T cell autoreactivity directed toward CD1c itself rather than toward carried self lipids.

The hallmark function of αß T cell antigen receptors (TCRs) involves the highly specific co-recognition of a major histocompatibility complex molecule and its carried peptide. However, the molecular basis of the interactions of TCRs with the lipid antigen-presenting molecule CD1c is unknown. We identified frequent staining of human T cells with CD1c tetramers across numerous subjects. Whereas TCRs typically show high specificity for antigen, both tetramer binding and autoreactivity occurred with CD1c in complex with numerous, chemically diverse self lipids. Such extreme polyspecificity was attributable to binding of the TCR over the closed surface of CD1c, with the TCR covering the portal where lipids normally protrude. The TCR essentially failed to contact lipids because they were fully seated within CD1c. These data demonstrate the sequestration of lipids within CD1c as a mechanism of autoreactivity and point to small lipid size as a determinant of autoreactive T cell responses.

History of tuberculosis disease is associated with genetic regulatory variation in Peruvians.

A quarter of humanity is estimated to have been exposed to Mycobacterium tuberculosis (Mtb) with a 5-10% risk of developing tuberculosis (TB) disease. Variability in responses to Mtb infection could be due to host or pathogen heterogeneity. Here, we focused on host genetic variation in a Peruvian population and its associations with gene regulation in monocyte-derived macrophages and dendritic cells (DCs). We recruited former household contacts of TB patients who previously progressed to TB (cases, n = 63) or did not progress to TB (controls, n = 63). Transcriptomic profiling of monocyte-derived DCs and macrophages measured the impact of genetic variants on gene expression by identifying expression quantitative trait loci (eQTL). We identified 330 and 257 eQTL genes in DCs and macrophages (False Discovery Rate (FDR) < 0.05), respectively. Four genes in DCs showed interaction between eQTL variants and TB progression status. The top eQTL interaction for a protein-coding gene was with FAH, the gene encoding fumarylacetoacetate hydrolase, which mediates the last step in mammalian tyrosine catabolism. FAH expression was associated with genetic regulatory variation in cases but not controls. Using public transcriptomic and epigenomic data of Mtb-infected monocyte-derived dendritic cells, we found that Mtb infection results in FAH downregulation and DNA methylation changes in the locus. Overall, this study demonstrates effects of genetic variation on gene expression levels that are dependent on history of infectious disease and highlights a candidate pathogenic mechanism through pathogen-response genes. Furthermore, our results point to tyrosine metabolism and related candidate TB progression pathways for further investigation.

Dual TCR-α Expression on Mucosal-Associated Invariant T Cells as a Potential Confounder of TCR Interpretation.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that are highly abundant in human blood and tissues. Most MAIT cells have an invariant TCRα-chain that uses T cell receptor α-variable 1-2 (TRAV1-2) joined to TRAJ33/20/12 and recognizes metabolites from bacterial riboflavin synthesis bound to the Ag-presenting molecule MHC class I related (MR1). Our attempts to identify alternative MR1-presented Ags led to the discovery of rare MR1-restricted T cells with non-TRAV1-2 TCRs. Because altered Ag specificity likely alters affinity for the most potent known Ag, 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil (5-OP-RU), we performed bulk TCRα- and TCRß-chain sequencing and single-cell-based paired TCR sequencing on T cells that bound the MR1-5-OP-RU tetramer with differing intensities. Bulk sequencing showed that use of V genes other than TRAV1-2 was enriched among MR1-5-OP-RU tetramerlow cells. Although we initially interpreted these as diverse MR1-restricted TCRs, single-cell TCR sequencing revealed that cells expressing atypical TCRα-chains also coexpressed an invariant MAIT TCRα-chain. Transfection of each non-TRAV1-2 TCRα-chain with the TCRß-chain from the same cell demonstrated that the non-TRAV1-2 TCR did not bind the MR1-5-OP-RU tetramer. Thus, dual TCRα-chain expression in human T cells and competition for the endogenous ß-chain explains the existence of some MR1-5-OP-RU tetramerlow T cells. The discovery of simultaneous expression of canonical and noncanonical TCRs on the same T cell means that claims of roles for non-TRAV1-2 TCR in MR1 response must be validated by TCR transfer-based confirmation of Ag specificity.

