CATIE News - Why all the fuss about inflammation?
2010 Aug 16 - The widespread availability of anti-HIV therapy (called ART or HAART) in high-income countries has had a hugely beneficial impact on the health of HIV-positive people. As a result of this therapy, the life-threatening infections that are the hallmark of AIDS are now rare among people who are engaged in care and treatment. Furthermore, researchers increasingly expect that HIV-positive people who have minimal co-existing health conditions and who begin ART today should live near-normal life spans.
A hole in the shield
ART works by suppressing HIV to very low levels, allowing the immune system to effect some repairs. However, the production of HIV and persistence of HIV-infected cells continue, albeit at relatively low levels. The continued long-term exposure to HIV may skew the immune system in unexpected ways.
In the normal course of things
In the case of a regular infection, the immune system becomes activated and marshals its cells to contain and eventually wipe out invading germs. After the invasion has been squelched, the immune system neatly suppresses excessive activity, dampening down activation to a normal state.
A system out of balance
However, in the case of a persistent infection such as HIV, the immune system shifts to a state of permanent activation. Its cells are constantly hyper-vigilant and produce higher-than-normal levels of chemical signals—called cytokines—that cause unnecessary activation and inflammation.
Cells of the immune system can be found all over the body, and some take up residence within organ/systems such as the brain, liver, lungs, blood vessels and so on. There, chronically activated immune cells release cytokines that help inflame the surrounding tissues and blood vessels, slowly degrading them.
Thus, it is possible that in chronic HIV infection, even with the use of ART, immune activation may play a role such as inciting or accelerating the development of certain complications, including the following:
- problems with memory and thinking clearly
- increased risk of the unnecessary formation of blood clots
- kidney dysfunction
- pre-diabetes
- pulmonary hypertension
- thinning bones
Researchers are trying to find ways to reduce HIV-related inflammation. In several upcoming CATIE News bulletins, we will explore some of the research that is trying to understand and in some cases suppress HIV-related inflammation, thereby improving the health of HIV-positive people.
—Sean R. Hosein
REFERENCES:
1. Dubé MP, Sattler FR. Inflammation and complications of HIV disease. Journal of Infectious Diseases. 2010 Jun 15;201(12):1783-5.
2. Neuhaus J, Jacobs DR Jr, Baker JV, et al. Markers of inflammation, coagulation, and renal function are elevated in adults with HIV infection. Journal of Infectious Diseases. 2010 Jun 15;201(12):1788-95.
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CATIE-News is written by Sean Hosein, with the collaboration of other members of the Canadian AIDS Treatment Information Exchange, in Toronto.
From Canadian AIDS Treatment Information Exchange (CATIE). For more information visit CATIE's Information Network at http://www.catie.ca
Source: CATIE: CANADIAN AIDS TREATMENT INFORMATION EXCHANGE
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