Independent levels of cell-free and cell-associated human immunodeficiency virus-1 in genital-tract secretions of clinically asymptomatic, treatment-naive African women

HIV and SIV in Body Fluids: From Breast Milk to the Genitourinary Tract

HIV-1 is present in many secretions including oral, intestinal, genital, and breast milk. However, most people exposed to HIV-1 within these mucosal compartments do not become infected despite often frequent and repetitive exposure over prolonged periods of time. In this review, we discuss what is known about the levels of cell-free HIV RNA, cell-associated HIV DNA and cell-associated HIV RNA in external secretions. Levels of virus are usually lower than contemporaneously obtained blood, increased in settings of inflammation and infection, and decreased in response to antiretroviral therapy. Additionally, each mucosal compartment has unique innate and adaptive immune responses that affect the composition and presence of HIV-1 within each external secretion. We discuss the current state of knowledge about the types and amounts of virus present in the various excretions, touch on innate and adaptive immune responses as they affect viral levels, and highlight important areas for further study.

A randomized clinical trial on the effects of progestin contraception in the genital tract of HIV-infected and uninfected women in Lilongwe, Malawi: Addressing evolving research priorities

Hormonal contraception is central in the prevention of unintended pregnancy; however there are concerns that certain methods may increase the risk of HIV acquisition and transmission. Hormonal contraceptives may modify the genital mucosa in several ways, however the mechanisms are incompletely understood. Few studies have examined genital HIV shedding prospectively before and after initiation of hormonal contraception. The effects of hormonal contraception on genital HIV shedding in the setting of antiretroviral therapy (ART) are also unknown. We designed a pilot clinical trial in which HIV-infected and uninfected women were randomized to either depot medroxyprogesterone acetate (DMPA) injectable or levonorgestrel (LNG) implant in Lilongwe, Malawi. The objectives were to: 1) assess the effect and compare the impact of type of progestin contraception (injectable versus implant) on HIV genital shedding among HIV-infected women, 2) assess the effect and compare the impact of type of progestin contraception on inflammatory/immune markers in the genital tract of both HIV-infected and uninfected women, and 3) assess the interaction of progestin contraception and ART by examining contraceptive efficacy and ART efficacy. An additional study aim was to determine the feasibility and need for a larger study of determinants of HIV transmissibility and acquisition. As injectable contraception is widely used in many parts of the world with high HIV prevalence, this study will provide important information in determining the need for and feasibility of a larger study to address these questions that can impact the lives of millions of women living with or at risk for HIV.

Contraceptive methods and risk of HIV acquisition or female-to-male transmission

Effective family planning with modern contraception is an important intervention to prevent unintended pregnancies which also provides personal, familial, and societal benefits. Contraception is also the most cost-effective strategy to reduce the burden of mother-to-child HIV transmission for women living with HIV who wish to prevent pregnancy. There are concerns, however, that certain contraceptive methods, in particular the injectable contraceptive depot medroxyprogesterone acetate (DMPA), may increase a woman's risk of acquiring HIV or transmitting it to uninfected males. These concerns, if confirmed, could potentially have large public health implications. This paper briefly reviews the literature on use of contraception among women living with HIV or at high risk of HIV infection. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) recommendations place no restrictions on the use of hormonal contraceptive methods by women with or at high risk of HIV infection, although a clarification recommends that, given uncertainty in the current literature, women at high risk of HIV who choose progestogen-only injectable contraceptives should be informed that it may or may not increase their risk of HIV acquisition and should also be informed about and have access to HIV preventive measures, including male or female condoms.

Mycoplasma genitalium is associated with increased genital HIV type 1 RNA in Zimbabwean women

BACKGROUND

Mycoplasma genitalium is a common sexually transmitted infection associated with human immunodeficiency virus (HIV) infection. Some studies suggest that M. genitalium may increase the risk of HIV acquisition. However, results have been inconsistent, and this association has never been examined longitudinally.

METHODS

Stored endocervical samples from a longitudinal cohort study of 131 Zimbabwean women in whom HIV-1 seroconversion recently occurred were tested for detection and quantity of M. genitalium using polymerase chain reaction analysis. The associations between M. genitalium and the detection and quantity of genital HIV type 1 (HIV-1) RNA, the detection and quantity of plasma HIV-1 RNA, and the CD4(+) T-cell count was analyzed using mixed-effects regression analysis.

