Substance use and other correlates of HIV infection among transwomen and men who have sex with men in Perú: Implications for targeted HIV prevention strategies for transwomen

Characterization of HIV risk factors among transwomen and men who have sex with men (MSM) should be assessed separately and independently. However, due to several constraints, these populations continue to be conflated in clinical research and data. There are limited datasets globally powered to make such comparisons. The study aimed to use one of the largest surveys of transwomen and MSM in Latin America to determine differences in HIV risk and related correlates between the two populations. Secondary data analysis was completed using a cross-sectional biobehavioral survey of 4413 MSM and 714 transwomen living in Perú. Chi Square analysis of selected HIV correlates was conducted to examine differences between transwomen and MSM. Additionally, stratified binary logistic regression was used to split data for further comparative analyses of correlates associated with transwomen and MSM separately. HIV prevalence among transwomen was two-fold greater than among MSM (14.9% vs. 7.0%, p<0.001). Transwomen had a higher prevalence of most HIV risk factors assessed, including presence of alcohol dependence (16.4% vs. 19.0%; p < .001) and drug use in the past 3 months (17.0% vs. 14.9%). MSM were more likely to use marijuana (68.0% vs. 50.0%, p < .001), and transwomen were more likely to engage in inhaled cocaine use (70.0% vs. 51.1%, p < .001). The regression exposed differences in correlates driving sub-epidemics in transwomen vs. MSM, with a trend of substance use increasing HIV risk for transwomen only. Transwomen were more likely to be HIV-infected and had different risk factors from MSM. Targeted prevention strategies are needed for transwomen that are at highest risk. Additionally, further research is needed to determine if these observations in Perú regarding substance use patterns and the role of substance use in HIV risk relate to other trans populations globally.

On the explainability of hospitalization prediction on a large COVID-19 patient dataset

We develop various AI models to predict hospitalization on a large (over 110k) cohort of COVID-19 positive-tested US patients, sourced from March 2020 to February 2021. Models range from Random Forest to Neural Network (NN) and Time Convolutional NN, where combination of the data modalities (tabular and time dependent) are performed at different stages (early vs. model fusion). Despite high data unbalance, the models reach average precision 0.96-0.98 (0.75-0.85), recall 0.96-0.98 (0.74-0.85), and F1-score 0.97-0.98 (0.79-0.83) on the non-hospitalized (or hospitalized) class. Performances do not significantly drop even when selected lists of features are removed to study model adaptability to different scenarios. However, a systematic study of the SHAP feature importance values for the developed models in the different scenarios shows a large variability across models and use cases. This calls for even more complete studies on several explainability methods before their adoption in high-stakes scenarios.

Prevalence of Intimate Partner Violence, Substance Use Disorders and Depression among Incarcerated Women in Lima, Perú

Background: Globally, there is evidence supporting the co-occurrence of intimate partner violence (IPV), substance use disorders (SUD) and mental health disorders among women in prisons, however, there is limited research investigating these domains in the Andean region where rates of female incarceration have increased. The study objective was to explore the prevalence of IPV, SUD and depression among incarcerated women in a Peruvian prison and explore associations among these variables and related correlates. Methods: 249 incarcerated women responded to a questionnaire about IPV, substance use, depression, and sexual behavior, and were screened for HIV/sexually transmitted diseases (STDs). Univariate analysis and logistic regression were used to estimate relative risk and the influence of substance use and depression on IPV rates. Results: Twelve months prior to incarceration, of the women with sexual partners pre-incarceration (n = 212), 69.3% experienced threats of violence, 61.4% experienced ≥1 acts of physical violence, and 28.3% reported ≥1 act of sexual aggression. Pre-incarceration, 68.1% of drug-using women had a SUD, and 61.7% of those who consumed alcohol reported hazardous/harmful drinking. There were 20 (8.0%) HIV/STD cases; and 67.5% of the women reported depressive symptoms. Compared to women with no experiences of physical violence, a greater proportion of women who experienced least l violent act had depressive symptoms and engaged in sex work pre-incarceration. Depression was associated with physical violence (adjusted relative risk = 1.35, 95% confidence interval: 1.14–1.58). Recommendations: The findings provide evidence of a syndemic of IPV, substance abuse and depression among incarcerated women in a Peruvian prison. To help guide policy makers, further research is needed to determine if this is indicative of trends for other at-risk women in the region, and viable options to treat these women during incarceration to prevent recidivism and other long-term negative sequalae.

