Immunohistochemical examination of Aκ amyloidosis with antibody against adjacent portion of the carboxy terminus of immunoglobulin kappa light chain.

For the purpose of investigating the carboxy terminus distribution of immunoglobulin κ light chain in Aκ amyloid deposits in tissue sections, we examined the immunostaining pattern of Aκ amyloidosis with conventional rabbit clonal antibody against peptide derived from the C-terminal sequence of human κ light chain. This antihuman kappa light chain clone II (clone H16-E) reacted with the adjacent region of the C terminus of the κ light chain constant region in SPOT analysis. Immunohistochemically, this antibody reacted with amyloid deposits in all 18 cases of Aκ amyloidosis. In 15 cases, this antibody reacted with amyloid deposits almost uniformly. In this study, we demonstrated for the fi rst time that the peptides adjacent to the carboxy terminus of immunoglobulin κ light chain or full-length κ light chain were constituents of Aκ amyloidosis, and these molecules were distributed uniformly in almost all cases of Aκ amyloidosis in tissue sections.