Plasma and cervical viral loads among Ugandan and Zimbabwean women during acute and early HIV-1 infection.

OBJECTIVES: High levels of HIV-1 viremia exist in peripheral blood during acute and early infection; however, data on HIV-1 viral loads in female genital secretions during this period are sparse. DESIGN: Prospective cohort of 188 African women with primary HIV-1 infection. METHODS: HIV-uninfected and infected women were followed quarterly; we tested serial plasma specimens by HIV PCR to estimate infection dates. We used the Loess procedure to estimate the magnitude and timing of viral setpoints in plasma and cervical secretions and generalized estimating equations (GEE) to identify predictors of plasma and cervical viral setpoints. RESULTS: We estimated the mean HIV-1 plasma setpoint to be 4.20 log10 HIV-1 RNA copies/ml [95% confidence interval (CI) 4.04-4.35] at 121 days (95% CI 91-137) from infection; an analogous mean cervical viral setpoint was 1.64 log10 HIV-1 RNA copies/swab (95% CI 1.46-1.82) at 174 days (95% CI 145-194) from infection. Cervical loads were significantly higher (0.7-1.1 log10 copies/swab) during acute infection than subsequently. Subtype D infection, pregnancy, breastfeeding, and older age at the time of infection were associated with higher plasma viral setpoint. Subtype C infection, nonviral sexually transmitted infections, having a partner spending nights away from home, recent unprotected sex, and shorter time since infection were associated with higher cervical HIV-1 loads. Hormonal contraception was not associated with either the HIV-1 plasma setpoint or cervical loads during early infection. CONCLUSION: Cervical HIV-1 viral loads were highest during acute infection and then declined up to 6 months following infection, when a 'setpoint' was attained. The prognostic value of a cervical 'setpoint' on future transmission risk remains unclear.

Sensitive oligonucleotide ligation assay for low-level detection of nevirapine resistance mutations in human immunodeficiency virus type 1 quasispecies.

This study has adapted the oligonucleotide ligation assay (OLA) to probe for low-level nevirapine (NVP) resistance mutations K103N and Y181C in the human immunodeficiency virus type 1 (HIV-1) population of infected mother-infant pairs from Uganda. When NVP is used to prevent perinatal transmission, NVP-resistant HIV-1 clones may be rapidly selected due to a low barrier for mutation and a relatively high level of fitness (compared to that of other drug-resistant HIV-1 clones). Monitoring for even a low frequency of NVP resistance mutations may help predict the success of subsequent treatment or warrant the use of another regimen to prevent transmission in a subsequent pregnancy. The standard OLA was optimized by using nonstandard bases in oligonucleotides to allow promiscuous base pairing and accommodate significant HIV-1 heterogeneity. Radiolabeled as opposed to fluorescently tagged oligonucleotides increased the sensitivity, whereas alteration of the template, oligonucleotides, salt, and thermostable DNA ligase concentrations increased the specificity for the detection of minority codons. This modified OLA is now capable of detecting mutants with the K103N or the Y181C mutation present in an HIV-1 population at a frequency of approximately 0.4% and is at least 10- to 30-fold more sensitive than the original protocol. A cohort of 19 Ugandan mothers who received NVP treatment perinatally were sampled 6 weeks postdelivery. Ten of 19 HIV-1 DNA samples extracted from peripheral blood mononuclear cells had a detectable K103N (0.5 to 44%) or Y181C (0.8 to 92.5%) mutation, but only one plasma HIV-1 RNA sample had a viral population with the Y181C mutation. These findings suggest that OLA is a robust, sensitive, and specific method for the detection of low-frequency drug resistance mutations in an intrapatient HIV-1 population.