Cytokine expression during syphilis infection in HIV-1-infected individuals

The serological dilemma: rethinking syphilis treatment evaluation

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

The Significance of the Cell-Mediated Host Immune Response in Syphilis

Syphilis, caused by the highly invasive pathogen Treponema pallidum, remains one of the oldest and most significant public health challenges. According to the World Health Organization (WHO), the number of new syphilis cases among adults aged 15-49 years in 2022 was estimated at approximately 8 million, with notable increases observed in Europe, the Americas, and Africa. The cellular immune response plays a critical role in combating this infection, and its insufficient activity may contribute to chronic progression of the disease. T. pallidum effectively evades the host immune response, enabling its prolonged survival within the host and increasing the risk of late complications such as neurosyphilis and cardiovascular syphilis. This review article discusses the mechanisms of cellular immune responses in T. pallidum infection, including T lymphocyte activation, proinflammatory cytokine production, and the roles of macrophages and dendritic cells in pathogen recognition and elimination. Additionally, it examines the immune evasion strategies employed by T. pallidum, such as the low immunogenicity of its antigens and its ability to suppress the activation of effector cells. A comprehensive understanding of the current knowledge regarding cellular immune mechanisms may contribute to the development of more effective diagnostic and therapeutic approaches in syphilis management.

HIV Infection Modifies the Role of Prior Treponema pallidum Infection in the Clinical Presentation of Early Syphilis Among Adult Patients From Sexually Transmitted Infection Clinics in Peru

BACKGROUND

We aimed to compare the clinical presentations (symptomatic vs. asymptomatic) with prior Treponema pallidum infection status (first infection vs. reinfection) among people with early syphilis.

METHODS

We used data from PICASSO, a cohort study in Peru that enrolled people with active syphilis from May 2019 to August 2021. Study participants had early syphilis and a prior syphilis serological test result within the prior 12 months to determine prior T. pallidum infection status. We calculated prevalence ratios (PRs) of symptomatic clinical presentation (primary or secondary syphilis) by prior T. pallidum infection status, stratified by HIV infection status. In addition, we explored the association of prior T. pallidum infection status and lesion presentation, stratified by primary and secondary syphilis cases, using the Fisher exact test.

RESULTS

We include 84 T. pallidum reinfection cases and 61 first infection cases. We found increased frequency of symptomatic clinical presentation among first-infection cases (39% vs. 20%; PR, 1.94; P = 0.014). This association was stronger among persons living without HIV infection (38% vs. 7%; adjusted PR, 6.63; P = 0.001) in comparison to those living with HIV infection (45% vs. 34%; adjusted PR, 1.38; P = 0.458). Among secondary syphilis cases, more participants from the reinfection group reported that their lesions improved 1 week after treatment (100% vs. 29%, P = 0.045) compared with those with a first infection. Among the primary syphilis cases, all participants reported that their lesions improved 1 week after treatment.

CONCLUSIONS

Prior syphilis was associated with a decreased prevalence of symptomatic reinfection, especially among persons not living with HIV infection.

Changes and Treatment Prognosis of Aqueous Humor Cytokine Concentrations of Patients with Acquired Immune Deficiency Syndrome Complicated by Cytomegalovirus Retinitis

Purpose: The purposes of this study were to investigate cytokine changes in the aqueous humor after treatment of acquired immune deficiency syndrome (AIDS) complicated with cytomegalovirus retinitis (CMVR) and to determine whether these changes are useful prognostic indicators. Methods: This study included 12 patients (15 eyes) undergoing treatment for AIDS and CMVR. The patients received intravitreal injections and systemic intravenous treatment with ganciclovir and foscarnet sodium. The aqueous humor of each eye was sampled before treatment and before the third and fifth injections. The samples were tested to determine the concentrations of each of 27 cytokines using the Luminex 200™ liquid phase chip. Results: The concentrations of cytokines interleukin (IL)-1rα (P = 0.002), IL-1b (P = 0.001), IL-8 (P = 0.001), basic fibroblast growth factor (bFGF) (P < 0.001), interferon γ-induced protein 10 (IP-10) (P = 0.001), and tumor necrosis factor (TNF)-α (P = 0.004) in the aqueous humor before the third and fifth injections were significantly lower after than before treatment. The reductions in TNF-α (P = 0.028) and IL-1b (P = 0.028) concentrations after treatment were statistically significant compared with the postoperative visual acuity improvement (≥3 lines and <3 lines). The difference in TNF-α (P = 0.018) level before and after treatment (the difference between before treatment and before the fifth intravitreal injection) was also statistically significant compared with the number of injections (≥6 times and <6 times). Conclusion: The cytokines IL-1rα, IL-1b, IL-8, bFGF, IP-10, and TNF-α may offer new avenues for evaluation of therapeutic effect, and TNF-α and IL-1b may be important cytokines for prognostic evaluation (based on visual acuity and the number of injections) in patients suffering from AIDS and CMVR. Clinical Trial Registration: Number: ChiCTR2200056955.

