Sensitive Method for Detection and Semiquantification of Bence Jones Protein by Cellulose Acetate Membrane Electrophoresis Using Colloidal Silver Staining

The monoclonal free light chain of immunoglobulin, Bence Jones protein (BJP), is associated with malignant monoclonal gammopathies, in particular with multiple myeloma, lymphoproliferative diseases such as Waldenstrom macroglobulinemia and malignant lymphoma, amyloidosis associated with light chain, and light chain deposition disease (1)(2). The detection of urinary BJP is useful for diagnosing and evaluating the prognosis for monoclonal gammopathies (3)(4)(5)(6)(7). BJP can be detected as a sharp band by urinary protein electrophoresis (UPE). UPE on cellulose acetate, cellulose nitrate, and agarose has been reported. More recently, sodium dodecyl sulfate-agarose gel electrophoresis and capillary electrophoresis of urinary proteins have been reported (8)(9)(10)(11)(12)(13). Electrophoresis on cellulose acetate membranes is carried out for serum protein fractions in many clinical laboratories, and it is a simple and easily reproducible technique. After UPE on cellulose acetate, membranes are stained with solutions containing Acid-violet 17 and Coomassie Brilliant Blue; however, extensive preconcentration of urine before electrophoresis generally is recommended because of the low concentrations of urinary proteins. This procedure for concentrating urine is time-consuming and has problems such as protein loss, aggregation, and degradation. Although highly sensitive staining methods using colloidal gold solution without preconcentration of urine have been reported (14)(15)(16), these methods require 2–3 h for protein staining. We previously reported a rapid and highly sensitive colloidal silver staining solution suitable for cellulose acetate membranes (17). In this study, we further modified the staining method and developed a more rapid and sensitive colloidal silver staining method to detect small amounts of BJP that does not require preconcentration of urine. We used urine samples obtained from inpatients with multiple …