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Arne Hansen

Publications and source records attributed to Arne Hansen.

15 recordsLinked to original sources
PubMed2006

Sensitive and specific method for detecting G protein-coupled receptor mRNAs.

G protein-coupled receptors (GPCRs) mediate effects of extracellular signaling molecules in all the body's cells. These receptors are encoded by scarce mRNAs; therefore, detecting their transcripts with conventional microarrays is difficult. We present a method based on multiplex PCR and array detection of amplicons to assay GPCR gene expression with as little as 1 mug of total RNA, and using it, we profiled three human bone marrow stromal cell (BMSC) lines.

Cell Line↗
PubMed2005

Dysregulation of chemokine receptor expression and function by B cells of patients with primary Sjögren's syndrome.

OBJECTIVE: To assess whether abnormal chemokine receptor expression and/or abnormal responsiveness to the cognate ligands might underlie some of the disturbances in B cell homeostasis characteristic of primary Sjögren's syndrome (SS). METHODS: Chemokine receptor expression by CD27- naive and CD27+ memory B cells from patients with primary SS and healthy control subjects was analyzed using flow cytometry, single-cell reverse transcriptase-polymerase chain reaction (RT-PCR), and migration assays. RESULTS: In contrast to healthy subjects, significantly higher expression of both surface CXCR4 and CXCR4 messenger RNA (mRNA) was seen in peripheral blood B cells from patients with primary SS. These differences were most prominent in CD27- naive B cells (P < or = 0.0006). In addition, significantly higher frequencies of CD27- naive B cells from patients with primary SS expressed mRNA for the inhibitory regulator of G protein signaling 13 (P = 0.001). Expression of CXCR5 by peripheral CD27+ memory B cells was moderately diminished in patients with primary SS compared with healthy controls (P = 0.038). No significant differences were noted in the expression of CXCR3, CCR6, CCR7, and CCR9 between B cells from healthy controls and those from patients with primary SS. Transmigration assays of blood B cells from patients with primary SS and healthy controls showed comparable responses of CD27- naive B cells but significantly diminished responses of activated primary SS CD27+ memory B cells to the ligands of CXCR4 and CXCR5, CXCL12 (P = 0.032), and CXCL13 (B lymphocyte chemoattractant; B cell-attracting chemokine 1; P = 0.018), respectively, when compared with those from healthy controls. Finally, compared with controls, peripheral reduction but glandular accumulation of CXCR4+,CXCR5+,CD27+ memory B cells was identified in patients with primary SS. CONCLUSION: In primary SS, overexpression of CXCR4 by circulating blood B cells does not translate into enhanced migratory response to the cognate ligand, CXCL12. This migratory response may be modulated by intracellular regulators. Retention of CXCR4+,CXCR5+, CD27+ memory B cells in the inflamed glands seems to contribute to diminished peripheral CD27+ memory B cells in primary SS.

Adult↗
PubMed2005

A method for the determination of the residual chloroform in defatted cancellous bone transplants.

The removal of fat from cancellous bone tissue promotes the clinical healing of the transplant and improves the penetration of chemical sterilisation media into the tissue. Treatment using chloroform/methanol (2:1, 2 h) is frequently used as a defatting procedure. Eight rinses with methanol followed by two rinses with aqua ad iniectabilia (20 min each, with ultrasonic effect) ensure depletion in the level of chloroform from defatted cancellous bone to a concentration below 25 ppm (limit value). For the necessary routine quality checks on the production process, a gas chromatography method has been developed that determines the level of chloroform in cancellous bone, for which the detection limit is 0.003 ppm.

Bone Transplantation↗
PubMed2005

Cryopreserved human B cells as an alternative source for single cell mRNA analysis.