RESULTS

M. genitalium was detected in 10.5% of stored specimens (44 of 420), and infection persisted for up to 300 days. M. genitalium was independently associated with detection of genital HIV-1 RNA (adjusted odds ratio, 2.67; 95% confidence interval, .99-7.20), after adjustment for plasma viral load, viral set point, CD4(+) T-cell count, herpes simplex virus type 2 detection, and gonorrhea. There was no evidence of an association between M. genitalium detection or quantity and either plasma HIV-1 RNA load or CD4(+) T-cell count.

CONCLUSIONS

The growing evidence for an association between M. genitalium and HIV genital shedding and the high prevalence and persistence of M. genitalium in this population suggest that further research into this association is important. Consideration of the cost-effectiveness of M. genitalium screening interventions may be warranted.

Associations between genital tract infections, genital tract inflammation, and cervical cytobrush HIV-1 DNA in US versus Kenyan women

Cervical shedding of HIV-1 DNA may influence HIV-1 sexual transmission. HIV-1 DNA was detected in 250 (80%) of 316 and 207 (79%) of 259 cervical cytobrush specimens from 56 US and 80 Kenyan women, respectively. Plasma HIV-1 RNA concentration was associated with increased HIV-1 DNA shedding among US and Kenyan women. Kenyan women had higher cervicovaginal concentrations of proinflammatory interleukins (IL)-1β, IL-6, IL-8, and anti-inflammatory secretory leukocyte protease inhibitor compared with US women (all P < 0.01). HIV-1 DNA shedding was associated with increased concentrations of IL-1β and IL-6 and lower secretory leukocyte protease inhibitor among US women but not Kenyan women.

Residual HIV-1 RNA and HIV-1 DNA production in the genital tract reservoir of women treated with HAART: the prospective ANRS EP24 GYNODYN study

BACKGROUND

The female genital tract constitutes a reservoir for HIV providing active production of both cell-free HIV RNA and cell-associated DNA within the cervicovaginal secretions. The objective of this study was to prospectively assess residual HIV-1 RNA and HIV-1 DNA production in the genital tract reservoir of women initiating HAART over an 18-month period.

METHODS

Paired blood and cervicovaginal lavage samples were collected at inclusion and 1, 6, 12 and 18 months after HAART initiation, in 23 women in first-line HAART and six women in virological failure, for measurement of HIV-1 RNA and HIV-1 DNA shedding and/or drug concentrations.

RESULTS

A dramatic decrease of HIV-1 RNA and HIV-1 DNA occurred in both blood and cervicovaginal samples over the first 6 months on HAART, followed by a shelf up to 18 months, independently of the drugs' genital pharmacokinetics. While cervicovaginal HIV-1 RNA became undetectable in >90% of women from 6 months on HAART, genital HIV-1 DNA remained frequently detectable (27-50%). Nearly 40% of women with sustained undetectable plasma HIV-1 RNA after 6-18 months on HAART harboured transient HIV-1 RNA (15% of women) or HIV-1 DNA (31% of women) in their genital secretions.

CONCLUSIONS

Low-level cervicovaginal HIV-1 shedding is frequently evidenced in HAART-treated women with transient HIV-1 RNA and persistent HIV-1 DNA despite a systemic control of viral replication, resulting in possible residual genital infectivity.

Low-dose combined oral contraceptive and cervicovaginal shedding of human immunodeficiency virus

BACKGROUND

The role of low-dose oral contraceptives on HIV cervicovaginal shedding among HIV-positive women is controversial.

STUDY DESIGN

We evaluated the effect of low-dose oral contraceptives on HIV cervicovaginal shedding in a cohort of 285 HIV-seropositive women followed for a median of 20 months. A sensitive, competitive polymerase chain reaction (cPCR) and a reverse transcription PCR (cRT-PCR) were applied for the quantification of HIV-associated and cell-free RNA and proviral DNA in cervicovaginal cells, as well as HIV-RNA in plasma.

