Background
Polymorphisms in CYP2B6 are known to predict increased steady-state plasma concentrations of efavirenz. We characterized relationships between genetic polymorphisms and plasma efavirenz concentrations among 45 Haitians who initiated antiretroviral therapy in Port-au-Prince.
Methods
An observational study characterized relationships between clinical factors, pharmacokinetics, and treatment response among antiretroviral-naïve patients initiating once-daily efavirenz plus twice-daily AZT/3TC. Plasma drug concentrations were determined at weeks 2 and 4. Drug doses were directly observed by field workers or designated family members. We retrospectively characterized relationships between efavirenz concentrations and 50 single nucleotide polymorphisms in CYP2B6, and several polymorphisms in CYP2A6, CYP3A4, CYP3A5 and ABCB1.
Results
Plasma for efavirenz assay was obtained 13.9 ±1.6 hours (mean ± SD) post-dose. As expected, CYP2B6 516G→T was associated with increased plasma efavirenz concentrations (Spearman’s rho=0.71, P<0.0001), as were 10 polymorphisms in linkage disequilibrium with 516G→T. Distinct CYP2B6 polymorphisms were associated with decreased plasma efavirenz concentrations (greatest absolute rho=0.48, P=0.0008). Associations were replicated by results from a recent pharmacokinetic study involving 34 healthy, HIV-negative African Americans.
Conclusions
Relatively frequent CYP2B6 polymorphisms may predict decreased plasma efavirenz exposure in patients of African descent. If replicated in other cohorts, the implications of these novel associations for treatment response warrant further study.
With global efforts to scale up the prevention of mother-to-child transmission services and pediatric antiretroviral therapy, there is an urgent need to introduce a simple, low-cost infant human immunodeficiency virus test in the field. We postulated that the p24 antigen capture enzyme-linked immunosorbent assay could be simplified by eliminating signal amplification without compromising diagnostic accuracy.
Objective To assess outcomes after antiretroviral therapy (ART) in adolescents and youth in Haiti, a country with a generalized epidemic of infection with HIV-1. Methods An assessment was made of survival, plasma HIV-1 ribonucleic acid (RNA) concentrations and HIV-1 drug resistance patterns after 12 months of ART in patients aged 13-25 years who presented to a clinic in Port-au-Prince, Haiti, with AIDS between 1 March 2003 and 31 December 2005. Participants received ART in accordance with WHO guidelines. Kaplan-Meier analysis was used to estimate survival probabilities and their 95% confidence intervals (CI) for the period from ART initiation to death. Findings Of a total of 146 patients, 96 (66%) were female; the median CD4+ T-cell count at baseline was 129 cells/ml. By Kaplan-Meier analysis, 13% of the patients had died at 12 months, 17% at 24 months and 20% at 36 months. A plasma HIV-1 RNA concentration ≥ 50 copies/ml was seen in 40 (51%) of 79 patients 12 months after treatment initiation and was associated with poor ART adherence. Among 29 patients with > 1000 copies/ml at 12 months, resistance mutations to non-nucleoside reverse transcriptase inhibitors (NNRTIs) were detected in 23 cases (79%); to both NNRTIs and lamivudine in 21 (72%) cases; and to NNRTIs, lamivudine and other nucleoside reverse transcriptase inhibitors in 10 (35%) cases. One hundred and six participants (73%) reported sexual intercourse without condoms, and 35 of the 96 women (36%) were pregnant during follow-up. Conclusion Adolescents and youth with AIDS receiving ART are at risk of virologic failure and disease progression and can therefore transmit HIV-1 to sexual partners and infants. Strategies to target the special needs of this age group are urgently needed.
Dengue is endemic to Haiti but not recognized as an important illness in the autochthonous population. To evaluate the prevalence of antibodies to dengue virus (DENV), serum samples from infants and young children 7–36 months of age (n = 166) were assayed by plaque reduction neutralization assays to each DENV serotype. Dengue virus serotype 1 had infected 40% of this study population, followed by serotype 2 (12%), serotype 3 (11%), and serotype 4 (2%). Fifty-three percent of infants and young children less than 12 months of age had already experienced DENV infection, and the seroprevalence of antibody to DENV increased to 65% by 36 months. Heterotypic antibody responses were an important component of the total dengue immunity profile.
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