Long-term clinical, virological and immunological outcomes following planned treatment interruption in HIV-infected children.

OBJECTIVES: Planned treatment interruption (PTI) of antiretroviral therapy (ART) in adults is associated with adverse outcomes. The PENTA 11 trial randomized HIV-infected children to continuous ART (CT) vs. CD4-driven PTIs. We report 5 years' follow-up after the end of main trial. METHODS: Post-trial, all children resumed ART. Clinical, immunological, virological and treatment data were collected annually. A sub-study investigated more detailed immunophenotype. CT and PTI arms were compared using intention-to-treat. Laboratory parameters were compared using linear regression, adjusting for baseline values; mixed models were used to include all data over time. RESULTS: In all, 101 children (51 CT, 50 PTI) contributed a median of 7.6 years, including 5.1 years of post-trial follow-up. Post-trial, there were no deaths, one pulmonary tuberculosis and no other CDC stage B/C events. At 5 years post-trial, 90% of children in the CT vs. 82% in the PTI arm had HIV RNA < 50 copies/mL (P = 0.26). A persistent increase in CD8 cells was observed in the PTI arm. The sub-study (54 children) suggested that both naïve and memory populations contributed to higher CD8 cells following PTI. Mean CD4/CD8 ratios at 5 years post-trial were 1.22 and 1.08 in CT and PTI arms, respectively [difference (CT - PTI) = -0.15; 95% CI: -0.34-0.05), P = 0.14]. The sub-study also suggested that during the trial and at early timepoints after the end of the trial, reduction in CD4 in the PTI arm was mainly from loss of CD4 memory cells. CONCLUSIONS: Children tolerated PTI with few long-term clinical, virological or immunological consequences.

Development of a one-step immunochromatographic strip test for the rapid detection of nevirapine (NVP), a commonly used antiretroviral drug for the treatment of HIV/AIDS.

Currently, high-performance liquid chromatographic (HPLC) methods are mainly used to measure antiretroviral plasma concentrations in HIV-infected patients. Although the utility of routine therapeutic drug monitoring (TDM) as an additional tool to optimize long-term antiretroviral therapy is unclear, if TDM is to be widely used, the availability of simple, cheap and reliable methods for the measurement of antiretroviral drug levels are needed, particularly in resource-limited settings. In this study, an immunochromatograhic (IC) strip test to detect the presence of nevirapine (NVP) in body fluids has been developed. Antiserum to NVP was first raised in rabbits by immunization against NVP chemically conjugated with bovine serum albumin, and subsequently validated by Western immunoblotting and competitive indirect ELISA. The partially purified anti-NVP antibodies were conjugated with colloidal gold particles. The conjugation of the colloidal gold and polyclonal antibodies was monitored by UV-vis spectroscopy, while transmission electron microscopy images were used to characterize the particle size and shape of the conjugates. The resulting colloidal gold conjugates were used for the production of an IC strip test to detect nevirapine in human plasma. Preliminary assessment suggests no-cross reactivity of the NVP polyclonal antibodies but assessment of plasma samples from HIV-infected patients receiving HAART needs to be conducted. This assay could potentially be used for drug monitoring as part of the clinical care of HIV infected patients.

Decreased telomerase activity is not a reliable indicator of chemosensitivity in testicular cancer cell lines.

Telomere stabilisation is a critical step in tumorigenesis and telomerase, an enzyme which counteracts telomeric DNA loss, is active in most tumours. Conflicting evidence has been published concerning the potential use of telomerase activity as a measurement of drug-induced tumour cell killing. In this study, the time courses of telomerase loss and induction of apoptosis were investigated in two testicular cell lines, Susa CP and 833 K, following 4-h exposure to cisplatin, melphalan or doxorubicin. Telomerase activity was only affected in both cell lines at 20 h following exposure to high concentrations of cisplatin (100x the drug concentrations causing 50% growth inhibition (IC(50) values)). The time course of melphalan-induced telomerase loss, which was again only apparent at 100x IC(50) concentrations, varied between the cell lines and doxorubicin (100x IC(50)) did not induce telomerase loss in either of the cell lines. Importantly, the levels and rates of appearance of apoptotic cells (nuclear morphology and annexin V staining) were similar for all three drugs in both cell lines; i.e. cisplatin, melphalan and doxorubicin (100x IC(50)) caused similar frequencies of apoptosis in Susa CP cells at 24 h whereas telomerase activities were 65, 123 and 96% of the control, respectively. The possibility that telomerase activity was lost following cisplatin treatment through a direct interaction of cisplatin with telomerase was discounted. Additionally, the relative levels of the RNA component of telomerase (hTR) and mRNA for the telomerase catalytic subunit (hTERT) were not related to the observed decreases in telomerase activity. These data indicate that telomerase activity is not a reliable indicator of chemosensitivity in human testicular cancer cells. Furthermore, cisplatin-induced loss of telomerase activity is not due to a direct reaction with the enzyme or decreased hTR levels.