Diffuse pulmonary amyloidosis and benign monoclonal IgG-kappa-gammopathy

Localized amyloidosis of the larynx: evidence for light chain composition

We report the biochemical characterization of amyloid fibrils from a patient with localized amyloidosis of the epiglottis and larynx. Biopsy specimens showed amorphous material consistent with amyloid deposits with a plasmacytic infiltrate. Both plasma cells and amyloid deposits stained positively by immunohistochemistry for kappa light chains. Amyloid fibrils were isolated. The major constituent resolved as a 13 kd band was sequenced and found to be consistent with a kappa 1 light chain. A tryptic digest was carried out and 3 tryptic peptides were sequenced defining the first 45 residues of the protein and residues 110 through 119. Four amino acid substitutions were found, 3 of which have not been described previously. This study defines the immunoglobulin origin of amyloid deposits in localized amyloidosis. The benign nature of localized amyloidosis suggests that a localized clone of plasma cells producing an amyloidogenic light chain may represent the pathogenetic mechanism of this disease, which appears to be a form of plasma cell dyscrasia.

Long-term survival with diffuse interstitial pulmonary amyloidosis

A 51 year old man presenting with amyloidosis involving the lungs, the testes, the skin and the stomach has been followed for eight years. Serial pulmonary function tests revealed slowly progressive physiologic deterioration. The various clinical features and the lengths of survival in the previously reported cases of diffuse interstitial pulmonary amyloidosis are reviewed. The unusually long survival of this patient and its implications are discussed.