[Clinical usefulness of serum free light chain measurement in monoclonal gammopathy].

Recently, a highly sensitive assay (FREELITE) capable of measuring serum immunoglobulin-free light chains (FLC) was developed. An abnormal kappa/lambda ratio supports the presence of clonal plasma cell expansion. Using this assay, we measured serum and urine samples of 178 healthy volunteers, 184 patients with polyclonal gamma-globulinemia and 150 patients with monoclonal gamma-globulinemia.

[Evaluation of the clinical relevance of serum measurements of free-light chains in patients with multiple myeloma].

Measurement of serum free-light chains (FLCs) was performed using a recently developed immunoassay in 180 healthy individuals, 16 patients with multiple myeloma, and each 1 patient with Waldenström's macroglobulinemia, primary amyloidosis, or MGUS (monoclonal gammopathy of undetermined significance) to evaluate the clinical relevance of FLCs in the diagnosis and disease monitoring. Serum FLC levels of each patient were elevated compared with the levels of healthy individuals. The changes in FLC levels after treatment and at the time of relapse occurred earlier than those in serum immunoglobulin levels due to the short half-life of FLCs.