Active syphilis and its association with HIV and sexual risk behaviours in a multicity sample of men who have sex with men and transgender women in Peru

Background Syphilis in Peru is heavily concentrated in men who have sex with men (MSM) and transgender women (TGW). The aim of the present study was to understand the risk factors for active syphilis infection among MSM and TGW in Peru.

METHODS

Independent correlates suggestive of active syphilis infection were examined to better understand risk factors for syphilis in MSM and TGW, with separate analyses conducted based on location and among TGW. In 2011, 5101 MSM and TGW completed both self-report surveys and HIV and syphilis testing in five Peruvian cities.

RESULTS

Overall, 261 (5.1%) MSM and TGW met the criteria for active syphilis, with higher prevalence in Lima than elsewhere (7.0% vs 3.0%) and in TGW than in MSM (10.7% vs 4.2%). Significant independent correlates of active syphilis infection differed greatly by location. In Lima, they included being HIV-infected (aware or unaware of status), being a TGW, being a high school graduate, engaging in receptive anal intercourse, no recent sex with a female partner and having had any symptomatic sexually transmissible infection, including syphilis, in the previous 6 months. Outside Lima, the independent correlates included being HIV-infected and unaware of status, engaging in recent sex work, no recent sex with a female partner and age 35-44 years. Among TGW, independent correlates of active syphilis included being HIV-infected (aware or unaware of status), a recent syphilis diagnosis in the previous 6 months and recent drug use.

CONCLUSION

The findings of the present study support the need not only for combined HIV and syphilis screening, but also for increased screening and treatment of syphilis in MSM and TGW populations. Stratified analyses suggest different syphilis epidemics throughout the country and in TGW, yet being HIV-infected and aware were consistently associated with active syphilis, suggesting higher syphilis risk in HIV-infected MSM and TGW.

Men Who Have Sex With Men in Peru: Acceptability of Medication-Assisted Therapy for Treating Alcohol Use Disorders

In Peru, the HIV epidemic is concentrated in men who have sex with men (MSM) and transgender women (TGW). Multiple studies correlate alcohol use disorders (AUDs) with risky sexual behaviors among Peruvian MSM. Qualitative research was used to inform a clinical trial on the acceptability of medication-assisted therapies to assist management of AUDs and improve antiretroviral therapy (ART) adherence among MSM/TGW in Peru. Three focus groups involving HIV-infected or HIV-uninfected MSM/TGW ( n = 26) with AUDs (AUDIT ≥ 8) were transcribed, translated from Spanish into English, and analyzed using thematic content analysis. Despite having an AUD, participants considered themselves "social" drinkers, minimized their drinking behaviors, and differed about whether or not alcohol problems could be treated. Participants expressed skepticism about medication for treating AUDs. Three concepts emerged as necessary components of a treatment program for alcohol problems: cost, family support, and the potential to drink less alcohol without attaining total abstinence. This study reveals important areas of education to increase potential acceptability of a medication for treating AUDs among MSM/TGW. Given the social conditions and knowledge base of the participants, medication-assisted therapies using naltrexone may be a beneficial strategy for MSM with AUDs.

A Qualitative Assessment of Alcohol Consumption and Sexual Risk Behaviors Among Men Who Have Sex With Men and Transgender Women in Peru

BACKGROUND

Peruvian men who have sex with men (MSM) and transgender women (TGW) experience the double burden of a highly concentrated HIV epidemic with a high prevalence of alcohol use disorders (AUDs). Recent research has associated both with risky sexual behaviors, including unprotected sex, having multiple sexual partners, engaging in sex work, having recent sexually transmitted infections, and having HIV-infected partners. AUDs have also been associated in MSM/TGW with being unaware of HIV+ status.

OBJECTIVES

This study aims to further examine issues associated with alcohol consumption, HIV infection, and risk behaviors in a qualitative analysis of focus groups conducted with MSM/TGW in Peru.

METHODS

A total of 26 MSM/TGW participants with AUDs participated in three semi-structured focus groups in Lima, Peru. Content analysis was facilitated by software, and specific themes were elucidated.

RESULTS

Participants described their drinking patterns, including the types of alcoholic drinks they consumed. They depicted drinking frequently and over multiple-day sessions. Problematic drinking behaviors were described, as well as the perceived characteristics of alcohol dependence. Interestingly, HIV-infected participants who were prescribed antiretroviral therapy did not believe that their drinking affected their medication adherence. These insights can aid in the design of future interventions aiming to reduce problematic drinking as well as HIV-related risk behaviors and, subsequently, HIV incidence.

