Changqiang Chen1, Peizhan Chen2, Xuqian Fang3. 1. Department of Clinical Laboratory, Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China. 2. Translational Medicine Research Center, Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China. 3. Department of Pathology, Ruijin Hospital North, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Abstract
BACKGROUND: Monoclonal free light chains (FLC) commonly exist in monomeric or dimeric forms but rarely as larger molecules. Little is known about whether polymeric molecules can affect urine protein electrophoresis (UPE) results. METHODS: Urine samples were collected from 72 multiple myeloma (MM) patients with Bence Jones protein (BJP). Urine protein and immunofixation electrophoresis were analyzed on Sebia SDS "agarose" gel electrophoresis system (SDS-AGE), and immunoglobulin free light chains were measured on the BNII nephelometric assay. RESULTS: A type of disulfide-bound FLC dimer shows a pattern shift to the position of the "albumin" band in urine protein electrophoresis in multiple myeloma (MM) patients according to the Sebia agarose gel-based detection system, which was validated by immunofixation, SDS-PAGE, and mass spectrometric methods. Similar cases were found in 21 (29.17%) of 72 MM patients with BJP, and 19 (90.5%) of 21 patients were the lambda type. CONCLUSIONS: These results indicate that BJP with lambda type has a strong tendency to abnormally migrate, which may increase the risk of misinterpretation of protein electrophoresis in clinics. Thus, when the urine protein electrophoresis is inconsistent with the result by nephelometric method, urine protein electrophoresis needs to be repeated on the deduced condition to confirm the essence of the originally identified "albumin."
BACKGROUND: Monoclonal free light chains (FLC) commonly exist in monomeric or dimeric forms but rarely as larger molecules. Little is known about whether polymeric molecules can affect urine protein electrophoresis (UPE) results. METHODS: Urine samples were collected from 72 multiple myeloma (MM) patients with Bence Jones protein (BJP). Urine protein and immunofixation electrophoresis were analyzed on Sebia SDS "agarose" gel electrophoresis system (SDS-AGE), and immunoglobulin free light chains were measured on the BNII nephelometric assay. RESULTS: A type of disulfide-bound FLC dimer shows a pattern shift to the position of the "albumin" band in urine protein electrophoresis in multiple myeloma (MM) patients according to the Sebia agarose gel-based detection system, which was validated by immunofixation, SDS-PAGE, and mass spectrometric methods. Similar cases were found in 21 (29.17%) of 72 MMpatients with BJP, and 19 (90.5%) of 21 patients were the lambda type. CONCLUSIONS: These results indicate that BJP with lambda type has a strong tendency to abnormally migrate, which may increase the risk of misinterpretation of protein electrophoresis in clinics. Thus, when the urine protein electrophoresis is inconsistent with the result by nephelometric method, urine protein electrophoresis needs to be repeated on the deduced condition to confirm the essence of the originally identified "albumin."
Authors: Lawreen H Connors; Yan Jiang; Marianna Budnik; Roger Théberge; Tatiana Prokaeva; Kip L Bodi; David C Seldin; Catherine E Costello; Martha Skinner Journal: Biochemistry Date: 2007-11-16 Impact factor: 3.162
Authors: Roshini S Abraham; M Cristine Charlesworth; Barbara A L Owen; Linda M Benson; Jerry A Katzmann; Craig B Reeder; Robert A Kyle Journal: Clin Chem Date: 2002-10 Impact factor: 8.327