Article Type

Original Study


Objective This work aimed to study CD73 expression in chronic lymphocytic leukemia (CLL) patients and its correlation with other disease characteristics. Background CLL is a common B-lymphoproliferative disorder, which can be diagnosed in most cases by morphology and flowcytometry. It displays heterogeneity in clinical presentation, course, and response to treatment, which is likely due to the diversity of the biological nature of the disease. Diagnostic difficulty might arise in some patients due to atypical morphology and/or immunophenotype. CD73 is an extracellular enzyme that hydrolyses adenosine monophosphate to adenosine and is expressed on a subset of T and B lymphocytes. A number of studies have shown CD73 as a contributing factor in the multistep process of carcinogenesis by inducing favorable environment for tumor growth. However, it was shown in some studies to induce apoptosis. Patients and methods CD73 expression on both B and T lymphocytes was measured in 25 cases of newly diagnosed CLL and 15 healthy controls. The levels of expression were correlated to other disease characteristics. Results CD73 expression on CD19 + B lymphocytes was significantly lower in CLL patients compared with controls (mean 3.74 vs. 29.35%, respectively, P < 0.001). CD73 expression on T lymphocytes was also significantly lower in patients compared with controls (mean 0.46 vs. 5.10%, P < 0.001). CD73 expression on T lymphocytes was significantly lower in patients with Binet stage C compared with those with earlier stages (i.e., A and B) (mean 0.15 vs. 0.68, P = 0.05). There was no significant correlation between CD73 expression on clonal B cells and B-symptoms, clinical stage, lactate dehydrogenase, or β2microglobulin. Conclusion CD73 expression is a potential diagnostic marker in CLL. This can be particularly relevant in cases with atypical immunophenotype using the current CLL scoring system. CD73 may have a role in CLL pathogenesis as low expression can lead to failure of termination of immune response with subsequent proliferation and clonal expansion of the involved clone.