Clinical significance of serum sCD23 and B-cell maturation antigen levels in patients with chronic lymphocytic leukemia

BACKGROUND: Chronic lymphocytic leukemia (CLL) is a malignancy of mature appearing clonal B lymphocytes where there is a progressive accumulation of leukemic cells in peripheral blood, bone marrow, and secondary lymphoid tissues as a consequence of defective apoptosis and survival signals derived from the microenvironment. The soluble CD23 (sCD23) is a 25 kDa fragment that can be found in serum, plasma, and urine in patients with CLL. It is a B-cell growth factor. B-cell maturation antigen (BCMA) is a member of the tumor necrosis factor superfamily, it enhances the survival and proliferation of mature B cells and plasma cells through signal transduction of the B-cell activating factor and a proliferation-inducing ligand. AIMS: The aims of this study were to assess the serum levels of sCD23 and BCMA in newly diagnosed CLL patients and to correlate them with clinical Binet staging and other hematological and clinical parameters. PATIENTS, MATERIALS AND METHODS: This study was conducted on 54 newly diagnosed CLL patients and 27 healthy controls. Diagnosis of CLL patients was based on lymphocyte count of >5 × 109/L and immunophenotyping. The serum levels of sCD23 and BCMA were measured in both groups using an enzyme-linked immunosorbent assay. RESULTS: Serum levels of sCD23 and BCMA were significantly higher in CLL patients in comparison with control group (P < 0.001 for both). There was a significant direct association between serum levels of sCD23 and BCMA with the clinical Binet stage of the disease (P < 0.001 for both). sCD23 showed significant correlation with hemoglobin (Hb) level (P < 0.001), total white blood cell (WBC) count (P = 0.001), lymphocyte count (P < 0.001), platelet count (P = 0.017), B-symptoms (P = 0.001), and splenomegaly (P = 0.019), whereas BCMA has significant correlations with Hb level, total WBC count, lymphocyte count (P < 0.001 for each one), B-symptoms (P < 0.001), lymphadenopathy (P = 0.001), splenomegaly (P = 0.024), and hepatomegaly (P = 0.04). CONCLUSIONS: The levels of serum sCD23 and serum BCMA increase with advancing Binet stages of the disease indicating their possible usefulness as good and reliable parameters for prognostic evaluation in CLL patients. The significant correlation of serum sCD23 and serum BCMA with hematological parameters and clinical features render them as reliable tumor burden markers in CLL patients.