Cognitive impairment in syphilis: Does treatment based on cerebrospinal fluid analysis improve outcome?

Background

Individuals with previous syphilis may experience cognitive impairment. The goal of this study was to determine if those at high risk for laboratory-defined neurosyphilis are cognitively impaired, and whether treatment based on cerebrospinal fluid (CSF) findings results in better outcomes.

Methods

Participants had a new syphilis diagnosis, serum RPR titer ≥ 1:32 or peripheral blood CD4+ T cells ≤ 350/ul (in persons living with HIV) and did not endorse neurological symptoms. They underwent computerized cognitive assessment with the CogState. Thirty-two were randomized to either undergo lumbar puncture (LP) or to not undergo LP and 14 underwent LP; 64 were not randomized and 48 opted to undergo LP.

Results

Demographics, cognitive complaints and cognitive impairment did not differ between randomized and nonrandomized participants. Two-thirds were cognitively impaired, and impairment was not more common in those with cognitive complaints. The adjusted odds of increased severity of impairment were 3.8 times greater in those with CSF pleocytosis compared to those without. Time to cognitive normalization, improvement or decline did not differ between those who did not undergo LP and those who underwent LP and whose treatment was based on CSF analysis. Taking into account pre-treatment cognitive impairment, the risk of cognitive decline was lower in those with CSF pleocytosis treated for neurosyphilis compared to those without CSF pleocytosis not treated for neurosyphilis, (HR 0.24 (95% CI 0.07–0.88], p = 0.03).

Conclusion

In individuals at high risk for laboratory-defined neurosyphilis, cognitive complaints are not a good indicator of cognitive impairment. Severity of cognitive impairment was greater in those with CSF pleocytosis. Identification and treatment of those with neurosyphilis may mitigate subsequent cognitive decline.

Biomarkers of Inflammation Correlate With Clinical Scoring Indices in Human Immunodeficiency Virus-Infected Kenyans

Background

In high-income countries, inflammation has been associated with increased morbidity and mortality in human immunodeficiency virus (HIV)-infected individuals despite treatment with antiretroviral therapy (ART). However, these findings may not be generalizable to low-income settings.

Methods

In this cross-sectional study, multivariable linear regression was used to compare 28 inflammatory biomarker levels in HIV-infected and -uninfected participants. Correlations between biomarkers and Veterans Aging Cohort Study (VACS) index, Fibrosis-4 (FIB-4) score, and Framingham risk score were assessed.

Results

Plasma samples from 304 Kenyans were analyzed. Compared to HIV-uninfected controls, virologically suppressed HIV-infected participants had higher levels of CCL5, CXCL10, fatty acid binding protein (FABP) 2, fas ligand (FASLG), matrix metalloproteinase (MMP) 1, MMP7, soluble CD14 (sCD14), and soluble CD163 (sCD163) and lower MMP9 (P < .01). CD4+/HLA-DR+CD38+ (ρ = 0.32; P < .001), sCD14 (ρ = 0.25; P = .004), and sCD163 (ρ = 0.24; P = .006) were correlated with the VACS index. FABP2 was positively correlated (ρ = 0.29; P = .002), whereas MMP1 (ρ = -.32; P < .001) and MMP2 (ρ = -0.28; P = .002) were inversely correlated with the FIB-4 score.

