What is Human Immunodeficiency Virus (HIV)?

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Last updated: May 12, 2025View editorial policy

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From the Guidelines

HIV is a retrovirus that infects cells with the CD4 receptor, causing depletion of CD4+ T-cells and leading to immunodeficiency. This infection is a major clinical finding in progressive infection, and depletion of these cells is associated with increased clinical complications 1. The virus works by inserting its genetic material into the host CD4 cells, using them to replicate itself and eventually destroying these cells, which weakens the immune system over time.

Key Characteristics of HIV

  • HIV stands for Human Immunodeficiency Virus and if left untreated, can lead to Acquired Immunodeficiency Syndrome (AIDS) 1.
  • HIV spreads through certain body fluids including blood, semen, vaginal fluids, rectal fluids, and breast milk.
  • While there is no cure for HIV, it can be effectively managed with antiretroviral therapy (ART) medications, which must be taken daily for life 1.
  • These medications prevent the virus from replicating and allow the immune system to recover.
  • With proper treatment, people with HIV can live long, healthy lives with an undetectable viral load, which means they cannot transmit the virus to others (known as U=U, or Undetectable equals Untransmittable).

Importance of Early Diagnosis and Treatment

  • Early diagnosis and treatment for human immunodeficiency virus (HIV) can prolong life, reduce transmission, and has been demonstrated to be a cost-effective public health intervention 1.
  • Regular medical care, adherence to medication, and HIV testing are essential components of HIV prevention and management.
  • Regular HIV testing is crucial for early detection and treatment, and can significantly improve morbidity, mortality, and quality of life outcomes 1.

From the Research

Definition of HIV

  • Human Immunodeficiency Virus (HIV) is a virus that attacks the body's immune system, specifically the CD4+ T cells 2, 3.
  • HIV controllers are individuals who have low plasma HIV RNA, typically less than 500 copies/mL, for an extended period, usually 12 months or more 2.
  • The virus can cause inflammation and immune exhaustion, even in individuals with low or undetectable viral loads 2.

HIV Replication and Persistence

  • Despite effective antiretroviral therapy (ART), HIV can still replicate and persist in the body, leading to residual viremia 2, 3.
  • The virus can integrate into the host genome, forming proviruses, which can remain dormant or actively replicate 3.
  • ART can reduce T-cell activation and immune exhaustion markers, but may not completely eliminate the virus 2.

Effects of Antiretroviral Therapy (ART)

  • ART can increase the proportion of individuals with undetectable residual viremia 2.
  • ART can reduce the levels of T-cell activation and immune exhaustion markers, such as CD38+HLA-DR+ CD8+ T cells 2.
  • ART may not significantly alter the provirus landscape or check clonal proliferation of infected cells 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Antiretroviral Therapy Reduces T-cell Activation and Immune Exhaustion Markers in Human Immunodeficiency Virus Controllers.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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