Persistent genital tract HIV-1 RNA shedding after change in treatment regimens in antiretroviral-experienced women with detectable plasma viral load.

OBJECTIVE: To longitudinally assess the association between plasma viral load (PVL) and genital tract human immunodeficiency virus (GT HIV) RNA among HIV-1 infected women changing highly active antiretroviral therapy (HAART) because of detectable PVL on current treatment. METHODS: Women were eligible for the study if they had detectable PVL (defined as two consecutive samples with PVL>1000 copies/mL) and intended to change their current HAART regimen at the time of enrollment. Paired plasma and GT HIV-1 RNA were measured prospectively over 3 years. Longitudinal analyses examined rates of GT HIV-1 RNA shedding and the association with PVL. RESULTS: Sixteen women were followed for a median of 11 visits contributing a total of 205 study visits. At study enrollment, all had detectable PVL and 69% had detectable GT HIV-1 RNA. Half of the women changed to a new HAART regimen with ≥3 active antiretroviral drugs. The probability of having detectable PVL ≥30 days after changing HAART was 0.56 (95% CI: 0.37 to 0.74). Fourteen women (88%) had detectable PVL on a follow-up visit ≥30 or 60 days after changing HAART; and 12 women (75%) had detectable GT HIV-1 RNA on a follow-up visit ≥30 or 60 days after changing HAART. When PVL was undetectable, GT shedding occurred at 11% of visits, and when PVL was detectable, GT shedding occurred at 47% of visits. CONCLUSIONS: Some treatment-experienced HIV-infected women continue to have detectable virus in both the plasma and GT following a change in HAART, highlighting the difficulty of viral suppression in this patient population.

Genital tract HIV-1 RNA shedding among women with below detectable plasma viral load.

OBJECTIVE: Few studies have assessed longitudinal genital tract HIV-1 shedding. We determined patterns of genital tract HIV-1 RNA shedding over time among women with suppressed plasma viral load (PVL) on antiretroviral treatment. METHODS: Paired plasma and genital tract HIV-1 RNA were measured every 4 weeks. Participants were classified as persistent, intermittent, or nonshedders. Longitudinal analysis examined rates of genital tract shedding and the association with PVL, CD4 cell count, and genital tract infections. Markov transition models were used to describe the dynamics of HIV-1 RNA in plasma and genital tract using visit-to-visit transitions from and to detectable and undetectable PVL or genital tract HIV-1 RNA. RESULTS: Fifty-nine women contributed 582 study visits of whom 95 and 98% had below-detectable PVL and genital tract viral load, respectively, at baseline. Thirty-two of 59 women (54%) had detectable HIV-1 RNA at least once in the genital tract. Twenty-two of 59 (37%) women had detectable genital tract HIV-1 RNA during a study visit when PVL was undetectable; 6.8% of the women were persistent shedders, 31% were intermittent shedders, and 45.8% were nonshedders. Sampling three subcompartments increased detection of HIV-1 genital tract viral load compared to sampling a single subcompartment. Overall, genital tract HIV-1 RNA shedding in any subcompartment occurred at about 13% of visits. Shedding in at least one of the three subcompartments occurred at 9% of visits when PVL was undetectable (95% confidence interval 6-14%). CONCLUSION: Women with below-detectable PVL may have less risk of HIV sexual transmission on a population level, but may continue to be infectious on an individual level.

Differences in HIV-1 pol sequences from female genital tract and blood during antiretroviral therapy.

OBJECTIVE: To determine whether HIV-1 replicates locally in the female genital tract during therapy, and to study whether endocervix is the dominant source of virus in cervicovaginal lavage fluid. DESIGN: Sequence analyses of HIV-1 pol were performed from cervicovaginal secretions and blood plasma of HIV-infected women failing antiretroviral therapy with detectable viral load in both compartments, as well as from drug-naive subjects. METHODS: Viral RNA was extracted from cervicovaginal lavage fluid, endocervical secretions collected by Sno-strips, and blood plasma. Population sequencing of HIV-1 pol was performed using cycle sequencing. Drug resistance mutations were analyzed. Phylogenies were constructed based on synonymous positions in the sequences. RESULTS: Resistant virus was detected concordantly in blood and genital tract specimens, consistent with drug selection pressure in both compartments. However, drug-selected mutations often differed in each compartment, and phylogenetic analysis showed differences in virus lineage in these compartments, consistent with local replication in female genital tract. Viruses in cervicovaginal lavage and endocervical secretions were genetically distinguishable, suggesting that endocervix is not the only source of virus found in cervicovaginal lavage. CONCLUSION: These data support the hypothesis that HIV replication is compartmentalized within the female genital tract during antiretroviral therapy, which has implications for pathogenesis and for epidemiologic surveillance of drug-resistant virus.

The protease inhibitor ritonavir inhibits the functional activity of the multidrug resistance related-protein 1 (MRP-1).

BACKGROUND: Efflux pumps situated on the plasma membrane, such as P-glycoprotein (Pgp) and the multidrug resistance related-protein 1 (MRP-1), have been shown to extrude HIV protease inhibitors from the cell. MRP-1 is present on many barrier sites throughout the body, such as the blood-brain and blood-testis interfaces and could reduce the concentration of protease inhibitors in these sanctuary sites for HIV-1 replication. Factors that modulate efflux pump function in vivo are poorly defined. OBJECTIVE: To analyze the inhibitory potential of the anti-retroviral drugs indinavir, amprenavir, ritonavir, lamivudine or zidovudine to modulate MRP-1 function. METHODS: Effect of anti-HIV drugs on the efflux pump activity of MRP-1 was evaluated in the presence of increasing concentrations of human plasma, using UMCC-1/VP cells which stably over-express MRP-1. MRP-1 activity was abrogated by probenecid. The potential of blocking MRP-1 function for an extended (3 day) time period, was also examined in MRP-1 over-expressing cells cultured with either probenecid or the anti-retroviral drugs and a cytotoxic compound (etoposide) that is transported by MRP-1. RESULTS: Ritonavir inhibited the functional activity of MRP-1 similarly to probenecid, as demonstrated by re-sensitization of MRP-1 over-expressing cells to cytotoxic effects of etoposide. Inhibition by ritonavir was inversely related to the concentration of human plasma added to the cells (r2 = 0.89). Other anti-HIV drugs didn't affect the MRP-1 mediated efflux of etoposide. CONCLUSIONS: These data may be exploitable to further improve sanctuary site concentrations of anti-HIV or anti-cancer drugs by using ritonavir as a lead compound to develop more potent MRP-1 inhibitors.