Immunoglobulin-related (AL) amyloidosis.

The amyloid fibril is the unique component of amyloid substances. Some amyloid fibrils (i.e. AL amyloid) are made up by homogeneous immunoglobulin light chains, and such fibrils are related to systemic and localized primary amyloidosis and amyloidosis associated with myelomatosis and Waldenstrøm's macroglobulinaemia. More lambda than kappa light chain proteins make up the amyloid in these cases, and it appears that lambda-chains are more prone to fibril formation than kappa-chains. Immunoglobulins are thus the precursor protein for AL amyloid, which shows that primary amyloidosis belongs to the plasma cell dyscrasias. Amyloid infiltration of the heart and the kidneys accounts for the most severe clinical consequences of AL amyloidosis. In addition, peripheral neuropathy, carpal tunnel syndrome, macroglossia, skin affections, amyloid arthropathy and autonomic disturbances (i.e. orthostatic hypotension) are characteristic features of the disease. Involvement of parenchymal organs (kidneys, liver, spleen, gastrointestinal tract and endocrine glands) are common to systemic AL amyloidosis and secondary amyloidosis. As protein AA is the major fibril constituent of secondary amyloid, this form of amyloid disease is not related to immunoglobulins. Like other forms of plasma cell dyscrasia, patients with AL amyloidosis are usually treated with cytotoxic drugs and corticosteroids, however, the prognosis is very poor with a reported survival time after diagnosis of less than two years.