of severe sequelae of syphilis.

Emerging trends and persistent challenges in the management of adult syphilis

There are an estimated 10.6 million incident cases of syphilis worldwide each year. We highlight some persistent challenges and emerging trends in the clinical management of syphilis with a particular focus on therapy, serology, diagnostics, and prevention. Decades after the introduction of penicillin, the optimal management of early syphilis continues to be a controversial topic, particularly in the setting of HIV co-infection. Similarly, the need for routine lumbar puncture in HIV co-infected asymptomatic persons is an unanswered question. Despite advances in both automation and point-of-care diagnostics, we continue to rely on indirect measures of disease activity to manage this infection. As syphilis rates in some populations continue to rise, novel and effective prevention strategies are needed.

Neurosyphilis in HIV-infected patients

A review article is addressed the issue of the diagnosis and treatment of neurosyphilis that is developing against the background of HIV-infection. HIV-infected patients are at higher risk of neurologic, ocular and auricular manifestation of syphilis as well as treatment failures and relapses. Diagnosis of neurosyphilis in HIV-positive patients is complicated because both infections cause similar changes in the cerebrospinal fluid (CSF). The effectiveness of neurosyphilis treatment in patients with HIV co-infection is difficult to estimate, since the normalization of their CSF goes slower comparing to HIV-negatives. The increase in incidence of syphilis and HIV co-infection is anticipated in the coming years. This necessitates a comprehensive study of the problem and requires the development of new approaches to neurosyphilis diagnosis and treatment in co-infected patients.

Neurosyphilis Update: Atypical is the New Typical

Syphilis has reemerged as an important cause of neurological disease, affecting any part of the neuraxis at any stage of infection. What was once a dwindling diagnosis is now redoubling, particularly in the HIV-positive and in men who have sex with men populations. In the era of antibiotics and HIV coinfection, neurosyphilis presentations are protean, making diagnosis notoriously challenging. Advanced disease may be irreversible, and so early detection and treatment are ideal. Herein, we review recent advances in understanding neurosyphilis.

Value of CXCL13 in diagnosing asymptomatic neurosyphilis in HIV-infected patients

Diagnosing asymptomatic neurosyphilis (ANS) in HIV-infected patients is difficult. A recent report suggested that CXCL13 is a promising diagnostic marker for neurosyphilis in HIV-positive patients. However, whether CXCL13 can be a diagnostic marker for ANS in HIV-infected patients remains unknown. The purpose of our study was to determine the role of CXCL13 in diagnosing ANS in HIV-infected patients. This study comprised two study and three control groups. Two study groups included 12 HIV-infected patients with ANS and 25 patients with syphilis and HIV co-infection (without ANS). Three control groups included 9 patients with ANS without HIV infection, 25 HIV-infected patients without syphilis and 10 healthy volunteers. Concentrations of CSF CXCL13 were measured before and after neurosyphilis therapy. Our results showed that CSF CXCL13 concentrations were significantly increased in all of the HIV-infected patients with ANS, the 25 HIV patients with syphilis and the 9 ANS patients without HIV, but not in the patients of the other two control groups. CSF CXCL13 concentrations declined in the two study groups of patients following neurosyphilis therapy. Therefore, CSF CXCL13 concentrations could improve the diagnosis of ANS in HIV-infected patients.

Neurosyphilis and the impact of HIV infection

Neurosyphilis is a complication of systemic syphilis. This review of the clinical presentation, diagnostic laboratory findings, treatment and management of neurosyphilis discusses the impact of HIV and the specific challenges it brings, focusing on areas of controversy, and highlighting important questions that remain to be answered.

Canadian Public Health Laboratory Network laboratory guidelines for the use of serological tests (excluding point-of-care tests) for the diagnosis of syphilis in Canada

Syphilis, caused by the bacterium Treponema pallidum subsp. pallidum, is an infection recognized since antiquity. It was first reported at the end of the 15th century in Europe. Infections may be sexually transmitted as well as spread from an infected mother to her fetus or through blood transfusions. The laboratory diagnosis of syphilis infection is complex. Because this organism cannot be cultured, serology is used as the principal diagnostic method. Some of the issues related to serological diagnoses are that antibodies take time to appear after infection, and serology screening tests require several secondary confirmatory tests that can produce complex results needing interpretation by experts in the field. Traditionally, syphilis screening was performed using either rapid plasma reagin or Venereal Disease Research Laboratory tests, and confirmed by treponemal tests such as MHA-TP, TPPA or FTA-Abs. Currently, that trend is reversed, ie, most of the laboratories in Canada now screen for syphilis using treponemal enzyme immunoassays and confirm the status of infection using rapid plasma reagin or Venereal Disease Research Laboratory tests; this approach is often referred to as the reverse algorithm. This chapter reviews guidelines for specimen types and sample collection, treponemal and non-treponemal tests utilized in Canada, the current status of serological tests for syphilis in Canada, the complexity of serological diagnosis of syphilis infection and serological testing algorithms. Both traditional and reverse sequence algorithms are recommended and the algorithm used should be based on a combination of local disease epidemiology, test volumes, performance of the proposed assays and available resources.

Impact of HIV-1 infection on the clinical presentation of syphilis in men who have sex with men

Men who have sex with men (MSM), especially those with HIV-1 infection, are disproportionately affected by syphilis in higher income countries. The course, and some of the clinical features of the disease, especially the development of neurosyphilis, can be affected by HIV-1 co-infection. This review documents potential differences in the clinical features of syphilis in HIV-1 infected and uninfected MSM and highlights the importance of a thorough examination and high index of suspicion when seeing and treating MSM at risk of sexually transmissible infections.