How HIV Affects the Immune System скачать в хорошем качестве

How HIV Affects the Immune System

MEDICAL ANIMATION TRANSCRIPT: HIV, or human immunodeficiency virus, is the retrovirus that eventually causes AIDS or acquired immunodeficiency syndrome. Over time, HIV infection suppresses the immune response, resulting in a spectrum of diseases leading to AIDS. HIV is transmitted from an infected person via specific bodily fluids, including blood, semen, vaginal fluids, and breast milk. White blood cells or leukocytes defend the body from infection. One group of leukocytes called T lymphocytes or T cells is part of a direct immune response against infected cells and tumor cells. During HIV infection, HIV targets and kills certain cells in the immune system. HIV attacks CD4 T cells, which are a sub-type of T cells that signal other leukocytes to attack a specific pathogen. HIV replicates inside the CD4 T cells, which not only kills them but also allows the virus to spread and infect healthy cells. As HIV continues to replicate and destroy more CD4 T cells, the body becomes defenseless, succumbing to infections. When a CD4 count drops below 200, a person is considered to have AIDS. This can take as long as ten years from the time a person is infected with HIV. This low CD4 count increases susceptibility to opportunistic infection, such as encephalitis and meningitis; debilitating illnesses, such as Pneumocystis jirovecii pneumonia and tuberculosis; and cancers, such as Kaposi's sarcoma. Patients can die from these opportunistic diseases, not from the HIV infection itself. Although there is no cure or vaccine for HIV infection or AIDS, medication can slow the progression of HIV infection. Antiretroviral medications, such as highly active antiretroviral therapy or HAART, combine several anti-HIV medications in a daily regimen. HAART attacks HIV at several points in its life cycle, slowing its replication. One drug in the cocktail, a fusion inhibitor, blocks HIV from binding to the cell. A second drug, reverse transcriptase inhibitor, blocks it from replicating. And a third drug, a protease inhibitor, prevents HIV from assembling a new virus. Though it is not possible to completely eliminate HIV from the body, HARRT slows progression and significantly reduces deaths from HIV-related diseases. In addition to HAART, there are other HIV medication drug classes available. Other treatment options for AIDS include specific medications for opportunistic infections. For example, licensed healthcare professionals prescribe certain antibiotics to treat tuberculosis and pneumonia. Blood tests are performed regularly to check CD4 counts and determine the efficacy of the cocktail and antiviral.