Increased Perforin- and IL-21-Expressing NK Cells in Patients with Early-Stage Chronic Lymphocytic LeukemiaFatih Akboğa, Fehmi Hindilerden, Emine Gültürk, İpek Yönal Hindilerden, Abdullah Yılmaz, Günnur Deniz, Metin Yusuf Gelmez
Objective: CD5+CD19+ cells have a low proliferation capacity and elevated expression of anti-apoptotic protein BCL-2, mostly in the G0/ G1 cell phase and accumulate in the pathogenesis of chronic lymphocytic leukemia (CLL). Natural killer (NK) cells have the ability to kill the intracellular pathogen-infected or cancer cells and secrete cytotoxic enzymes. This study evaluated the frequency, expression of cytotoxic enzymes, and intracellular cytokine levels of NK cells in CLL patients. Materials and Methods: In this study, peripheral blood mononuclear cells were isolated from peripheral blood samples of CLL patients (n=29) and healthy controls (n=16) by density gradient centrifugation method. The frequency of the total NK cells and the intracellular levels of perforin, granzyme, interferon (IFN)-γ, interleukin (IL)-21, IL-4 and IL-17 in NK cells were investigated. Results: Elevated total NK cell frequency were found in the CLL patients compared to the healthy controls, and negatively correlated with CD5+CD19+ malign B cell frequency. Increased perforin expression was observed in patients’ total NK cells. Additionally, increased levels of IL-17 and IL-21 in total NK cell of CLL patients were obtained compared to healthy subjects. Conclusion: The findings suggest that in the early stage of CLL, increased total NK cell frequency, and elevated perforin and IL-21 levels in NK cells might have a protective impact against the progression of the disease for CLL patients.