Biomedical subjects

Ingrid Böhm

Publications and source records attributed to Ingrid Böhm.

10 recordsLinked to original sources

PubMed2005

Nuclear-targeting autoantibodies induced nuclear PARP cleavage accompanied by more pronounced decrease of peripheral white blood cells than Ro/SSA and La/SSB antigen-targeting autoantibodies.

Autoantibody production and leukocytopenia may be linked in patients with lupus erythematosus (LE). Unclear is the ability of different autoantibody species to induce apoptosis and cell loss. Laboratory routine analyses (white blood cell counts, autoantibody detection), and flow cytometry (annexin V, CD3, CD4, CD8) have been performed in 126 consecutive LE-patients. Nuclei of PBMC were investigated flow cytometrically for the presence of the 85 kDa poly-(ADP-ribose)-polymerase (PARP) fragment. Peripheral total white blood cells (WBC), lymphocytes, T-cells, CD3+ CD4+, and CD3+ CD8+ cells were significantly decreased in patients with LE (P from 1.2 x 10(-14) to P < .0008). In the presence of either antinuclear (P from 1.2 x 10(-14) to P < .0008) or anti-dsDNA antibodies (P from 2.9 x 10(-12) to P < .007) were significantly diminished. Differences in cell numbers in LE patients with versus without anti-Ro/SSA were less pronounced: significant differences could be only obtained in lymphocytes and T-cells (P < .02). Anti-La/SSB antibodies were accompanied by significant increased leukocytes (P < .02). PARP cleavage (85 kDa) in nuclei was preferentially observed in cases with nuclear targeting autoantibodies. These results indicate that nuclear targeting autoantibodies are associated to lower peripheral blood cells counts than Ro/SSA, and La/SSB cytoplasmic targeting autoantibodies. This provides an explanation for the pathogenesis of cytopenias associated with SLE.

Adolescent↗

PubMed2005

A possible role for cysteinyl-leukotrienes in non-ionic contrast media induced adverse reactions.

PURPOSE: To test whether mono- or dimeric X-ray contrast media (CM) may induce the de novo production of cysteinyl-leukotriens (cys-LT), that could contribute to allergic/allergy-like side effects. MATERIALS AND METHODS: Leukocytes from 39 patients receiving iopromide or iotrolan for routine CT-examination were analyzed for the production of cys-LT. Histamine levels were analyzed in plasma specimens. One patient with a positive history of a previous CM-reaction did not receive CM-injection. RESULTS: Three patients of the iopromide and five of the iotrolan group showed adverse reactions. Reactors had increased cys-LT values in samples obtained before CM-injection induced by the positive control (anti-FcepsilonRI antibodies) (6763.7 pg/ml+/-1367.3 versus 2299.8 pg/ml+/-399.2; p<0.007). Patients with versus without CM-reaction did not differ significantly with respect to their histamine values before CM-administration. In vitro iopromide (p<0.0002) and iotrolan (p<0.0008) induced significant cys-LT production as compared to IL-3 stimulation. In vivo both CM induced a significant increase 6h after CM administration (p<0.05). CONCLUSION: Our findings suggest that both CM seem to induce cys-LT production. As to whether the observed increased values in pre-dose samples of patients with as compared to those without reactions could contribute to identify high risk patients should be investigated in larger patient groups in future.

Adult↗

PubMed2004

Environment-dependent down-modulation of CD45 cell surface expression on polymorphonuclear cells.

CD45, a transmembrane protein tyrosine phosphatase, regulates important cell functions. Its involvement in clearing tissues from dead or dying cells by polymorphonuclear cells (PMNs) is unclear. Therefore, in this study the influence of exogenous factors (e.g., temperature and phagocytosis) on the CD45 expression on PMNs (in patients with lupus erythematosus (LE) vs. controls) was analysed by flow cytometry. The data showed a significant down-regulation of CD45 at 4 degrees C in controls, but not on LE-PMNs. In the presence of targets, CD45 was significantly decreased (P<0.00002). Substrate-dependent down-regulation was greater in the presence of nuclei than in the presence of dead cells(68.98%+/-2.28% vs. 47.89%+/-2.75%; P<0.002), and on LE-PMNs than on control-PMNs (45.93%+/-4.92% vs. 53.65%+/-2.2%). Target pretreatment with anti-dsDNA antibody-containing serum resulted in a lower CD45 expression compared to treatment with normal serum. This effect was more pronounced on PMNs of LE patients than on those of controls. Phagocytosis was inversely correlated with CD45 expression (P<0.0007). These data suggest that phagocytic clearance of cellular debris by PMNs may modulate the function of the effector cells, and that anti-dsDNA antibodies apparently enhance the phagocytic clearance.

