2010 Volume 51 Issue 4 Pages 270-274
Quantitative assay for serum free light chains (sFLC) is reported as a useful test for diagnosis and monitoring of patients with nonsecretory multiple myeloma (NSM). We performed serial sFLC assays in a patient with NSM with light chain cast nephropathy (LCCN) and light chain deposition disease (LCDD). After 3 cycles of VAD induction therapy, while plasma cells in the marrow decreased from 93.0% to 0.2%, sFLCκ/λ ratio remained abnormal. Flow cytometry assay also showed that these plasma cells were CD19 negative. After the subsequent high dose melphalan therapy followed by autologous peripheral blood stem cell transplantation (PBSCT), the sFLCκ/λ ratio returned to normal and the patient achieved a stringent complete response (sCR). One year after PBSCT, the patient remained in sCR with improved renal function. The quantitative FLC assay was useful for the diagnosis and monitoring of NSM and LCDD in this patient.