High levels of mild to moderate depression among men who have sex with men and transgender women in Lima, Peru: implications for integrated depression and HIV care.

ABSTRACTDepression disproportionally affects people at risk of acquiring or living with HIV and is associated with worse health outcomes; however, depression care is not routinely integrated with HIV prevention and treatment services. Selection of the best depression intervention(s) for integration depends both on the prevalence and severity of depression among potential users. To inform depression care integration in a community-based setting in Lima, Peru, we retrospectively analyzed routinely collected depression screening data from men who have sex with men and transgender women seeking HIV prevention and care services (N = 185). Depression was screened for using the Patient Health Questionnaire-9. Prevalence of any depression (PHQ-9 ≥ 5) was 42% and was significantly associated with the last sexual partner being "casual" (p = 0.01). Most (81%) depressive symptoms were mild to moderate (≥5 PHQ-9 ≤ 14). Integrating depression care with HIV prevention and treatment services in Peru should begin by implementing interventions targeting mild to moderate depression.

A TCR ß-Chain Motif Biases toward Recognition of Human CD1 Proteins.

High-throughput TCR sequencing allows interrogation of the human TCR repertoire, potentially connecting TCR sequences to antigenic targets. Unlike the highly polymorphic MHC proteins, monomorphic Ag-presenting molecules such as MR1, CD1d, and CD1b present Ags to T cells with species-wide TCR motifs. CD1b tetramer studies and a survey of the 27 published CD1b-restricted TCRs demonstrated a TCR motif in humans defined by the TCR ß-chain variable gene 4-1 (TRBV4-1) region. Unexpectedly, TRBV4-1 was involved in recognition of CD1b regardless of the chemical class of the carried lipid. Crystal structures of two CD1b-specific TRBV4-1+ TCRs show that germline-encoded residues in CDR1 and CDR3 regions of TRBV4-1-encoded sequences interact with each other and consolidate the surface of the TCR. Mutational studies identified a key positively charged residue in TRBV4-1 and a key negatively charged residue in CD1b that is shared with CD1c, which is also recognized by TRBV4-1 TCRs. These data show that one TCR V region can mediate a mechanism of recognition of two related monomorphic Ag-presenting molecules that does not rely on a defined lipid Ag.

Quality Improvement to Address Surgical Burden of Disease at a Large Tertiary Public Hospital in Peru.

BACKGROUND: In resource-limited settings, there is a unique opportunity for using process improvement strategies to address the lack of access to surgical care. By implementing organizational changes in the surgical admission process, we aimed to decrease wait times, increase surgical volume, and improve patient satisfaction for elective general surgery procedures at a public tertiary hospital in Lima, Peru. METHODS: During the first phase of the intervention, Plan-Do-Study-Act (PDSA) cycles were performed to ensure the surgery waitlist included up-to-date clinical information. In the second phase, Lean Six Sigma methodology was used to adapt the admission and scheduling process for elective general surgery patients. After six months, outcomes were compared to baseline data using Wilcoxon rank-sum test. RESULTS: At the conclusion of phase one, 87.0% (488/561) of patients on the new waitlist had all relevant clinical data documented, improved from 13.3% (2/15) for the pre-existing list. Time from admission to discharge for all surgeries improved from 5 to 4 days (p<0.05) after the intervention. Median wait times from admission to operation for elective surgeries were unchanged at 4 days (p=0.076) pre- and post-intervention. There was a trend toward increased weekly elective surgical volume from a median of 9 to 13 cases (p=0.24) and increased patient satisfaction rates for elective surgery from 80.5 to 83.8% (p=0.62), although these were not statistically significant. CONCLUSION: The process for scheduling and admitting elective surgical patients became more efficient after our intervention. Time from admission to discharge for all surgical patients improved significantly. Other measured outcomes improved, though not with statistical significance. Main challenges included gaining buy-in from all participants and disruptions in surgical services from bed shortages.

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

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

Peripheral Blood Mucosal-Associated Invariant T Cells in Tuberculosis Patients and Healthy Mycobacterium tuberculosis-Exposed Controls.

