Abstract

MADALENA, Leticia B. et al. Urinary excretion of low molecular weight proteins in patients with monoclonarl light chain proteinuria as marker of renal dysfunction. Acta bioquím. clín. latinoam. [online]. 2004, vol.38, n.1, pp.17-22. ISSN 0325-2957.

The urinary excretion of low molecular weight proteins (LMWP) beta-2microglobulin (B2m), retinol binding protein (RBP) and alfa-1 microglobulin (A1m) were performed in the urine of 65 patients with monoclonal light chains (MLC) and in 47 patients with different renal diseases (DRD), to evaluate the clinical utility of their determination and the effect of the MLC presence. Immunonephelometry (Beckman) for the quantitation of kappa, lambda and A1m was used, together with immunoturbidimetry for B2m (Roche) and ELISA (Randox) for RBP. The A1m and RBP quantitation had a correlation with the concentration of MLC (r = 0.49, p < 0.01) (r = 0.33, p < 0.05). The mean average of the values of LMWP showed differences for the origin of the disease (p < 0.05) and the presence of renal failure (RF) (p < 0.001). The A1m was different among patients with and without RF (p < 0.05 for MLC, and p < 0.01 for DRD). The number of patients without RF with an increased excretion of A1m showed differences between MLC and DRD (80% and 35.7%; p < 0.01). In patients with MLC, the high excretion of LMWP in the presence or not of RF, would indicate a tubular dysfunction. A1m in patients with MLC without RF, could constitute an early diagnostic tool, as indicator of nephrotoxicity.

Keywords : Monoclonal light chains.; Bence Jones.; Urinary low molecular weight proteins.; Alfa-1 microglobulin.; Nephrotoxicity.; Monoclonal gammopathies.; Renal failure.

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