CLINICAL IMPLICATION OF IMMUNOGLOBULIN FREE LIGHT CHAINS STUDY IN PATIENTS WITH MULTIPLE MYELOMA
The paper describes results of immunoglobulin light chain measurements in serum from 107 patients with monoclonal gammopathies. Sensitivity of electrophoresis, immunofixation and free light chain assays was assessed for detection of serum monoclonal protein during screening. Monoclonal gammopathy was diagnosed in 100% of cases using all the three assays. A total of 85 sera from patients with active myeloma and 65 sera from patients in remission were studied. Cases with remission demonstrated a statistically significant reduction in concentration of involved and uninvolved immunoglobulin free light chains as compared to active myeloma patients. Patients with remission also presented with a lower ratio of involved and uninvolved immunoglobulin free light chains and decreased differences between these parameters. Response to chemotherapy by immunoglobulin free light chain measurement was assessed in 21 patients with measurable disease by both protein electrophoresis in serum and urine and immunoglobulin free light chain concentration. Immunoglobulin free light chain concentration was measured on chemotherapy in 12 cases. Remission by standard immunochemical assays was detected after 3 to 6 chemotherapy cycles. Partial remission by changes in immunoglobulin free light chain concentration was discovered in all cases following 1 to 2 chemotherapy cycles. Early response by immunoglobulin free light chain testing after 1 to 2 chemotherapy cycles is a prognostic factor of remission.