Conclusions

Differences in biomarker levels exist between well-controlled HIV-infected participants on ART and uninfected controls. Some biomarkers are correlated to scoring indices predictive of morbidity and mortality. These biomarkers could serve as prognostic indicators and inform therapeutic development.

Immunological Changes in Monocyte Subsets and Their Association With Foxp3+ Regulatory T Cells in HIV-1-Infected Individuals With Syphilis: A Brief Research Report

The incidence of syphilis has increased dramatically in men who have sex with men (MSM), especially those with HIV-1 infection. Treponema pallidum and HIV-1 are bidirectionally synergistic, accelerating disease progression reciprocally in co-infected individuals. We have shown that monocytes have different effects on T helper cells at different stages of HIV-1 infection. However, the immunological changes in the three monocyte subsets and in regulatory T cells (Tregs), and the associations between these cell types during syphilis infection among HIV-1-infected MSM remain unclear. Herein, we used cell staining methods to explore changes in monocyte subsets and Tregs and any associations between these cells. We found that the frequency of classical monocytes was higher in the rapid plasma reagin (RPR⁺) group than in the healthy controls (HCs) and the chronic HIV-1 infection (CHI) plus RPR⁺ (CHI&RPR⁺) group. The frequencies of Foxp3⁺CD25⁺CD45RA⁺ and Foxp3⁺Helios⁺CD45RA⁺ Tregs were significantly higher in the RPR⁺, CHI, and CHI&RPR⁺ groups than in HCs, whereas the frequency of CD45RA⁺ Tregs was lower in the CHI&RPR⁺ group than in CHI group. The frequencies of Foxp3⁺CD25⁺CD45RO⁺ and Foxp3⁺Helios⁺CD45RO⁺ Tregs were lower in the RPR⁺, CHI, and CHI&RPR⁺ groups than in HCs. The frequency of intermediate monocytes was inversely correlated with the frequency of CD45RA⁺ Tregs and positively correlated with the frequency of CD45RO⁺ Tregs. These results demonstrate for the first time that intermediate monocytes control the differentiation of Treg subsets in Treponema pallidum/HIV-1 co-infections. These findings provide new insights into an immunological mechanism involving monocytes/Tregs in HIV-infected individuals with syphilis.

Syphilis reinfection is associated with an attenuated immune profile in the same individual: a prospective observational cohort study

Background

Ascertaining if the clinical and immunological response to repeat syphilis differs from that in initial syphilis may assist in designing optimal syphilis screening strategies and vaccine design.

Methods

We prospectively recruited 120 patients with a new diagnosis of (baseline) syphilis. During a 24-month follow-up period, 11 of these patients had a further diagnosis of (repeat) syphilis. We conducted a paired comparison of their plasma cyto-chemokines at baseline and repeat syphilis.

Results

Comparing to their baseline infection, paired analyses of the 11 individuals with repeat infections during follow-up revealed that these reinfections had lower concentrations of Interferon (IFN)α (0.8 [Interquartile range (IQR) 0.8–0.8 vs. 12.2 [IQR 1.6–24.2], P = 0.004) and Chemokine (C-C motif) ligand (CCL) 4 (0.9 [IQR 0.9–12.2 vs. 17.5 [IQR 4.9–32.8], P = 0.022].

Conclusion

In this small study of 11 individuals, repeat syphilis was found to present with an attenuated immune response. The relevance of these findings to the design of optimal syphilis screening programs is discussed.

Repeat syphilis has a different immune response compared with initial syphilis: an analysis of biomarker kinetics in two cohorts

OBJECTIVE

We aimed to asses if there are differences in the clinical presentation and immune response of repeat as compared with initial syphilis.

METHODS

Prospective study: we prospectively recruited all patients with a new diagnosis of syphilis and tested their plasma for a range of cytochemokines and rapid plasma reagin (RPR) at baseline pretreatment and 6 months following therapy. Retrospective study: we compared RPR assay response kinetics between initial and repeat syphilis in persons attending our HIV/STI clinic from 1993 to 2016.

