title: Comparative analysis of monocytic and granulocytic myeloid-derived suppressor cell subsets in patients with gastrointestinal malignancies.
abstract: Myeloid-derived suppressor cells (MDSC) are a heterogenous population of cells comprising myeloid progenitor cells and immature myeloid cells, which have the ability to suppress the effector immune response. In humans, MDSC have not been well characterized owing to the lack of specific markers, although it is possible to broadly classify the MDSC phenotypes described in the literature as being predominantly granulocytic (expressing markers such as CD15, CD66, CD33) or monocytic (expressing CD14). In this study, we set out to perform a direct comparative analysis across both granulocytic and monocytic MDSC subsets in terms of their frequency, absolute number, and function in the peripheral blood of patients with advanced GI cancer. We also set out to determine the optimal method of sample processing given that this is an additional source of heterogeneity. Our findings demonstrate consistent changes across sample processing methods for monocytic MDSC, suggesting that reliance upon cryopreserved PBMC is acceptable. Although we did not see an increase in the population of granulocytic MDSC, these cells were found to be more suppressive than their monocytic counterparts.
authors.affiliation: GI Malignancy Section, Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: Austin
authors.initials: A
authors.lastname: Duffy
authors.forename: Fei
authors.initials: F
authors.lastname: Zhao
authors.forename: Lydia
authors.initials: L
authors.lastname: Haile
authors.forename: Jaba
authors.initials: J
authors.lastname: Gamrekelashvili
authors.forename: Suzanne
authors.initials: S
authors.lastname: Fioravanti
authors.forename: Chi
authors.initials: C
authors.lastname: Ma
authors.forename: Tamar
authors.initials: T
authors.lastname: Kapanadze
authors.forename: Kathryn
authors.initials: K
authors.lastname: Compton
authors.forename: William D
authors.initials: WD
authors.lastname: Figg
authors.forename: Tim F
authors.initials: TF
authors.lastname: Greten
mesh_terms: D005260:Female; D005770:Gastrointestinal Neoplasms / Q000276:immunology*; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D022423:Myeloid Cells / Q000276:immunology*; D012720:Severity of Illness Index; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014407:Tumor Cells, Cultured