MetaPathogen.com/Human Immunodeficiency Virus 1 - Disease Progression

 

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Human Immunodeficiency Virus 1
(HIV-1)

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HIV-1 taxonomy

Retroviridae - Orthoretrovirinae - Lentivirus - Primate lentivirus group - Human immunodeficiency virus 1

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HIV-1 disease progression

The clinical course of untreated HIV infection proceeds through four stages. The different clinical stages of HIV infection reflect patient immunological status and virological status. These two surrogate markers are currently widely used in HIV medicine to monitor progression of the infection.

The immunological status is determined by the absolute (cells/ml) or relative (% lymphocytes) number of CD4+ T-cell count.

The virological status is guided by the number of HIV RNA viral load expressed as copies/ml.

The progression of the disease is influenced by several factors, such as co-infection with hepatitis B virus (HBV), hepatitis C virus (HCV) and tuberculosis (TB), viral genetic makeup, and genetic makeup of the host.

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Mechanisms for CD4+ cell loss

Immune Reconstitution Inflammatory Syndrome (IRIS)

Also known as Immune Restoration Disease (IRD). The immune reconstitution inflammatory syndromes (IRIS) is a serious problem complicating the treatment of AIDS. IRIS refers to a group of syndromes characterized by paradoxical clinical worsening that usually occurs within the first 4 to 8 weeks after starting cART. Fever, along with swelling, redness, or discharge at the site of an injury or infection, may signal that an infection that was previously unnoticed by a weak immune system is now a target of a stronger immune system. This exaggerated "dysregulated" inflammatory response is characterized by massive infiltration of CD81 cells. Although IRIS indicates that a person's immune system improves, it can be a serious, sometimes fatal condition especially when Central Nervous Systems is involved. Among the most common CNS complications reported to be involved in IRIS are HIV encephalitis, Progressive Multifocal Leukoencephalopathy (PML), Most patients survive the syndrome. Some studies have reported both active lesions containing the pathogen (HIV-associated multinucleated giant cells, Toxoplasma parasites, etc), and "sterile" lesions with inflammatory infiltrates. The treatment of CNS IRIS with corticosteroids has been advocated and remains controversial.

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Viral load (VL) dynamics and CD4+ cell count are presented by red and blue curve respectively. HAART therapy started when CD4+ count dropped lower than 350 cells/ml. At that time viral load was still at its setting point of about 10,000 copies/ml. Without the therapy CD4+ cells count would continue to decrease rapidly accompanied by moderate but steady VL increase leading to immune system's collapse, AIDS and patient's death within next 1-3 years.

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Literature

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