Serological response to therapy following retreatment of serofast early syphilis patients with benzathine penicillin

Evaluating the clinical utility of semi-quantitative luciferase immunosorbent assay using Treponema pallidum antigens in syphilis diagnosis and treatment monitoring

To assess the clinical applicability of a semi-quantitative luciferase immunosorbent assay (LISA) for detecting antibodies against Treponema pallidum antigens TP0171 (TP15), TP0435 (TP17), and TP0574 (TP47) in diagnosing and monitoring syphilis. LISA for detection of anti-TP15, TP17, and TP47 antibodies were developed and evaluated for syphilis diagnosis using 261 serum samples (161 syphilis, 100 non-syphilis). Ninety serial serum samples from 6 syphilis rabbit models (3 treated, 3 untreated) and 110 paired serum samples from 55 syphilis patients were used to assess treatment effects by utilizing TRUST as a reference. Compared to TPPA, LISA-TP15, LISA-TP17, and LISA-TP47 showed a sensitivity of 91.9%, 96.9%, and 98.8%, specificity of 99%, 99%, and 98%, and AUC of 0.971, 0.992, and 0.995, respectively, in diagnosing syphilis. Strong correlations (rs = 0.89-0.93) with TPPA were observed. In serial serum samples from rabbit models, significant differences in the relative light unit (RLU) were observed between the treatment and control group for LISA-TP17 (days 31-51) and LISA-TP47 (day 41). In paired serum samples from syphilis patients, TRUST titres and the RLU of LISA-TP15, LISA-TP17, and LISA-TP47 decreased post-treatment (P < .001). When TRUST titres decreased by 0, 2, 4, or ≥8-folds, the RLU decreased by 17.53%, 31.34%, 48.62%, and 72.79% for LISA-TP15; 8.84%, 17.00%, 28.37%, and 50.57% for LISA-TP17; 22.25%, 29.79%, 51.75%, and 70.28% for LISA-TP47, respectively. Semi-quantitative LISA performs well for syphilis diagnosis while LISA-TP17 is more effective for monitoring syphilis treatment in rabbit models and clinical patients.

Serofast status in syphilis: Pathogenesis to therapeutics

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

Plasma Exosome-Derived microRNAs Profiles in Patients with Serofast Status: A Cross-Sectional Study

Purpose

Syphilis is a sexually transmitted bacterial infection caused by Treponema pallidum (T. pallidum), which can lead to chronic morbidity and adverse complications. In clinical practice, serofast status (SF) patients present with clinical symptoms that are very similar to those of healthy individuals or syphilis-cured patients, and often require prolonged follow-up for diagnosis. Currently, there is increasing interest in the potential of plasma exosome-derived miRNA as a biomarker for the detection of infectious diseases. In this study, we aimed to explore the diagnostic potential of miRNA in SF and its possible biological implications.

Patients and Methods

Exosome-derived miRNAs were isolated from peripheral plasma samples obtained from 20 patients with secondary syphilis (SS), SF, serologically cured syphilis (SC), and healthy controls (HC), and differentially expressed miRNAs (DEmiRNAs) were identified by microarray analysis. Prediction of potential target genes, functional annotation, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were then performed. The expression of selected miRNAs was confirmed in 37 patients by quantitative reverse transcription polymerase chain reaction (RT-qPCR). A receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of these miRNAs in differentiating syphilis from HC or SC.

Results

The expression profile of plasma exosome-derived miRNA was discovered in individuals with SF through microarray analysis. The targeted genes of DEmiRNAs were found to be involved in diverse biological processes according to GO and KEGG analysis, such as regulation of transcription, mitochondria, Golgi, immune system, apoptosis, Ras signaling pathway, etc. Using RT-qPCR validation, miR-1273g-3p, miR-4485-5p, miR-197-3p, and miR-1908-3p showed significant upregulation in patients with SF. These miRNAs exhibited a superior diagnostic ability, either individually or combined, to distinguish SF from SC or HC.

Conclusion

The DEmiRNAs in plasma exosomes may play a role in the pathogenesis of SF and have the potential to become a noble and effective diagnostic method.

Antibody responses to the host microbiome in chronic rhinosinusitis

BACKGROUND

The role of microbes in chronic rhinosinusitis (CRS) is poorly understood. We hypothesize that analyzing prior microbial exposures via assessing microbial protein serological reactivity in CRS versus controls may offer insights for CRS etiopathogenesis.

