Quantitation of antigen-specific immune responses in human immunodeficiency virus (HIV)-infected individuals by limiting dilution analysis

The lymphocyte proliferative response to recall antigens is lost following HIV infection. We sought to devise a means by which the functional immune status of persons in the early stages of HIV infection could be monitored quantitatively. The response to tetanus toxoid was examined in 45 HIV-infected individuals and 11 controls using conventional lymphocyte proliferative assays concurrently with limiting dilution analysis utilizing the secretion of interleukin-2 as the measure of a response. Our data show that the limiting dilution analysis detects tetanus toxoid-reactive T cells in 80% of those tested, as compared to only 44% by proliferation. However, the frequency of tetanus-reactive T cells in HIV-infected individuals (median frequency = 1/59,156) is decrease five-fold as compared to seronegative controls (median frequency = 1/11,599). Longitudinal studies demonstrated a time-dependent decrease in the frequency of tetanus-specific T cell responses in the HIV-infected individuals. Thus, the limiting dilution analysis is a quantitative approach for detecting antigen-specific T cells in HIV-infected individuals, and may be used to monitor changes in T cell function in HIV infection.     

HIV/STI Risk Among Venue-Based Female Sex Workers Across the Globe: A Look Back and the Way Forward

Female sex workers (FSWs) continue to represent a high-risk population in need of targeted HIV prevention interventions. Targeting environmental risk factors should result in more sustainable behavior change than individual-level interventions alone. There are many types of FSWs who operate in and through a variety of micro- (eg, brothels) and macro-level (eg, being sex-trafficked) contexts. Efforts to characterize FSWs and inform HIV prevention programs have often relied on sex work typologies or categorizations of FSWs by venue or type. We conducted a systematic search and qualitatively reviewed 37 published studies on venue-based FSWs to examine the appropriateness of sex work typologies, and the extent to which this research has systematically examined characteristics of different risk environments. We extracted information on study characteristics like venue comparisons, HIV/STI prevalence, and sampling strategies. We found mixed results with regards to the reliability of typologies in predicting HIV/STI infection; relying solely on categorization of FSWs by venue or type did not predict seroprevalence in a consistent manner. Only 65 % of the studies that allowed for venue comparisons on HIV/STI prevalence provided data on venue characteristics. The factors that were assessed were largely individual-level FSW factors (eg, demographics, number of clients per day), rather than social and structural characteristics of the risk environment. We outline a strategy for future research on venue-based FSWs that ultimately aims to inform structural-level HIV interventions for FSWs.     

Therapeutic Riding or Mindfulness: Comparative Effectiveness of Two Recreational Therapy Interventions for Adolescents with Autism

Journal of Autism and Developmental Disorders - Therapeutic riding (THR) and HeartMath (HM) mindfulness-based interventions have promise for reducing stress in adolescents with autism spectrum...     

Injection Drug Use Trajectories among Migrant Populations: A Narrative Review

Background: Dual epidemics of injection drug use and blood-borne disease, characterized as “syndemics,” are present in a range of settings. Behaviors that drive such syndemics are particularly prevalent among mobile drug-using populations, for whom cross-border migration may pose additional risks. Objectives: This narrative review aims to characterize the risk factors for injection drug use initiation associated with migration, employing a risk environment framework and focusing on the San Diego–Tijuana border region as the most dynamic example of these phenomena. Methods: Based on previous literature, we divide migration streams into three classes: intra-urban, internal, and international. We synthesized existing literature on migration and drug use to characterize how mobility and migration drive the initiation of injection drug use, as well as the transmission of hepatitis and HIV, and to delineate how these might be addressed through public health intervention. Results: Population mixing between migrants and receiving communities and the consequent transmission of social norms about injection drug use create risk environments for injection drug use initiation. These risk environments have been characterized as a result of local policy environments, injection drug use norms in receiving communities, migration-related stressors, social dislocation, and infringement on the rights of undocumented migrants. Conclusion: Policies that exacerbate risk environments for migrants may inadvertently contribute to the expansion of epidemics of injection-driven blood-borne disease. Successful interventions that address emerging syndemics in border regions may therefore need to be tailored to migrant populations and distinguish between the vulnerabilities experienced by different migration classes and border settings.     

