A Case of Primary IgG-κ with κ Free Light Chain Plasma Cell Leukemia with Literature Review.

[BACKGROUND] The aim of this study was to investigate the clinical and laboratory features of primary IgG-κ with κ free light chain plasma cell leukemia.

[METHOD] We retrospectively analyzed the clinical and laboratory features of a case of primary plasma cell leukemia of the IgG-κ with κ free light chain type and reviewed the literature on patients with primary plasma cell leukemia.

[RESULT] The patient's white blood cell count was 36.95 x 109/L, hemoglobin was 43 g/L, platelet count was 64 x 109/L. Push film review: the number of white blood cells was significantly increased, and a type of cell was seen, with medium cytosol, polarized nucleus, abundant cytoplasm, stained areas, and rounded inclusions, which accounted for 90% of the total number of white blood cells. IgG 89.8 g/L, IgA < 0.26 g/L, IgM < 0.26 g/L, complement C3 0.33 g/L, complement C4 0.09 g/L; blood β2 microglobulin > 24.4 mg/L, ferritin 429.72 ng/mL. Serum protein electrophoresis: M protein bands were found, and the M protein content was 71.84 g/L. Serum immunofixation electrophoresis: precipitating bands were found in the IgG lane, two precipitating bands were found in the κ lane, and the monoclonal immunoglobulin type was IgG-κ with κ free light chain type. Flow cytometry: plasma cells accounted for 69.61% of the total, and their immunophenotypes were CD28+, CD38+, CD138+, CD27+ partially, CD269+ in small amount, CD19-, CD20-, and intracellular immunoglobulin Kappa light chain restriction expression, suggesting primary plasma cell leukemia.

[CONCLUSIONS] For primary plasma cell leukemia, we should pay attention to the changes in the abnormal morphology and number of plasma cells. With the help of bone marrow smear, flow cytometry and other tests, we can make a clear diagnosis as early as possible and actively carry out treatment at an early stage.