Summary Mechanisms of resistance against Fas-mediated cell killing have been reported in different malignancies. However, the biological response of immune escape mechanisms might depend on malignant transformation of cancer cells. In this study we investigated different mechanisms of immune escape in 2 well-differentiated low-grade (RT4 and RT112) and 2 poorly differentiated high-grade (T24 and TCCSUP) bladder cancer cell lines. Fas, the receptor of Fas-ligand, is expressed and shedded by human transitional bladder carcinoma cell lines RT4, RT112, T24 and TCCSUP. Cytotoxicity and apoptosis assays demonstrate that in spite of the Fas expression, poorly differentiated T24 and TCCSUP cells are insensitive towards either recombinant Fas-ligand or agonistic apoptosis-inducing monoclonal antibody against Fas. In poorly differentiated T24 and TCCSUP cell lines we were able to detect marked Fas-ligand protein by flow cytometry and Western blot analysis. In grade 1 RT4 and RT112 cells only minor expression of Fas-ligand possibly because of proteinase action. Fas-ligand mRNA translation or post-translational processing seems to be regulated differentially in the cancer cell lines depending on malignant transformation. In co-culture experiments we show that poorly differentiated cells can induce apoptosis and cell death in Jurkat cells and activated peripheral blood mononuclear cells. This in vitro study suggests that bladder cancer cells can take advantage of different mechanisms of immune evasion and become more competent in avoiding immune surveillance during transformation to higher-grade malignant disease.

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Summary:In order to evaluate the Cobas Argos 5 Diff, a five-part differential haematological analyser, we performed a comparative study using our current analyser, the Toa E-5000, and the manual leukocyte differential. Samples (n = 593) were collected from various departments in our hospital and were tested on both Cobas Argos 5 Diff and Toa E-5000. Regression lines were calculated for all standard haematological quantities. A group of 100 samples, including 50 negative (absence of flags) and 50 positive (presence of flags), on the Cobas Argos 5 Diff were randomly selected from the above-mentioned collection. All these samples had been checked under the microscope by two persons counting 200 cells each. The correlation between Cobas Argos 5 Diff and the manual leukocyte differential shows good correlation for lymphocytes and neütrophils, with acceptable correlation for eosinophils. The correlation for basophils and monocytes was less acceptable, especially for normal samples. We conclude that the efficiency of the Cobas Argos 5 Diff is good (93%) and that it is a suitable haematological cell analyser.

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