Abstract
INTRODUCTION: B-cell chronic lymphocytic leukemia (B-CLL) is a common form of leukemia affecting mostly elderly individuals. The course of the disease is usually unremarkable, but because it may proceed with impaired immune defense, B-CLL might be complicated with infections and even death. The leukemic microenvironment containing a number of immune cells, mainly lymphocytes and macrophages capable to produce various molecules including inflammatory cytokines, plays an important role in the development and outcome of the disease. We studied the capacity of Epstein-Barr virus (EBV)-transformed B-cell chronic lymphocytic leukemia (B-CLL) cell line (EHEB) cells, an EBV-transformed line established from a B-CLL patient, to affect the production of inflammatory cytokines by human peripheral blood mononuclear cells (PBMC). METHODS: PBMC isolated from peripheral blood of healthy donors were incubated either with EHEB cells or with their supernatants and the production of the following cytokines: tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, interferon (IFN)-γ, IL-1ra, and IL-10 were detected using the enzyme-linked immunosorbent assay method. RESULTS: Direct contact of PBMC incubated with EHEB cells induced a marked increase of TNFα, IL-1β, IL-6, IFNγ, and IL-10 release by the immune cells. Yet, incubation of PBMC with EHEB cells' supernatant resulted in a mild production of the same cytokines. CONCLUSIONS: The noticeable increased production of inflammatory cytokines by PBMC following direct contact with EHEB cells and to a lesser degree with their supernatants implies the existence of an immune dialogue between these two types of cells. The results support the concept that not only leukemic cells, but also peripheral blood mononuclears could serve as a therapeutic target for B-CLL.