Patients with head and neck squamous cell carcinoma (HNSCC) have profound immune deficiencies. In 65% of these patients, there is an increased intra‐tumoral presence of immune‐suppressive CD34+ progenitor cells. The goal of the present study was to determine whether CD34+ cell levels were also increased in the peripheral blood of HNSCC patients and if these immune‐suppressive cells could be differentiated into dendritic cells. Our results showed that CD34+ cell levels are increased in the peripheral blood of HNSCC patients. To assess if these CD34+ cells could differentiate into dendritic cells, they were isolated from the blood of HNSCC patients and cultured for 12 days with various cytokine combinations. Culturing CD34+ cells with stem cell factor (c‐kit ligand) plus granulocyte‐macrophage colony‐stimulating factor resulted in the appearance of a significant proportion of cells expressing phenotypic markers characteristic of dendritic cells. Also, including tumor necrosis factor‐α yielded a significant proportion of cells resembling the bi‐potential precursor cells for dendritic cells and monocytes (CD14+CD1a+), in addition to the dendritic‐like cells. When the differentiation inducer 1α,25‐dihydroxyvitamin D3 [1,25(OH)2D3] was added along with the cytokine combinations, the yield of cells having characteristics of dendritic cells was further increased. Cells that were derived from CD34+ cell cultures containing 1,25(OH)2D3 had a more potent capacity to present the recall antigen tetanus toxoid to autologous peripheral blood leukocytes and to stimulate a mixed leukocyte response compared to cultures to which 1,25(OH)2D3 had not been added. Our results show that CD34+ cells, whose frequency is increased in HNSCC patients, can be differentiated into cells that phenotypically and functionally resemble dendritic cells and that 1,25(OH)2D3 accentuates this differentiation. Int. J. Cancer 73:663–669, 1997. © 1997 Wiley‐Liss, Inc.

Freshly excised human head and neck cancers (219 primary cancers; 64 metastatic lymph node cancers) were analyzed for the immune inhibitory mediators released from the cancer tissues and the immune infiltrate within the tumor. Significant levels of the immune inhibitory mediators transforming growth factor-beta (TGF-beta), prostaglandin E2 (PGE2) and interleukin-10 (IL-10) were released from these cancers. Also released was granulocyte-macrophage colony-stimulating factor (GM-CSF), whose secretion was associated with an intratumoral presence of CD34+ cells. We have previously shown that CD34+ cells within human head and neck cancers are immune inhibitory granulocyte-macrophage progenitor cells. The presence of TGF-beta, PGE2 and IL-10 was associated with a reduced content of CD8+ T-cells within the cancers. The CD4+ cell content appeared to be less affected by these immune inhibitory mediators. Instead, parameters indicative of CD4+ cell function (p55 IL-2 receptor expression, release of IL-2 and IFN-gamma) were diminished in cancers that released higher levels of TGF-beta, IL-10 and GM-CSF and had a higher CD34+ cell content. Furthermore, metastatic cancers released higher levels of the soluble immune inhibitory mediators and lower levels of IFN-gamma and IL-2 than did primary cancers, although CD34+ cells were similarly present in both primary and metastatic cancers. Our results show that human head and neck cancers have a multiplicity of non-mutually exclusive mechanisms of immune suppression that are most prominently associated with reduced CD8+ cell influx and reduced influx and altered function of intratumoral CD4+ cells.

