[Value of Serum Light Chain in Diagnosis and Evaluation of Efficacy for Multiple Myeloma]

To explore the clinical application value of serum light chain (sLC) in the diagnosis and therapeutic efficacy evaluation for multiple myeloma.

46 patients with newly diagnosed multiple myeloma were selected as MM group and 50 healthy persons as control group. Rate scattering immunoturbidimetry was used to detect serum light chain and immunoglobulin (Ig) in two groups, serum protein electrophoresis was used to detect M protein by agarose gel. Then, the sensitivity and specificity of the two methods in MM diagnosis were analyzed and compared, and the significance of sLC detection in MM diagnosis were discussed. In addition, 15 MM patients after received conventional therapy were tracked, sLC levels in five different therapentic times were recorded, and the effect of sLC in efficacy evaluation of MM was analyzed.

There were 11 cases of IgA type, 15 cases of IgG type, 8 cases of light chain κ type, 8 cases of light chain λ type, 2 cases of IgD type, and 2 cases of non-secretion type. The sLC-κ, sLC-λ and their ratio (including light chain type and double clone type), IgA and IgG (except IgD type), as well as albumin, beta-globulin and gamma-globulin levels showed statistically significant differences (P＜0.05) compared with the control group. The sensitivity of serum protein electrophoresis, Ig quantification, sLC and its ratio in the diagnosis of multiple myeloma were 57%, 76% and 65%, and their specificity were 83%, 61% and 90%, respectively. After the second or third chemotherapy, the sLC-κ/λ ratio gradually approached the normal range as the disease reliefes, and the sLC-κ/λ ratio continued to be on or off the line at outliers or further away from the reference value as the disease progresses in MM patients with κ type or λ type.

sLC detection shows positive significance in early diagnosis of multiple myeloma, SLC monitoring can be used for the efficacy evaluation for treatment of MM patients.