2 ZO hiv

Question 1

pathogenese hiv

Answer 1

HIV infection leads to a progressive loss of CD4 cells by cell death. This makes an infected individual vulnerable to infections. As the immune system weakens, pathogens that are normally harmless now cause disease

incubatie 1-6 weken

Question 2

behandeling hiv

Answer 2

With the development of anti-retroviral therapy (ART), HIV cannot be cured but HIV replication can be stopped. This prevents loss of CD4+ T-cells and thus protects the immune system. Patients on ART may have a normal life expectancy, but lifelong drug use is required.

Question 3

hiv detectie

Answer 3

During an acute HIV infection, only p24 antigen but no HIV-1 antibodies may be present (‘window-period’ for antibody detection

The presence of a pallet of antibodies against 3 distinct parts of HIV (capsid, envelope and regulatory proteins) proves infection with HIV virus.

The presence of antibodies against P24 (capsid protein) and P17 and P32 (regulatory proteins) does not discriminate between HIV-1 and HIV-2 infections.

The presence of antibodies against HIV-1 envelope proteins (GP-41 and GP-120) and HIV -2 envelope proteins (GP-36, GP-) proves the presence of both HIV-1 and HIV-2.

Absence of P24 antigen is normal during chronic asymptomatic HIV, this result shows that the acute phase of infection has passed.

Question 4

summary

Answer 4

Summary

Antibody detection in blood can be a reliable way to find out whether a patient has contracted a specific pathogen (i.e. virus) recently or in the past. A most striking example of this concept is HIV infection. If a patient is ‘seropositive’ for HIV (i.e. has serum antibodies he makes antibodies against HIV), this means that the patient contracted HIV somewhere in the past and therefore inevitably harbours an on-going HIV infection.

Testing ‘seropositive’ therefore has tremendous consequences for the patient and antibody assays for HIV (and for some other viruses) must be extremely reliable as to prevent any false positive or false negative results. For this purpose, it is very important for health care workers to know about test performances including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

For HIV antibody testing, a two-step approach is used. Initially a highly sensitive screening test is performed, which, if positive, is confirmed by a highly specific confirmatory test. Currently, 4th generation antibody enzyme immunoassay (EIA) antibody test are being used as screening test for HIV. Line-immunoblot tests are being used to confirm the results retrieved with EIA. These assays are extremely specific, allow for differentiation between HIV-1 and HIV-2, and show the complete pattern of specific antibodies.

It is of utmost importance to know if a person is HIV positive to prevent further deterioration of the immune system, to find the causes of diseases that affect a patient (opportunistic infections are not seen regularly) and to prevent further HIV transmission (to an unborn child or to sexual partners for example).

Question 5

officieel seropositief voor HIV-1

Answer 5

D12 op immunoblot

bands can be identified at gp160, p68, p55, p34, p24 and p17

Question 6

HIV 1 proteins

Answer 6

HIV-1 proteins are: gp120, gp41, p17 and p24

Question 7

HIV 2 proteins

Answer 7

HIV-2 proteins are: gp105 and gp36