Bence Jones Protein Strip Rapid Test

Serum free light chain (sFLC) assay is an important marker in plasma cell dyscrasia. It is thus recommended for the diagnosis of monoclonal gammopathy, together with serum protein electrophoresis and immunofixation. sFLC assay has also a prognostic value and is a criterion for treatment response and relapse of some monoclonal gammopathies. Three assays are currently available in France, the gold standard being the Freelite (R) assay, the two others requiring further validation. These three assays are not interchangeable during patient's follow-up. The Freelite (R) assay is integrated in the myeloma diagnostic criteria by the International Myeloma Working Group 2014, and has a higher sensitivity than Bence Jones protein test for diagnosis, treatment response and follow-up of light chain myeloma. The Freelite (R) assay is the main marker of therapeutic response in light chain amyloidosis and allows to stratify the risk of progression in monoclonal gammopathy of undetermined significance. Some studies have also shown its usefulness in diagnosis of multiple sclerosis and in screening for monoclonal gammopathy in cases of acute renal failure. The Freelite (R) assay is then currently essential in myeloma or amyloidosis, and could be soon extended to the management of autoimmune diseases. (C) 2019 Societe Nationale Francaise de Medecine Interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.

The surface morphology of Bence-Jones protein (BJP) crystals was investigated during growth and dissolution by using in situ atomic force microscopy (AFM). It was shown that over a wide supersaturation range, impurities adsorb on the crystalline surface and ultimately form an impurity adsorption layer that prevents further growth of the crystal. At low undersaturations, this impurity adsorption layer prevents dissolution. At greater undersaturation, dissolution takes place around large particles incorporated into the crystal, leading to etch pits with impurity-free bottoms. On restoration of supersaturation conditions, two-dimensional nucleation takes place on the impurity-free bottoms of these etch pits. After new growth layers fill in the etch pits, they cover the impurity-poisoned top layer of the crystal face. This leads to the resumption of its growth. Formation of an impurity-adsorption layer can explain the termination of growth of macromolecular crystals that has been widely noted. Growth-dissolution-growth cycles could be used to produce larger crystals that otherwise would have stopped growing because of impurity poisoning. (C) 2003 Wiley-Liss, Inc.