Prognostic significance of serum immunoglobulin paraprotein in patients with chronic lymphocytic leukemia

The aim of this study was to explore the clinical and other associated laboratory features of chronic lymphocytic leukemia (CLL) patients with immunoglobulin (Ig) paraproteinemia. Serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE) were performed to measure serum Ig paraprotein. The correlations between serum Ig paraprotein and other prognostic factors were analyzed. Univariate and multivariate Cox regression analyses were used to assess associations between survival time and potential risk factors. In 133 Chinese CLL patients, 27 (20.3%) patients occurred Ig paraproteinemia at diagnosis. According to the correlation analysis, advanced Binet stage (r = 0.314, P < 0.001), direct antiglobulin test (DAT)-positive (r = 0.366, P < 0.001), high level of serum β2-microglobulin (β2-MG) (r = 0.296, P = 0.001) and thymidine kinase (TK) 1 (r = 0.227, P = 0.037), unmutated immunoglobulin heavy chain variable gene (IGHV) status (r = 0.284, P = 0.002), ZAP-70-positive (r = 0.305, P = 0.001), CD38-positive (r = 0.284, P = 0.002), and cytogenetic abnormalities of del(17p13) or del(11q22.3) (r = 0.208, P = 0.032) emerged as factors significantly related to the occurrence of Ig paraproteinemia. Survival analysis showed that the patients with Ig paraproteinemia had significantly shorter survival times than the patients without serum Ig paraprotein (P = 0.013). Binet stage (P = 0.028), high levels of lactate dehydrogenase (LDH) (P = 0.004), IgG paraproteinemia (P = 0.048), IgM paraproteinemia (P = 0.001), ZAP-70-positive (P = 0.003), DAT-positive (P = 0.013), unmutated IGHV status (P = 0.009), and del(17p13) (P = 0.001) were the adverse factors in determining overall survival (OS). Del(17p13) (P = 0.006), ZAP-70 (P = 0.030), and IgM paraproteinemia (P = 0.040) were the variables strongly associated with OS by multivariate Cox regression analysis. It was showed that serum Ig paraprotein might be applied for the assessment of prognosis in patients with CLL.