Nodular primary cutaneous amyloidosis. Isolation and characterization of amyloid fibrils.

A case of nodular cutaneous amyloidosis and Sjögren's syndrome occurred in a 63-year-old woman. Nodules had been seen for the past ten years and Sjögren's syndrome had accompanied amyloidosis for the last three years. The concomitant occurrence of nodular cutaneous amyloidosis and Sjögren's syndrome may not be by chance, since four of 12 cases of nodular cutaneous amyloidosis that have been reported to date in Japan were in patients with both amyloidosis and Sjögren's syndrome. The amyloid deposits in the tissue were stained with anti-lambda light-chain amyloid antibody. Amyloid fibrils were purified from the skin lesions in this patient and were characterized biochemically, immunologically, and ultrastructurally. The results indicated that the amyloid fibrils consisted of 29,000-, 20,000-, and 17,000- dalton peptides, the 29,000-dalton peptide of which was shown to react with the lambda light chain of immunoglobulin by immunoblot study.