Reverse transcription-polymerase chain reaction (RT-PCR) of individual B-lymphocytes has been shown to be a powerful tool for the simultaneous analysis of different mRNA specificities in both malignant and non-malignant B cell subpopulations. However, especially for longitudinal studies, this may also require analyses of cryopreserved cells. Therefore, the current study assessed whether cryopreserved (liquid nitrogen, dimethyl sulfoxide [DMSO]-stored) viable B cells are an alternative source for single cell RT-PCR analysis. Fresh (non-frozen) and post-thawed human peripheral blood B cells were analyzed by fluorescence-activated cell sorting (FACS). As a result, different B cell subpopulations could be reliably stained and separated from both fresh and post-thawed cells by four-color flow cytometry, although slightly diminished fluorescence intensities of some subpopulation markers were observed when analyzing cryopreserved cells. Subsequently, viable individual CD19+CD27+ memory B cells were sorted into single wells and analyzed for the expression of mRNA transcripts of the 'house-keeping gene' glyceraldehyde phosphate dehydrogenase (GAPD), the constitutive B cell homing receptor CXCR4, and immunoglobulin heavy chain variable region (IgVH) genes by nested RT-PCR protocols. Comparing both B cell sources, RT-PCR analysis revealed comparable yields of cells expressing transcripts for the three mRNA specificities tested (GAPD, CXCR4, IgVH) indicating the integrity of the respective mRNAs in cryopreserved B cells. In conclusion, these data indicate that optimally cryopreserved B cells may be an alternative source for single-cell RT-PCR analysis, especially in longitudinal B cell studies. However, the settings for both FACS analysis and RT-PCR should be re-evaluated for each distinct subpopulation and target mRNA of interest when analyzing post-thawed cells.

Antigens, Surface↗
PubMed2005

Immunopathogenesis of primary Sjögren's syndrome: implications for disease management and therapy.

PURPOSE OF REVIEW: Recent studies have broadened our understanding of the etiopathogenesis and immunopathology of primary Sjögren's syndrome. This review highlights recent advances in understanding the underlying mechanisms of the disease as well as their implications for clinical handling and therapeutic options. RECENT FINDINGS: It becomes increasingly apparent that certain disturbances of the immune system (i.e. B-cell hyperreactivity and enhanced levels of B-cell-activating factor/B-lymphocyte stimulator) play a central role in this entity. Whether this is a primary abnormality or the result of predisposing factors or infectious, e.g. viral, agents remains uncertain. New insights into the pathogenesis also provide candidates for better diagnosis and classification of disease severity, such as flow cytometric analysis, measurement of soluble cell surface molecules, autoantibodies, cytokines, and ligands (B-cell-activating factor/B-lymphocyte stimulator). Whether B-cell-directed therapies (i.e. blocking B-cell-activating factor/B-lymphocyte stimulator, anti-CD20 therapy) will have an impact on primary Sjögren's syndrome needs to be shown in clinical trials. Alternative therapeutic approaches such as organ-targeted gene transfer are in development but must be carefully evaluated for safety and efficacy in preclinical models that resemble human primary Sjögren's syndrome. SUMMARY: The pathogenesis of primary Sjögren's syndrome is complex and the factors initiating and driving autoimmunity in this entity are largely unknown. Recent studies provide new insights into potential pathogenetic mechanisms of the disease and, thereby, the chance for improved strategies in disease management and therapy.

Animals↗
PubMed2004

Generation of migratory antigen-specific plasma blasts and mobilization of resident plasma cells in a secondary immune response.

Maintenance of protective humoral immunity depends on the generation and survival of antibody-secreting cells. The bone marrow provides niches for long-term survival of plasma cells generated in the course of systemic immune responses in secondary lymphoid organs. Here, we have analyzed migratory human plasma blasts and plasma cells after secondary vaccination with tetanus toxin. On days 6 and 7 after immunization, CD19(+)/CD27(high)/intracellular immunoglobulin G(high) (IgG(high))/HLA-DR(high)/CD38(high)/CD20(-)/CD95(+) tetanus toxin-specific antibody-secreting plasma blasts were released in large numbers from the secondary lymphoid organs into the blood. These cells show chemotactic responsiveness toward ligands for CXCR3 and CXCR4, probably guiding them to the bone marrow or inflamed tissue. At the same time, a population of CD19(+)/CD27(high)/intracellular IgG(high)/HLA-DR(low)/CD38(+)/CD20(-)/CD95(+) cells appeared in the blood in large numbers. These cells, with the phenotype of long-lived plasma cells, secreted antibodies of unknown specificity, not tetanus toxoid. The appearance of these plasma cells in the blood indicates successful competition for survival niches in the bone marrow between newly generated plasma blasts and resident plasma cells as a fundamental mechanism for the establishment of humoral memory and its plasticity.

