Metabolism of Radio-iodinated Human Serum Albumin in Patients With Monoclonal Gammopathy

(mean HSA level 3.3 g/100 ml, normal with ¹²⁵I-labeled human serum albumin (HSA) in five patients with monoclonal gammopathy; three with Waldenström’s macroglobulinemia (one also had a γG monoclonal protein) and one patient each with γG multiple myeloma and γG benign gammopathy. Several abnormalities in HSA metabolism occurred in different combinations in different patients and no single consistent pattern was seen. The abnormalities included hypoalbuminemia (means HSA level 3.3 g/100, normal controls 4.7 g/100 ml); hypervolemia due to an expanded plasma volume (mean plasma volume 54.4 ml/kg, normal controls 41.0 ml/kg); decreased plasma and total body albumin pools; increased plasma localization of albumin; shortened plasma T ½; reduced fractional turnover rate; and reduced albumin synthesis rate. The most marked changes were noted in two patients with Waldenström’s macroglobulinemia who required plasma-pheresis for the hyperviscosity syndrome.