Establishing a Binational Student-Run Free-Clinic in Tijuana,Mexico: A Model for US–Mexico Border States

In 2011, a bi-national student-run free clinic for the underserved, known as “Health Frontiers in Tijuana” (HFiT), was created in Tijuana, Mexico. Students and faculty from one Mexican and one US medical school staff the clinic and attend patients on Saturdays. Students from both medical schools enroll in a didactic course during the quarter/semester that they attend the free clinic. The course addresses clinical, ethical, cultural, population-specific issues and the structure, financing and delivery of medical care in Mexico. The clinic implements an electronic medical record and is developing telemedicine for consulting on complex cases. Despite challenges related to sustaining adequate funding, this program may be replicated in other border communities.     

People Who Inject Drugs in Intimate Relationships: It Takes Two to Combat HIV

We reviewed papers published during the past 18 months (2012-2013) focusing on micro-social contexts of gender and power inequalities as drivers of HIV risks among people who inject drugs (PWID) in intimate heterosexual relationships. Although there has been a proliferation of social and behavioral research on the micro-social contexts of drug injection in heterosexual intimate relationships, there is still a gap in knowledge of these issues, particularly in low- and middle-income countries. Research has identified couple-based approaches for PWID in intimate relationships as an effective HIV prevention strategy to address micro-social contexts driving HIV risks. While HIV incidence has declined in many countries, prevalence remains at troubling levels among PWID and transmission from PWID to their sex partners is increasing in many parts of the world. HIV prevention among drug-using couples must address the importance of the relationship dyad and micro-social contexts.     

Cross-reactive CD8+ T cell epitopes identified in US adolescent minorities

Vaccines designed to bring forth CD8+ T cell responses in different racial and ethnic groups will require inclusion of T cell epitopes presented by various MHC class I molecules. This study was designed to identify new CD8+ T cell epitopes in HIV-infected African American and Hispanic youth as well as to determine the frequency of responses to both novel and previously described HIV-1 epitopes in a cohort of racially and ethnically diverse individuals. We found 8 MHC class I-restricted CD8+ T cell epitopes that had not been previously described, another 8 epitopes that were restricted by class I alleles not previously associated with these epitopes, and 8 additional epitopes that have been described previously. In a larger cohort, we demonstrated that 11 (69%) of these 16 newly described immunogens were recognized by individuals of different race or ethnicity. Most HIV-1-specific CD8+ T cell epitopes identified were either novel or restricted by alternative MHC class I alleles. Frequent recognition of several of these CTL epitopes in persons of diverse racial backgrounds bodes well for the development of a broadly reactive HIV-1 vaccine.     

Multiperson use of syringes among injection drug users in a needle exchange program: a gene-based molecular epidemiologic analysis

Syringe-sharing behaviors among injection drug users (IDUs) are typically based on self-reports and subject to socially desirable responding. We used 3 short tandem repeat (STR) genetic biomarkers to detect sharing in 2,512 syringes exchanged by 315 IDUs in the Baltimore needle exchange program (NEP; 738 person-visits). Demographic characteristics as well as direct and indirect needle-sharing behaviors corresponding to the closest AIDS Link to Intravenous Experience (ALIVE) study visits were examined for association with multiperson use (MPU) of syringes. Overall, 56% of the syringes exchanged at the Baltimore NEP had evidence of MPU. Less MPU of syringes (48% vs. 71%; P < 0.0001) was seen with more rapid syringe turnaround (<3 days). IDUs always exchanging their own syringes ("primary" syringes) were less likely to return syringes with evidence of MPU (52%) than those who exchanged syringes for others ("secondary" syringes; 64%; P = 0.0001) and those exchanging primary and secondary syringes (58%; P = 0.004). In a multivariate analysis restricted to primary exchangers, MPU of syringes was associated with sharing cotton (adjusted odds ratio [AOR] = 2.06, 95% confidence interval [CI]: 1.30 to 3.28), lending syringes (AOR = 1.70, 95% CI: 1.24 to 2.34), and injecting less than daily (AOR = 0.64, 95% CI: 0.43 to 0.95). These findings support additional public health interventions such as expanded syringe access to prevent HIV and other blood-borne infections. Testing of STRs represents a promising approach to examining and accessing complex behavioral data, including syringe sharing.