Adult↗
PubMed2004

Abnormalities in peripheral B cell memory of patients with primary Sjögren's syndrome.

OBJECTIVE: To delineate disturbances in peripheral B cell memory in primary Sjögren's syndrome (SS). METHODS: Isotype-specific immunoglobulin (Ig) heavy-chain transcripts were analyzed in single-sorted CD19+,CD27- naive and CD19+,CD27+ memory B cells from patients with primary SS and normal healthy control subjects. RESULTS: A significantly higher frequency of B cells expressing mu-, alpha-, and/or gamma-chain transcripts were found in patients with primary SS compared with controls (58.0% versus 14.3%; P < 0.0001). Notably, 30.5% of individual B cells (for primary SS, 38.7%; for controls, 12.7% [P < 0.0001]) simultaneously expressed transcripts for different Ig heavy-chain isotypes using identical V(H)-D-J(H) rearrangements. However, these cells lacked surface expression of more than one of the respective Ig heavy-chain isotypes as well as messenger RNA (mRNA) transcripts for 2 germinal center markers, activation-induced cytidine deaminase, and Bcl-6. In contrast with the findings in normal healthy controls, peripheral B cell memory in patients with primary SS was characterized by 1) circulating CD27+ B cells expressing heavily mutated Ig V(H) transcripts (mutational frequency 8.6% versus 4.3%; P < 0.0001), 2) significantly enhanced mutational frequencies of C mu transcripts (9.6% versus 2.5%; P < 0.0001), 3) a high proportion (61.2%) of CD27+ B cells expressing transcripts for multiple Ig heavy-chain isotypes, and 4) a CD27- memory-type B cell subpopulation expressing mutated C mu transcripts. CONCLUSION: Altogether, both B cell hyperactivity and striking abnormalities in peripheral B cell memory are indicated at the single-cell mRNA level in patients with primary SS. Detection of multiple Ig heavy-chain transcripts in peripheral CD19+,CD27+ memory B cells of patients with SS may represent the abnormal retention of pre-switch mRNA transcripts in circulating post-switch B cells.

Adult↗
PubMed2003

New concepts in the pathogenesis of Sjögren syndrome: many questions, fewer answers.

Although a modified European-American consensus classification of Sjögren syndrome has been introduced during the last year, the etiopathogenesis of this disease characterized by chronic lymphocytic inflammation, impaired function, and, finally, destruction of the salivary and lacrimal glands as well as systemic manifestations remains to be elucidated. Recent insights into the pathogenesis of Sjögren syndrome resulting from immunogenetic, hormonal, and epidemiologic evaluations as well as animal and in vitro studies are highlighted by this review. Evidence confirms that lymphocytic disturbances, including ectopic germinal center formation and aberrations of cellular signaling play a significant role in Sjögren syndrome. Although some of these features are unique to Sjögren syndrome, others are also found in a number of systemic autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. The underlying cause of Sjögren syndrome remains largely enigmatic. However, distinct characteristics may provide the basis for the classification of the disease entities. Finally, an enhanced risk of lymphomagenesis is a well-known hallmark of primary Sjögren syndrome, indicating the central role of derangement of lymphocyte regulation. As demonstrated by the introduction of the new targeted therapeutic approaches in rheumatoid arthritis, solid insights into the pathogenesis of Sjögren syndrome may pave the way toward new therapeutic approaches.

Animals↗
PubMed2003

Peracetic acid-ethanol treatment of allogeneic avital bone tissue transplants--a reliable sterilization method.