RESULTS

Prospective study: a total of 91 individuals, 36 with initial syphilis and 55 with repeat syphilis, were included in the study. At baseline visit, those with initial syphilis were more likely to be symptomatic and have higher levels of interleukin-10 than repeaters. At baseline, median RPR titres were higher in the repeat than the initial infection groups. Repeaters were less likely than those with initial infections to serorevert to a negative RPR and be serofast (<4-fold RPR titre decline) at 6 months.Retrospective study: syphilis was diagnosed in 1027/43 870 individuals tested. At diagnosis, repeaters had higher RPR titres and a stepwise increase in RPR titre with number of syphilis episodes. They had a different RPR test response kinetic: they were less likely to be serofast and to serorevert than initial syphilis at 6 and 12 months. No individuals with four or more previous episodes of syphilis seroreverted.

CONCLUSION

Repeat syphilis has a different clinical presentation and immunological response to initial infection.

The immunological response to syphilis differs by HIV status; a prospective observational cohort study

Background

It is not known if there is a difference in the immune response to syphilis between HIV-infected and uninfected individuals.

Methods

We prospectively recruited all patients with a new diagnosis of syphilis and tested their plasma for IFNα, IFNγ, IL-1β, IL-12p40, IL-12p70, IP-10, MCP-1, MIP-1α, MIP-1β, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10 and IL-17A at baseline pre-treatment and 6 months following therapy.

Results

A total of 79 HIV-infected [44 primary/secondary syphilis (PSS) and 35 latent syphilis (LS)] and 12 HIV-uninfected (10 PSS and 2 LS) cases of syphilis and 30 HIV-infected controls were included in the study. At the baseline visit, compared to the control group, concentrations of IL-10 were significantly elevated in the HIV-infected and uninfected groups. The level of IL-10 was significantly higher in the HIV-infected compared to the HIV-uninfected PSS group (25.3 pg/mL (IQR, 4.56–41.76) vs 2.73 pg/mL (IQR, 1.55–9.02), P = 0.0192). In the HIV-infected PSS group (but not the HIV-infected LS or HIV-uninfected PSS groups) the IP-10, MIP-1b, IL-6 and IL-8 were raised compared to the controls. IL-10 levels decreased but did not return to control baseline values by 6 months in HIV infected PSS and LS and HIV uninfected PSS.

Conclusion

PSS and LS in HIV-infected individuals is characterized by an increase in inflammatory and anti-inflammatory cytokines such as IL-10. The increase of IL-10 is greater in HIV-infected than uninfected individuals. Further work is required to ascertain if this is part of an immunological profile that correlates with adverse outcomes such as serofast syphilis and neurosyphilis, in HIV-infected individuals.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2201-7) contains supplementary material, which is available to authorized users.

Cytokine Profiles in Aqueous Humor and Plasma of HIV-infected Individuals with Ocular Syphilis or Cytomegalovirus Retinitis

PURPOSE

To characterize the immunologic profile in aqueous humor (AqH) of HIV-infected individuals with cytomegalovirus retinitis (CMVr) or ocular syphilis and to assess if AqH and plasma represent independent cytokine compartments.

METHODS

Concentrations of 27 cytokines in AqH and plasma of HIV-infected individuals with CMVr (n = 23) or ocular syphilis (n = 16) were measured by multiplex assay. Cytokine profiles of both groups were compared.

RESULTS

Individuals with CMVr had higher plasma concentrations of interleukin (IL)-7, IL-8, IL-10, interferon (IFN)-γ, IFN-α2, G-CSF, IP-10 and IL-1α; as well as higher AqH concentrations of IL-1α, IP-10 and GM-CSF than those with ocular syphilis. AqH and plasma levels correlated only for IP-10 in both ocular infections.

CONCLUSIONS

Individuals with CMVr had higher plasma cytokine levels than those with ocular syphilis. The immunologic profiles in AqH and plasma are independent. Therefore, AqH cytokine concentrations cannot be inferred from plasma cytokine concentrations in the population studied.

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.

