Roles of immunoglobulins in amyloidogenesis in cutaneous nodular amyloidosis.

Immunoglobulin heavy and light chains and C3 were detected on amyloid deposits in cutaneous nodular amyloidosis (NA) by a direct immunofluorescence method. These immunoglobulin chains and C3 could be removed except lambda (lambda) light chain after treating sections with 0.05% Tween 20 solution, 0.1 M glycine buffer pH 7.4 or 0.5% Triton X solution. Lambda light chain was detected consistently after these treatments. Amyloid filaments were not altered with these treatments. Immunoelectron microscopy demonstrated persistent antigenicity of lambda light chain on amyloid filaments. It was suggested that lambda light chain is an inherent component of amyloid filaments in NA, whereas other chains and complement represent nonessential absorption on amyloid material.