Generation of monocyte-derived dendritic cells from patients with renal cell cancer: modulation of their functional properties after therapy with biological response modifiers (IFN-alpha plus IL-2 and IL-12).

Abstract

The combination of interferon-alpha (IFN-alpha) plus interleukin (IL-2) has been accepted in the treatment of metastatic renal cell carcinoma (MRCC), whereas vaccines based on IL-12 or dendritic cells (DCs) are still being investigated. Here the authors analyzed 1) the feasibility to generate functional monocyte-derived DCs (MDDCs) from patients treated with biological response modifiers (BRMs) who have MRCC, 2) the phenotypic modulations of these MDDCs during BRM treatment. Eight and 13 MRCC patients received IL-2 plus IFN-alpha or IL-12 immunotherapy, respectively. The adherent fraction of mononuclear cells from patients' blood drawn before, during, and after immunotherapy was incubated in clinically approved culture medium supplemented with 5% autologous serum, rhu granulocyte macrophage colony-stimulating factor, and rhuIL-4 for a week. At day 7 or 8 of culture, floating cells were examined in flow cytometric and functional assays (alloreactivity, proliferation assays in the presence of tetanus toxoid or tumor peptides, IL-12 secretion). In all patients except two, MDDCs could be generated but at a lower rate compared with healthy volunteers. Morphologic and phenotypical analyses revealed immature DCs with low levels of CD1a or CD83 expression throughout therapy with BRMs. Capacities in mixed leukocyte reactions were similar to those of healthy volunteers and stable during immunotherapy, whereas presentation of major histocompatibility complex class II tetanus toxoid peptide complexes was slightly enhanced during and after IL-12 therapy. IL-12 expression levels under IFN-gamma and CD40L stimulation were significantly lower in MDDC cultures from patients with MRCC compared with healthy volunteers. Overall, peripheral blood mononuclear cells from a cohort of 21 patients with metastatic disease who were treated with BRMs maintained their ability to differentiate into functional MDDCs with no selective quantitative or qualitative advantage.