Serum B-Cell maturation antigen is an independent prognostic marker in previously untreated chronic lymphocytic leukemia

Abstract

B-Cell maturation antigen (BCMA) is a cell membrane receptor expressed on mature B lymphocytes, with elevated serum levels found among patients with B-cell malignancies, including chronic lymphocytic leukemia (CLL). Serum BCMA (sBCMA) levels were measured in 331 untreated, newly diagnosed CLL patients using an enzyme-linked immunosorbent assay with a polyclonal anti-BCMA antibody. Elevated sBCMA levels were found among patients with CLL compared with age- and sex-matched healthy controls and those with more active CLL based on prognostic factors. The relationships between sBCMA, time to first treatment (TTFT), overall survival (OS) and multiple prognostic factors were compared using Mann-Whitney and Kruskal-Wallis tests. The median sBCMA level in the CLL cohort (48.6 ng/mL) was significantly higher (p < 0.001) compared with those of age- and sex-matched healthy subjects (n=100; 37.8 ng/mL). Serum BCMA correlated with TTFT(hazard ratio [HR]=2.9, 95% confidence interval 2.0-4.2, p < 0.001) and OS (HR=2.5, 95% confidence interval: 1.5-4.0, p < 0.001). Multiple models were used to test the predictive effects of sBCMA, sex, CLL International Prognostic Index (CLL-IPI) and International Prognostic Score for early-stage CLL (IPS-E) on TTFT and OS. The addition of sBCMA to CLL-IPI and IPS-E improved their prognostic ability to predict TTFT and OS. Thus, sBCMA is a new promising prognostic biomarker for CLL.