Cellular immune suppression in cancer patients and its implication for dendritic cell therapy

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Background: The treatment of human cancer with monocyte-derived dendritic cells (MoDC) is a promising and innovative approach. However, many of the treated patients fail to respond to therapy. The reduced clinical antitumor response may be due to an inflammatory immune-suppressive tumor microenvironment. Regulatory T-cells (T-reg) and other cells with suppressive potential can promote an immune suppressive tumor microenvironment and thus play an important role in regulation of the immune response. Methods: Whole blood from n=100 cancer patients with various tumor types and from n=30 healthy donors were analysed by flow cytometry. CD4+ lymphocytes with immune suppressive potential were characterized by analysing the expression of CD25, CD39, CD127. Results: We found a significantly higher proportion of CD25+/CD39+ and of CD25+/CD127low T-helper cells in the blood of cancer patients as compared to healthy donors. This may indicate two different types of T-reg involved in immune suppression in cancer patients. Treatment of patients with metronomic chemotherapy induced a down-regulation of these cells. Interestingly, we found a subpopulation of cells within the lymphocyte gate characterized by CD2high and CD86 expression in cancer patients with very advanced stage, similar to such normally found in hemaphagocytic lymphohistiocytosis (HLH) patients characterized by exceeding high plasma concentration of IFN-g and IL-10 (Schneider et al. 2002). These cells can be down-regulated by treatment with a tetradecapeptide (Ezrin) known to act as an immune modulator with anti-viral activity leading to reduction of inflammatory cytokines. Conclusions: An efficient induction of a clinical antitumor response requires both a polarization of MoDC in a TH1 direction as well as changing an immune suppressive tumor microenvironment. For the first time, we identified HLH associated cells in advanced cancer patients. As HLH is characterized by hyperinflammation, these cells may indicate an inflammatory tumor microenvironment. Thus, anti-inflammatory therapy should be considered as co-treatment with immunotherapy with dendritic cells for down-regulation of immune suppressive cells (T-reg, CD2high/CD86+ cells) to promote a clinical antitumor response.

No significant financial relationships to disclose.

Dendritic cell therapy in glioblastoma multiforme

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Background: Malignant brain tumors belong to the tumors with unfavorable prognosis. The most aggressive form, glioblastoma multiforme (GBM WHO grade IV glioma), is categorized as incurable with median survivals less than 12–18 months and 90–95% of patients surviving less than 2 years. Here we show that immunotherapy with monocyte-derived dendritic cells (MoDC) can induce a clinical response in advanced GMB, especially when combined with the non human pathogenic oncolytic virus NDV (New Castle Disease Virus). Methods: After isolating monocytes from peripheral blood of n=21 patients dendritic cells were generated ex vivo in the presence of recombinant cytokines (IL-4, GM-CSF) and 2,5% autologous serum. If tumor tissue was available the MoDC were primed on day 5 with tumor- lysate and co-cultured with poly:IC and IFN-alpha. The MoDC were harvested on day 7 of culture and administered to the patients, intradermally. In 5 patients NDV was added to the MoDC for one hour prior to administration. These patients received an infusion with NDV one day before vaccination. Results: We were able to induce a clinical response in 33% (n=7) of the treated patients. The median survival after onset of DC-therapy was 10 months. With respect to primary diagnosis the median survival was 19 months with 1- and 2-years survival rates of 81% and 14%, respectively. Improvement of the clinical response can be observed by combination of NDV. None of the 5 patients treated with this combination therapy died of the disease (9–19 months after primary diagnosis). Three of them (60%) show a response with 2 clear partial remissions (40%). Conclusions: Taken together, a dendritic-cell based therapy can be successful in the treatment of GBM. Enhancement of the therapeutically outcome can be induced by a combination therapy with New Castle Disease Virus leading to the suggestion that there may be an interaction between the dendritic cells and the NDV.

No significant financial relationships to disclose.

Cancer therapy with tumor cell lysate pulsed monocyte-derived dendritic cells in patients with metastastic colon cancer: Improvement by danger signals

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Background: The prognosis of colon cancers with hematogenous spread remains poor at 12–20 months. We report the use of a dendritic cell based immunotherapy to improve patient survival, especially with cell culture conditions mimicking infection. Methods: After isolating monocytes from the blood of 39 patients with metastasized colon cancer, dendritic cells were generated ex vivo in the presence of recombinant cytokines (IL-4; GM-CSF) and autologous serum. The DC loaded with tumor cell lysate were administered to the patients intradermally. Culture conditions were tested for upregulation of costimulatory molecules, downregulation of IL-10 and upregulation of IL-12 secretion by ELISPOT and fluorescence cytometry. Results: DC vaccination induced a clinical response in 9 (23%) patients with a median overall survival after onset of DC-therapy of 12 months (11–44 months for responders and 1–20 months for non-responders) and 23 months after diagnosis of metastases (16–63 months for responders and 1–23 months for non-responders). These data show that a dendritic cell based immunotherapy may prolong the patients overall survival. However, complete remissions are rare. This can be due to weak stimulation of CTL response due to insufficient antigen presentation, lack of costimulatory molecules as well as secretion of IL-10 rather than IL-12 by the DC’s. Here we could show that Toll-like receptors (TLR) ligands like Poly-I:C or lipopeptides as so called danger signals in combination with interferons can induce an upregulation of costimulatory molecules accompanied by inhibition of IL-10 and induction of IL-12 secretion in vitro. By using these culture conditions we induced a clinical complete remission of liver metastases after failure of standard therapy in one patient (overall survival after onset of DC-therapy 13 months, after diagnosis 24 months). Conclusions: According to Matzinger’s hypothesis an effective immune response occurs only by responding to a danger signal associated with infection or stress. Thus, cell culture condition should be used with TLR ligands mimicking a bacterial or viral infection. In general, a dendritic cell based immunotherapy can be successful in advanced stages of colon cancer patients.

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Uvulopalatopharyngoplasty changes fundamental frequency of the voice--a prospective study

The aim of the study was to find whether a muscle-sparing uvulopalatopharyngoplasty (UPPP) and tonsillectomy cause a measurable change in the voice. The fundamental frequency and the first two formants of five sustained vowels were measured before and nine (six to 15) months following operation. The operation consisted of tonsillectomy and UPPP with preservation of the musculature of the soft palate. All patients received a pre- and post-operative 12-canal polysomnography (level-I sleep study). No patient showed signs of any post-operative velopharyngeal insufficiency. Acoustic analysis showed a significant raising of the fundamental frequency of up to 10 Hz. There was also a lowering of the second formant in two of the five vowels. This was correlated with the volume of the excised tissue. The minimal changes will probably have no significance for those who place no special reliance on their voice, but the possible post-operative changes should be made clear to singers and those relying on their voice for professional reasons.