Biclonality in Amyloidosis Patient MAL: One Clone Produncing an Amyloidogenic, the Other a Non-Amyloidogenic Kappa L-Chain — AL Amyloidosis

Abstract

Investigation of liver, urine, and serum of amyloidosis patient MAL established the presence of two idiotypically different kappa L-chains. The liver kappa-chain was isolated as an intact fibril precursor from the sodium chloride extracts of the liver and as a kappa L-chain fragment (pos.1-113) from the water extracts representing the fibril. The missing C-part was found in the urine. Kappa L-chain fragments were isolated from the urine consisting of V- and glycosylated J-C fragments reported in the previous paper. Inspite of 20 amino acid substitutions no V-region sequences characteristic of the liver fragment could be detected in the urine and vice versa. The MAL serum contained an intact monoclonal IgG1 (kappa) protein whose L-chain was structurally identical to the urinary L-chain fragments.