Effect of cytokine level variations in individuals on the progression and outcome of bacterial urogenital infections--a meta-analysis

Bacterial urogenital infections such as chlamydia, gonorrhoea and syphilis are widespread inflammatory diseases, which may be accompanied by severe complications. These complications can range from basic inflammation to tubal pathology, infertility and neurological dysfunction, though infections go unnoticed in the majority of cases. Cytokines in the host play a vital role in both the initial and long-term immune response and inflammation. However, levels of cytokine expression vary between individuals. A meta-analysis was performed to evaluate the effect of cytokine expression differences on severity of infections with these pathogens. Studies comparing expression of cytokines in humans with inflammation or inflammation-based complications were identified using NCBI, Google Scholar and Cochrane databases. Only studies into human cytokine expressions were included, and three articles per subject were required to be suitably analysed during meta-analysis. A total of 52 articles were included for meta-analysis. It was shown that differences in IL-1, IL-6, IL-8, IL-10, TNFα and IFNγ affect the clinical outcome of Chlamydia trachomatis infection significantly. Similarly, IL-1 and IL-8 expression during Neisseria gonorrhoeae infection significantly affects the outcome of the disease. For Treponema pallidum infection, it was shown that IFNγ variation in hosts could be linked to severity of disease. However, a lack of studies to use in the meta-analysis and fluctuation in the resulting data depending on the adjustments makes adequate evaluation difficult.

Clinical Outcomes of In Vitro Fertilization among Chinese Infertile Couples Treated for Syphilis Infection

To compare the clinical outcomes of infertile patients with and without syphilis after in vitro fertilization and embryo transfer (IVF-ET), in this case-control study, 320 infertile couples were enrolled and divided into syphilis (n = 160) and control groups (n = 160). The primary IVF outcomes were the clinical pregnancy rate and the birth of a healthy baby. All syphilis patients received the standard anti-syphilis treatment before undergoing IVF/ICSI. Our results showed that the endometrial thickness of the syphilis group was greater than that of the control group following hCG injection (16.9±5.4 vs. 13.0±4.7 mm, P<0.001). The numbers of normally fertilized eggs and normally cleaved fertilized eggs and the implantation rate were 6.8±4.8, 6.3±4.7 and 24.2%, respectively, for the syphilis group and 8.3±4.6, 8.1±4.6 and 34.4%, respectively, for the control group, and these values were significantly different between the groups. The clinical pregnancy rate was lower in the syphilis group compared with that in the control group (43.8% vs. 55.6%, P = 0.03). Lower offspring birth weight was observed in the infected male group compared with those in the infected female (2.7±0.4 vs. 3.0±0.4 kg, P = 0.01) and infected couple groups (2.7±0.4 vs. 3.1±0.5 kg, P = 0.007). Therefore, syphilis infection reduces the clinical pregnancy rate after IVF/ICSI.

Undetectable hepatitis C virus RNA during syphilis infection in two HIV/HCV-co-infected patients

BACKGROUND

Treponema pallidum, the causative agent of syphilis, elicits a vigorous immune response in the infected host. This study sought to describe the impact of syphilis infection on hepatitis C virus (HCV) RNA levels in patients with HIV and chronic HCV infection.

METHODS

Patients with chronic HIV/HCV and syphilis co-infection were identified by their treating physicians from 1 October 2010 to 31 December 2013. Stored plasma samples obtained before, during, and after syphilis infection were analysed for interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and IFN-γ-inducible protein 10 kDa (IP-10).

RESULTS

Undetectable HCV RNA at the time of early latent syphilis infection was observed in 2 patients with HIV and chronic HCV infection. After treatment of the syphilis infection, HCV RNA levels increased again in patient 1, whereas patient 2 initiated HCV therapy and remained HCV RNA-negative. Available plasma samples obtained before and after the episode with undetectable HCV RNA were phylogenetically identical, making the possibility of spontaneous clearance and HCV reinfection less likely. The IL-10, TNF-α, and IP-10 levels increased at the time of syphilis diagnosis in patient 1 and decreased again after treatment of the syphilis infection.

CONCLUSIONS

We propose that T. pallidum-induced cytokine secretion resulted in an immune response hindering HCV replication during syphilis infection. We suggest that HIV/HCV-co-infected patients with unexpected undetectable HCV RNA are tested for syphilis infection and that the serological tests include both non-treponemal and treponemal tests to avoid false-positive results caused by HCV.

