09 Oct 2001

Researchers have suspected retroviruses to play a role in amyotrophic lateral sclerosis (ALS) since the 1960s, when poliomyelitis was proposed to contribute to progression of the disease. Through the '80s and '90s, ALS syndromes associated with retroviral infection have been reported, though a direct correlation between the two has been lacking. In last month's Neurology, papers by Moulignier et al. and MacGowan et al. describe seven new cases of ALS-like symptoms in patients infected with HIV. Interestingly, the ALS symptoms responded to retroviral therapy.

MacGowan et al. report a patient, positive for HIV, who had rapidly progressing ALS-like symptoms. The ALS functional rating score dropped from 34/40 at the initial visit, to 13/40 three weeks later, at which time the patient was in a quadriplegic state. She was started on antiretroviral therapy and within six months could again walk with assistance; four years later she has almost fully recovered, with an ALS functional rating of 40/40.

Moulignier et al. identified six HIV-infected patients with ALS-like symptoms, from approximately 1,700 referrals over a 13 year period. The ALS symptoms improved in all patients under antiretroviral therapy, though in two cases symptoms reappeared when therapy failed. In two patients ALS symptoms completely disappeared.

"These data validate the idea that ALS-like symptoms seen in such cases are a consequence of HIV infection and suggest, as the authors point out, that an overactivated immune system may have an effect on motor neurons similar to classical ALS," notes Harvey Cantor, of the Dana-Farber Cancer Institute.—Tom Fagan