The biology and therapy of brain metastasis: targeting the astrocytes

Fourteen monoclonal antibodies with specificity against native or recombinant antigens within the S100 family were investigated with regard to immunoreactivity. The specificities of the antibodies were studied using ELISA tests, Western blotting epitope mapping using competitive assays, and QCM technology. The mimotopes of antibodies against S100A4 were determined by random peptide phage display libraries. Antibody specificity was also tested by IHC and pair combinations evaluated for construction of immunoradiometric assays for S100B. Out of the 14 antibodies included in this report eight demonstrated specificity to S100B, namely MAbs 4E3, 4D2, S23, S53, 6G1, S21, S36, and 8B10. This reactivity could be classified into four different epitope groups using competing studies. Several of these MAbs did display minor reactivity to other S100 proteins when they were presented in denatured form. Only one of the antibodies, MAb 3B10, displayed preferential reactivity to S100A1; however, it also showed partial cross-reactivity with S100A10 and S100A13. Three antibodies, MAbs 20.1, 22.3, and S195, were specific for recombinant S100A4 in solution. Western blot revealed that MAb 20.1 and 22.3 recognized linear epitopes of S100A4, while MAb S195 reacted with a conformational dependent epitope. Surprisingly, MAb 14B3 did not demonstrate any reactivity to the panel of antigens used in this study.     

Volume Flow in Arteriovenous Fistulas Using Vector Velocity Ultrasound

Volume flow in arteriovenous fistulas for hemodialysis was measured using the angle-independent ultrasound technique Vector Flow Imaging and compared with flow measurements using the ultrasound dilution technique during dialysis. Using an UltraView 800 ultrasound scanner (BK Medical, Herlev, Denmark) with a linear transducer, 20 arteriovenous fistulas were scanned directly on the most superficial part of the fistula just before dialysis. Vector Flow Imaging volume flow was estimated with two different approaches, using the maximum and the average flow velocities detected in the fistula. Flow was estimated to be 242 mL/min and 404 mL/min lower than the ultrasound dilution technique estimate, depending on the approach. The standard deviations of the two Vector Flow Imaging approaches were 175.9 mL/min and 164.8 mL/min compared with a standard deviation of 136.9 mL/min using the ultrasound dilution technique. The study supports that Vector Flow Imaging is applicable for volume flow measurements.     

Differences in anatomical distribution,gender, and sidedness between ruptured and unruptured intracranial aneurysms in a defined patient population

Background  

Working with patients with intracranial aneurysms, we have developed a clinical suspicion that there may be differences in the rupture rate of aneurysms depending on the aneurysm’s anatomical location. The aim of the study was to examine the anatomical distribution of ruptured and unruptured intracranial aneurysms in a defined population.     

Therapeutic dendritic cell vaccination of patients with metastatic renal cell carcinoma: a clinical phase 1/2 trial

Therapeutic dendritic cell (DC) vaccination against cancer is a strategy aimed at activating the immune system to recognize and destroy tumor cells. In this nonrandomized phase 1/2 trial, we investigated the safety, feasibility, induction of T-cell response, and clinical response after treatment with a DC-based vaccine in patients with metastatic renal cell carcinoma. Twenty-seven patients with progressive cytokine-refractory metastatic renal cell carcinoma were vaccinated with DCs loaded with either a cocktail of survivin and telomerase peptides or tumor lysate depending on their HLA-A2 haplotype, and low-dose IL-2 was administered concomitantly. Tumor response, immune response, and serum IL-6 and YKL-40 were measured during treatment. Vaccine generation was successful in all patients and no serious adverse events were observed. None of the patients had an objective response but 13/27 patients obtained disease stabilization (SD) for more than 8 weeks. An antigen-specific immune response was demonstrated in 6/6 patients tested. Furthermore, significant alterations in serum YKL-40 and IL-6 were found during treatment. In conclusion, DC vaccination in our setting is feasible and without severe toxicity. Almost half of the patients obtained SD, and in more than 1/3 of the patients, SD persisted for more than 6 months. However, the evaluation of SD is difficult to interpret in the absence of a randomized trial and, therefore, these results should be interpreted with caution. Antigen-specific immune responses were observed in a subset of the treated patients.     

Spontaneous cytotoxic T-Cell reactivity against indoleamine 2,3-dioxygenase-2

Several lines of data have suggested a possible link between the indoleamine 2,3-dioxygenase (IDO)-like protein IDO2 and cancer. First, IDO2 expression has been described in human tumors, including renal, gastric, colon, and pancreatic tumors. Second, the apparent selective inhibition of IDO2 by the D stereoisomer of the IDO blocker 1-methyl-tryptophan (1MT), which tends to be more active than the L-isomer in a variety of biological assays for IDO function, suggests that IDO2 may be important to sustain immune escape and growth of tumors. Especially, D-1MT heightens chemotherapeutic efficacy in mouse models of cancer in a nontoxic fashion. Here, we describe the immunogenicity of IDO2 by showing the presence of spontaneous cytotoxic T-cell reactivity against IDO2 in peripheral blood of both healthy donors and cancer patients. Furthermore, we show that these IDO2-specific T cells are cytotoxic effector cells that recognize and kill tumor cells. Our data suggest that IDO2 might be a useful target for anticancer immunotherapeutic strategies.     

High expression of carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 6 and 8 in primary myelofibrosis

Primary myelofibrosis (PMF) is characterized by leukoerythroblastic anemia with circulating immature myeloid cells, including CD34+ cells, progressive splenomegaly and accumulation of connective tissue and neoangiogenesis in the bone marrow. Altered bone marrow stroma and cell adherence account for the egress of CD34+ cells from the bone marrow. Carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 6 has been implicated in cell adhesion, cellular invasiveness, angiogenesis, and inflammation, which are all key processes in the pathophysiology of PMF. Accordingly, CEACAMs may play an important role in these processes in patients with myelofibrosis as well. Using a genome-wide approach, several genes of the CEACAM family were found to be deregulated in patients with PMF and related myeloproliferative neoplasms (n = 69). In PMF patients, the CEACAM6 and 8 were significantly upregulated (fold change (FC) 12.5 and 14.0, respectively and FDR adjusted p values 7.71 × 10⁻⁷ and 1.48 × 10⁻⁵, respectively). The elevated expression of CEACAM genes may reflect clonal myeloid expansion and neutrophil activation being most exaggerated in patients with PMF. Alternatively, the highly elevated gene expression of CEACAM6 and 8 in PMF may be molecular markers of myelofibrotic transformation, implying enhanced proteolytic activity, egress of CD34+ cells into the circulation, and neoangiogenesis.