OBJECTIVES: Based on the European Standard EN 1040, the validation guidelines of the German Federal Institute for Drugs and Medical Devices and CPMP guidelines we tested the antimicrobial effectiveness of a peracetic acid-ethanol sterilization procedure (PES) in allogenic avital bone transplants. STUDY DESIGN: Delipidated human bone spongiosa cubes (15 x 15 x 15 mm) served as tissue. Three enveloped viruses (human immunodeficiency virus type 2, pseudorabies virus, bovine virus diarrhoea virus) and three non-enveloped viruses (hepatitis A virus, poliovirus, porcine parvovirus) were used. The reduction of virus infectivity was measured as TCID50/ml in neutralized supernatants and bone homogenates. Staphylococcus aureus. Enterococcus faecium, Pseudomonas aeruginosa. Bacillus subtilis. Clostridium sporogenes, Mycobacterium terrae. Candida albicans, Aspergillus niger as well as spores of Bacillus subtilis were tested additionally. PES led to a reduction of virus titres by more than 4 log10. Only HAV showed a reduction below 4 log10 (2.87) with residual infectivity. After including a delipidating step for HAV-infected cells, a reduction of over 7 log10 HAV titre was found. For viable bacteria, fungi and spores a titre reduction below the detection level (5 log10) was achieved after an incubation time of 2 hours. CONCLUSIONS: The peracetic acid-ethanol procedure proved to be a reliable method for the sterilization of human bone transplants (layer thickness < or = 15 mm). However, additional safety measures (anamnestic informations, infectious serology, HIV-/HBV-/HCV-PCR in case of multiorgan donors) should be taken.

Bacteria↗
PubMed2002

Chronic lymphocytic leukemia preceded by cold agglutinin disease: intraclonal immunoglobulin light-chain diversity in V(H)4-34 expressing single leukemic B cells.

Autoimmune phenomena may precede or accompany lymphoid malignancies, especially B-chronic lymphocytic leukemia (B-CLL). We report a patient with a 7-year history of primary (idiopathic) cold agglutinin (CA) disease in whom B-CLL subsequently developed. Immunophenotyping and single-cell reverse transcription-polymerase chain reaction (RT-PCR) were applied to investigate the origin and diversification of leukemic B cells. The obtained data indicate a memory cell-type origin of the B-CLL cells. Remarkably, the IgV(kappa) genes of the B-CLL cells showed intraclonal diversity, whereas the mutational pattern of their paired IgV(H) genes were invariant. Thus, the light-chain-restricted intraclonal diversity in individual leukemic B cells in this patient strongly indicates a differential regulation or selection of the ongoing mutational process. Of note, our findings suggest that this B-CLL had developed from the patient's CA-producing B-cell population.

Anemia, Hemolytic, Autoimmune↗
PubMed2002

Analysis of immunoglobulin light chain rearrangements in the salivary gland and blood of a patient with Sjögren's syndrome.

Patients with Sjögren's syndrome (SS) have characteristic lymphocytic infiltrates of the salivary glands. To determine whether the B cells accumulating in the salivary glands of SS patients represent a distinct population and to delineate their potential immunopathologic impact, individual B cells obtained from the parotid gland and from the peripheral blood were analyzed for immunoglobulin light chain gene rearrangements by PCR amplification of genomic DNA. The productive immunoglobulin light chain repertoire in the parotid gland of the SS patient was found to be restricted, showing a preferential usage of particular variable lambda chain genes (V lambda 2E) and variable kappa chain genes (V kappa A27). Moreover, clonally related V(L) chain rearrangements were identified; namely, V kappa A27-J kappa 5 and V kappa A19-J kappa 2 in the parotid gland, and V lambda 1C-J lambda 3 in the parotid gland and the peripheral blood. V kappa and V lambda rearrangements from the parotid gland exhibited a significantly elevated mutational frequency compared with those from the peripheral blood (P < 0.001). Mutational analysis revealed a pattern of somatic hypermutation similar to that found in normal donors, and a comparable impact of selection of mutated rearrangements in both the peripheral blood and the parotid gland. These data indicate that there is biased usage of V(L) chain genes caused by selection and clonal expansion of B cells expressing particular V(L) genes. In addition, the data document an accumulation of B cells bearing mutated V(L) gene rearrangements within the parotid gland of the SS patient. These results suggest a role of antigen-activated and selected B cells in the local autoimmune process in SS.

