Immunocytochemical characterization of neurofibrillary tangles in amyotrophic lateral sclerosis and parkinsonism-dementia of Guam.

Cryostat-cut sections of formalin-fixed and unfixed hippocampus from 23 Guamanian Chamorros with clinically and neuropathologically verified amyotrophic lateral sclerosis (ALS) (8 cases) and parkinsonism-dementia (PD) (15 cases) and from 12 neurologically normal Guamanians (5 with and 7 without neurofibrillary degeneration) were evaluated by the immunoperoxidase technique, using monoclonal antibodies against phosphorylated neurofilament, human fetal microtubule-associated protein tau, and paired helical filaments. On immunostaining, all three antibodies showed intracellular tangles in the hippocampal neurons of patients with ALS, patients with PD, and in neurologically normal Guamanians with neurofibrillary pathology, but the correlation of immunostaining between these antibodies was not absolute. Extracellular or ghost tangles were immunostained only with the antibody against paired helical filaments. Our immunocytochemical data indicate that the antigenic composition of neurofibrillary tangles in Guamanian ALS and PD is similar to that of Alzheimer's disease, suggesting a common pathogenetic pathway for neurofibrillary tangle formation in these neurodegenerative disorders.