Amyloidosis of a possible new type in patients receiving long-term hemodialysis

Carpal tunnel syndrome developed in six patients receiving long-term (12 to 17 years) hemodialysis. Biopsy specimens of tendons and synovial-tendon sheaths showed deposition of eosinophilic hyalin material exhibiting many properties of amyloid. However, this material did not react with antibodies to known amyloid proteins, except for the P component. On electron microscopy, the material consisted of fine filaments, 9 to 10 nm thick, that showed a marked tendency to parallel alignment and arrangement in bundles. The same material was found in arterioles of the rectum in three of four patients who were examined. We suggest that this material represents a previously undescribed type of amyloid. Its deposition may be due to the effects of long-term hemodialysis, or to the long-term uremic state, and may pose a potential problem to dialyzed patients.