Background & objective: Interferon-alpha (IFN-alpha), an important immunoregulatory cytokine, has been widely used in treating virus hepatitis, lymphoma, and chronic myeloid leukemia (CML), and showed evident effect, but the mechanism is unclear. Dendritic cells (DCs), specialized antigen-presenting cells (APCs), play a pivotal role in activating initial T cells, and maintaining cell immune responses. Does the efficiency of IFN to CML relate to the DCs induced by IFNy What kind of effect do DCs have on IFN therapy for CMLy Up to now, few researches are available. This study aimed to observe whether the DCs were induced through culturing bone marrow mononuclear cells (BMMNCs) of CML in vitro, investigate the mechanism of IFN-alpha therapy for CML, and then provide a new strategy for clinical therapy.
Methods: BMMNCs were obtained from blood of CML patients by Ficoll-Paque density gradient centrifugation, and induced with IFN-alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF) (IFN-alpha/ GM-CSF group), or interleukin-4 (IL-4) and GM-CSF (IL-4/ GM-CSF group), or IFN-alpha, GM-CSF, and IL-4 (IFN-alpha/GM-CSF/IL-4 group) for 7 days. Morphology of BMMNCs was observed under transmissional and optical microscope. The phenotypes [CD1a, CD83, CD86, human leukocyte antigen (HLA)-ABC, HLA-DR, CD54] were assayed by flow cytometry (FCM). The mixed lymphocyte reaction(MLR) of DCs was evaluated by MTT assay.
Results: After inducements, BMMNCs showed typical dendritic projections, and highly expressed CD1a, CD83, CD86, HLA-ABC, HLA-DR, and CD54. Positive rates of HLA-ABC and HLA-DR were higher in IFN-alpha/ GM-CSF group and IFN-alpha/GM-CSF/IL-4 group than in IL-4/ GM-CSF group (P<0.05). Positive rate of CD86 and MLR were the highest in IFN-alpha/GM-CSF/IL-4 group (P<0.05). Positive rates of DC antigens and MLR in IFN-resistant group were significantly lower than those in newly diagnosed group and IFN-sensitive group (P<0.05), but positive rate of CD86 and MLR have no significant difference among 3 groups in the presence of IFN-alpha/GM-CSF/IL-4 (P>0.05).
Conclusions: The BMMNCs of CML cultured in the presence of IFN-alpha and other cytokines can be induced into DCs with morphologic and immunophenotypic characteristics, overexpresses major histocompatibility complex (MHC) molecules, co-stimulatory molecules, and adhesion molecules, and have enhancing MLR. The possible mechanism of IFN-alpha therapy for CML may be relate to DCs.