RESULTS

In multivariable logistic generalized estimating equations, plasma viral load >100 copies/mL (OR=1.81, 95% CI=1.3-2.53) and bacterial vaginosis (OR=1.49, 95% CI=1.1-2.02) were associated with an increased risk of HIV-1 DNA shedding, whereas current use of oral contraceptive was associated with a reduced risk (OR=0.55, 95% CI=0.33-0.92). Oral contraceptives were also associated with a reduction of risk (OR=0.38, 95% CI=0.21-0.69) of cell-associated but not cell-free HIV-1 RNA.

CONCLUSIONS

In HIV-positive women with low levels of HIV viremia, low-dose oral contraceptives were associated with a modest but significant reduction of HIV-1 DNA and cell-associated HIV-1 RNA genital shedding.

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.

Trichomonas vaginalis treatment reduces vaginal HIV-1 shedding

BACKGROUND

Vaginal HIV-1 shedding has been associated with Trichomonas vaginalis (TV) infection and could play a role in HIV transmission. The purpose of the study was to examine if effective TV treatment reduces the presence of vaginal HIV-1 RNA.

METHODS

TV+ women attending an HIV outpatient clinic in New Orleans, LA, who resolved infection (n = 58) and TV-negative controls (n = 92), matched on antiretroviral therapy (ART) were examined and interviewed at baseline, 1, and 3 months. TV status was tested by culture and the amount of cell free HIV-1 RNA in the vaginal fluids was determined by the Amplicor HIV-1 Monitor ultrasensitive assay.

RESULTS

: Most women (81.3%) were black and the mean age was 37.5 (SD 8.7). At baseline, 46.0% had plasma HIV-1 RNA >/=10,000 copies/mL, 26.4% had CD4<200 cells/muL, 54.7% were taking ART, and only 26.0% had detectable HIV-1 RNA in their vaginal fluids. TV-positive women who were effectively treated for TV were less likely to shed HIV vaginally at 3-months post-treatment compared to baseline (R.R. 0.34, 95% CI: 0.12-0.92, P = 0.03), whereas there was no change for TV-negative women.

CONCLUSION

This study provides additional support that reducing TV infection among HIV-positive women may have an impact on the prevention of HIV transmission. Reasons for the delayed treatment effect and the effect on cervical shedding need further investigation.

Genetic and phenotypic features of blood and genital viral populations of clinically asymptomatic and antiretroviral-treatment-naive clade a human immunodeficiency virus type 1-infected women

In the present study, we assessed whether human immunodeficiency virus type 1 (HIV-1) genetic compartmentalization was associated with phenotypic CCR5 (R5) or CXCR4 (X4) coreceptor usage differences between the systemic and the genital viral populations. Four clinically asymptomatic and treatment-naïve clade A HIV-1-infected patients were selected from a cohort of 274 African women, because they were free of all the biological cofactors known to modify the kinetics of viral production in the genital tract. HIV RNA envelope sequences (V1 to V3) derived from plasma and cervicovaginal secretions (CVS) were amplified, subcloned, and sequenced. CCR5 or CXCR4 coreceptor usage was determined by production of recombinant viral particles, followed by single-cycle infection assays of indicator cell lines, using the tropism recombinant test. In these four selected patients, CVS-derived sequences appeared to be genetically distinct from blood-derived sequences (P < or = 0.001). Two patients were found to harbor virus populations with only the R5 phenotype in both compartments, whereas viruses using CXCR4 in addition to CCR5 were detected in two other patients. In particular, one woman harbored genital virus populations with mixed R5 and X4 phenotypes associated with peripheral blood populations with only the R5 phenotype. These results demonstrate genetic compartmentalization of HIV between the plasma and genital secretions of clinically asymptomatic, treatment-naïve, clade A-infected women. Also, for one patient, we report phenotypic coreceptor usage differences between the systemic (R5) and genital (R5/X4) viral populations. These features may be critical for the development of further mucosal vaccines, therapies, or new preventive strategies to block heterosexual transmission.

