Brain Damage in Alzheimer's and AIDS Linked

The results of a new study suggest that the brain damage in patients with Alzheimer's disease and patients with AIDS may both involve inflammation. Conducted by researchers from the San Francisco Veterans Affairs (VA) Medical Center (CA, USA), the study was published in AIDS (2001;15:1-8).

The researchers found that immune cell markers of AIDS dementia remain even after a patient is treated with anti-retroviral drugs. These same markers are elevated in patients with Alzheimer's disease. Specifically, a subset of monocyte/macrophages that are more numerous in AIDS dementia and Alzheimer's disease display a surface molecule called CD69, which is also more prolific in the blood of patients with AIDS dementia or Alzheimer's. Even after treatment with a complete anti-AIDS drug regimen, the levels of CD69 were somewhat lower but still higher than in nondemented patients and similar to those of patients with Alzheimer's.

"Although treatment with anti-retroviral drugs appears to cause monocyte/macrophages to secrete lower levels of toxins, a more subtle neurotoxicity continues to disable neurons,” said Lynn Pulliam, chief of microbiology at the VA Medical Center and lead author. This neurotoxicity appears to alter levels of structural and functional proteins in the brain, she noted. An earlier study by the same researchers found that treatment with an experimental anti-inflammatory drug prevented the toxicity.