HIV symposium Flashcards

Question

What is U=U

Answer 1

Undetectable=Untransmittable ART is now so effective that those who are treated and have an undetectable viral load (<200 copies) have levels of virus that are untransmissible, even if having sex without condoms. This is sometimes referred to as U=U. The Swiss Statement 2008 Partner study - zero transmissions after >58,000 episodes sex without condoms when viral load was undetectable <200

Answer 2

Aim for 90% of new diagnoses to be taking ARVs by 90 daysAim for 98-100% PLWH to be taking effective treatmentAim for 100% PLWH have undetectable viral loads

Answer 3

Pre-exposure prophylaxis (or PrEP) is when people at very high risk of HIV take daily HIV medicines to reduce the chances of getting infected It works – trials showed 86% effective, but actually 100% for those who took it Historical lack of availability on NHS… Truvada (tenofovir/emtricitabine)

Answer 4

``` 10,000 patients (then 13,000, now 26,000) 3 years Generic Truvada – daily or event based GUM clinics across UK Open for recruitment ```

Answer 5

HIV testing Sexually transmitted infection treatment - 40% reduction (1) Circumcision - South Africa, Kenya, Uganda - 58% reduction

Answer 6

Most of the pathogens that cause the deaths of large numbers of people are those of mucosal surfaces or enter the body through these routes. The genitourinary, rectal and oral mucosa are the mucosal HIV transmission routes. An effective vaccine that can induce both systemic and local mucosal immunity is generally accepted as a major means of protection against mucosal HIV transmission and AIDS.

Answer 7

CD4 T cells are the main host cells for HIV. Entry: CD4/gp120 & CXCR4/CCR5

Answer 8

Activated CD4 T-cells are primary targets for infection. Activated CD4 T cells in the terminal ileum are CCR5+ HIV can use CCR5 (‘R5 viruses’) CXCR4 (‘X4 viruses’) Or both (‘R5X4 viruses’)

Answer 9

During primary HIV infection (mostly R5), effector CD4 T cells are eliminated rapidly owing to their high expression of CCR5 and their highly activated state, which supports lytic viral replication. Although CD4 T-cells are essentially depleted from the effector lymphoid tissues, most of the CD4 T cells residing in the inductive lymphoid tissues are spared owing to their lack of CCR5 expression.

Answer 10

R5 viruses are the strains most commonly transmitted sexually. This is in agreement with the high resistance to infection of individuals lacking CCR5. After about five years, viruses that are able to use CXCR4, with or without concurrent use of CCR5, evolve in about 50% of patients. These viruses would now be called R5X4 and X4 viruses, respectively.

Answer 11

Cytopathic effects Apoptosis CTL mediated killing

Answer 12

60% or so of all CD4 T cells are in the gut, a minority is in the blood (think of other compartments: lung, spleen etc.) The main mucosal sites for HIV entry are oral, rectal, and vaginal mucosa. Depletion of CD4 T-cells in the gut is rapid (weeks in the monkey model)

Answer 13

Bacterial translocation is a good measure of intestinal leakage and hence a measure for the destruction of the gut mucosal immune system after HIV infection.

Answer 14

Early conditions: Rash, fever, myalgia, arthralgia Guillian-Barre syndrome, chronic demyelinating neuropathy, Bell's palsy, Sjogren's syndrome Intermediate: gingivitis, warts, TB, herpes Zoster, oral candidiasis, Kaposi's sarcoma Late: Pneumocystitis, toxoplasmosis, cryptococci

Answer 15

Poor CD4 T cell proliferation after stimulation by specific antigen Normal CD8 T cell activity Reduced ability of TH1 cells to proliferate Some histological abnormalities in lymph nodes Elevated IgG and A (but non-specific), reduced IgM Small changes in cytokine levels

Answer 16

Dramatic loss of CD4 T cells and function Reduction of cytotoxic capacity of CD8 T cells Complete loss of tuberculin-type response Major histological disruption of lymph nodes & loss of DCs Eventual loss of anti-HIV antibody Significant change from TH1 to TH2 type cytokine production

Answer 17

Anyone who has ever been exposed to even a small risk of HIV infection needs an HIV test. It is better to test more people than not enough, because a positive test always requires action. Widespread testing is the best way to stop the virus from being passed on.

Answer 18

HIV antibody and HIV p24 ELISA So-called ‘fourth-generation’ HIV tests have been successfully used for the past decade. Compared with third-generation assays, fourth-generation assays have greater sensitivity because of their ability to detect p24 antigen as well as conventional HIV antibodies.