[Modulatory effect of fumaric acid esters on superoxide-anion generation in human phagocytes].

Fumaric acid esters (FAE), mainly dimethylfumarate (DMF), have been shown to be highly efficacious in the treatment of psoriasis. Among the potential side effects of FAE therapy, lymphocytopenia is sometimes observed. In order to address the question whether FAE may interfere with systems of the innate defense, the modulatory role of FAE on the generation of superoxide-anion by human monocytes and neutrophils was studied by measuring the reduction of cytochrome c. Various concentrations of DMF and its metabolite methylhydrogenfumarate (MHF) were used to observe their modulatory effect on superoxide-anion generation by monocytes and neutrophils in response to bacteria (S. aureus and E. coli) and candida (C. albicans). Dexamethasone (DXM, 1 x 10(-7) mol x L(-1)) was also studied at the same time. We found that DXM significantly inhibited superoxide-anion generation from monocytes in response to bacteria and C. albicans, whereas DMF and MHF (10-20 microg x mL(-1)) significantly increased the production of superoxide-anion in monocytes in response to the above mentioned bacteria. DXM, DMF and MHF did not affect superoxide-anion generation of neutrophils. Our data indicate that DMF and MHF enhance superoxide-anion generation in human monocytes as one of the important mechanisms of innate defense against microorganisms.

[Effects of drugs known to trigger psoriasis on HaCaT keratinocytes].

To investigate whether lithium carbonate, propranolol or chloroquine aggravate psoriasis through influencing cytokines of the psoriatic cytokine network, HaCaT keratinocytes were stimulated with TNF-a after treatment with these drugs. Protein secretion of a set of multiple different cytokines and growth factors in culture supernatants were measured by using a cytokine antibody array technology. Expression of IL-8 and IL-6 mRNA was determined by real-time PCR. In culture supernatants of TNF-alpha-stimulated HaCaT cells, production of IL-6 and TNF-alpha could be enhanced by lithium carbonate; production of IL-6 and a panel of cytokines and growth factors could be enhanced by propranolol hydrochloride; and IL-6 was up-regulated by chloroquine diphosphate as well. Real-time PCR analysis showed a significantly dose-dependent increase of IL-8 and IL-6 mRNA expression in HaCaT cells stimulated with TNF-a as compared to cells without TNF-alpha-stimulation, the mRNA expression of IL-8 was higher than that of IL-6 with the same concentration of TNF-alpha (P < 0.01). Compared with HaCaT cells cultured with medium alone, propranolol hydrochloride at the concentration of 1 x 10(-6) mol x L(-1) could stimulate HaCaT cells to express higher level of IL-6 mRNA (P < 0.05). The drugs investigated show a modulatory effect on certain cytokines and growth factors which are able to modulate inflammatory type of immune reaction present in psoriatic lesions.

Increased endocytic activity in monocyte-derived dendritic cells in patients with psoriasis vulgaris.

BACKGROUND & OBJECTIVE: The understanding of the pathogenesis of psoriasis vulgaris has focused on T cell mediated immune disorder for many years. Recent studies provide evidence that dendritic cells may be of major importance as regulatory cells driving the psoriasis tissue reaction, and they are one of the therapeutic targets. In order to further characterize the role of dendritic cells in psoriasis, this study was designed to assess the differentiation of dendritic cells from monocytes (MoDC), the expression of phagocytosis related receptors by MoDC, their endocytic activity for fluorescent beads and lucifer yellow as well as their superoxide generation in patients with psoriasis. METHODS: Twenty eight patients with psoriasis vulgaris and 12 healthy controls were included in the study. MoDC were obtained by culturing monocytes with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 5 days. Cell surface expression of CD1a, CD14, CD40, CD80, CD83, CD86, HLA-DR, mannose receptor (MR) and Fcg receptors by MoDC and their endocytosis of dextran and lucifer yellow were analyzed by flow cytometry. Zymosan ingestion was measured to access the phagocytosis of MoDC. RESULTS: Differentiation of monocytes to dendritic cells was upregulated in patients manifested as significantly increased expression of CD40, CD80, CD86 and HLA-DR compared with that in healthy controls (P<0.01). Expression of MR and Fcg receptor II (CD32) by MoDC was significantly increased in patients with psoriasis as well (P<0.01). Endocytosis of dextran but not lucifer yellow in patients was significantly higher than controls (P<0.01), and significantly enhanced phagocytosis by increasing zymosan ingestion was also observed (P<0.01) in patients. Taken together, endocytic and phagocytic activity of MoDC in psoriasis was increased than normal persons. INTERPRETATION & CONCLUSION: Enhanced activity of dendritic cells binding and capturing foreign antigens for subsequent antigen presentation and the initiation of immune responses in psoriasis may contribute to the pathogenesis of the disease. The upregulated expression of MR and the enhanced endocytic activity of DC might be an explanation for the absence of skin infection observed in psoriasis.

Toll like receptor agonists augment HPV 11 E7-specific T cell responses by modulating monocyte-derived dendritic cells.

Impaired local cellular immunity is one of the mechanisms responsible for condyloma acuminatum (CA) recurrence. The activation of dendritic cells (DCs) is important in vaccine development. We investigated the effect of different toll like receptor (TLR) agonists including LPS (TLR4 agonist), polyinosinic acid-polycytidylic acid (PIC, TLR3 agonist), CpG oligonucleotide (TLR9 agonist), and imiquimod (TLR7 agonist) on human monocyte-derived dendritic cells (mdDCs) loading of human papillomavirus (HPV) type 11 E7 epitope. As a result, we found that mdDCs loading HLA-A*0201-restricted HPV 11 E7 CTL epitope peptide could respond to the TLR agonists, especially LPS and PIC. This was characterized by an enhanced expression of CD40, CD80, CD86, CD83 and HLA-DR, and a high level of IL-12 production. TLR agonists, especially PIC, enhanced the ability of E7-loaded mdDCs to induce IFN-gamma-secretion CD4(+) naïve T cells. Moreover, E7-loaded mdDCs exposed to TLR agonists augmented autologous T cell responses including effector cytokines production and specific cytotoxic T lymphocyte (CTL) responses. In addition, the inhibitory effect of IL-10 on mdDCs maturation could be partially restored by LPS, PIC or imiquimod. Taken together, these results demonstrate that TLR agonists promoted the maturation of E7-loaded mdDCs and their ability to induce T help type 1 polarization and augment E7-specific T cell responses. These data also indicated that TLR3/4 agonists might be effective adjuvants of mdDC-based vaccines against CA.

Imiquimod inhibits the differentiation but enhances the maturation of human monocyte-derived dendritic cells.

Imiquimod is a topically used immune response modifier effective in the treatment of genital warts caused by HPV. Its therapeutic effects are believed to be the release of proinflammatory cytokines from the monocyte-macrophage lineage resulting in a cascade of events abating the HPV replication. Dendritic cell maturation and activation have also been found to be induced by imiquimod. We hypothesized that imiquimod may promote the development of DC at all levels of their life cycle. In this study, in vitro cultured monocyte-derived dendritic cells (MoDC) were used to evaluate the effect of imiquimod regarding the modulation of DC differentiation, terminal maturation and their function by phenotypic cell surface molecules expression, cytokine secretion and T cell stimulation in allogeneic system. We demonstrate that imiquimod exerts differential effects on DC biology at different stages of DC development. It inhibits the differentiation of DC, which may indicate a more potent antigen uptake activity. DC maturation is induced by imiquimod with an enhanced antigen presenting activity and IL-12 production. These evidence might be relevant with the clinically proven effectiveness of imiquimod in the treatment of genital warts.