Retroviral interference with neuronotrophic signaling in human motor neuron disease?

We tested 13/32 patients with non-familial amyotrophic lateral sclerosis (ALS) positive (41%) for human spuma retrovirus (HSRV) seroreactivity. Half the non-ALS HSRV-positive neurologic patients (12/25) reported multiple fasciculations within the last two years. Sera from four HSRV-env negative ALS patients measurably competed with visna antibodies on maedi-visna antigen. The serologies for bovine leukemia virus, Borna disease virus and GM1IgM-antibodies remained negative. Both visna and foamy virus sequences share epitopes with motor nervous system signal polypeptides, suggesting a retroviral interference with motor neurono-axonal function and neuronotrophic signals.