[Analysis of serum antibodies to nerve tissue antigens in patients with lateral amyotrophic sclerosis].

We used non-direct immunofluorescence microscopy, immunoblotting and affinity chromatography on A-protein Superose to study antibodies to neural tissue antigens in sera from 11 patients with ALS and from 10 healthy donors. In all sera the majoric antigens had molecular masses of 150-200kD, 70kD and 50kD. No consistent differences were found between ALS patients and controls. Antibodies to 50kD and 70kD proteins from patients with ALS were found to be mostly IgM, whereas antibodies from control sera were mostly IgG. Antibodies to high molecular weight proteins (150-200kD) in ALS and controls belonged to both classes of immunoglobulins. Immunoblotting studies of neural tissue proteins after treatment blots with alkaline phosphatase showed considerable decrease of antibodies binding to neural tissue antigens in sera of ALS patients. The same results were obtained by immunofluorescence assay. The alkaline phosphatase experiments suggest that in ALS patients the sera antibodies are directed mainly against phosphoepitopes in protein antigenic determinants of the neural tissue. This results can lead to conclusion of a role for the altered phosphorylation of the neural proteins in the ALS pathogenesis.