Cytokine Contents in Chronic Lymphocytic Leukemia: Association with ZAP70 Expression

Chronic lymphocytic leukemia (CLL) is a disease that shows varying clinical progression, and expression of the protein tyrosine kinase ZAP70 has been described as a very valuable prognostic factor. Patients with ZAP70 positivity are characterized by worse clinical course and significantly shorter progression-free and overall survival. In this study, intracytoplasmic interferon gamma (IFN-γ) and interleukin-4 (IL-4) content of T, B, and CLL cells in CLL patients and their correlations with Rai staging and ZAP70 positivity were investigated.

CLL patients newly diagnosed or in follow-up at the İstanbul University İstanbul Medical Faculty Hematology Department were included in this study. These patients were classified according to Rai staging and ZAP70 expression. IL-4, IFN-γ, and ZAP70 expressions in peripheral blood T, B, and CLL cells were measured by four-color flow cytometry.

There was a statistically significant correlation between advanced disease and ZAP70 positivity. IL-4-secreting T cells were significantly increased; however, IFN-γ secretion was significantly decreased in CLL patients compared to healthy individuals, whereas IL-4-secreting B cells were significantly diminished in contrast to T cells.

These findings suggest damage in the cellular immunity and that IL-4 might lead to many complications and may be important in disease progression.