Immunochemical analysis of the monoclonal paraprotein in scleromyxedema

The monoclonal paraprotein from a typical case of scleromyxedema was isolated and characterized. The isolated paraprotein was of the IgG-lambda class, with a molecular weight of approximately 110,000 daltons compared with 160,000 daltons for normal IgG. Immunochemical studies indicated that the paraprotein was an incomplete IgG molecule which was missing a significant antigenic portion of the Fd fragment.