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G Schmidtke

Publications and source records attributed to G Schmidtke.

24 records · Page 2Linked to original sources
PubMed1996

Lymphocyte gating of peripheral blood in patients with leukemic low-grade non-Hodgkin's lymphoma by multiparametric flow cytometry.

The standardized fluorescence intensity as expressed in molecules of equivalent soluble fluorescence (MESF) of lymphocytes from normal individuals and patients suffering from low-grade non-Hodgkin's-lymphomas was obtained comparing different staining patterns of CD45(FITC) and CD20(PerCP). After standardization of the flow cytometer using standardized fluorescent particles ('beads') significant differences could be obtained for hairy cell leukemia, chronic lymphocytic leukemia and immunocytomas in the peripheral blood. In contrast, centroblastic-centrocytic as well as centrocytic lymphomas showed no significant variations as compared to normal peripheral blood lymphocytes. According to these results, a new lymphocyte gating procedure was established by adding CD14(PE) and three-color measurement by CD45/CD14/CD20 staining of peripheral blood using erythrocyte lysis. The established gating procedure leads to a crucial discrimination and quantification of abnormal and normal lymphocytes per one measurement, whereas the 'leucogate' as defined by CD45/CD14 staining alone was insufficient for correct lymphocyte gate setting. In conclusion, the different staining of CD45 and CD20 in leukemic peripheral blood should be considered when fluorescence intensity or atypical peaks occurred in flow cytometric histograms suggesting for abnormal cell populations. In addition, it is possible to use this information to classify low-grade lymphomas.

Adult↗
PubMed1996

Multiparametric immunophenotyping of B cells in peripheral blood of healthy adults by flow cytometry.

The investigation of patients suffering from malignant lymphomas of the B-cell type requires flow cytometric immunophenotyping. Several reports described the expression of almost all B lineage antigens on normal and abnormal B lymphocytes. Thus, immunophenotyping of lymphomas must be interpreted in the context of the reference values obtained for healthy control individuals. For this purpose multiparametric flow cytometric analysis offers the unique feature for lymphocyte subset analysis. In the present study B lymphocytes in the peripheral blood of healthy adults were investigated by multiparametric flow cytometric immunophenotyping for the detection of the frequency (in percent) of antigens provided by the revised European-American classification of lymphoid neoplasms (REAL) classification. Thus, 84 healthy adults were investigated and grouped by age (average ages were as follows: group 1, 25.38 years; group 2, 33.86 years; group 3, 44.17 years; group 4, 55.67 years; group 5, 66.67 years). Analysis was done for surface immunoglobulins (kappa and lambda chains of immunoglobulin M [IgM] and IgD) as well as CD10, CD11c, CD23, CD38, CD103, FMC-7, and B-B4. Three-color immunophenotyping was performed for kappa/CD19/CD5, lambda/CD19/CD5, surface IgM/surface IgD/CD19, FMC-7/CD19/CD5, CD103/CD11c/CD19, CD10/CD23/CD19, and CD38/B-B4/CD19 by live gating of CD19+ events (n = 2,000). Although some numerical differences could be obtained for the different groups, statistical differences (P < 0.005) could only be obtained for the CD19+/CD5+ B-cell subset, which was decreased in the elderly patients (group 5). The established two-color and three-color stainings will serve as a basis for future multiparametric immunophenotyping of abnormal lymphocytes (e.g., for patients suffering from non-Hodgkin's lymphoma of the B-cell type).

Adult↗
PubMed1995

Immunophenotyping of B lymphocytes by multiparametric flow cytometry in bone marrow aspirates and peripheral blood of healthy adults.

Establishing reference ranges by multiparametric immunophenotyping of mature B cells in bone marrow and peripheral blood of healthy adults is of interest because the detection of bone marrow infiltration, persistance of light chain restriction as well as discrimination between reactice and malignant lymphocytes are important applications of B-cell immunophenotyping. To determine the pattern of antigens as expressed by malignant mature B lymphocytes, bone marrow aspirates and peripheral blood of healthy adults in the present study were investigated for the presence and percentage frequency of those antigens as defined for immunophenotyping of B-cells by the REAL-Classification. For this purpose analysis of CD19 positive B lymphocytes by Live Gate analysis was performed. The established two-color as well as three-color stainings will serve as a basis for future investigations designed to test multiparametric analysis of B lymphocytes in bone marrow aspirates and peripheral blood. In conclusion, all investigated antibodies stained in varying percentage frequency on B-cell subtypes and statistical significant differences could be considered only for the CD19/CD10 staining in bone marrow aspirates. On the basis of this analysis, all the reported lineage antigen combinations are present both in malignant B lymphocytes as well as normal B cells in considerable percentage frequency. These findings are of important interest for follow-up investigations of patients with non-Hodgkin s lymphomas by multiparametric immunophenotyping.

Adult↗
PubMed1995

Immunophenotyping of B lymphocytes by multiparametric flow cytometry in bone marrow aspirates of healthy adults.

Establishing reference ranges by multiparametric immunophenotyping of mature B cells in bone marrow of healthy adults is of interest because the detection of bone marrow infiltration and persistence of light chain restriction, as well as discrimination between reactive and malignant lymphocytes are important applications of B-cell immunophenotyping. To determine the pattern of antigens as expressed by malignant mature B lymphocytes in the present study, bone marrow aspirates of healthy adults were investigated for the presence and percentage frequency of those antigens as defined for immunophenotyping of B cells by the REAL Classification. For this purpose, analysis of CD19-positive B lymphocytes by 'live gate' analysis was performed. The established two-color as well as three-color stainings will serve as a basis for future investigations designed to test multiparametric analysis of B lymphocytes in bone marrow aspirates. All investigated antibodies stained with varying percentage frequency on B-cell subtypes, and no statistical significant difference was found between bone marrow aspirates of women and those of men. On the basis of this analysis, all the reported lineage antigen combinations are present both in malignant B lymphocytes and in normal B cells in considerable percentage frequency. These findings are of importance for follow-up investigations of patients with non-Hodgkin's lymphomas by multiparametric immunophenotyping.

Adult↗
PubMedDate not supplied

Interferon-gamma inducible exchanges of 20S proteasome active site subunits: why?

When cells are stimulated with the cytokines IFN-gamma or TNF-alpha, the synthesis of three proteasome subunits LMP2 (beta1i), LMP7 (beta5i), and MECL-1 (beta2i) is induced. These subunits replace the three subunits delta (beta1), MB1 (beta5), and Z (beta2), which bear the catalytically active sites of the proteasome, during proteasome neosynthesis. The cytokine-induced exchanges of three active site subunits of a complex protease is unprecedented in biology and one may expect a strong functional driving force for this system to evolve. These cytokine-induced replacements of proteasome subunits are believed to favour the production of peptide ligands of major histocompatibility complex (MHC) class I molecules for the stimulation of cytotoxic T cells. Although the peptide production by constitutive proteasomes is able to maintain peptide-dependent MHC class I cell surface expression in the absence of LMP2 and LMP7, these subunits were recently shown to be pivotal for the generation or destruction of several unique epitopes. In this review we discuss the recent data on LMP2/LMP7/MECL-1-dependent epitope generation and the functions of each of these subunit exchanges. We propose that these subunit exchanges have evolved not only to optimize class I peptide loading but also to generate LMP2/LMP7/MECL-1-dependent epitopes in inflammatory sites which are not proteolytically generated in uninflamed tissues. This difference in epitope generation may serve to better stimulate T cells in the sites of an ongoing immune response and to avoid autoimmunity in uninflamed tissues.

Animals↗