Pathophysiology of paraprotein production.

Paraproteins or monoclonal proteins are the result of clonal B-cell or plasma cell proliferation of a malignant, premalignant or non-malignant nature. Monoclonal proteins may consist of intact immunoglobulin molecules or of heavy or light chains only. Depending on their rate of production and/or secretion they may accumulate in the serum and/or urine of patients. Their presence in the circulation may remain silent, as in monoclonal gammopathy of undetermined significance (MGUS), or may lead to clinical syndromes such as Hyperviscosity, Acrocyanosis, Cold hemagglutination, hemolysis and hemorrhagic manifestations. Their tissue deposition may be localized, with the kidney being the most frequent target as in Myeloma Cast Nephropathy or systemic, as in AL amyloidosis where heart, liver, nerves, tongue are usual targets, in addition to the kidneys.