Light chain amyloidosis (AL) is both a disorder of protein conformation and a plasma cell dyscrasia, with secretion of altered light chains that polymerize systemically into amyloid fibrils leading to organ failure. Knowledge of the biological features of amyloid cells and of the mechanisms determining light chain organ targeting and cytotoxicity is improving rapidly. Manipulation of the immune response via passive or active immunotherapy could open new perspectives for the therapy of this complex disorder.