The spreading of HIV-1 infection in the human organism is caused by fractalkine trafficking of the infected lymphocytes—a review, hypothesis and implications for treatment

The reviews on HIV-1/AIDS [1-8] highlighted the mechanism by which HIV-1 virions utilize dendritic cells (DCs) for transport from the genitals, the portal of virus infection, to the draining lymph nodes where DCs carry HIV-1 virions and present viral antigens by HLA class I and II to CD4(+) T cells. Interaction of the T cells with viral antigens presented by HLA class II molecules polarizes them to become Th2 cells, the targets of HIV-1 infection and producers of HIV-1 progeny virions. The T cells which interact with viral antigen presented by HLA class I polarize to become Th1 cells, which stimulate the CD8(+) T cell precursors to develop into antiviral cytotoxic T cells. In addition, HIV-1 virions shed gp120 glycoprotein molecules which bind to IgE immunoglobulin molecules bound to FCepsilonRI+ innate system cells (basophils, mast cells and monocytes) and induce them to release large amounts of Th2 cytokines (IL-4, IL-5, IL-10, IL-13), thereby creating an allergy-like condition. The present review attempts to define the role of chemokine receptors like CCR5 and CXCR4, and especially fractalkine receptor CX3CR1 in the trafficking of lymphocytes in healthy individuals and HIV-1/AIDS patients. The role of chemokine receptors as co-receptors for HIV-1 virion gp120 glycoprotein has been defined, but the role of fractalkine and fractalkine receptor has been clarified only recently [9-19]. In healthy individuals fractalkine is expressed by blood vessel endothelial cells and the CX3CR1 receptors are expressed on leukocytes that migrate in the peripheral blood in the direction of increased fractalkine concentration. In HIV-1/AIDS patients the virus-infected CD4(+) Th2 cells migrate to organs that harbor the adaptive immune system cells in the thymus, genitals, gastrointestinal tract, and to the brain. A most significant finding which revealed the importance of the human CX3CR1 gene expression to the progression of the infection to the stage of AIDS was recently reported by Faure and collaborators [20, 21] who showed that the delayed or rapid progression to AIDS was affected in HIV-1-infected individuals who had inherited a fractalkine receptor gene with the polymorphisms V249I or T280M, respectively, located in the sixth and seventh transmembrane domains of CX3CR1 protein. The T280M mutation in the CX3CR1 gene caused a rapid progression to AIDS, while in patients with the V249I mutation progression to AIDS was much slower. These studies led to the idea that it might be possible to slow or prevent HIV-1/AIDS progression in HIV-1 patients by treating them with fractalkine antagonists that will bind to and inhibit the activity of the fractalkine receptor. It is hypothesized that treatment of HIV-1/AIDS patients with a combination of fractalkine antagonists, IL-4 antagonist IL-4delta2 and the adjuvant CpG ODN induced release of type I IFN from PDF, and may inhibit HIV-1 infection, especially in HAART-treated patients infected with drug-resistant HIV-1 mutants due to prevention of the availability of immune cells needed for the viral evasion of the immune response. The hypothesis implies that the advantage of the suggested mode of treatment of HIV-1-infected people is prevention of cellular processes that are used by the viral protein to cause immunodeficiency, and prevention of HIV-1 replication without induction of resistant mutants.

Quantification of genital human immunodeficiency virus type 1 (HIV-1) DNA in specimens from women with low plasma HIV-1 RNA levels typical of HIV-1 nontransmitters

Studies of human immunodeficiency virus type 1 (HIV-1) transmission suggest that genital HIV-1 RNA and DNA may both be determinants of HIV-1 infectivity. Despite its potential role in HIV-1 transmission, there are limited quantitative data on genital HIV-1 DNA. Here we validated an in-house real-time PCR method for quantification of HIV-1 DNA in genital specimens. In reactions with 100 genomes to 1 genome isolated from a cell line containing one HIV-1 provirus/cell, this real-time PCR assay is linear and agrees closely with a commercially available real-time PCR assay specific for a cellular housekeeping gene. In mock genital samples spiked with low numbers of HIV-1-infected cells such that the expected HIV-1 DNA copy number/reaction was 100, 10, or 5, the average copy number/reaction was 80.2 (standard deviation [SD], 28.3), 9.1 (SD, 5.4), or 3.1 (SD, 2.1), respectively. We used this method to examine genital HIV-1 DNA levels in specimens from women whose low plasma HIV-1 RNA levels are typical of HIV-1 nontransmitters. The median HIV-1 DNA copy number in endocervical secretions from these women (1.8 HIV-1 DNA copies/10,000 cells) was lower than that for women with higher plasma HIV-1 RNA levels (16.6 HIV-1 DNA copies/10,000 cells) (P=0.04), as was the median HIV-1 DNA copy number in vaginal secretions (undetectable versus 1.0 HIV-1 DNA copies/10,000 cells). These data suggest that women with low plasma HIV-1 RNA and thus a predicted low risk of HIV-1 transmission have low levels of genital HIV-1 cell-associated virus. The assay described here can be utilized in future efforts to examine the role of cell-associated HIV-1 in transmission.

