HIV and AIDS
Acquiored ImmunoDeficiency Syndrome

* General plan of Immunity:

To Understand the Essentials for HIV infection , a background of Human Immune system and Immunology Must Be Introduced.. However this is Just an Outline Of Immunity..
- Immunity is Roughly can be defined as the Human response against a Forign Body which is scientifically called an ANTIGEN(immunogen) which maybe a Protein"mostly" , Carbohydrate Or even Fat Or Inorganic material .. Therefore, a Bacterium will contain Multiple antigens in its Body which will elicit different Immune responses against it
- Immunity is Roughly divided into Humoral and Celluar-Mediated Immunity :

* Humoral Immunity:
This is the Immune response elicited By Non-celluar elements of Human Immune system.. this Includes a group of substanced as: Defensins , Lysins , Acute Phase Proteins " e.g C-reactive protein " , Complement System and Interferons .... This Have an Important role against Non-Specific Foreign Body (i.e) it is NOT programmed against specific Foreign Body to destroy.

* Celluar - Mediated Immunity:
This consists Of various elements That reast to SPECIFIC antigen in which it is programmed to respond to :

T-Lymphocytes: these cells have the main role of immunity and consists of many types..
T-Helper (CD4) This send alarm to all Immune system By releasing substances called Cytokines Once it Binds to an antigen
T-Cytotoxic (CD8) This directly Kill Cancer Cells and Cells INfected with Virus and can also Kills some celluar organisms as Bacteria
T- Suppressor (CD8) This suppress the Immune system to prevent OverActivity

B-Lymphocytes: Once it is stimualted By T-helper cells.. it Releases antibodies that Bind directly to the antigen and destroys it Immediately also.. its Binding to Virus Infected cell OR cancer cell makes it accessible to NK and T-cytotoxic cells to destroy which is a mechanism called AntiBody-Dependent Cell CytoToxicity (ADCC).

Natural Killer cells (NK): this Cell directly KILL cancer and Virus infected cells by releasing cytocidins and Perforins in the target cell ..it can kill either directly or through ADCC "see above".. NK cells activated By T-Helper cells is called Lak Cell.

Macrophages: these cells Roam Inside Human Body inside and Outside Body stream detecting any Foreign body .. then engulf it and destroys it as well as prestenting it to T-helper cells to elicit mass immune response against it (like peeling the Orange for T-helper)

* There is Other aspects of immunity which is NOT in concern during HIV infection as Hypersensitivity Reactions ..etc...
-- a Specific approach to Immune responses against Viral infections Must be Taken into consideration..

AntiViral Immuunity:
1- T-Cytotoxic Cells
2- NK and Lak cells
3- Interferons especially Gamma- INF. "infected cells"
4- Direct antibody mediated Virus Neutrilization (By B-cells) it is the ONLY mechanism that can destroy a FREE virus.

*Properties Of Virus:

HIV "Human ImmunoDefieceincy Virus" is Classified as RetroVirus .. Lentivirinae Family which are viruses responsible for Slow Progressive Chronic Diseases
There is 2 major types of HIV virus : HIV-1 (worlwide) and HIV-2 (west africa)
HIV was first descriped in 1981 and first Isolated in 1983

HIV-1  Responsible for most AIDS cases in western countries
HIV-2  Responsible for most AIDS cases in west Africa

* Mode Of Transmission Of Virus:

1- Sexual Route:

High Risk Factors:
1- Dry Anal INterCourse Without Using a Condom With Ejaculation "NO LuB"
2- Wet Anal INtercourse without using a condom With Ejacualtion "using LuB"
3- Vaginal INterCourse without using a condom with Ejacualtion
4- Anal INtercoure with Condom with ejaculation
5- Vaginal Intercourse with Condom with ejaculation
6- Vaginakl INtercourse with Latex Diaphragm with Ejaculation
7- Anal Intercourse with condom without ejacualation
8- Vaginal INtercourse with condom/latex diaphragm without Ejacualtion
9- Anal / Vaginal INtercourse without neither Condom or ejaculation
10- fetishes including Blood Or Body Fluids exposure

Moderate Risk Factors:
1- Sucking without condom with ejaculation
2- sucking without condom with NO ejacualtion
3- sucking with Condom with ejaculation
4- sucking with condom with NO ejacualtion
5- vaginal Sucking with NO latex diaphragm
6- Vaginal Sucking with Latex Diaphragm
7- Rimming

