Evidence of reduced treatment adherence among HIV infected paediatric and adolescent populations in Nairobi at the onset of the UNAIDS Universal Test and Treat Program.

OBJECTIVE: We conducted a retrospective cohort study to evaluate the efficacy of the World Health Organization (WHO) "Universal Test and Treat" (UTT) policy, initiated in Kenya in September 2016. Under this policy, every human immunodeficiency virus (HIV)-infected person should be initiated on antiretroviral therapy (ART). We compared intra- and inter-group viral suppression and ART adherence rates for pre-UTT (initiated on ART in March-August 2016) and UTT groups (initiated in September 2016). The study was conducted in a community outreach Program in Nairobi with 3500 HIV-infected children enrolled. RESULTS: 122 children and adolescents were initiated on first-line ART pre-UTT, and 197 during the UTT period. The 6 month viral suppression rate was 79.7% pre-UTT versus 76.6% UTT (P < 0.05). Suboptimal adherence was higher in the UTT than pre-UTT period (88 of 197, 44.7% and 44 of 122, 34%; P < 0.001). The decrease in adherence was greater among orphans (91.7% pre-UTT and 87.2% UTT, P = 0.001) and children 11-18 years. Our results show that successful implementation of the UTT policy in Africa is challenged by an increased risk of suboptimal adherence. There is a need to develop extra strategies to support adherence, especially among orphans and teenagers.

Multiple U2AF65 binding sites within SF3b155: thermodynamic and spectroscopic characterization of protein-protein interactions among pre-mRNA splicing factors.

Essential, protein-protein complexes between the large subunit of the U2 small nuclear RNA auxiliary factor (U2AF65) with the splicing factor 1 (SF1) or the spliceosomal component SF3b155 are exchanged during a critical, ATP-dependent step of pre-mRNA splicing. Both SF1 and the N-terminal domain of SF3b155 interact with a U2AF homology motif (UHM) of U2AF65. SF3b155 contains seven tryptophan-containing sites with sequence similarity to the previously characterized U2AF65-binding domain of SF1. We show that the SF3b155 domain lacks detectable secondary structure using circular dichroism spectroscopy, and demonstrate that five of the tryptophan-containing SF3b155 sites are recognized by the U2AF65-UHM using intrinsic tryptophan fluorescence experiments with SF3b155 variants. When compared with SF1, similar spectral shifts and sequence requirements indicate that U2AF65 interactions with each of the SF3b155 sites are similar to the minimal SF1 site. However, thermodynamic comparison of SF1 or SF3b155 proteins with minimal peptides demonstrates that formation the SF1/U2AF65 complex is likely to affect regions of SF1 beyond the previously identified, linear interaction site, in a remarkably distinct manner from the local U2AF65 binding mode of SF3b155. Furthermore, the complex of the SF1/U2AF65 interacting domains is stabilized by 3.3 kcal mol-1 relative to the complex of the SF3b155/U2AF65 interacting domains, consistent with the need for ATP hydrolysis to drive exchange of these partners during pre-mRNA splicing. We propose that the multiple U2AF65 binding sites within SF3b155 regulate conformational rearrangements during spliceosome assembly. Comparison of the SF3b155 sites defines an (R/K)nXRW(DE) consensus sequence for predicting U2AF65-UHM ligands from genomic sequences, where parentheses denote residues that contribute to, but are not required for binding.