Amyotrophic Lateral Sclerosis

To the Editor.—  I have read with great interest a recent article in the Archives (1980;37:312-313) that concerned studies in a case of amyotrophic lateral sclerosis (ALS) that had occurred 32 years after acute poliomyelitis. We have described two women in whom spinal cord tumors developed 30 years after paralytic poliomyelitis.¹ After we had published a comprehensive hypothesis on this subject,² another severely affected (polioencephalomyelitic) woman was operated on in Sheba Medical Center, Israel, for removal of an occipital meningioma. In this case, 40 years had passed between the viral attack and the operation. The "late ALS-like poliomyelitis" is often described as occurring 30 years after the infection. Are these phenomena only coincidental or do they really represent a late effect (slow virus, immunologic reactions) of the old antecedent poliomyelitis?