Swedish study confirms abnormal kappa lambda ratio predicts risk for progression of MGUS

17 January 2014

Using a large, independent cohort of 728 MGUS patients followed for up to 30 years, this study confirms a previous Mayo Clinic, USA publication that an abnormal free light chain ratio predicts risk of progression to Multiple Myeloma from MGUS (monoclonal gammopathy of undetermined significance). The polyclonal Freelite® serum free light chain assays were used to measure the κ/λ ratio.

Results also confirmed the predictive value of a high monoclonal protein concentration (> 1.5 g/dL or >15 g/L); both these factors were reported as predictive by the Mayo Clinic in 2005.

A novel observation in this study was that the addition of immunoparesis - a reduction of 1 or 2 non-involved immunoglobulin isotype levels - to the Mayo Clinic risk model (abnormal κ/λ ratio, non-IgG isotype, and M-protein >1.5 g/dL) better predicted the risk of progression. Patients with all 4 risk factors had a very high (40%) risk of progression within 10 years.

Monoclonal gammopathy of undetermined significance and risk of lymphoid and myeloid malignancies: 728 cases followed up to 30 years in Sweden

Ingemar Turesson, Stephanie A. Kovalchik, Ruth M. Pfeiffer, Sigurdur Y. Kristinsson, Lynn R. Goldin, Mark T. Drayson and Ola Landgren

Prepublished online November 12, 2013;