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.
Berg
A M
AM
Amyloid Treatment and Research Center, Arthritis Center, Boston, Massachusetts.
Troxler
R F
RF
Grillone
G
G
Kasznica
J
J
Kane
K
K
Cohen
A S
AS
Skinner
M
M
D000595:Amino Acid Sequence; D000682:Amyloid / Q000032:analysis; D000686:Amyloidosis / Q000000981:diagnostic imaging / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000032:analysis*; D007818:Laryngeal Diseases / Q000000981:diagnostic imaging / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D007830:Larynx / Q000276:immunology; D008875:Middle Aged; D008969:Molecular Sequence Data; D014057:Tomography, X-Ray Computed
D000682:Amyloid; D007145:Immunoglobulin kappa-Chains