Alterations in the Frequency of Dendritic Cell Subsets in the Peripheral Circulation of Patients with Squamous Cell Carcinomas of the Head and Neck 1 Thomas K. Hoffmann, 2 Jan Mu ¨ ller-Berghaus, 2 Robert L. Ferris, Jonas T. Johnson, Walter J. Storkus, and Theresa L. Whiteside 3 University of Pittsburgh Cancer Institute [T. K. H., T. L. W.], Departments of Pathology [T. L. W.], Surgery [J. M-B., W. J. S.], and Otolaryngology [R. L. F., J. T. J., T. L. W.], University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213 ABSTRACT Patients with advanced squamous cell carcinomas of the head and neck (SCCHN) are frequently immunocom- promised. Dendritic cells (DCs) are potent antigen-present- ing cells that play a role in antitumor immune responses. Using multicolor flow cytometry, the percentages of lineage- negative (LIN  ) and DR  DC precursors, as well as their LIN  DR  CD11c  (myeloid) and LIN  DR  CD123  (lymphoid) subsets, were determined in the peripheral blood of 36 patients with SCCHN before surgery. Peripheral blood mononuclear cells of 28 age- and sex-matched healthy indi- viduals were used as controls. The proportions of LIN  DR  cells were found to be comparable in the circulation of patients and controls. However, the relative level of DR expression in LIN  DR  DC was lower in patients than in controls, suggesting a difference in the maturity of DC. The relative proportion of LIN  DR  CD123  cells in the LIN  DR  subset of DC did not differ significantly in pa- tients compared with normal individuals. However, the per- centage of myeloid-derived LIN  DR  CD11c  DCs was sig- nificantly lower (P < 0.002) in SCCHN patients than in controls. Of the 13 patients who were restudied 6 weeks after surgery, 9 showed an increase of the myeloid-derived LIN  DR  CD11c  DC subset postoperatively. This obser- vation suggests that deficiency in the myeloid-derived DC precursors in patients with SCCHN is related to the pres- ence of tumor and is reversible. An overall decrease in the myeloid-derived subset of DC could contribute to the failure of SCCHN patients to develop effective antitumor immune responses. INTRODUCTION Patients with advanced SCCHN 4 are known to have dys- functions of the immune system (1–3). Signaling defects have been described in circulating and tumor-infiltrating T cells of these patients (3), and a higher proportion of spontaneously apoptotic T cells has been detected in the peripheral blood of patients compared with that of healthy individuals (4). However, only limited information about DCs and their subsets is avail- able for patients with SCCHN. DCs are potent antigen-present- ing cells, which migrate, phagocytose, and process antigens and present them to T cells, thereby playing a crucial role in the initiation and maintenance of T-cell immunity (5). We have reported previously that ex vivo generation of T cells specific for SCCHN-associated tumor antigens, using autologous DCs pulsed with tumor peptides or whole tumor cells, is not impaired in patients with SCCHN (6, 7). For these ex vivo studies, DCs were generated from monocytes in the presence of cytokines (IL-4 and granulocyte macrophage colony stimulating factor), and T cells were cultured with DCs in the presence of IL-2 and IL-7. However, cytokine-driven activity of cultured DCs is unlikely to reflect the functional status of DC populations found in vivo. Attempts have been made to enumerate and characterize DCs in the microenvironment of SCCHN tumors, and the num- ber of DCs present in the tumor has been described as a highly significant prognostic, as well as survival, biomarker (8 –10). Phenotypic analysis of DCs performed with PBMC of patients with SCCHN and other cancers has indicated that maturational defects might be present (11, 12), possibly because of the presence of a granulocyte macrophage colony stimulating factor-dependent immunosuppressive subset of CD34 + progen- itor cells, which have been reported to impair DC development and differentiation (13). Currently, two peripheral blood DC subsets have been described, which are distinguishable by their ability to express CD11c (14, 15). The CD11c-negative (CD11c - ) DCs, which express high levels of CD123 also known as IL-3 receptor  (16), are designated as lymphoid-derived DCs, whereas the CD11c + CD123 - subset represents myeloid-derived DCs. Al- though both subsets express high levels of HLA-DR and lack the lineage markers CD3, CD14, CD19, CD20, CD16, and Received 12/29/00; revised 3/4/02; accepted 3/8/02. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 1 Supported in part by NIH Grant PO1-DE 12321 (to T. L. W.) and a postdoctoral training fellowship from the Dr. Mildred Scheel Stiftung fu ¨r Krebsforschung (Grant D/99/08916 to T. K. H. and Grant D/98/ 14794 to J. M-B.). 2 T. K. H. and J. M-B. contributed equally to this work. 3 To whom requests for reprints should be addressed, at University of Pittsburgh Cancer Institute, W 1041 Biomedical Science Tower, 200 Lothrop Street, Pittsburgh, PA 15213-2582. Phone: (412) 624-0096; Fax: (412) 624-0264; E-mail: whitesidetl@msx.upmc.edu. 4 The abbreviations used are: SCCHN, squamous cell carcinoma of the head and neck; DC, dendritic cell; IL, interleukin; LIN - , lineage- negative; MoAb, monoclonal antibody; PBMC, peripheral blood mono- nuclear cell; PE, phycoerythrin. 1787 Vol. 8, 1787–1793, June 2002 Clinical Cancer Research Research. on December 11, 2021. © 2002 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Research. on December 11, 2021. © 2002 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Research. on December 11, 2021. © 2002 American Association for Cancer clincancerres.aacrjournals.org Downloaded from