Dendritic cells are dysfunctional in patients with operable breast cancer

Abstract

Background: Dendritic cells (DCs) play a crucial role in presenting antigens to T lymphocytes and inducing cytotoxic T cells. DCs have been studied in patients with breast cancer to define the factors leading to failure of an effective systemic and locoregional anticancer host response.

Methods: Purified DCs were obtained from peripheral blood (PB) and lymph nodes (LNs) of women with operable breast cancer, using immunomagnetic bead selection. The stimulatory capacity of DCs in the allogeneic mixed leukocyte reaction (MLR) and autologous T cell proliferation test (purified protein derivative (PPD) as stimulator), the expression of surface markers on DCs and the production of cytokines in vitro by DCs from patients with operable breast cancer and from healthy donors (controls) were studied.

Results: 70-75% purified DCs were isolated from PB and LNs. PBDCs and LNDCs from patients with operable breast cancer demonstrated a reduced capacity to stimulate in an MLR, compared with PBDCs from normal donors (p<0.01). Autologous T cell proliferation in patients had a decreased ability to respond to PPD, when compared with controls (p<0.01). However, T cells from patients responded as well as control T lymphocytes in the presence of control DCs. PBDCs and LNDCs from patients expressed low levels of HLA-DR and CD86, and induced decreased interleukin-12 (IL-12) secretion in vitro, compared with DCs from normal donors (p<0.01).

Conclusion: These data suggest a defective DC function in patients with operable breast cancer. Switched-off DCs in patients with early breast cancer and decreased IL-12 production may be important factors for progressive tumour growth.

Fig. 1

Isolation of DCs by immunomagnetic bead selection method (negative selection). Representative results from FACScan analysis of PBDCs isolated by immunomagnetic bead negative selection method from peripheral blood. DCs are Lin⁻ and HLA-DR⁺

Fig. 2

Blastogenesis in MLR: allogeneic T lymphocyte (normal donor) proliferation, in cultures containing various ratios of DCs from the peripheral blood of healthy donors. The stimulatory capacity of DCs was estimated from the incorporation of [³H]-thymidine (shown as CPM) during the last 18 h of 6 days of in vitro culture containing T cells (5×10⁴ cells/well) from a normal volunteer and irradiated PBDCs (n=10) from healthy donors. Results shown are means ± SE

Fig. 3

Decreased blastogenesis of MLR. The stimulatory capacity of DCs (PB and LNs) was estimated from the incorporation of [³H]-thymidine (shown as CPM) during the last 18 h of 6 days of in vitro culture containing T cells (5×10⁴ cells/well) from a normal volunteer and irradiated DCs (2.5×10³ cells/well) from patients with breast cancer (PBDCs and LNDCs) and healthy donors (control PBDCs). Values shown are means ± SE. Asterisks indicate significant (p<0.01) reduction of PBDC and LNDC activity, compared with healthy control PBDC function

Fig. 4

PBDCs from control individuals effectively stimulate PB T lymphocytes from patients with breast cancer (MLR). The stimulatory capacity of PBDCs was estimated from the incorporation of [³H]-thymidine (shown as CPM) during the last 18 h of 6 days of in vitro culture containing T cells (five different patients with breast cancer [5×10⁴ cells/well]) and irradiated PBDCs (control [2.5×10³ cells/well]). Control bloods were obtained from six healthy donors

Fig. 5

Decreased blastogenesis of autologous T lymphocyte proliferation. Cultures containing DCs (PB and LNs) and T lymphocytes (PB and LNs) from patients with breast cancer and healthy donors (control PB) and PPD (5 μg/ml) as the stimulator were set up. The stimulatory capacity of DCs (PB and LNs) was estimated from the incorporation of [³H]-thymidine (shown as CPM) during the last 18 h of 6 days of in vitro culture containing autologous T cells (PB and LNs) (5×10⁴ cells/well) and irradiated DCs (2.5×10³ cells/well). Asterisks indicate significant (p<0.01) reduction of PBDC and LNDC activity, compared with healthy control PBDC function

Fig. 6

DCs were stained with multicolour-labeled mAbs. Lin⁻ cells were selectively gated and analysed. Asterisks indicate decreased expression (p<0.01) of HLA-DR, CD40 and CD86 on DC surface (PB and LNs) from patients with breast cancer. Percentage of cells expressing of HLA-DR, CD40 and CD86