Christine Greil1, Gabriele Ihorst2, Felix Gaiser1, Ulrich Salzer3, Emanuel Bisse4, Efstathios Kastritis5, Heinz Ludwig6, Ralph Wäsch1, Monika Engelhardt1. 1. Department of Medicine I, Hematology, Oncology & Stem Cell Transplantation, Faculty of Medicine, Medical Center - University of Freiburg, Freiburg, Germany. 2. Faculty of Medicine, Clinical Trials Unit, University of Freiburg, Freiburg, Germany. 3. Department of Rheumatology and Clinical Immunology, Faculty of Medicine, Medical Center - University of Freiburg, Freiburg, Germany. 4. Central Laboratory, Medical Center, University of Freiburg, Freiburg, Germany. 5. University of Athens, Athens, Greece. 6. Zentrum für Onkologie, Wihelminenkrebsforschungsinstitut, Beethovengasse, Österreich.
Abstract
OBJECTIVE: The heavy/light chain (HLC)-immunoassay quantifies light chain types of each immunoglobulin class in patients with monoclonal gammopathies. METHODS: We assessed 147 consecutive patients with different forms and stages of plasma cell dyscrasias (PCD) who received standard tests (serum and urine protein electrophoresis [SPEP, UPEP], immunofixation [IFE], serum-free light chain [SFLC]), and HLC-immunoassay. Patients with multiple myeloma (MM, n = 102), smoldering MM (SMM, n = 5), monoclonal gammopathy of undetermined significance (MGUS, n = 28), and Waldenström's macroglobulinemia (WM, n = 12) were included. RESULTS: We verified a significant correlation between HLC- and standard monoclonal protein (mp)-parameters, and HLC-increases with higher disease stage and unfavorable remission status. In patients with difficult to quantify mp, more abnormal HLC- than SPEP-, immunoglobulin-, or SFLC-results were found. In WM, a pathological HLC κ/λ-ratio and M-component were observed in 95% and 58%, respectively. In 21/28 MGUS and 5/5 SMM patients, HLC κ/λ-ratios were abnormal. Testing different HLC cutoffs, patients with extreme HLC values showed impaired progression-free survival (PFS). CONCLUSIONS: Despite the fact that different PCD patients were included, the assessment of the HLC-immunoassay in MGUS, SMM, MM, and WM, our comparison with standard mp-assays, and relevant PFS differences may excite future applications, which should be confirmed in prospective multicenter trials.
OBJECTIVE: The heavy/light chain (HLC)-immunoassay quantifies light chain types of each immunoglobulin class in patients with monoclonal gammopathies. METHODS: We assessed 147 consecutive patients with different forms and stages of plasma cell dyscrasias (PCD) who received standard tests (serum and urine protein electrophoresis [SPEP, UPEP], immunofixation [IFE], serum-free light chain [SFLC]), and HLC-immunoassay. Patients with multiple myeloma (MM, n = 102), smoldering MM (SMM, n = 5), monoclonal gammopathy of undetermined significance (MGUS, n = 28), and Waldenström's macroglobulinemia (WM, n = 12) were included. RESULTS: We verified a significant correlation between HLC- and standard monoclonal protein (mp)-parameters, and HLC-increases with higher disease stage and unfavorable remission status. In patients with difficult to quantify mp, more abnormal HLC- than SPEP-, immunoglobulin-, or SFLC-results were found. In WM, a pathological HLC κ/λ-ratio and M-component were observed in 95% and 58%, respectively. In 21/28 MGUS and 5/5 SMM patients, HLC κ/λ-ratios were abnormal. Testing different HLC cutoffs, patients with extreme HLC values showed impaired progression-free survival (PFS). CONCLUSIONS: Despite the fact that different PCDpatients were included, the assessment of the HLC-immunoassay in MGUS, SMM, MM, and WM, our comparison with standard mp-assays, and relevant PFS differences may excite future applications, which should be confirmed in prospective multicenter trials.
Authors: Jo Caers; Laurent Garderet; K Martin Kortüm; Michael E O'Dwyer; Niels W C J van de Donk; Mascha Binder; Sandra Maria Dold; Francesca Gay; Jill Corre; Yves Beguin; Heinz Ludwig; Alessandra Larocca; Christoph Driessen; Meletios A Dimopoulos; Mario Boccadoro; Martin Gramatzki; Sonja Zweegman; Hermann Einsele; Michele Cavo; Hartmut Goldschmidt; Pieter Sonneveld; Michel Delforge; Holger W Auner; Evangelos Terpos; Monika Engelhardt Journal: Haematologica Date: 2018-08-31 Impact factor: 9.941