Antibodies, Antinuclear↗

PubMed2004

LE cell phenomenon: nuclear IgG deposits inhibit enzymatic cleavage of the nucleus of damaged cells and support its phagocytic clearance by PMN.

Apoptotic cell death, phagocytic uptake, and their interplay may induce/trigger autoantibody production and autoimmunity. Herein the role of immunoglobulin G (IgG) anti-dsDNA autoantibodies in nucleo-phagocytosis by polymorpho-nuclear cells (PMN) has been analyzed. Necrotaxis, phagocytosis and PMN with engulfed nuclei can be imaged by vital microscopy. Vital microscopy revealed dead neutrophils with persistence of nuclei or ingested nuclei in 8/10 patients with lupus erythematosus (LE) and in 4/20 healthy controls (P < 0.0006). The phagocytic clearance of dead cells/nuclei did not correspond to any of the analyzed apoptosis markers (annexin V, CD95, and active caspase 3). IgG staining of isolated PBMC nuclei as detected by flow cytometry was significantly higher in parallel to NUC+ (P < 0.02). In vitro phagocytosis of substrates pre-treated with anti-dsDNA containing serum induced an increased phagocytic capacity as compared to normal serum. These data suggest that anti-dsDNA antibodies seem to inhibit enzymatic cleavage of nuclei from damaged cells, and improve their phagocytic uptake by PMN, which finally results in LE cell formation.

Adult↗

PubMed2004

Increased peripheral blood B-cells expressing the CD5 molecules in association to autoantibodies in patients with lupus erythematosus and evidence to selectively down-modulate them.

The present investigation has been undertaken to analyze absolute and relative CD5+ B-cell numbers in patients with lupus erythematosus (LE), and concomitant B-CLL, and to monitor them under therapy. Peripheral blood lymphocytes of LE-patients, and healthy controls were analyzed by flow cytometry and direct immunofluorescence technique. Patients were treated with low-dose methotrexate (MTX). Before and during MTX treatment laboratory monitoring has been done. LE-patients had increased percentages of CD5+CD19+ as compared to controls (p < 0.0002), the absolute number of CD5+ B-cells was equal in controls and patients. Autoantibodies were positively correlated to the number of CD5+ B-cells in LE-patients. In a total of 140 LE-patients one male patient suffered from both LE and B-CLL (0.7%). He had increased absolute and relative CD5+ B-cells. MTX induced significant decrease of both total B-cell numbers, and CD5+ B-cells. The decrease of CD5+CD19+ cells was more pronounced than the decrease of total B-cells. Apoptosis rate increased in parallel to the drop-down of elevated CD5+CD19+ cells. Peripheral T-cell subsets remained stable under low-dose MTX. Both absolute and relative numbers of CD5+CD19+ cells should be taken into account in patients with LE. MTX seems to decrease B-cells, and preferentially to down-regulate B-cells expressing the CD5 molecule, which opens new therapeutic options and cell biological activities. The mechanism is unclear but apoptosis induction seems to be likely.

Adult↗

PubMed2004

Flow cytometric analysis of the LE cell phenomenon.

A flow cytometry-based phagocytosis assay was developed and utilized to measure the LE cell phenomenon at the single cell level in vitro. Since the lupus erythematosus (LE) cell phenomenon is a special form of necro-phagocytosis in the presence of anti-dsDNA antibodies, dead substrate cells or chicken erythrocytes nuclei (CEN) served as targets that were labeled with propidiumiodide (PI). Phagocytes (PMN) were stained by anti-CD45 mAb FITC. After co-incubation phagocytosis was measured by flow cytometry. Flow cytometric analysis enabled the discrimination between PI+/CD45- targets, PI-/CD45+ phagocytes, and PI+/CD45+ phagocytes with engulfed targets. Maintaining the samples on ice significantly reduced the phagocytic uptake as compared to samples co-cultivated at 37 degrees C (p < 0.0002). The phagocytic up-take was lowest after substrate pre-treatment in normal serum as compared to samples with either no serum exposure or pre-treatment in LE-serum with anti-dsDNA antibodies (p < 0.05). Taken together, these data suggest the phagocytosis-based flow cytometry assay is suitable for analyzing the LE cell phenomenon. This method provides an interesting, simple and rapid new tool, and will possibly alleviate further studies on the LE cell phenomenon with modified cell models and/or conditions.

Animals↗

PubMed2003

Decrease of B-cells and autoantibodies after low-dose methotrexate.