CONCLUSIONS

Peruvian MSM/TGW exhibit problematic drinking, which may be associated with risky sexual behaviors and HIV transmission. Interest in reducing alcohol consumption was high, suggesting the need for targeted behavioral and pharmacological interventions.

An explanatory factor analysis of a brief self-report scale to detect neurocognitive impairment among HIV-positive men who have sex with men and transgender women in Peru

Neurocognitive impairment (NCI) has been associated with poor clinical outcomes in various patient populations. This study used exploratory factor analysis (EFA) to examine the factor structure of the existing 95-item Neuropsychological Impairment Scale (NIS) to create a suitable NCI screening instrument for people living with HIV (PLH). In Lima, Peru, 313 HIV-positive men who have sex with men (MSM) and transgender women (TGW) prescribed antiretroviral therapy (ART) completed the NIS using computer-assisted self-interviews (CASI). The EFA used principal axis factoring and orthogonal varimax rotation, which resulted in 42 items with an 8-factor solution that explained 51.8% of the overall variance. The revised, 8-factor, Brief Inventory of Neurocognitive Impairment for Peru (BINI-P) showed a diverse set of factors with excellent to good reliability (i.e., F₁ α = 0.92 to F₈ α = 0.78). This EFA supports the use of the BINI-P to screen for NCI among Spanish-speaking, HIV-positive MSM and TGW. Future research should examine the effectiveness of the BINI-P in detecting NCI in clinical care settings and the impact of NCI on HIV health-related outcomes, including linkage and retention in care, ART adherence and HIV risk behaviors.

HIV-infected men who have sex with men, before and after release from jail: the impact of age and race, results from a multi-site study

The US HIV/AIDS epidemic is concentrated among men who have sex with men (MSM). Black men are disproportionately affected by incarceration and Black MSM experience higher infection rates and worse HIV-related health outcomes compared to non-Black MSM. We compared HIV treatment outcomes for Black MSM to other HIV-infected men from one of the largest cohorts of HIV-infected jail detainees (N = 1270) transitioning to the community. Of the 574 HIV-infected men released, 113 (19.7%) self-identified as being MSM. Compared to other male subgroups, young Black MSM (<30 years old, N = 18) were significantly less likely: (1) before incarceration, to have insurance, access to an HIV healthcare provider, and use cocaine; (2) during incarceration, to receive a disease management intervention; and (3) in the 6 months post-release, to link to HIV care. Interventions that effectively link and retain young HIV-infected Black MSM in care in communities before incarceration and post-release from jail are urgently needed.

Validation of the 'drinking expectancy questionnaire for men who have sex with men' in Peru

INTRODUCTION AND AIMS

Alcohol use disorders are highly prevalent among men who have sex with men (MSM) in Peru, where the HIV epidemic is concentrated 100-fold greater among MSM than in the general population. Drinking expectancies have been associated with the intent to drink and engage in high-risk behaviours. Assessing them in this population may uncover attractive intervention targets that in turn can be used to reduce problematic drinking and risky sexual behaviours. The drinking expectancy questionnaire for MSM (DEQ-MSM) was developed to accurately measure drinking expectancies, specifically among MSM. This study aimed to validate this instrument for the first time in Spanish, in South America and among MSM in Peru.

DESIGN AND METHODS

To validate the DEQ-MSM among Spanish-speaking MSM in Peru, we used exploratory and confirmatory factor analysis in a sample of 5148 MSM, including 700 transgender women (TGW).

RESULTS

Exploratory factor analysis showed a two-factor structure to the Spanish version of the DEQ-MSM (DEQ-MSM-S), which was similar for MSM and TGW. The reliability of the translated DEQ-MSM was excellent (α = 0.91).

DISCUSSION AND CONCLUSIONS

The DEQ-MSM-S was shown to be highly reliable in a large population of Peruvian MSM and TGW. This short instrument can be effectively integrated into research or clinical practice, in order to identify alcohol-consuming, high-risk MSM, who can then be directed for further screening and/or intervention. Future research should aim to associate the Spanish version of the DEQ-MSM with risky sexual behaviours among this population, in order to identify potential intervention targets. [Vagenas P, Wickersham JA, Calabrese SK, Lama JR, Benites CM, Pun M, Sanchez J, Altice FL. Validation of the 'drinking expectancy questionnaire for men who have sex with men' in Peru. Drug Alcohol Rev 2015;34:559-66].

