Amyloid in intervertebral discs of surgery and autopsy material. A new class of amyloid?

Intervertebral discs from 82 consecutive operations on herniation and 59 autopsies (one case with generalized amyloidosis) were studied. Amyloid deposits observed in surgical and autopsy specimens increased with age in both series. Degenerative changes were related to age and to amyloid deposits in autopsy, but not in surgical cases. Calcium pyrophosphate dihydrate deposits (often in proximity to amyloid deposits) were found in autopsy discs of six patients and in surgical specimens of three patients with previous operations on herniated discs. Antisera against amyloid fibril proteins of different types including AA-, A lambda-, A kappa, AF- and AB-types showed no reaction with disc amyloid. In one case with generalized A lambda-amyloidosis the disc amyloid was not of the A lambda-type. Based on our results, we suppose that disc amyloid is a form of localized senile amyloidosis - possibly representing a new class of amyloid limited to cartilage tissue.