MONDAY, Sept. 24, 2001 (HealthDayNews) -- Doctors have discovered a link between the virus that causes AIDS and a condition resembling Lou Gehrig's disease, and have found that drugs can help the disorder.
In two separate studies, American and French researchers describe rare cases of HIV-infected patients who develop a syndrome similar to amyotrophic lateral sclerosis (ALS), the more formal term for Lou Gehrig's disease. ALS is a progressive neurodegenerative disorder that causes muscle weakness, impaired movement, and, ultimately, paralysis and death.
But although drugs can only modestly slow the course of conventional ALS, the multi-drug therapy used to treat AIDS patients appears to improve and even reverse this virus-related, ALS-like syndrome.
The findings, which appear in the Sept. 25 issue of Neurology, bolster an existing theory that some cases of ALS are the result of viral infections. Moreover, the effect of AIDS drugs in these rare cases raises hopes for an effective treatment for ALS patients.
ALS, which affects approximately 20,000 Americans, got its nickname from the legendary New York Yankee who died of the disorder in 1941. It results from the progressive death of motor neurons, which normally allow the brain to control muscle movement. As this occurs, muscles waste away until the person can no longer speak, swallow, or breathe. In a cruel twist, a person's mental faculties, however, are completely unaffected.
Patients typically survive for three to five years, although some can live as long as 10 years after diagnosis. The average age at which patients develop ALS is 55.
In October 1997, doctors at the Beth Israel Medical Center in New York City encountered a 32-year-old woman who for three months had struggled with painless but progressive muscle weakness, speech problems, and weight loss, along with other reflex abnormalities similar to those seen in ALS patients.
Within three weeks of her admission to the hospital, the woman was bed-bound, and lead author Dr. Daniel MacGowan, an assistant professor of neurology, found evidence of motor neuron loss on a brain imaging scan.
After a battery of tests, MacGowan discovered that the woman was HIV-positive, and she was started on a cocktail of AIDS drugs known as highly active antiretroviral therapy (HAART).
Six months later, levels of HIV were undetectable in the patient's blood. She was out of bed and able to walk with assistance, and she could also swallow and speak normally and had returned to her normal weight. Four years later, there were only trace signs of weakness and other abnormal reflexes.
But MacGowan says that despite the effect of therapy in this patient, it's not clear from this study whether HIV is directly responsible for the ALS-like symptoms or if another virus is involved. HIV is known to affect inflammatory immune cells called macrophages, which then invade the brain and spinal cord, causing nerve cell damage. But it has never been shown to damage motor neurons.
"Maybe there's another virus that could be causing ALS," says MacGowan.
The study also raises questions about why HAART reversed the symptoms. "We know that [AIDS drugs] have activity [not] just against HIV itself," says MacGowan. "They seem to block a process called apoptosis [cell death] in lymphocytes in the blood.
"Apoptosis is one of the primary mechanisms for motor neuron death in ALS," MacGowan continues. "So that raises an issue: Maybe the drugs were working by that action as well."
In the French study, researchers at the Adolph Rothschild Foundation and the Infectious and Tropical Disease Service in Paris studied 1,700 HIV-positive people with neurological symptoms, and identified five men and one woman with symptoms similar to ALS. Their ages ranged from 22 to 61.
Unlike patients with conventional ALS, their symptoms worsened rapidly, progressing within just a few weeks.
But after treatment with AIDS drugs, two of the patients recovered completely, while three improved and the sixth patient stabilized.
Dr. Burk Jubelt, a neurovirologist at the State University of New York Upstate Medical University in Syracuse, says that researchers must continue to look for other viruses that may be responsible for other cases of ALS.
At the same time, he adds, these studies suggest that doctors considering a diagnosis of ALS should make sure the patient is tested for HIV, especially if he or she is young. "Maybe HIV is allowing some other virus to infect the nerve cells," he says.
"There had been some cases where HTLV [human T-cell lymphotrophic virus type I] had caused some [ALS-like] cases reported back in the 1980s." HTLV, like HIV, is part of the retrovirus family.
MacGowan says that not every patient who visits a doctor with ALS symptoms is tested for HIV, although the test is done on anyone with risk factors for the virus.
The American researchers are now preparing a trial of the HAART drug indinovir on conventional ALS cases, where they will also examine fluid from the patients' spinal columns for signs of any viruses, as well as any effect of the therapy on motor cell death.
What To Do : You can find out more about ALS from the Web sites for the ALS Association, the Les Turner ALS Foundation, or the National Institute of Neurological Disorders and Stroke.
