The Study On Dendritic Cells Derived From Chronic Myeloid Leukemia Induced By Low Dose Cytosine Arabinoside Combined With Interferon-α

Objective Interferon-alpha(IFN-α),an important immunoregulatory cytokine,has been widely used for immunoregulatory in chronic myeloid leukemia (CML)since 1980s, moreover, the patients that achieve above partial cytogenetic response after IFN-αtreatment,present obviously more survival superiority than the patients whose IFN-αtreatment is ineffective. clinical data discoverd: Low dose cytosine arabinoside (LD-Ara-C) combined with IFN-αis superior to IFN-αalone, which presents striking cytogenetic remission. One of the mechanisms of IFN-αtherapy for CML is related to dendritic cells, Which can enhance the phenotype and function of dendritic cells (DCs). DCs, specialized antigen-presenting cells (APCs),play a pivotal role in activating initial T cells,and maintaining cell immune responses. However, LD-Ara-C plays a role in the differentiation of acute myeloid leukemia(AML), Does the superiority of LD-Ara-C combined with IFN-αto CML related to induction of more mature DCs,and then further strengthen the function of DCs? Up to now, no research is available. This study aimed to observe whether the DCs were induced more mature through culturing bone marrow mononuclear cells(BMMNCs) of CML by LD-Ara-C combined with IFN-αin vitro, investigate the mechanism of LD-Ara-C combined with IFN-αtherapy for CML, and then provide theoretical foundation for clinical therapy.Methods BMMNCs were obtained from CML patients by Ficoll-Paque density gradient centrifugation, and induced with granulocyte-macrophage colony-stimulating factor(GM-CSF),interleukin-4(IL-4),IFN-αand Ara-C, we put them into five groups because of different doses of Ara-C: 5ng/ml group,10ng/ml group,25ng/ml group,50ng/ml group and IFN-αgroup. Morphology of BMMNCs was observed under transmissional and optical microscope. The phenotypes (CD1a,CD54,CD83,CD86,HLA-DR) 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, some of them displayed eccentric and bilobed nuclei with Wright-Giemsa (R-G)staining. The DCs cultured in 5ng/ml group and 10ng/ml group showed significantly higher levers of CD1a, CD54, CD83, CD86, HLA-DR expression than the other three groups, which had significant difference (P<0.05). 10ng/ml group displayed the highest phenotypes ,which had significant difference between 5ng/ml group (P<0.05). It also had difference on phenotypes of IFN-αgroup and 25ng/ml group(P<0.05). Large part of cells in the 25ng/ml group died. All cells in the 50ng/ml group died. MLR of DCs was coincide with phenotypes expression of DCs,that is 10ng/ml group > 5ng/ml group > IFN-αgroup > 25ng/ml group > 50ng/ml group, which had significant difference (P<0.05).Conclusion The BMMNCs of CML cultured in the presence of LD-Ara-C and IFN-αcan be induced into DCs which is superior to IFN-αalone,with morphologic and immunophenotypic characteristics, overexpressed major histocompatibility complex (MHC) molecules, co-stimulatory molecules, and adhesion molecules, and have enhancing MLR. The possible mechanism of LD-Ara-C combined with IFN-αtherapy for CML may be related to DCs.