METHODS

We profiled IgG and IgA antibodies to individual microbial proteins in serum samples of CRS patients and controls using a novel high-throughput microarray protein technology, Nucleic Acid Programmable Protein Array (NAPPA). The study was conducted on 118 subjects (39 CRS, 79 controls). A CRS-focused NAPPA array, with 1557 potentially sero-reactive microbial proteins elected from a pre-screening of 6500 genes of interest was constructed. It included membrane-associated proteins from 47 bacterial species and all proteins from 43 viral strains. Differences between CRS and controls were compared across individual antimicrobial antibodies and the species.

RESULTS

Chronic rhinosinusitis patients had significantly elevated antimicrobial antibodies compared with controls. One bacterium (Staphylococcus aureus) and three viral strains (human metapneumovirus, human herpesvirus 5, and human herpesvirus 4) were identified as sources of the proteins that showed significantly elevated sero-reactivity in CRS patients. Within CRS, patients with polyps had elevated antibodies against S. aureus, influenza A virus (H1N1, H3N2), and rhinovirus B14. CRS patients without polyps showed more antibodies against human herpesvirus 1 and vaccinia virus WR.

CONCLUSIONS

Compared with healthy controls, CRS patients' serum samples showed significantly increased sero-reactivity to both bacterial and viral proteins, reflecting recent or current infection or active colonization. Significantly higher antibodies against S. aureus, human metapneumovirus, human herpesvirus 5, and human herpesvirus 4 in CRS need further study.

An Updated Review of Recent Advances in Neurosyphilis

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

A suite of PCR-LwCas13a assays for detection and genotyping of Treponema pallidum in clinical samples

The performance of commonly used assays for diagnosis of syphilis varies considerably depending on stage of infection and sample type. In response to the need for improved syphilis diagnostics, we develop assays that pair PCR pre-amplification of the tpp47 gene of Treponema pallidum subsp. pallidum with CRISPR-LwCas13a. The PCR-LwCas13a assay achieves an order of magnitude better analytical sensitivity than real-time PCR with equivalent specificity. When applied to a panel of 216 biological specimens, including 135 clinically confirmed primary and secondary syphilis samples, the PCR-LwCas13a assay demonstrates 93.3% clinical sensitivity and 100% specificity, outperforming tpp47 real-time PCR and rabbit-infectivity testing. We further adapt this approach to distinguish Treponema pallidum subsp. pallidum lineages and identify genetic markers of macrolide resistance. Our study demonstrates the potential of CRISPR-based approaches to improve diagnosis and epidemiological surveillance of syphilis.

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.

Outcomes From Re-Treatment and Cerebrospinal Fluid Analyses in Patients With Syphilis Who Had Serological Nonresponse or Lack of Seroreversion After Initial Therapy

BACKGROUND

We conducted an observational study to determine whether patients with syphilis who do not demonstrate serological cure or lack of seroreversion in nontreponemal (NT) antibody titers after initial therapy benefit from re-treatment and cerebrospinal fluid (CSF) analysis.

METHODS

We enrolled patients with syphilis from sexually transmitted disease clinics in Guangzhou, China, who had persistent NT titers after therapy. Serological nonresponse was defined as a <4-fold decline in baseline NT titers after therapy. Lack of seroreversion was defined as demonstrating a ≥4-fold NT titer decline but without seroreversion to negative, or having persistent low-level titers (i.e., 1:1-1:2) after therapy. After consent, we abstracted medical record data regarding syphilis diagnoses, initial and re-treatment regimens, and serological outcomes. Nontreponemal titers were obtained from participants at enrollment and follow-up. We evaluated CSF findings among a subgroup of participants relative to re-treatment.

RESULTS

From March 2012 to February 2016, we enrolled 135 HIV-negative patients with syphilis with persistent NT titers after initial therapy. Among 116 participants with ≥12 months of follow-up, 60 (52%) received re-treatment of syphilis. Overall, there were no significant differences in serological response between those who were re-treated and those who were not among serological nonresponders (29% vs. 27%; P = 1.0) or among participants without seroconversion (41% vs. 37%; P = 0.8). Of 60 participants who underwent CSF analyses, 8 (13%) had CSF abnormalities, but only 2 (3%) met the neurosyphilis criteria after re-treatment.

