** اسير الفراق**
08-04-2008, 03:45 PM
AIDS
Scanning electron micrograph of HIV-1 budding from cultured lymphocyte.
AIDS is the most severe acceleration of infection with HIV. HIV is a retrovirus that primarily infects vital organs of the human immune system such as CD4+ T cells (a subset of T cells), macrophages and dendrites cells. It directly and indirectly destroys CD4+ T cells.[36] CD4+ T cells are required for the proper functioning of the immune system. When HIV kills CD4+ T cells so that there are fewer than 200 CD4+ T cells per micro liter (µL) of blood, cellular immunity is lost. In some countries, such as the United States, this leads to a diagnosis of AIDS. In other jurisdictions, such as in Canada, AIDS is only diagnosed when a person infected with HIV is diagnosed with one or more of several AIDS-related opportunistic infections or cancers. Acute HIV infection progresses over time to clinical latent HIV infection and then to early symptomatic HIV infection and later to AIDS, which is identified either on the basis of the amount of CD4+ T cells in the blood, and/or the presence of certain infections, as noted above.[37]
Patients with HIV infection have substantially increased incidence of several malignant cancers.
This is primarily due to co-infection with an oncogenic DNA virus, especially Epstein-Barr virus (EBV)
, Kaposi's sarcoma-associated herpes virus (KSHV), and human papillomavirus (HPV).[31][32]
Kaposi's sarcoma (KS) is the most common tumor in HIV-infected patients.
The appearance of this tumor in young homosexual men in 1981 was one of the first signals of the AIDS epidemic.
Caused by a gamma herpes virus called Kaposi's sarcoma-associated herpes virus (KSHV),
it often appears as purplish nodules on the skin, but can affect other organs, especially the mouth,
gastrointestinal tract, and lungs.
Multimedia
Scanning electron micrograph of HIV-1 budding from cultured lymphocyte.
AIDS is the most severe acceleration of infection with HIV. HIV is a retrovirus that primarily infects vital organs of the human immune system such as CD4+ T cells (a subset of T cells), macrophages and dendrites cells. It directly and indirectly destroys CD4+ T cells.[36] CD4+ T cells are required for the proper functioning of the immune system. When HIV kills CD4+ T cells so that there are fewer than 200 CD4+ T cells per micro liter (µL) of blood, cellular immunity is lost. In some countries, such as the United States, this leads to a diagnosis of AIDS. In other jurisdictions, such as in Canada, AIDS is only diagnosed when a person infected with HIV is diagnosed with one or more of several AIDS-related opportunistic infections or cancers. Acute HIV infection progresses over time to clinical latent HIV infection and then to early symptomatic HIV infection and later to AIDS, which is identified either on the basis of the amount of CD4+ T cells in the blood, and/or the presence of certain infections, as noted above.[37]
Patients with HIV infection have substantially increased incidence of several malignant cancers.
This is primarily due to co-infection with an oncogenic DNA virus, especially Epstein-Barr virus (EBV)
, Kaposi's sarcoma-associated herpes virus (KSHV), and human papillomavirus (HPV).[31][32]
Kaposi's sarcoma (KS) is the most common tumor in HIV-infected patients.
The appearance of this tumor in young homosexual men in 1981 was one of the first signals of the AIDS epidemic.
Caused by a gamma herpes virus called Kaposi's sarcoma-associated herpes virus (KSHV),
it often appears as purplish nodules on the skin, but can affect other organs, especially the mouth,
gastrointestinal tract, and lungs.
Multimedia