Communication technology use and mHealth acceptance among HIV-infected men who have sex with men in Peru: implications for HIV prevention and treatment

The HIV epidemic in Peru is concentrated among men who have sex with men (MSM). Given that MSM have been documented as early adopters of emerging technology, we examined communication technology access and utilization, and mobile health (mHealth) acceptance among Peruvian MSM and transgender women (TGW) in order to gauge opportunities for mHealth-enabled HIV interventions. A convenience sample of 359 HIV-infected MSM and TGW recruited from three sites in Lima, Peru completed standardized assessments of alcohol use disorders (AUDs), risky sexual behavior, and antiretroviral therapy (ART) adherence along with self-constructed measures of communication technology access and utilization, and mHealth acceptance. Most participants (86%) had daily access to any cell phone, including smartphones (30%). The most frequent communication activities were receiving and making calls, and receiving and sending text messages using cell phones. On a 5-point Likert scale, participants expressed interest in using mHealth for medication reminders (M = 3.21, SD = 1.32) and engaging in anonymous online interactions with health professionals to discuss HIV-related issues (M = 3.56, SD = 1.33). Importantly, no significant differences were found in communication technology use and mHealth acceptance among participants with AUDs, depression, and suboptimal ART adherence, all of which are associated with poor HIV treatment outcomes. Findings show support for implementing mHealth-based intervention strategies using cell phones to assess and reduce HIV-risk behaviors among HIV-infected MSM and TGW.

Alcohol use disorders negatively influence antiretroviral medication adherence among men who have sex with men in Peru

As international guidelines increase access to antiretroviral therapy (ART) globally, ART adherence becomes increasingly important to achieve HIV treatment as prevention (TasP) goals. In the concentrated HIV epidemic among men who have sex with men (MSM) and transgendered women (TGW) in Lima, Peru, the independent correlates of ART nonadherence were examined to inform treatment intervention priorities. Cross sectional survey of HIV-infected MSM and TGW who are engaged in clinical care in Lima, Peru. From June to August 2012, 302 HIV-infected Peruvian MSM/TGW from three clinical care sites were recruited using convenience sampling to participate in a cross-sectional computer-assisted adherence survey. Several standardized screening measures associated with ART nonadherence were examined in order to determine the independent correlates of optimal (≥90%) and perfect (100%) adherence, which were assessed using logistic regression. Of the 302 participants recruited, 263 (87.1%) were prescribed ART. Among those prescribed ART, 229 (87.1%) reported optimal and 146 (55.5%) reported perfect adherence. The prevalence of alcohol use disorders (AUD; 43.2%), alcohol dependence (5.3%), recent drug use (6.0%), and depression (44.5%) was high, and most participants had some evidence of neurocognitive impairment. Meeting criteria for having an AUD and depression were collinear (p < 0.001). On multivariate analysis, having an AUD was inversely related and the only independent correlate of optimal (AOR = 0.427; 95% CI = 0.187-0.976) and perfect (AOR = 0.552; 95% CI = 0.327-0.930) ART adherence. AUDs are highly prevalent among Peruvian HIV-infected MSM and contribute significantly to ART nonadherence. These findings support the need for screening and treating underlying AUDs. In order to meet HIV TasP goals, evidence-based strategies targeting AUDs are likely to directly improve ART adherence and indirectly improve overall individual health, HIV treatment engagement, and reduce transmission to sexual partners among this vulnerable and disproportionally affected population.

Being unaware of being HIV-infected is associated with alcohol use disorders and high-risk sexual behaviors among men who have sex with men in Peru

This study compared the correlates of HIV risk among men who have sex with men (MSM) with newly diagnosed versus previously known HIV infection among 5,148 MSM recruited using modified snowball sampling in 5 Peruvian cities. Participants, if age ≥18 years and reporting sex with a male in the previous 12 months, underwent standardized computer-assisted risk assessments and HIV and syphilis testing. Overall, 420 (8.2 %) participants tested HIV seropositive, most of whom (89.8 %) were unaware of their HIV status. Compared to those who knew themselves to be HIV-infected, multivariate logistic regression demonstrated that unprotected anal intercourse at last encounter [AOR = 2.84 (95 % CI 1.09-7.40)] and having an alcohol use disorder (AUD) [AOR = 2.14 (95 % CI 1.01-5.54)] were independently associated with a newly diagnosed HIV infection. Being unaware of being HIV-infected was associated with high-risk sexual behaviors and AUDs, both of which are amenable to behavioral and medication-assisted therapy interventions.

