Impact of a teen club model on HIV outcomes among adolescents in rural Neno district, Malawi: a retrospective cohort study.

OBJECTIVE: To compare the impact of a teen club model to the standard care model on HIV treatment outcomes among adolescents (10-19 years of age). DESIGN: Retrospective cohort study. SETTING: HIV clinics in Neno district, Malawi. PARTICIPANTS: Adolescents living with HIV enrolled in teen clubs (n=235) and matched participants in standard HIV care (n=297). OUTCOME MEASURES: Attrition from HIV care, defined as a combination of treatment outcomes 'died', 'defaulted' and 'transferred out'. RESULTS: Over a 4-year follow-up period, adolescents who participated in the teen club had a significantly higher likelihood of remaining in care than those who did not (HR=2.80; 95% CI: 1.46 to 5.34). Teen clubs also increased the probability of having a recent measured viral load (VL) and BMI, but did not change the probability of VL suppression. The age at antiretroviral treatment initiation below 15 years (aHR=0.37; 95% CI: 0.17 to 0.82) reduced the risk of attrition from HIV care, while underweight status (aHR=3.18; 95% CI: 1.71 to 5.92) increased the risk of attrition, after controlling for sex, WHO HIV staging and teen club participation. CONCLUSIONS: The teen club model has the potential to improve treatment outcomes among adolescents in rural Neno district. However, in addition to retaining adolescents in HIV care, greater attention is needed to treatment adherence and viral suppression in this special population. Further understanding of the contextual factors and barriers that adolescents in rural areas face could further improve the teen club model to ensure high-quality HIV care and quality of life.

A model system to study the environment-dependent expression of the Bet v 1a gene encoding the major birch pollen allergen.

BACKGROUND: The major birch pollen allergen Bet v 1 (or Bet v 1a) is one of the main causes of seasonal type I allergies. Various environmental factors such as light, temperature and air pollution may influence the activity of the Bet v 1a gene. The creation of a model system to evaluate the role of environmental factors affecting the Bet v 1a gene expression would be highly desirable. We suggest the use of transgenic tobacco plants carrying a Bet v 1a promoter-reporter gene fusion as such a system. METHODS: The promoter of the Bet v 1a gene was isolated with the use of the Universal Genome Walker kit (BD Biosciences Clontech, USA). Web Software was used to search for putative cis-regulatory elements within the promoter. Transgenic tobacco plants harboring the promoter-beta-glucuronidase (GUS) reporter gene fusion were obtained via Agrobacterium tumefaciens-mediated transformation. Promoter activity was examined with histochemical and quantitative assays. RESULTS: Structural analysis predicted elements responsible for pollen-specific, light-, stress- and hormone-mediated induction within the Bet v 1a promoter. The evaluation of GUS activity in transgenic tobacco plants showed that the Bet v 1a promoter is pollen-specific. Moreover, the Bet v 1a promoter is considered to be the strongest isolated pollen-specific promoter reported to date. It was shown that temperature and abscisic acid positively regulate the activity of the Bet v 1a promoter during pollen development, providing evidence for environment-dependent regulation of the Bet v 1a gene. CONCLUSIONS: A model system to study the effect of environmental factors on the expression of the Bet v 1a gene encoding the major birch allergen in pollen was generated. Additionally, we suggest that this system could be used to search for factors that inhibit the activity of the gene in pollen in order to reduce the potential allergenicity of birch trees.