Deposits of IgG and C3 in the spinal cord and motor cortex of ALS patients

Deposits of IgG and complement were demonstrated by direct immunofluorescent techniques with sections of motor cortex and spinal cord from amyotrophic lateral sclerosis (ALS) patients. Six of 16 ALS patients showed deposits within the spinal cord while 5 of 13 showed similar deposits within the motor cortex. The specificity of this staining was shown by blocking experiments and the use of conjugated F(ab')2. Similar deposits were found in the CNS in disease states associated with possible immune or infectious etiologies and were not found in the CNS of normal controls.