BACKGROUND: In human blood, mucosal-associated invariant T (MAIT) cells are abundant T cells that recognize antigens presented on non-polymorphic major histocompatibility complex-related 1 (MR1) molecules. The MAIT cells are activated by mycobacteria, and prior human studies indicate that blood frequencies of MAIT cells, defined by cell surface markers, decline during tuberculosis (TB) disease, consistent with redistribution to the lungs. METHODS: We tested whether frequencies of blood MAIT cells were altered in patients with TB disease relative to healthy Mycobacterium tuberculosis-exposed controls from Peru and South Africa. We quantified their frequencies using MR1 tetramers loaded with 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil. RESULTS: Unlike findings from prior studies, frequencies of blood MAIT cells were similar among patients with TB disease and latent and uninfected controls. In both cohorts, frequencies of MAIT cells defined by MR1-tetramer staining and coexpression of CD161 and the T-cell receptor alpha variable gene TRAV1-2 were strongly correlated. Disease severity captured by body mass index or TB disease transcriptional signatures did not correlate with MAIT cell frequencies in patients with TB. CONCLUSIONS: Major histocompatibility complex (MHC)-related 1-restrictied MAIT cells are detected at similar levels with tetramers or surface markers. Unlike MHC-restricted T cells, blood frequencies of MAIT cells are poor correlates of TB disease but may play a role in pathophysiology.

Individual-level characteristics associated with oral HIV test acceptability among Peruvian men who have sex with men and transgender women: a cross-sectional study.

OBJECTIVES: Peruvian men who have sex with men (MSM) and transgender women (TGW) are highly vulnerable to HIV infection (HIV), but stigma, access issues and fear of venipuncture hamper testing. The oral HIV test-which uses oral fluids and provides results in 20 minutes-could reduce these barriers. The objective of this study was to determine the acceptability of the oral HIV test and the individual-level factors associated with its acceptability among MSM and TGW. METHODS: We conducted a cross-sectional secondary analysis among Peruvian MSM and TGW attending a community-based health centre between February 2012 and February 2013 to determine the individual-level factors associated with oral HIV test acceptability. RESULTS: Of 334 participants, 88% were MSM and 12% TGW. Overall, 85% of participants indicated their acceptability of the oral HIV test. Acceptability was higher in MSM than TGW (85.7% vs 80.0%) but this difference was not significant. Factors associated with acceptability in MSM were: tertiary or higher education (prevalence ratio (PR)=1.18, 95% CI 1.06 to 1.32 and PR=1.16, 95% CI 1.03 to 1.30, respectively); sex with drug use (PR=1.19, 95% CI 1.05 to 1.36); believing that HIV is transmitted by saliva (PR=1.20, 95% CI 1.08 to 1.33); and potential use of the oral test at home (PR=1.56, 95% CI 1.32 to 1.85). The only factor associated with lower acceptability was having had first anal intercourse between 14 and 19 years of age (PR=0.89, 95% CI 0.80 to 0.98). CONCLUSIONS: We identified the individual factors associated with oral HIV test acceptability among Peruvian MSM and TGW. Expanded use of the oral HIV test to increase testing rates among Peruvian MSM and TGW is recommended. TRIAL REGISTRATION NUMBER: NCT01387412, post-results.

Feasibility of the string test for tuberculosis diagnosis in children between 4 and 14 years old.

BACKGROUND: The enteric string test can be used to obtain a specimen for microbiological confirmation of tuberculosis in children, but it is not widely used for this. The aim of this analysis to evaluate this approach in children with tuberculosis symptoms. METHODS: We conducted a cross-sectional study to assess children's ability to complete the test (feasibility), and self-reported pain (tolerability). We examined caregivers' and children's willingness to repeat the procedure (acceptability) and described the diagnostic yield of cultures for diagnostic tools. We stratified estimates by age and compared metrics to those derived for gastric aspirate (GA). RESULTS: Among 148 children who attempted the string test, 34% successfully swallowed the capsule. Feasibility was higher among children aged 11-14 than in children 4-10 years (83% vs 22% respectively, p < 0.0001). The string test was better tolerated than GA in both age groups; however, guardians and older children reported higher rates of willingness to repeat GA than the string test (86% vs. 58% in children; 100% vs. 83% in guardians). In 9 children with a positive sputum culture, 6 had a positive string culture. The one children with a positive gastric aspirate culture also had a positive string culture. CONCLUSION: Although the string test was generally tolerable and accepted by children and caregivers; feasibility in young children was low. Reducing the capsule size may improve test success rates in younger children.

