Summary
Highlights
HIV (Human Immunodeficiency Virus) is a retrovirus that ultimately causes AIDS (Acquired Immunodeficiency Syndrome). HIV infection gradually suppresses the immune system over time, leading to AIDS. It is transmitted through specific bodily fluids like blood, semen, vaginal fluids, and breast milk.
White blood cells, particularly T lymphocytes (T Cells), are crucial for immune response. HIV specifically targets and kills CD4 T cells, a subtype of T cells that signal other immune cells to fight pathogens. HIV replicates inside CD4 T cells, destroying them and spreading to new healthy cells. This continuous destruction of CD4 T cells weakens the body's defenses.
When the CD4 count drops below 200, a person is diagnosed with AIDS. This can take up to 10 years after initial HIV infection. A low CD4 count makes the body highly susceptible to opportunistic infections like encephalitis, meningitis, debilitating illnesses such as Pneumocystis jiroveci pneumonia and tuberculosis, and cancers like Kaposi's sarcoma. Patients often die from these opportunistic diseases, not from HIV directly.
Although there is no cure or vaccine for HIV/AIDS, medications can slow its progression. Highly Active Antiretroviral Therapy (HAART) combines several anti-HIV drugs into a daily regimen. HAART attacks HIV at multiple stages of its life cycle, including blocking its binding to cells (fusion inhibitors), preventing replication (reverse transcriptase inhibitors), and inhibiting new virus assembly (protease inhibitors). HAART significantly reduces deaths from HIV-related diseases and slows progression, though it cannot completely eliminate the virus. Other HIV drug classes and specific medications for opportunistic infections (e.g., antibiotics for tuberculosis and pneumonia) are also used. Regular blood tests monitor CD4 counts and the effectiveness of treatment.