Aged↗
PubMed2002

Diminished peripheral blood memory B cells and accumulation of memory B cells in the salivary glands of patients with Sjögren's syndrome.

OBJECTIVE: To delineate the mechanism of the abnormalities in B cell biology found in patients with primary Sjögren's syndrome (SS). METHODS: The distribution of peripheral B cell subpopulations in 21 patients with primary SS was analyzed by immunofluorescence labeling and flow cytometry. Immunoglobulin rearrangements were analyzed in single B cells isolated from the peripheral blood and parotid glands by fluorescence-activated cell sorting. RESULTS: A significant reduction in the number of peripheral CD27+ memory B cells was found in SS patients, including a significantly reduced number of CD27+/IgD+/IgM+/CD5+ memory B cells. Remarkably, SS patients with secondary lymphoma uniquely exhibited an increase in CD27-expressing peripheral B cells, including CD27(high) plasmablasts. Molecular analysis for mutated Ig gene rearrangements confirmed that CD27 expression distinguished naive and memory cells in SS. In contrast to the peripheral blood, the majority of parotid B cells from 1 patient examined exhibited both the mutational status and phenotype of memory B cells. Accordingly, the mutational frequencies of V(H) rearrangements were significantly greater in parotid B cells than in peripheral blood B cells, whereas the V(H) gene repertoire appeared to be very similar between the compartments. CONCLUSION: These data indicate that there is an accumulation/retention of memory B cells in the inflamed salivary glands of SS patients. It is possible that preferential accumulation of CD27+ memory B cells in the inflamed parotid gland explains their reduction in the peripheral blood.

Adult↗
PubMed2002

Immunglobulin repertoire analysis provides new insights into the immunopathogenesis of Sjögren's syndrome.

This review focuses on the use of immunglobulin (Ig) variable region genes by B cells from patients with primary Sjögren's syndrome (pSS) and the biologic insights that this provides. Comparison of the Ig repertoire from the blood and parotid gland of pSS patients with that of normal donors suggests that there are typical disturbances of B cell homeostasis with depletion of memory B cells from the peripheral blood and accumulation/retention of these antigen-experienced B cells in the inflamed tissue. Although there are clonally expanded B cells in the parotid gland, generalized abnormalities in the B cell repertoire are also found in pSS patients. The vast majority of the current data indicate that there is no major molecular abnormality in generating the IgV chain repertoire in patients with pSS. In contrast, disordered selection leads to considerable differences in the V(L) gene usage and V(H) CDR3 length of the B cell Ig repertoire in pSS patients. The nature of the influences that lead to disordered selection in pSS remains to be determined, but should provide important clues to the etiology of this autoimmune inflammatory disorder.

Autoimmunity↗
PubMed2002

Dose-reduced conditioning regimen followed by allogeneic stem cell transplantation in patients with myelofibrosis with myeloid metaplasia.

Three patients with myelofibrosis received allogeneic stem cell transplantation after a dose-reduced conditioning regimen of busulphan (8 mg/kg), fludarabine (180 mg/m2) and antithymocyte globulin (4 x 10 mg/kg). The median age at transplantation was 51 years (range 44-58). All patients engrafted with a leucocyte count > 1.0 x 10(9)/l after a median of 18 d (range 16-20). Grade II acute skin graft-versus-host disease (GvHD) occurred in one patient. One limited and one extensive chronic GvHD was observed. All patients achieved complete haematological remission. In one patient the fibrosis resolved completely 180 d post transplant. All patients are alive 126, 466 and 764 d after transplantation.

Adult↗