Revised: March 29, 2013
Accepted: April 10, 2013
Published online: May 6, 2013
New assays for serum immunoglobulin (Ig) free and heavy chain quantification were developed for routine clinical practice. Serum free light chain (sFLC) assay was shown to improve detection, management and prognostication in all plasma cell dyscrasias. More precisely, sFLC measurements proved to be prognostic for the progression of monoclonal gammopathy of undetermined significance and smoldering multiple myeloma (MM), became markers of response and survival in amyloid light-chain amyloidosis and contributed to accurate follow-up of patients with light chain and non secretory MM. In addition, sFLC and they ratio (sFLCR) were shown useful for the prognosis and monitoring of intact Ig myeloma; their evaluation was incorporated in the new uniform response criteria. sFLC or sFLCR were also observed abnormal in B-cell non-Hodgkin lymphoma/chronic lymphocytic leukemia (CLL). Moreover, increased sFLC levels, summated sFLC or abnormal sFLCR predict shorter overall survival in early-stage CLL while increased sFLC constituted an independent, adverse prognostic factor for event-free and overall survival in diffuse large B-cell lymphoma and Waldenstrom’s macroglobulinemia. Clinical applications of heavy Ig chain separately (HLC) measurements are more recent and mainly concern MM in which HLC deriving ratios correlated with parameters of disease activity and constituted an adverse survival marker.
Core tip: Recently manufactured assays allow the quantification of serum immunoglobulin (Ig) free light chain (sFLC) or of κ or λ restricted heavy Ig chain separately (HLC). These measurements, or the calculation of their corresponding ratios, were shown useful for routine clinical practice in Hematology. sFLC measurements added important prognostic information for monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM), amyloid light-chain (AL) amyloidosis, Waldenstrom’s macroglobulinemia and chronic lymphocytic leukemia while they contributed to accurate follow-up of MGUS, MM and AL amyloidosis patients. HLC measurements are more recent and mainly concern MM in which they constituted a prognostic marker.