A review of medical and substance use co-morbidities in Central Asian prisons: implications for HIV prevention and treatment

BACKGROUND

HIV incidence in Central Asia is rising rapidly. People who inject drugs (PWIDs) contribute greatest to the epidemic, with more than a quarter of all HIV cases being in the criminal justice system (CJS). This review assembled and aggregated recent data on drug-related health problems and respective healthcare services in the CJS of Central Asia and the Republic of Azerbaijan.

METHODS

Online databases and published literature (peer-reviewed and gray) were reviewed. Additionally, prison officials in the 6 countries were invited to participate in a survey and prison administrators from Kazakhstan, Kyrgyzstan and Tajikistan completed it.

RESULTS

The data on conditions and healthcare in Central Asian prisons are inconsistent and lack unbiased details. Reporting is primarily based on "official" disease registries, which markedly underestimate prevalence. Even these limited data, however, indicate that HIV prevalence and drug-related health problems are high, concentrated and, in some countries, rising rapidly in CJS. Only some of the range of HIV prevention interventions recommended by international organizations have been implemented in the region with two of the crucial interventions, needle and syringe exchange programs (NSP) and opioid substitution therapy (OST), only available in prisons in Kyrgyzstan, with Tajikistan implementing a pilot NSP and contemplating introduction of prison-based OST.

CONCLUSIONS

Despite deficiencies in routine health reporting and insufficient HIV sentinel surveillance undertaken in prisons, the data available on the concentration of HIV within at-risk populations in prisons indicate a necessity to broaden the range and increase the scale the scale of HIV prevention and treatment services.

Correlates of retention in HIV care after release from jail: results from a multi-site study

Retention in care is key to effective HIV treatment, but half of PLWHA in the US are continuously engaged in care. Incarcerated individuals are an especially challenging population to retain, and empiric data specific to jail detainees is lacking. We prospectively evaluated correlates of retention in care for 867 HIV-infected jail detainees enrolled in a 10-site demonstration project. Sustained retention in care was defined as having a clinic visit during each quarter in the 6 month post-release period. The following were independently associated with retention: being male (AOR = 2.10, p ≤ 0.01), heroin use (AOR 1.49, p = 0.04), having an HIV provider (AOR 1.67, p = 0.02), and receipt of services: discharge planning (AOR 1.50, p = 0.02) and disease management session (AOR 2.25, p ≤ 0.01) during incarceration; needs assessment (AOR 1.59, p = 0.02), HIV education (AOR 2.03, p ≤ 0.01), and transportation assistance (AOR 1.54, p = 0.02) after release. Provision of education and case management services improve retention in HIV care after release from jail.

A systematic review of alcohol use and sexual risk-taking in Latin America

OBJECTIVE

To provide an account of published literature on the association between alcohol use and sexual risk-taking, focusing on Latin America.

METHODS

A search of MEDLINE, Embase, Web of Science, LILACS, and Cochrane databases identified 561 unique articles. After excluding those that were not directly relevant, 30 studies were retained for review.

RESULTS

Twenty-seven studies showed direct or indirect associations between alcohol abuse and unprotected/risky sex. Three studies, however, showed no association between these variables, suggesting that the public health message of safer sex may have been effective.

CONCLUSIONS

Further research is needed to identify factors and behaviors that could be modified to reduce the association between alcohol use disorders and risky sexual behavior.

Screening for drug and alcohol use disorders and their association with HIV-related sexual risk behaviors among men who have sex with men in Peru

Background

Peru's HIV epidemic is concentrated among men who have sex with men (MSM). The contribution of alcohol use disorders (AUDs) to known high-risk behaviors associated with HIV transmission in this context has not been well characterized.

Methods

Between June and October 2011, 5,148 sexually active MSM were recruited using convenience sampling in five cities to participate in a cross-sectional bio-behavioral survey. Five high-risk sexual criteria previously associated with incident HIV infection in this setting were selected a priori as the dependent outcomes. Screening for AUDs used the validated Alcohol Use Disorders Identification Test (AUDIT) and AUDS were stratified by severity. Unadjusted and adjusted odds ratios (AOR) were computed to establish the independent correlates of the five dependent outcomes.