Transient aortitis documented by positron emission tomography in a case series of men and transgender women infected with syphilis.

OBJECTIVES: Syphilis infection persists globally contributing to preventable and treatable morbidity and mortality. How extensive early syphilis disseminates is unknown. To better understand the relationship between early syphilis infection and inflammation over time, our study enrolled six individuals recently infected with syphilis for sequential positron emission tomography (PET) scans. METHODS: We evaluated a case series of six individuals with high syphilis titres (two secondary, two early latent and two latent, unknown duration, but with high titre) who received sequential PET scans to assess inflammation over time and its response to treatment. RESULTS: At time of PET scan, four of the six individuals were co-infected with HIV. One of the four was not on antiretroviral therapy and three of the four were not virally suppressed (viral load of >400 copies/mL). Baseline rapid plasma reagin (RPR) titres ranged from 1:64 to 1:256 (four of the six participants had prior non-reactive RPR results). Five of the six participants had mild to intense hypermetabolic PET scan activity consistent with cervical (n=5), axillary (n=4), inguinal (n=5) and retroperitoneal (n=1) adenopathy. Mild hypermetabolic activity in the thoracic aortic wall, suggesting aortitis, was present among the same five participants and resolved within 30 days for four of the five participants and 60 days for the other participant. However, widespread lymphadenopathy remained present in PET scans up to 3 months following treatment in two participants. We did not find any abnormal PET scan activity of the central nervous system. CONCLUSION: We found abnormal aortic wall PET scan activity suggesting aortitis to be common in a case series of patients with early syphilis. In research settings, PET scans may be a sensitive tool to monitor inflammation associated with syphilis.

HIV Status Communication with Sex Partners and Associated Factors Among High-Risk MSM and Transgender Women in Lima, Peru.

Men who have sex with men (MSM) and transgender women (TW) are key populations in the HIV epidemic. HIV status communication between sex partners can inform decisions regarding sexual behavior. MSM and TW were asked about HIV status communication with sex partners at baseline, 9- and 18-months. GEE models assessed associations with HIV status communication at baseline using prevalence ratios (PRs) and longitudinally using odds ratios (ORs). At baseline, those who had previously had an HIV test, disclosed their HIV status to 42 % of their sex partners. HIV status communication was associated with knowing their sex partner's HIV status at baseline (aPR 5.20) and longitudinally (aOR 1.86). HIV positivity at baseline was negatively associated with HIV status communication during follow-up (aOR 0.55). All reported aPRs and aORs have p < 0.05. Interventions promoting HIV status communication and more frequent HIV testing should be explored as current efforts are insufficient.

The PICASSO Cohort: baseline characteristics of a cohort of men who have sex with men and male-to-female transgender women at high risk for syphilis infection in Lima, Peru.

BACKGROUND: Men who have sex with men (MSM) and male-to-female transgender women (transwomen) are disproportionately at risk of syphilis infection in Peru. METHODS: From 2013 to 2014, MSM and transwomen seeking human immunodeficiency virus (HIV) or sexually transmitted infection (STI) testing and/or treatment were recruited into a 2-year observational cohort study to determine predictors of recently acquired syphilis infection (defined as a rapid plasma reagin [RPR] titer ≥1:16 and a reactive treponemal antibody test) in Lima, Peru. At baseline, interviewers collected sociodemographic, behavioral, and medical characteristics from participants. All cohort participants were tested for syphilis, HIV, Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (NG) infection. Using cross-sectional analyses, bivariate and multivariate models were used to determine factors associated with recently acquired syphilis infection and calculate adjusted prevalence ratios. RESULTS: We recruited 401 participants, 312 MSM and 89 transwomen, with median ages of 29.0 and 32.5 years old (interquartile ranges: 23.3, 37.4 and 27.2, 39.5, respectively). The prevalence of recently acquired syphilis infection at baseline was 16.8% for MSM and 6.7% for transwomen. Among MSM and transwomen, 30.1 and 33.7% were infected with HIV, 18.6 and 24.7% were infected with CT, and 14.2 and 19.1% were infected with NG, respectively. Co-infection rates among MSM with recently acquired syphilis infection included: 44.2% with HIV, 40.4% with CT (32.7% with anal CT and 7.7% with pharyngeal CT), and 19.2% with NG (11.5% with anal NG and 7.7% with pharyngeal NG). Co-infection rates among transwomen with recently acquired syphilis infection included: 66.7% with HIV, 0% with CT, and 16.7% with anal NG. In multivariate analysis among the entire cohort, recently acquired syphilis infection was independently associated with younger age (adjusted prevalence ratio [aPR] = 0.96, 95% confidence interval [CI] = 0.93-0.99), receptive role during anal sex (aPR = 2.56, 95% CI = 1.05-6.25), prior HIV diagnosis (aPR = 1.70, 95% CI = 1.11-2.61), anal CT or NG infection (aPR = 1.69, 95% CI = 1.09-2.60), and prior syphilis diagnosis (aPR = 3.53, 95% CI = 2.20-5.68). CONCLUSIONS: We recruited a cohort of MSM and transwomen who had a high prevalence of recently acquired syphilis infection in Lima, Peru. Recently acquired syphilis infection was associated with socio-demographic characteristics, sexual risk, and sexually transmitted co-infections.

