Localized light chain amyloidosis of the stomach that regressed after eradication of Helicobacter pylori over 15 years of follow-up: a case report and new hypothesis.

Localized light chain amyloidosis is considered to be a plasmacytic B-cell lymphoproliferative disorder caused by antigenic induction. A hypothesis has been proposed that antigen-induced local plasmacytic B cells produce amyloidogenic proteins that are processed into amyloid fibrils in giant cells leading to amyloid fibril deposition. However, the inciting antigen exposure or immune response that signals plasmacytic B-cell infiltration, activation, and selection, is unknown.