High levels of C3c in the cerebrospinal fluid from amyotrophic lateral sclerosis patients.

A study of several parameters of the humoral immunity in the serum and the cerebrospinal fluid (CSF) of thirteen Amyotrophic Lateral Sclerosis (ALS) patients was carried out. A significant increase in CSF C3c was shown. This feature was found to be significantly correlated to the CSF albumin/serum albumin ration (r = 0.70; p less than 0.05) and to the total CSF proteins (r = 0.86; p less than 0.01). The possible effect of the blood-brain barrier breakdown on the CSF complement levels was evaluated. On the basis of the recently found biochemical changes in ALS cell membranes it is proposed that the high levels of the CSF C3c may also be due to a defective binding to the lymphocytes C3 receptors.