Low CD4+ T lymphocyte counts: A variety of causes and their implications to a multifactorial model of AIDS


Low CD4+ T lymphocyte counts (CD4 counts) are associated with a variety of conditions, including many viral infections, bacterial infections, parasitic infections, sepsis, tuberculosis, coccidioidomycosis, burns, trauma, intravenous injections of foreign proteins, malnutrition, over-exercising, pregnancy, coricosteroid use, normal daily variation, psychological stress, and social isolation. It is also possible that anti-HIV medications can lower CD4 counts when used for long periods, and the short term rise in CD4 counts that is associated with their use may be due to a variety of factors that are unrelated to any anti-HIV activity. Finally, there are a number of people who are completely healthy and who have low CD4 counts for no apparent reason. This paper presents a brief review of several studies documenting low CD4 counts in people who are experiencing these conditions. The low CD4 counts caused by some of these conditions often fall below 200 per cubic millimeter, which is the level needed to diagnose acquired immunodeficiency syndrome (AIDS) in someone who was previously positive for antibodies to the human immunodeficiency virus (HIV-positive). In addition to the diagnosis of AIDS, CD4 counts are regularly used to make treatment decisions in people diagnosed HIVpositive, such as when to start antiretroviral medications and when to begin preventative antibiotics. Because many of the conditions that cause low CD4 counts are common in people diagnosed HIV-positive, caution is advised regarding the use of CD4 counts to make treatment and diagnostic decisions. This is made more urgent since some of the conditions, like psychological stress, are greatly increased when people are told that their CD4 counts are low, which may compound the problem and cause the CD4 count to fall even furthur. Psychological stress and social isolation are also created by the diagnosis, HIV-positive, and by the diagnosis of AIDS, which may have chronic effects on the CD4 count. Finally, the widely accepted argument that HIV specifically targets CD4+ T lymphocytes is also called into question, because it appears that low CD4 counts are a common reaction to many kinds of physical and psychological stressors. Other alterations in immune system parameters which are thought to be specific to HIV are also replicated extremely well by the conditions to be reviewed, making it impossible to distinguish any effects attributed to HIV that could not also be caused by these other factors. When several of these factors are combined, as is often the case in people diagnosed HIVpositive, extremely low CD4 counts may be a natural result.


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@inproceedings{Irwin2011LowCT, title={Low CD4+ T lymphocyte counts: A variety of causes and their implications to a multifactorial model of AIDS}, author={Matt Irwin}, year={2011} }