HIV/AIDS (IMMUNOLOGY)

HIV/AIDS

BY

OGUNBAYODE OLUWAKEMI

KHARKOV NATIONAL MEDICAL UNIVERSITY

DEPARTMENT OF IMMUNOLOGY

FUN FACT#

• Did you know that worlds AIDS DAY is on 1st December ?

The first reported case of HIV was in 1981.. The syndrome was characterized by a predisposition to opportunistic infections, it was suspected that AIDS was caused by a previously unknown virus, as it spreads thought contact with bodily fluids, and in 1983 HIV 1 was isolated

There are two closely related HIVs ;

HIV-1, HIV-2 the later which is less virulent. They majority of cases is found in HIV-1, HIV-2 is predominantly found in west Africa. Both HIV-1 and HIV-2, have their origin from non human primate. Based on similarities in sequence with SIMIAN IMMUNODEFICIENCY virus. HIV is likely to be the evolutionary product of closely related SIVs that crossed from nonhuman to human in the early twenties

‘the leading hypothesis is that SIVs were transmitted to humans through cutaneous or mucosal exposure to infected animal blood

ETIOLOGY

RNA virus, family retroviridae, subfamily lentivirus

Proteins: envelope glycoprotein, group specifies ag, polymerase

The virus is not stable in the environment, temperatures of 52-54 degrees can kill the virus in 20-30 mins , and 100 degrees celsius in 5 minutes

Detergents and antiseptics can also inactivate the virus

EPIDEMIOLOGY

EPIDEMIOLOGY contd..

HAART drug therapy (HIGHLY Active antretoviral therapy) has slowed the pandemic in countries with money

2 nucleoside transcriptase inbh+ 1 protease inhb+1 non nucleoside inhb OR 1 fusion inhb OR 1 integrase inhb

BUT…..

There's is as yet no cure- we cant get get rid of virus from an infected individual

There is no vaccine- can block primary infection

Cant stop taking antiviral drug- if you stop the virus will return because they integrate in to the human DNA

Drugs are expensive

AIDS IS a becoming in third world countries

HOW IS HIV TRANSMITTED?

SEXUAL

Transfusion and blood and its products

Vertical (perinatal, intranatal, postnatal)

HIV is transmitted primarily via unprotected sexual intercourse (including anal (most dangerous) and even oral sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding. Some bodily fluids, such as saliva and tears, do not transmit HIV

But not through respiratory alimentary, or vector

HIV does not usually cause AIDS immediately and controversy

still remain as to precisely how the virus

damages the immune system and whether all HIV-1 infected individuals will necessarily develop disease. Great strides have been made since the identification of HIV but much remains a puzzle and a cure or a vaccine are exclusive

PATHOGENESISAFTER the virus enter the

• Body------ dendritic cells-------lymph nodes (cd4 tcells)

Gp120 + cd4 receptor

Gp41+ccr5/cxcr4.

• The capsid of the virus are released into the cd4 t cells,

• Rna are converted to dna via reverse transriptase enzyme

• HIV Dna gets into the human dna genome and integrates it

• The cd4 tcell are begin killed by the cd8 t cells because they express abnormal protins by the MHC class 1

And over time the cd4 tcells decrease

PATHIGENESIS CONTD..

Cytopathic effect:

Fusion of the cd4 t cell so as to prevent it from antibodies

NEF gene:

Down regulates the class 1 molecule, and the cytotoxic t cells (cd8) find it difficult to kill cd4 t cells

TAT gene: impairs the production of cytokines

HEAVY glycosylation of gp120: hides some epitome( particular spots that can trigger the immune system to produce antibodies)

CLINICAL COURSE

• Incubation period 2 weeks – 10 years

• 1 acute infection: 4-8 weeks

• 2 virus carrier- 4-8 weeks

• AIDS- 1-2 YEARS

CLINICAL MANIFESTATION

• Stage of acute infection (ARS): basically characterized by flu like symptoms

( fever, headache…) virus are present antibodies are also present CD8 increase

• Viral carriage ( asymptomatic): no symptoms CD4:CD8 is decreased. Virus and antibodies are present

• Progressive lymphadenopathy (PLA): enlarged lymph nodes in extrainguinal region >1cm in 2 or more site. CD4 decreases <500ml, CD8 cells increase, CD4:CD8 decrease

• AIDS related complex: accompanied by many opportunistic infections MTB, pneumocystis Caroni, Kaposi sarcoma, CMV, candidiasis, toxoplasmosis, Cryptococcus CD4 >200ml<500ml

• AIDS: AIDS related complex + decrease level of CD4 <200ml+ cachexia, polyneuropathy, dementia etc….

DIAGNOSIS

• ELISA Test — ELISA, which stands for enzyme-linked immunosorbent assay, is used to detect HIV infection. If an ELISA test is positive, the Western blot test is usually administered to confirm the diagnosis. If an ELISA test is negative, but you think you may have HIV, you should be tested again in one to three months.

• ELISA is quite sensitive in chronic HIV infection, but because antibodies aren't produced immediately upon infection, you may test negative during a window of a few weeks to a few months after being infected. Even though your test result may be negative during this window, you may have a high level of the virus and be at risk of transmitting infection.

• Western Blot — This is a very sensitive blood test used to confirm a positive ELISA test result.

• Saliva Tests — A cotton pad is used to obtain saliva from the inside of your cheek. The pad is placed in a vial and submitted to a laboratory for testing. Results are available in three days. Positive results should be confirmed with a blood test.

• Viral Load Test — This test measures the amount of HIV in your blood. Generally, it's used to monitor treatment progress or detect early HIV infection. Three technologies measure HIV viral load in the blood — reverse transcription polymerase chain reaction (RT-PCR), branched DNA (bDNA) and nucleic acid sequence-based amplification assay (NASBA). The basic principles of these tests are similar. HIV is detected using DNA sequences that bind specifically to those in the virus. It is important to note that results may vary between tests

STOP STIGMATISATION

OUR HEARTS GOES OUT TO ALL THOSE WHO HAVE DIED OF AIDS

THANKS A LOT !!!!!