CD33(+) HLA-DR(–) Myeloid-Derived Suppressor Cells Are Increased in Frequency in the Peripheral Blood of Type1 Diabetes Patients with Predominance of CD14(+) Subset

INTRODUCTION: Type 1 Diabetes Mellitus (T1D) is an autoimmune disease that results from the destruction of insulin-producing beta cells of the pancreas by autoreactive T cells. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells that can potently suppress T cell responses. AIM: To detect the presence of MDSCs in T1D and compare their percentage in T1D versus healthy individuals. METHOD: Thirty T1D patients were included in the study. Diabetic patients with nephropathy (n = 18) and diabetic patients without nephropathy (n = 12). A control group of healthy individuals (n = 30) were also included. CD33(+) and HLA-DR– markers were used to identify MDSCs by flow cytometry. CD14 positive and negative MDSCs subsets were also identified. RESULTS: MDSCs was significantly increased in T1D than the control group and diabetic patient with nephropathy compared to diabetic patients without nephropathy. M-MDSCs (CD14(+) CD33(+) HLA–DR(−)) were the most abundant MDSCs subpopulation in all groups, however their percentage decrease in T1D than the control group. CONCLUSION: MDSCs are increased in the peripheral blood of T1D with a predominance of the CD14(+) MDSCs subset. Future studies are needed to test the immune suppression function of MDSCs in T1D.