Results

The majority (62.8%) of participants met screening criteria for having an AUD, which were independently correlated with each of the following high-risk sexual risk behaviors in the previous 6 months: 1) >5 sexual partners [AOR = 1.76; (1.54–2.02)]; 2) sex with an HIV-infected partner [AOR = 1.29; (1.03–1.62)]; 3) having a sexually transmitted infection [AOR = 1.38; (1.13–1.68)]; 4) being a sex worker [AOR = 1.61; (1.40–1.87)]; and 5) unprotected sex during last encounter [AOR = 1.22; (1.09–1.38)]. Recent drug use was also correlated with having >5 sexual partners [AOR = 1.42 (1.19–1.71)], sex work [AOR = 1.97 (1.63–2.39)] and unprotected sex during last encounter [AOR = 1.31 (1.11–1.54)]. For each dependent variable, the association with AUDs significantly increased with increasing AUD severity.

Conclusions

AUDs are highly prevalent among MSM in Peru and are associated with increased HIV risk-taking behaviors that are associated with HIV transmission. Strategies that target problematic drinking such as medication-assisted therapy, behavioral counseling and structural interventions could potentially reduce risky behaviors and ultimately reduce HIV transmission among MSM in Peru.

Current concepts of HIV transmission

The epithelial surface acts as an effective barrier against HIV. The various mucosal surfaces possess specific mechanisms that help prevent the transmission of virus. Yet, HIV manages to cross these barriers to establish infection, and this is enhanced in the presence of physical trauma or preexisting sexually transmitted infections. Once breached, the virus accesses numerous cells such as dendritic cells, T cells, and macrophages present in the underlying epithelia. Although these cells should contribute to innate and adaptive immunity to infection, they also serve as permissive targets to HIV and help in the initiation and dissemination of infection. Understanding how the various mucosal surfaces, and the cells within them, respond to the presence of HIV is essential in the design of therapeutic agents that will help to prevent HIV transmission.

Current concepts of HIV transmission

The epithelial surface acts as an effective barrier against HIV. The various mucosal surfaces possess specific mechanisms that help prevent the transmission of virus. Yet, HIV manages to cross these barriers to establish infection, and this is enhanced in the presence of physical trauma or pre-existing sexually transmitted infections. Once breached, the virus accesses numerous cells such as dendritic cells, T cells, and macrophages present in the underlying epithelia. Although these cells should contribute to innate and adaptive immunity to infection, they also serve as permissive targets to HIV and help in the initiation and dissemination of infection. Understanding how the various mucosal surfaces, and the cells within them, respond to the presence of HIV is essential in the design of therapeutic agents that will help to prevent HIV transmission.

Bilateral congenital anterior diaphragmatic hernia: a case report

The anteromedial diaphragmatic hernias of Morgagni and Larrey are the least common defects that occur in this organ. Simultaneous occurrence has been described but remains an absolute rarity. We herein present a case of this bilateral herniation with a unique presentation. The paper refers to the basic anatomic, diagnostic and therapeutic considerations for this entity.

What does tumour necrosis factor excess do to the immune system long term?

Members of the tumour necrosis factor (TNF)/TNF-receptor (TNF-R) superfamily coordinate the immune response at multiple levels. For example, TNF, LTalpha, LTbeta and RANKL provide signals required for lymphoid neogenesis, CD27, OX-40, 4-1BB and CD30 deliver costimulatory signals to augment immune responses, while pro-apoptotic members such as TNF, CD95L and TRAIL may contribute to the termination of the response. Biological identity of individual family members has been revealed through studies of gain of function or gene deficient mutants. Most notable are the development of spontaneous inflammatory polyarthritis in human TNF-globin transgenic mice, the auto-inflammatory syndromes resulting from mutations in the 55-kDa TNF-R, and, in particular, the obligatory role for the RANKL/RANK axis in osteoclastogenesis and bone remodelling. A growing appreciation of the molecular basis of signalling pathways transduced by TNF-R has provided a framework for better understanding the biology of this expanding family. For while the rapid and robust activation of NF-kappaB and MAPK pathways is typical of acute TNF-R engagement, the molecular basis of sustained receptor signalling remains a mystery, in spite of its relevance to chronic inflammatory and immune responses. Focusing on T cells, this report describes some of the molecular footprints of sustained TNF-R engagement and illustrates how these may influence immune function. A common theme arising is that prolonged TNF stimulation alters signalling thresholds over time. The authors propose that one major outcome of long term exposure to TNF is a state of localised IL-2 deficiency at sites of inflammation. The implications of this deficiency are discussed.