HIV Infections
Conditions
Brief summary
There is great variability in susceptibility from one person to another, and less than one in a hundred sexual exposures to HIV results in infection. In addition, some recent trial of methods to prevent HIV - including vaccines and microbicides - have actually increased HIV acquisition among trial participants for reasons that we do not fully understand. While we know that immune differences in the genital lining are an important determinant of whether a person is infected after a sexual HIV exposure, we don't know enough about these differences to be able to accurately assess a person's individual HIV risk. Therefore, the development of safe and non-invasive laboratory tests to estimate a person's susceptibility in the genital tract would be useful in clinical studies of new HIV prevention tools.
Detailed description
Heterosexual intercourse is the most common mode of transmission of HIV, but the risk of HIV acquisition after exposure is so low that studies to assess HIV risk must have a huge sample size. The goal of this study is to assess the suitability of a prototype pseudovirus assay to identify early HIV target cells in the female genital tract, using cervical cytobrush samples collected from healthy women, and to optimize assay sensitivity. This novel HIV entry assay may overcome the need for a large sample size by directly measuring how susceptible a person is by using a sample similar to a PAP test. The assay is performed on immune cells obtained from a cervical cytobrush and enables assessment of HIV cell entry within 24 hours. If the assay works, this technique may have the potential to assess the impact of clinical parameters such as stage of menstrual cycle, or sexually transmitted infections and their treatment on HIV susceptibility in the female genital tract. Therefore, the assay may serve as an important monitoring tool in clinical trials of HIV prevention, serving as an invaluable intermediate endpoint to assess HIV acquisition risk, rather than relying on actual participant HIV seroconversion/infection.
Interventions
BIOLOGICALVaginal and blood sample collection
The researchers will obtain approximately 20 mL of blood from participants. Participants will also undergo a pelvic exam where a sample of cells will be collected from the cervix using two small cytobrushes. In addition, a cervicovaginal lavage will be collected using saline.
Sponsors
Unity Health Toronto
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
FEMALE
Age
19 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* women over the age of 18 years
Exclusion criteria
1. pregnant 2. actively menstruating 3. known HIV infection 4. genital ulceration or discharge on history or physical examination
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| CD4 cell infection | Assay to be conducted within 24 hours of sample collection | The absolute number of CD4+ cells per cytobrush that are infected by HIV |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Type of infected CD4 cells | Assay to be conducted within 24 hours of sample collection | Nature of the CD4+ cells that are infected, ie: identification of immune characteristics that are associated with preferential HIV cell entry. Parameters to be assessed include immune activation markers and the expression of HIV coreceptors and integrins. |
Outcome results
None listed