In vitro microbicidal activity of the nonnucleoside reverse transcriptase inhibitor (NNRTI) UC781 against NNRTI-resistant human immunodeficiency virus type 1

The nonnucleoside reverse transcriptase inhibitor (NNRTI) UC781 is under development as a microbicide to prevent sexual transmission of the human immunodeficiency virus type 1 (HIV-1). However, NNRTI-resistant HIV-1 is increasingly prevalent in the infected population, and one of the concerns for NNRTI-based microbicides is that they will be ineffective against drug-resistant virus and may in fact selectively transmit NNRTI-resistant virus. We evaluated the microbicidal activity of UC781 against UC781-resistant (UCR), efavirenz-resistant (EFVR), and nevirapine-resistant (NVPR) strains in a variety of microbicide-relevant tests, including inactivation of cell-free virus, inhibition of cell-to-cell HIV-1 transmission, and the ability of UC781 pretreatment to protect cells from subsequent infection in the absence of exogenous drug. UC781 was 10- to 100-fold less effective against NNRTI-resistant HIV-1 compared to wild-type (wt) virus in each of these tests, with UC781 microbicidal activity against the various virus strains being wt > or = NVPR > UCR > or = EFVR. Breakthrough experiments using UC781-pretreated cells and mixtures of wt and NNRTI-resistant HIV-1 showed that UC781-pretreatment selected for NNRTI-resistant HIV-1. However, the efficacy of UC781 was dose dependent, and 25 microM UC781 provided essentially equivalent microbicidal activity against NNRTI-resistant and wt virus. The amount of UC781 in topical microbicide formulations under current development is approximately 100-fold greater than this concentration, so transmission of NNRTI-resistant virus may not be an issue at these microbicide formulation levels of UC781. Nonetheless, the reduced microbicidal activity of UC781 against NNRTI-resistant HIV-1 suggests that additional antiviral agents should be included in NNRTI-based microbicide formulations.

Real-time PCR quantification of genital shedding of herpes simplex virus (HSV) and human immunodeficiency virus (HIV) in women coinfected with HSV and HIV

The accuracy and usefulness of laboratory-developed real-time PCR procedures using a Light Cycler instrument (Roche Diagnostics) for detecting and quantifying human immunodeficiency virus type 1 (HIV-1) RNA and DNA as well as herpes simplex virus type 1 (HSV-1)/HSV-2 DNA in cervicovaginal secretions from women coinfected with HIV and HSV were evaluated. For HIV-1, the use of the NEC152 and NEC131 primer set and the NEC-LTR probe in the long terminal repeat gene allowed us to detect accurately the majority of HIV-1 subtypes of group M circulating in sub-Saharan Africa, including subtypes A, B, C, D, and G as well as circulating recombinant forms 02 and 11. The detection threshold of real-time PCR for HIV in cervicovaginal lavage samples was 5 copies per assay for both RNA and DNA; the intra- and interassay coefficients of variation of C(T) values were 1.30% and 0.69% (HIV-1 RNA) and 1.84% and 0.67% (HIV-1 DNA), respectively. Real-time PCR for HSV using primers and probe targeting the HSV DNA polymerase gene allowed both detection and quantification of HSV DNA and also differentiation between HSV-1 and HSV-2 genotypes. The detection threshold of real-time PCR for HSV was 5 copies per assay; the intra- and interassay coefficients of variation of C(T) values were 0.96% and 1.49%, respectively. Both manual and automated silica-based procedures were appropriate for combined extraction of HIV and HSV genomes from female genital secretions. Taken together, these findings indicate that real-time PCR may be used as a unique nucleic acid amplification procedure to detect and quantify HIV and HSV genomes in cervicovaginal secretions and thus to assess at reduced costs the genital shedding of both viruses in women included in intervention studies.