The purpose was to assess the efficacy of low-dose methotrexate (MTX) on immunological parameters in patients with lupus erythematosus (LE) under short- (</=10 weeks) vs. long-term (>10 weeks) conditions. Patients who did not respond to classical LE treatment (antimalarials and/or glucocorticosteroids) were retrospectively analyzed. Twenty-two LE-patients received 10-30 mg MTX per week. Sera and ethylenediaminetetra-acetic blood specimens were analyzed for autoantibodies and lymphocyte subsets (flow cytometry), respectively. Clinical improvement occurred in 21 patients (complete response n = 15, 68.2%). B-cells were the main targets: their absolute number significantly dropped down after long-term treatment (290 +/- 49 vs. 221 +/- 41 microl(-1), P = 0.00254). This was accompanied by down-regulation of autoantibodies. The effect on B-cells was more pronounced in patients with (before vs. long-term 172 +/- 34 vs. 99 +/- 15 microl(-1), P = 0.02853) than without autoantibodies (169 +/- 40 vs. 144 +/- 51 microl(-1), P = 0.55406). MTX did not induce immunosuppression. Low-dose MTX has different short- and long-term effects on immunologic parameters, which could explain the clinical improvement.

Adjuvants, Immunologic↗

PubMed2003

Disruption of the cytoskeleton after apoptosis induction with autoantibodies.

F-actin cleavage was studied in PBMC after treatment with anti-dsDNA antibodies. Significant changes in F-actin disruption detected by decrease of FITC-phalloidin staining occurred after apoptosis induction with anti-dsDNA antibodies (p < 0.006). Despite of similar F-actin disruption, the switch of phosphatidylserine (PS) to the outer leaflet of the cell membrane as detected by annexin V binding was lower after anti-dsDNA antibody than without antibody treatment (58.4 +/- 11.0% vs. 81.9 +/- 7.7%). F-actin disruption was accompanied by activation of caspase 3 within the cytoplasm (r = -0.92599; p < 8.87446 x 10-(10)) under both conditions with and without autoantibodies. These findings indicate that anti-dsDNA antibody-induced apoptosis is more marked within the cell than upon the cell surface. The diminished externalization of PS might result in a decreased phagocytosis. Thereby, the reduced clearance of apoptotic cells could induce autoantibody production possibly against epitopes which arise due to the apoptotic disruption of cells.

Actins↗

PubMed2003

Cytokine profiles after nonionic dimeric contrast medium injection.

RATIONALE AND OBJECTIVES: Mediators of contrast media (CM)-induced allergic/pseudoallergic side effects are largely unknown. We evaluated the possibility of cytokines released as surrogate markers for allergic/pseudoallergic responses in patients who tolerated CM injection well. MATERIALS AND METHODS: Interleukin-1beta (IL-1beta), -2, -4, -5, -6; tumor necrosis factor-alpha; plasma histamine level; and the anaphylatoxin C5a were measured by enzyme-linked immunosorbent assay technique in 9 patients who received the nonionic dimeric iodinated CM iotrolan under routine computed tomography examination conditions. Serum samples were collected before, 1 hour, 6 hours, and 24 hours after contrast medium injection. RESULTS: The cytokine values did not correlate with the hematocrit. Kinetic studies revealed a trend, although not statistically significant (P>0.05), for an early increase of IL-2 (1 hour after CM), followed by delayed increase of IL-4 and IL-6. Histamine significantly decreased after iotrolan injection and C5a increased 6 hours (P>0.05) after CM administration in parallel to IL-6. IL-1beta decreased (with the lowest value measured 6 hours after CM injection; P>0.05), and tumor necrosis factor-alpha did not show any tendency. Patients with late adverse reactions had a T helper 1 to T helper 2 shift and 24 hours after CM injection had the highest histamine values. CONCLUSION: The results suggest CM-related liberation of cytokines with a sequential T helper type 1 (IL-2 after 1 hour), and T helper type 2-like pattern (IL-4, -5, and -6).

Adult↗

PubMedDate not supplied

Apoptosis: the complex scenario for a silent cell death.

In multicellular organisms, homeostasis is maintained by a balance between cell proliferation and apoptosis (programmed cell death). It is a physiological form of cell death responsible for the deletion of not reparable damaged, mutated, or cells which have lost their function. Apoptosis can be distinguished by morphological and biochemical characteristics from necrosis (pathological cell death). Apoptotic cell death does not disturb surrounding cells. To achieve the elimination of cells without an inflammatory reaction, a complex interplay of several molecules is necessary. Apoptosis either starts from the cell surface (CD95-CD95L), the mitochondrion or from the nucleus. The cell biological events run in a cascaded fashion and are regulated by either enhancer or anti-apoptotic signals that probably may stop the executions machinery. The knowledge about apoptosis helps to understand pathophysiologic conditions, to better diagnose and treat them by molecular radiological techniques.

Animals↗