Research Article
Johannes Matschke, Lewin Ei
Abstract
Serum Free Light Chains (FLC) have prognostic significance in diverse plasma cell dyscrasias. Although monoclonal protein secretion is a typical feature of these diseases, it can also be detected in other B cell malignancies including chronic lymphocytic leukemia. Recent data suggests a significant correlation between abnormal ratio of FLC and outcome. Therefore, we investigated the role of FLC in a large cohort of 135 patients and the correlation to immunofixation (IF) and flow cytometry. Abnormal FLC ratios were found in 78 patients (58%) whereas the IF was positive in only 32 cases (24%). In 55 cases the FLC ratio was positive while IF was negative and in only 9 cases IF was positive while the FLC ratio was normal. In 52 of 98 patients (53%) light chain restriction determined by flow cytometry was concordant with the monoclonal FLC whereas in 5 patients they did not agree. In 41 of 98 patients (42%) a normal ratio of FLC was observed while the immunophenotype was positive for lambda or kappa. Patients with an abnormal FLC ratio for lambda had a significantly shorter time to first therapy (TFT) than patients with an abnormal ratio for kappa FLC or with a normal FLC ratio (median TFT: 34 versus 76 versus 88 months, p for trend=0.039). Additionally, monoclonal FLC had a significantly shorter time to first treatment compared to polyclonal normal and abnormal FLC ratios (p for trend=0.0489). As expected, polyclonal sFLC correlated significantly with normal and abnormal serum-creatinine (p