Cervical intraepithelial neoplasia and cervicovaginal shedding of human immunodeficiency virus

OBJECTIVE

Although human immunodeficiency virus (HIV) infection is a well-known risk factor for cervical intraepithelial neoplasia (CIN), the influence of CIN on cervicovaginal shedding of HIV is poorly understood. The purpose of this study was to evaluate the association between CIN and the shedding of HIV in cervicovaginal secretions.

METHODS

Two hundred sixteen HIV-seropositive patients were followed up by Pap test, colposcopy, and targeted cervical biopsies for a median of 16 months (range 0-94). A diagnosis of low-grade CIN was made on the basis of Pap test and either colposcopy or cervical biopsy. High-grade CIN was diagnosed solely on the basis of cervical biopsy. At each follow-up visit, we measured HIV-1 RNA in plasma, proviral HIV-1 DNA, and cell-associated and cell-free HIV-1 RNA in cervicovaginal secretion by competitive polymerase chain reaction (cRT-PCR) and reverse transcriptase PCR. The univariable and multivariable associations between the occurrence of CIN and the presence of HIV-related nucleic acids in cervicovaginal secretions were evaluated with logistic generalized estimating equations.

RESULTS

Overall, at enrollment and during the follow-up period, a diagnosis of either low-grade or high-grade CIN was made in 14.4% (99/689) and 6.7% (46/689) of the visits, respectively. The presence of measurable levels of plasma HIV-1 RNA was a significant risk factor for the detection of cervicovaginal HIV-1 DNA (odds ratio [OR] 1.86, 95% confidence interval [CI] 1.32-2.61, P < .001), cell-associated (OR 1.69, 95% CI 1.18-2.43, P = .004), and cell-free HIV-1 RNA (OR 1.84, 95% CI 1.28-2.63, P = .001). After the adjustment for the effect of plasma HIV-1 RNA, CD4(+) positive cell counts less than 200 mm(3), and bacterial vaginosis, the detection of cell-associated (OR 1.75, 95% CI 1.23-2.49, P = .006) and cell-free HIV-1 RNA (OR 2.0, 95% CI 1.39-2.87, P = .001) in cervicovaginal secretions was significantly associated with the diagnosis of CIN.

CONCLUSION

The presence of CIN lesions is a significant risk factor for genital HIV shedding. Given the high prevalence of cervical disease among HIV-positive women, this finding could have important epidemiological implications in both heterosexual and perinatal transmission of HIV.

LEVEL OF EVIDENCE

II-2.

Transmission of HIV-1 drug resistance

BACKGROUND

The use of highly-active anti-retroviral therapy (HAART) for treating HIV infections is increasing. Recent studies have demonstrated that HAART is improving both the length and quality of life in HIV-infected patients. Resistant strains of HIV arise when drug adherence is poor. This can lead to the transmission of drug-resistant strains of HIV to susceptible individuals. This can lead to suboptimal first-line therapy, if the resistance profile of the transmitted virus is unknown.

OBJECTIVES

To review the mechanisms of how drug resistance arises; the methods used to characterise drug resistance; the problems arising with compliance leading to the development of drug-resistant HIV strains; the evidence for the incidence, prevalence and trends in the transmission of resistant HIV strains in different risk groups; and the evidence of suboptimal response to first-line therapy where transmission of a resistant HIV strain has occurred. On the basis of this, a case is presented for the routine resistance testing of all newly diagnosed HIV-infected individuals.

STUDY DESIGN

Literature review.

RESULTS AND CONCLUSIONS

There is evidence, though limited at present, that transmission of drug-resistant HIV strains can lead to suboptimal response to first-line therapy in newly diagnosed HIV-infected individuals. As the use of HAART can only increase in the future, and compliance will always be a problem in such HAART-treated patients, baseline resistance testing should become a routine part of their management.