CONCLUSIONS

Most HIV-negative patients with syphilis who have serological nonresponse or lack of seroreversion after therapy do not benefit from re-treatment in the short term, and neurosyphilis is uncommon.

The prevalence of asymptomatic neurosyphilis among HIV-negative serofast patients in China: A meta-analysis

Introduction

Neurosyphilis can occur at any stage of syphilis. After treatment, 30%-40% of syphilis patients remained serofast. But the prevalence of asymptomatic neurosyphilis (ANS) among serofast syphilis patients remains unclear. Untimely treatment or improper management for ANS may result in neurological complications. So we perform the meta-analysis to evaluate the prevalence of ANS cases among HIV-negative serofast syphilis patients for exploring their relationship and addressing their clinical management.

Methods

We searched CNKI, Wan Fang, VIP, CBMdisc, PubMed, Embase and Medline from January 1^st 1990 to September 22^nd 2020 for both English and Chinese records. We strictly restrict the eligibility criteria. STROBE was used for reporting quality assessment. We examined forest plots and conducted both fix-effects and random-effects to estimate prevalence by R version 3.6.2/R studio 1.2.1335 statistical software packages META version 4.9–9. If appropriate, between-study heterogeneity was examined using the I² statistic and subgroup analysis.

Results

Of 77 screened records, 5 were included. The pooled prevalence of ANS among HIV-negative serofast syphilis patients was 13% (95% CI 3%-23%; I² = 93% P<0.01, 417 people). The prevalence of ANS for the verified ANS classification definition was 3% (95% CI 0%-7%; I² = 67% P = 0.08, two studies, 189 people), and 21% (95% CI 6%-36%; I² = 86% P<0.01, three studies, 228 people) for the likely ANS classification. The prevalence of ANS among the serofast syphilis patients who were followed up for one year was 29% (95% CI 22%-36%; I² = 0% P = 0.5, two studies, 167 people) and 5% (95% CI 0%-13%; I² = 79% P = 0.03, two studies, 144 people) for two years. The prevalence in the studies from different geographical subgroups was as follows: 9% (95% CI 0%-19%; I² = 82% P<0.01, three studies, 169 people) in South-central China, 6% (95% CI 1%-10%; one study, 106 people) in East China, and 30% (95% CI 23%-38%; one study, 142 people) in North China.

Conclusion

This meta-analysis showed a high estimated prevalence of ANS in HIV-negative serofast syphilis patients, the prevalence of ANS among patients diagnosed with the verified ANS case definition is much lower than that for the likely ANS classification. It may be necessary to carry out nontreponemal test, protein test and leukocyte count for cerebrospinal fluid (CSF) in treated serofast patients for better clinical management to avoid neurological complications. The case classification definition of ANS is a key factor to evaluate the prevalence. Geographical heterogeneity needs more studies to detect. In future we need better-design studies to explore relationship between ANS and serofast status.

Is repeated retreatment necessary for HIV-negative serofast early syphilis patients?

A persistent non-treponemal serological response can be observed in patients with syphilis after treatment and is referred to as serofast. This status makes it difficult for clinicians to judge the curative effect of treatment, particularly in patients with early syphilis. In the present study, a total of 114 eligible serofast patients treated between January 2009 and June 2016 were retrospectively analyzed. All patients were subjected to rapid plasma reagin (RPR) serological tests and followed up for 24 months. The patients who remained serofast after initial therapy were given the first retreatment, and at 12 months, those who were still serofast received a second retreatment. After the first retreatment (6 months), 33.3% of the subjects (38/114) were serologically cured (≥4-fold decline in RPR titer). At 24 months, the patients that had achieved serological cure accounted for 23.7% (18/76) of the patients that received the second retreatment. Furthermore, 26.3% of subjects that achieved serological cure (10/38) and had not been further treated after the first retreatment spontaneously presented with a ≥4-fold decline in RPR titer or negative status. In conclusion, the present study indicated that in patients with early syphilis and serofast status after initial treatment, retreatments may not provide any significant benefit. The second retreatment did not significantly improve the patient's serological cure rate. There is no evidence that patients with early syphilis and serofast should receive multiple retreatments, in spite of this being commonly performed in clinical practice.

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.