Human head and neck squamous cell carcinomas (HNSCC) that produce high levels of granulocyte-macrophage colonystimulating factor (GM-CSF) have been shown to contain CD34 1 natural suppressor cells that inhibit the activity of intratumoral T-cells. The present study evaluated whether GM-CSF production and the presence of CD34 1 cells within primary HNSCC would translate into increased recurrence, metastasis or cancer-related death during the 2 years following surgical excision. Freshly excised primary HNSCC of 20 patients that subsequently developed disease, and of 17 patients that remained with no evidence of disease were analyzed for production of GM-CSF and for CD34 1 cell content. The cancers of patients that subsequently developed recurrences or metastatic disease produced almost 4-fold the levels of GM-CSF and had approximately 2.5-fold the number of CD34 1 cells as did cancers of patients that remained disease-free. In a second method of analysis, the prognostic significance of high vs. low GM-CSF and CD34 1 cell values was evaluated. These analyses showed that patients whose cancers produced high GM-CSF levels or had a high CD34 1 cell content had a disproportionately high incidence of recurrence or metastatic disease (94% and 100%, respectively), while the majority of patients whose primary cancers produced low levels of GM-CSF or had a low CD34 1 cell content remained disease-free (16% and 19%, respectively). Our results indicate that the presence of CD34 1 cells in GM-CSFproducing HNSCC is associated with a poorer prognosis for the cancer patients and suggest the utility of these parameters as prognostic indicators of outcome. Mechanistically, our results suggest that the presence of immune suppressive CD34 1 cells in GM-CSF-producing HNSCC leads to increased tumor recurrence or metastasis. Int. J. Cancer 74:69-74.r 1997 Wiley-Liss, Inc.Head and neck cancers, most of which are squamous cell carcinomas (HNSCC), are vulnerable to immune effector cells such as macrophages, natural killer cells and cytotoxic T-lymphocytes (Chikamatsu et al., 1995;Rabinowich et al., 1992). However, patients with HNSCC cancers are particularly prone to have defects in their immune defenses (Gooding et al., 1995;Hadden et al., 1994). Part of this immune suppression has been shown to be directly induced by soluble immune suppressive factors produced by the cancer (O'Mahony et al., 1993). However, cancers can also mediate immune suppression indirectly by stimulating immune suppressor cell activity. The immune suppressor cells that may be induced by human HNSCC have not been extensively studied or described, but have been well documented in many other cancer types of both humans and animals. Some human cancers induce suppressive T-cells that are inhibitory to immune functions, including anti-tumor T-cell reactivities (Chakraborty et al., 1991). Suppression of T-cell function in patients with HNSCC as well as with other cancers can also be due to monocytes or macrophages secreting the immune suppressive mediator prostaglandin E 2...

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Human head and neck squamous cell carcinomas (HNSCC) that produce high levels of granulocyte-macrophage colonystimulating factor (GM-CSF) have been shown to contain CD34 1 natural suppressor cells that inhibit the activity of intratumoral T-cells. The present study evaluated whether GM-CSF production and the presence of CD34 1 cells within primary HNSCC would translate into increased recurrence, metastasis or cancer-related death during the 2 years following surgical excision. Freshly excised primary HNSCC of 20 patients that subsequently developed disease, and of 17 patients that remained with no evidence of disease were analyzed for production of GM-CSF and for CD34 1 cell content. The cancers of patients that subsequently developed recurrences or metastatic disease produced almost 4-fold the levels of GM-CSF and had approximately 2.5-fold the number of CD34 1 cells as did cancers of patients that remained disease-free. In a second method of analysis, the prognostic significance of high vs. low GM-CSF and CD34 1 cell values was evaluated. These analyses showed that patients whose cancers produced high GM-CSF levels or had a high CD34 1 cell content had a disproportionately high incidence of recurrence or metastatic disease (94% and 100%, respectively), while the majority of patients whose primary cancers produced low levels of GM-CSF or had a low CD34 1 cell content remained disease-free (16% and 19%, respectively). Our results indicate that the presence of CD34 1 cells in GM-CSFproducing HNSCC is associated with a poorer prognosis for the cancer patients and suggest the utility of these parameters as prognostic indicators of outcome. Mechanistically, our results suggest that the presence of immune suppressive CD34 1 cells in GM-CSF-producing HNSCC leads to increased tumor recurrence or metastasis. Int. J. Cancer 74:69-74.r 1997 Wiley-Liss, Inc.Head and neck cancers, most of which are squamous cell carcinomas (HNSCC), are vulnerable to immune effector cells such as macrophages, natural killer cells and cytotoxic T-lymphocytes (Chikamatsu et al., 1995;Rabinowich et al., 1992). However, patients with HNSCC cancers are particularly prone to have defects in their immune defenses (Gooding et al., 1995;Hadden et al., 1994). Part of this immune suppression has been shown to be directly induced by soluble immune suppressive factors produced by the cancer (O'Mahony et al., 1993). However, cancers can also mediate immune suppression indirectly by stimulating immune suppressor cell activity. The immune suppressor cells that may be induced by human HNSCC have not been extensively studied or described, but have been well documented in many other cancer types of both humans and animals. Some human cancers induce suppressive T-cells that are inhibitory to immune functions, including anti-tumor T-cell reactivities (Chakraborty et al., 1991). Suppression of T-cell function in patients with HNSCC as well as with other cancers can also be due to monocytes or macrophages secreting the immune suppressive mediator prostaglandin E 2...