Field evaluation of a dual rapid diagnostic test for HIV infection and syphilis in Lima, Peru.

OBJECTIVES: Screening for HIV and syphilis in key populations is recommended by the WHO to reduce the morbidity, mortality and transmission associated with undiagnosed and untreated infections. Rapid point-of-care tests that can detect multiple infections with a single fingerprick whole blood specimen using a single device are gaining popularity. We evaluated the field performance of a rapid dual HIV and syphilis test in people at high risk of HIV and syphilis infections. METHODS: Participants included men who have sex with men and transgender women recruited in Lima, Peru. Reference standard testing for detection of HIV and syphilis infections, conducted using blood samples from venipuncture, included Treponema pallidum particle agglutination and fourth-generation HIV enzyme immunoassay for which positive results had a confirmation HIV Western blot test. For the evaluation test, SD BIOLINE HIV/Syphilis Duo test (Standard Diagnostics, Korea), a fingerprick blood specimen was used. Sensitivity and specificity were calculated and the exact binomial method was used to determine 95% CIs. RESULTS: A total of 415 participants were recruited for the study. The dual test sensitivity for detection of T. pallidum infection was 89.2% (95% CI 83.5% to 93.5%) and specificity 98.8% (95% CI 96.5% to 99.8%). For detection of HIV infection, the sensitivity of the dual test was 99.1% (95% CI 94.8% to 100%) and specificity 99.4% (95% CI 97.7% to 99.9%). CONCLUSIONS: This high performing dual test should be considered for the use in clinical settings to increase uptake of simultaneous testing of HIV and syphilis and accelerate time to treatment for those who need it.

Field Evaluation of a Dual Rapid Immunodiagnostic Test for HIV and Syphilis Infection in Peru.

BACKGROUND: Integrated prevention for HIV and syphilis is warranted because both syphilis and HIV infections have evidence-based, scalable interventions using current health care mechanisms. The advent of dual rapid point-of-care tests, single devices that can detect multiple infections using the same specimen, provides the opportunity to integrate the screening of syphilis into HIV prevention programs, potentially increasing the numbers of people tested and allowing for same-day testing and treatment. The aim of our study was to evaluate the MedMira Multiplo Rapid TP/HIV Antibody Test (MedMira Inc, Halifax, Nova Scotia, Canada), a qualitative, rapid immunoassay that detects antibodies to Treponema pallidum and HIV. METHODS: The reference test for comparison to the T. pallidum component of the Multiplo TP/HIV Test was the T. pallidum particle agglutination assay. For the HIV component, the reference test included a fourth-generation enzyme immunoassay with a confirmatory Western blot test. RESULTS: The sensitivity and specificity for the HIV antibody component were 93.8% (95% confidence interval [CI], 69.8%-99.8%) and 100% (95% CI, 97.7%-100%), respectively. The T. pallidum component of the test had a sensitivity of 81.0% (95% CI, 68.1%-94.6%) and a specificity of 100% (95% CI, 97.6%-100%). CONCLUSIONS: Our study showed excellent performance of the HIV antibody component of the test and very good performance for the T. pallidum antibody component of the MedMira Multiplo Rapid TP/HIV Antibody Test, which should be considered to improve screening coverage. Use of effective dual tests will create improved access to more comprehensive care by integrating the screening of syphilis into HIV prevention programs.