Low Risk Factors:
1- Mutual Masturbation " Naked"
2- Wet Kissing " French"
3- Body Licking

NO or Unrevolved risk Factors:
1- Masturbating alone
2- Frisking "masturbation while dressed"
3- Dry Kissing
Extracted from a AIDS epidemic medical textBook

So.. as we see, Risk Factors are Many and Numerous and Well specified in this Extract.. but we Repeat Homosexual Sex Cannot CREATE the HIV virion.. One member must previously be infected . however HIV virus is Very weak Virus regarding its Surviving Outside Body.

2- Parentral Route:
This is common Way of Infection through BLOOD.. as example Blood Transfusions and Infected syringes as well as drug abusers and Tattoos and any contaminated Blood Invasing Instrument.

3- Mother to Fetus Transmission:
This is common either through Placenta OR during suckling of child .. However IF child is Born infected with HIV, The other have to Continue suckling him to provide essential Immunity in facing HIV infection.

*How Virus Infects Cell ?

Once Blood reaches Blood Stream either directly OR passing through Mucous Membranes Of rectum OR vagina it Binds to specific receptors in Immunity Cells:
1- T-helper cell : it binds to CD4
2- various other Lymphocyte : it binds to co-receptor CXCR4 "it is a chemokine receptor"
3- macrophages : it binds to CD4 or CCR5 receptors ..however macrophages is specifically resistant to HIV damaging effect on the cell.. so not only the virus survives undetectedly inside it BUT also can reach internal organs outside Blood stream as Lung , Liver and brain
so it is quite clear that the virus uses the body own natural physiological mechanisms "receptors" to infect cells..

Then the virus successfully injects his Core RNA inside cytoplasm of infected cell, to start reproduction By changing the RNA to DNA by reverse Transcriptase enzyme then Integrating this DNA inside DNA of host cell .. these cells continues to produce viruses to infect other cells and eventually cells Die which is the major cause of disease due to death of most immune cells esp. T-Helper Cells..(depletion of cell-mediated immunity)

* Clinical Course Of Disease:

1- Acute Retroviral stage: in 10% of infected people , glandular fever-like symptoms occur concomitant with sero-conversion

2- Asymptomatic stage: the patient is clinically free of symptoms, but lab. Diagnostics can detect HIV infection

3- Persistent Generalized Lymphadenopathy: all lymph nodes over the body except cervical and axillary shows mobile non-tender enlargement

4- AIDS- related complex
5- Full blown AIDS

• Major criteria for Case finding include weight loss > 10% , Diarrhea > 1 month Or Fever > 1 month
• Minor criteria for case finding include cough > 1 month, generalized dermatitis with itching, recurrent herpes zoster infection, chronic disseminated herpes simplex, oro-pharyngeal moniliasis, generalized lymphadenopathy

AIDS is characterized by Opportunistic infections that arise in the ARC stage:

1- Meningitis, Encephalitis and space-occupying lesions in brain (tumors and opportunistic infections)
2- Pneumonia (esp. penumocystitis carinii “protozoa”)
3- Tuberculosis
4- Malignancy and infections of Gastrointestinal tract including Monilia, strongyloids stercoralis “a parasite infest only in immumo-compromized individuals”
5- Lymphomas
6- Sebborrheic dermatitis-like lesions
7- Herpes Simplex & Zoster infestations
8- Genital and common warts
9- Molluscum contagiosum
10- Kaposi sarcoma : is a viral-caused cancer that manifests as purple raised papules starts at the extremities and proceed to cover all over the body , it is also present on the organs inside . . it is enough to diagnose AIDS and one of the main causes of death in HIV+ patient beside Cryptococcal meningitis and HIV Encephalitis

* Treatment:

There are no treatements to cure HIV, the current HIV treatements can only limit the devellopement of the virus but does not eleminate it.

Anti Retroviral Therapy (ART) including Zidovudine, Nevirapine and saquinavir

There’re Protocols of Postexposure prevention, It requires medical supervision so it will not be mentioned in details
On suspicion of exposure to HIV positive patient, You should visit a doctor immediately for initiating post-exposure prevention maneuvers to minimize the risk of getting HIV infection