Prognostic significance of serum monoclonal immunoglobulin in B-chronic lymphocytic leukemia

Abstract

Background Serum immunoglobulin (Ig) paraprotein can be detected in a subset of patients with chronic lymphocytic leukemia (CLL) by serum protein electrophoresis and immunofixation electrophoresis. CLL with Ig paraproteinemia had an inferior survival compared with patients with CLL without serum paraprotein. Participants and methods The present study was carried out on 100 patients with B-CLL (60 men and 40 women) ranging in age from 33 to 75 years. The staging of CLL was performed according to the Binet staging system. Venous blood samples were obtained from B-CLL patients for a complete blood count. Serum was separated for the measurement of lactate dehydrogenase (LDH), β 2 -microglobulin (β 2 -MG) levels by ELISA, and Ig paraprotein. Bone marrow aspiration was carried out for all B-CLL cases. Prognostic markers of CD38 and z-chain-associated protein kinase-70 (ZAP-70) expression were also analyzed. Results Twenty-two patients had Ig paraproteinemia of a total of 100 untreated patients with CLL, frequency 22%. There was a highly significant elevation in LDH, β 2 -MG, CD38, ZAP-70, IgG, and IgM in CLL with monoclonal paraprotein versus CLL without monoclonal paraprotein. There were positive correlations of serum IgG paraprotein and serum IgM paraprotein with advanced Binet stage (P 2 -MG (P=0.00 and 0.00) and LDH (P=0.00 and 0.00), CD38 positivity (P=0.00 and 0.02), and ZAP-70 positivity (P=0.00 and 0.01). Also, there was a positive correlation between high serum β 2 -MG concentration with Binet stage (P=0.00), high level of LDH (P=0.00), CD38 positivity (P=0.00), and ZAP-70 positivity (P=0.02). After a follow-up of 60 months, 15 patients (15%) died. Eight (36.3%) patients with Ig paraproteinemia died during the observation period, whereas among the 78 patients without Ig paraproteinemia, seven (8.9%) died. Conclusion β 2 -MG and Ig paraprotein serve as poor prognostic markers for B-CLL. Patients with CLL with serum Ig paraprotein represent a heterogeneous group with an inferior clinical outcome. Serum Ig paraprotein might be applied for the assessment of prognosis in patients with CLL.