HIV Infection in Uncircumcised Men Is Associated With Altered CD8 T-cell Function But Normal CD4 T-cell Numbers in the Foreskin

BACKGROUND

Human immunodeficiency virus (HIV)-infected (HIV+) men are more susceptible to sexually transmitted infections, and may be superinfected by HIV. We hypothesized that HIV induces immune alterations in the foreskin that may impact the subsequent acquisition/clearance of genital coinfections.

METHODS

Foreskin tissue and blood were obtained from 70 HIV-uninfected and 20 HIV+ men undergoing circumcision. T cells were characterized by flow cytometry, immunohistochemistry, and polymerase chain reaction.

RESULTS

There was substantial influx of CD8 T-cells into the foreskins of HIV+ men (108.8 vs 23.1 cells/mm(2); P < .001); but foreskin CD4 T-cell density was unchanged (43.0 vs 33.7/mm(2); P = .67), despite substantial blood depletion (409.0 vs 877.8 cells/µL; P < .001). While frequencies of foreskin C-C chemokine receptor type 5(+) (CCR5(+)) T cells, T regulatory cells, and T-helper 17 cells were unaltered in HIV+ men, CD8 T-cell production of tumor necrosis factor α (TNFα) was decreased. HIV-specific CD8 T cells were present in the foreskins of HIV+ men, although their frequency and function was reduced compared to the blood.

CONCLUSIONS

Foreskin CD4 T-cell density and CCR5 expression were not reduced during HIV infection, perhaps explaining susceptibility to HIV superinfection. Foreskin CD8 T-cell density was increased, but decreased production of TNFα may enhance susceptibility to genital coinfections in HIV+ men.

Characterizing the syphilis epidemic among men who have sex with men in Lima, Peru to identify new treatment and control strategies

BACKGROUND

Syphilis is an important sexually transmitted infection (STI) with serious public health consequences. Among men who have sex with men (MSM) in Lima, the prevalence and incidence are extraordinarily high. Current syndromic approaches, however, fail to identify asymptomatic cases, and in settings where large proportions of individuals test positive again after treatment, it is frequently difficult to distinguish treatment failure from re-infection. Thus, new approaches are needed to improve treatment strategies and public health control efforts.

METHODS/DESIGN

Study participants will undergo baseline testing for syphilis infection along with a behavioral survey covering demographics, sexual behavior, drug and alcohol abuse and health-care seeking behavior. The cohort will be followed for 18 months at three-month intervals. Blood and earlobe scrapings will also be collected for T. pallidum DNA testing, to create molecular markers for subtyping. We will also perform cytokine testing on collected samples in order to create host immunologic profiles associated with recurrence, re-infection, treatment failure and success.

DISCUSSION

Advances in social epidemiology, molecular typing and characterization of host immune responses will offer promise in developing new understandings of syphilis management. We will share our findings with the Peruvian Ministry of Health and other public health organizations, to identify new approaches of case detection and successful treatment.

Neurocognitive impairment in HIV-infected individuals with previous syphilis

Cognitive impairment is common in HIV-infected individuals, as is syphilis. Treponema pallidum, the bacterium that causes syphilis, invades the central nervous system early in disease. We hypothesized that HIV-infected patients with a history of syphilis or neurosyphilis would have more cognitive impairment than HIV-infected individuals without these infections. Eighty-two of 1574 enrollees in CHARTER, a prospective, observational study, had reactive serum rapid plasma reagin (RPR) tests. They were matched to 84 controls with non-reactive RPR by age, gender, ethnicity and HIV risk factor. Participants underwent comprehensive neuropsychological (NP) evaluations. RPR results were confirmed and serum fluorescent treponemal antibody absorption (FTA-ABS) test reactivity determined at a central laboratory. Sera from 101 of 166 participants were FTA-ABS reactive, indicating past or current syphilis. Among the 136 individuals without confounding conditions, compared with patients who had never had syphilis, those with prior syphilis had a greater number of impaired NP test domains (1.90 SD [1.77] versus 1.25 [1.52], P = 0.03), a higher global deficit score (0.47 [0.46] versus 0.31 [0.33], P = 0.03), and more were impaired in the NP learning domain (36 [42.9%] of 84 versus 13 [25.0%] of 52, P = 0.04). These effects of prior syphilis remained after controlling for education and premorbid intelligence.