Evaluation The Role of CD33+ CD11b+ myeloid-derived Suppressor Cells in Patients With AML

Abstract

Acute myeloid leukemia is a genetically heterogeneous clonal disease defined by the accumulation of immature cells in bone marrow and blood. The aim of this study is to evaluate the CD33, CD11b, and HLA-DR expression in Iraqi AML patients and its role in evasion of malignant cells from the immune system. This study was conducted on 60 patients with AML and 20 healthy individuals as a control group to evaluate the expression of CD33 and CD11b using flow-cytometry in peripheral blood, and evaluate Interferons-γ (IFN-γ) and Transforming Growth Factor-β1 (TGF-β1) levels. A statistically non-significant difference (P < 0.005) between the AML patients and control group with regard to the expression of CD33, CD11b, and HLA-DR was observed. Analysis of CD33 expression in myeloid-derived suppressor cells (MDSCs) showed a significant decrease in the proportion of CD33 positive MDSC cells in isolated peripheral blood samples (88.078 ± 1.284). Also, the expression of CD11b in MDSC cells was high (98.841±1.935) in MDSC cells. The mean level of IFN-γ (pg/ml) increased in AML in compared to control group (9.202 ± 0.244), (7.906±1.22), respectively. While TGF- β1 (pg/ml) concentration was found to be elevated in AML patients (69.04 ± 9.92) compared to control group (33.884 ± 2.888). In conclusion, circulating MDSCs were significantly elevated in peripheral blood of patients with AML and characterized by the CD33+CD11b + phenotype; TGF-β1 and IFN-γ can be released in the presence of native human AML cells and affect AML cell proliferation and evasion from immune system.

Keywords

CD11b, CD33, HLA-DR, MDSC, AML.