Rectal Douching Prevalence and Practices Among Peruvian Men Who have Sex with Men and Transwomen: Implications for Rectal Microbicides.

Peruvian men who have sex with men (MSM) and transwomen (TW) could benefit from a rectal microbicide (RM) formulated as a rectal douche to prevent HIV infection. However, little is known about rectal douching practices among Peruvian MSM and TW, information necessary to inform RM douche development and future uptake. Using a self-administered interview, we examined the prevalence of and factors associated with rectal douching among a convenience sample of 415 Peruvian MSM and 68 TW. In the previous 6 months, 18 % of participants reported rectal douching using pre-filled commercial kits or plastic bottles or enema bags filled with water, water/soap or saltwater. Multivariate logistic analysis found that "equally insertive and receptive" or "exclusively/mainly receptive" sex roles were associated with douche use. Rectal douching among Peruvian MSM and TW is similar to reports from other studies and supports the potential uptake of a douche-formulated RM in these populations.

Laboratory evaluation of a dual rapid immunodiagnostic test for HIV and syphilis infection.

New dual tests for HIV and syphilis have been developed. Our study aimed to evaluate the laboratory performance of a dual rapid immunodiagnostic test for HIV and syphilis. Our evaluation showed high performance of this dual rapid test, which should be considered for implementation to increase screening coverage and efficiency.

Factors associated with visible anogenital warts among HIV-uninfected Peruvian men who have sex with men and transwomen: a cross-sectional study.

BACKGROUND: Visible, anogenital warts may be associated with risk factors for HIV infection. This cross-sectional study examined the factors associated with visible anogenital warts among HIV-uninfected Peruvian men who have sex with men (MSM) and transwomen. METHODS: Six hundred HIV-uninfected MSM and transwomen were recruited from a community-based setting in metropolitan Lima, Peru, through outreach activities. Participants were tested for syphilis, completed a behavioral questionnaire, and were examined for visible anogenital warts. Logistic regression was used to assess the independent association between sample characteristics, HIV-related risk factors, and visible anogenital warts. RESULTS: A tertiary education versus a primary/secondary (adjusted odds ratio [AOR], 1.79; 95% confidence interval [CI], 1.07-2.99), a first experience of anal intercourse at age 20 years or older versus younger ages (AOR, 2.80; 95% CI, 1.45-5.38), and self-reporting of current sexually transmitted infection symptoms (AOR, 2.38; 95% CI, 1.61-3.52) were significant correlates of visible anogenital warts, whereas syphilis infection, transactional sex, receptive anal intercourse, and self-identifying as a transwoman were not. CONCLUSIONS: Although not associated with key risk factors for HIV infection in Peruvian MSM and transwomen, the presence of visible anogenital warts should prompt clinicians to consider the possibility of unreported same-sex sexual behaviors and other risk sexually transmitted infection/HIV risk factors.

Relationship between alcohol consumption prior to sex, unprotected sex and prevalence of STI/HIV among socially marginalized men in three coastal cities of Peru.

This article presents data about the relationship between alcohol consumption prior to sex and unprotected sex and the prevalence of at least one sexually transmitted infection (STI) including HIV among socially marginalized men in three coastal Peruvians cities. During an epidemiological survey with 2,146 men, we assessed their STI prevalence, frequency of alcohol consumption prior to sex, unprotected sex and other sexual risk behaviors. The overall prevalence of at least one STI/HIV was 8.5 % (95 % CI 7.3-9.7), the prevalence of unprotected sex was 79.1 % (95 % CI 77.8-80.3) and alcohol consumption prior to sex with any of the last five sex partners in the previous 6 months was 68.9 % (95 % CI 66.9-70.9). Bivariate and multivariate analysis showed that alcohol consumption of participants or their partners prior to sex were associated with the prevalence of at least one STI, adjusted Prevalence Ratio (aPR) = 1.3 (95 % CI 1.01-1.68). Unprotected sex was significantly associated with alcohol consumption prior to sex when both partners used alcohol, aPR = 1.15 (95 % CI 1.10-1.20) or when either one of them used alcohol aPR = 1.14 (95 % CI 1.09-1.18). These findings concur with previous literature suggesting a relationship between alcohol consumption prior to sex and STI and HIV. These data improve our understanding of this relationship in this context and could be used to enhance STI and HIV prevention strategies for socially marginalized men in Peru.

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.