INTERDEPENDENCE BETWEEN THE PHENOTYPE OF DENDRITIC CELLS AND AMOUNTS OF BLOOD PROINFLAMMATORY MONOCYTES IN PATIENTS WITH KIDNEY CANCER

Abstract

The aim of the study was to investigate an interdependence between the phenotype of dendritic cells (DC) differentiated from monocytes and the number of pro-inflammatory monocytes in peripheral blood of patients with kidney cancer (KC). The study involved 28 patients at the age of 40-55 years suffering with KC (Т3N0М0, clear cell type) before surgical treatment. The diagnosis was verified histologically. 31 healthy agematched persons were examined as a control group. Mononuclear cells were isolated from heparinized venous blood by centrifugation in a Histopaque®-1077 density gradient followed by plastic adsorption in RPMI 1640 medium supplied with 10% autologous serum. Immature DCs (iDCs) were generated from blood monocytes by culturing for 5 days with GM-CSF and IFNα. Activation of DCs (mDCs) was induced by incubation with the tumor cell lysate and TNFα, followed by incubation for 48 hours. A tumor fragment was used to prepare the lysate of autologous tumor cells. Phenotyping of blood monocytes and DC at various maturation stages was performed by flow cytometry. The numbers of CD14+CD16+ monocytes in peripheral blood of KC patients were decreased (up to 42% of the total monocyte level) against the control ranges. In this regard, the analysis of the dependence between the phenotype of DCs differentiated from monocytes and the number of pro-inflammatory blood monocytes was carried out by comparing the groups with a high content of pro-inflammatory monocytes in the blood in KC patients (> 42%, near-control range) and low content (resp., < 42%). We have found that the contents of tolerogenic iDC in cell culture are increased in KC patients with low amounts of pro-inflammatory monocytes in blood (< 42%). A relatively increased expression of antigen-presenting and co-stimulatory molecules proved to be the specific feature of iDC phenotype in patients with high contents (> 42%) of proinflammatory monocytes in blood. The phenotype of dendritic cells in KC patients with different content of proinflammatory monocytes during maturation/activation showed more differences. In the patients with low levels of pro-inflammatory monocytes, the cell pool of in vitro maturing DCs was characterized by low level of CD86 and HLA-DR receptor expression, thus reflecting a weak co-stimulating and antigen-presenting activity. In the patients with high levels of pro-inflammatory monocytes in blood, the in vitro activated DCs showed higher level of functional activity using the above markers. The revealed differences in the DC phenotype and interrelations with amounts of blood monocyte subpopulations in KC patients may presume the programmed cell differentiation mechanisms depending on the microenvironment, under pathogenic conditions (i.e., in presence of malignant tumor growth).

Keywords

• dendritic cells
• monocytes
• kidney cancer
• phenotype
• costimulatory molecules
• antigen presentation