Double light-chain disease: a case report.

A patient with massive proteinuria was discovered to have double light-chain disease. Immunological studies demonstrated monoclonal light chains of both the lambda and kappa type in urine. The light chains were separate and distinct and were not found to be a part of any of the whole molecule immunoglobulins such as IgG, IgM, IgA, IgD, or IgE. Uniqueness of the proteins was confirmed by column chromatography. Clinical studies showed that the patient had multiple myeloma.