Evaluation of interleukin-6 level in patients with chronic lymphocytic leukemia and its correlation with the stage of the disease

Abstract: BACKGROUND: Chronic lymphocytic leukemia (CLL) is not an uncommon hematological malignancy which affects elderly individuals primarily. It is more common in developed world. Interleukin-6 (IL-6) is a soluble mediator with a pleiotropic effect on inflammation, immune response, and hematopoiesis. Due to its major role in initiation as well as resolving inflammation, deregulation of IL-6 is a mainstay of chronic inflammatory and autoimmune diseases. In addition, IL-6 has been shown to be implicated in the pathogenesis of many human malignancies. OBJECTIVES: The aim of the study was to measure the plasma level of IL-6 in newly diagnosed pretreated CLL patients and its association with disease stage and peripheral blood indices. PATIENTS, MATERIALS AND METHODS: A case–control study included 60 patients who are newly diagnosed untreated CLL patients classified into three stages according to the Binet classification system as a patient group and 20 healthy individuals as a control group. The samples were collected from the patients during their attendance at the laboratories of the Hematology Center of the Medical City in Baghdad. For the determination of plasma level of IL-6 in both patient and control groups, an ELISA-based method was used. RESULTS: IL-6 plasma level was higher significantly in the patient’s group than in the control group ( P < 0.001), with the highest IL-6 level found in Stage C and the least IL-6 level found in Stage A ( P = 0.043). The white blood cell count shows a high correlation to IL-6 level when compared to other peripheral blood elements (hemoglobin and platelet count) but is still not statistically significant. Regarding age and gender, they did not have a statistical significance ( r = 0.081, P > 0.05) on the mean plasma level of IL-6 within both the patient and control group. CONCLUSIONS: In this study, IL-6 plasma levels are significantly correlated with the stage of the disease as its level is the highest in CLL patients with advanced disease. IL-6 is an independent prognostic factor in the prediction of the activity and the stage of the disease in these patients.