Malin Hansson

University of Gothenburg, Göteborg, Vaestra Goetaland, Sweden

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Publications (9)39.45 Total impact

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    ABSTRACT: Infection with Helicobacter pylori is associated with development of ulcer disease and gastrointestinal adenocarcinoma. The infection leads to a large infiltration of immune cells and the formation of organized lymphoid follicles in the human gastric mucosa. Still, the immune system fails to eradicate the bacteria, and the substantial regulatory T cell (Treg) response elicited is probably a major factor permitting bacterial persistence. Dendritic cells (DC) are professional antigen presenting cells that can activate naïve T cells, and maturation of DC is crucial for the initiation of primary immune responses. The aim of this study was to investigate the presence and localization of mature human DC in H. pylori infected gastric mucosa. Gastric antral biopsies were collected from patients with H. pylori associated gastritis and healthy volunteers, and antrum tissue from patients undergoing gastric resection. Immunohistochemistry and flow cytometry showed that DC expressing the maturation marker dendritic cell lysosome-associated membrane glycoprotein (DC-LAMP; CD208) are enriched in the H. pylori infected gastric mucosa and that these DC are specifically localized within or close to lymphoid follicles. Gastric DC-LAMP(+) DC express CD11c and high levels of HLA-DR, but little CD80, CD83, and CD86. Furthermore, immunofluorescence analyses demonstrated that DC-LAMP(+) DC are in the same location as FoxP3(+) putative Treg in the follicles. In conclusion, we show that DC-LAMP(+) DC with low co-stimulatory capacity accumulate in the lymphoid follicles in human H. pylori infected gastric tissue, and our results suggest that Treg-DC interactions may promote chronic infection by rendering gastric DC tolerogenic.
    Infection and immunity 07/2013; · 4.21 Impact Factor
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    ABSTRACT: Persistent colonization with the gastric bacterial pathogen Helicobacter pylori causes gastritis and predisposes infected individuals to gastric cancer. Conversely, it is also linked to protection from allergic, chronic inflammatory, and autoimmune diseases. We demonstrate here that H. pylori inhibits LPS-induced maturation of DCs and reprograms DCs toward a tolerance-promoting phenotype. Our results showed that DCs exposed to H. pylori in vitro or in vivo failed to induce T cell effector functions. Instead, they efficiently induced expression of the forkhead transcription factor FoxP3, the master regulator of Tregs, in naive T cells. Depletion of DCs in mice infected with H. pylori during the neonatal period was sufficient to break H. pylori-specific tolerance. DC depletion resulted in improved control of the infection but also aggravated T cell-driven immunopathology. Consistent with the mouse data, DCs infiltrating the gastric mucosa of human H. pylori carriers exhibited a semimature DC-SIGN(+)HLA-DR(hi)CD80(lo)CD86(lo) phenotype. Mechanistically, the tolerogenic activity of H. pylori-experienced DCs was shown to require IL-18 in vitro and in vivo; DC-derived IL-18 acted directly on T cells to drive their conversion to Tregs. CD4(+)CD25(+) Tregs from infected wild-type mice but not Il18(-/-) or Il18r1(-/-) mice prevented airway inflammation and hyperresponsiveness in an experimental model of asthma. Taken together, our results indicate that tolerogenic reprogramming of DCs ensures the persistence of H. pylori and protects against allergic asthma in a process that requires IL-18.
    The Journal of clinical investigation 03/2012; 122(3):1082-96. · 15.39 Impact Factor
  • Malin Hansson, Tone Ahlborg
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    ABSTRACT: To describe experienced relationship quality, and in particular sensuality and sexuality, in first-time parents over time from when the firstborn is six months (T1), four years (T2) and eight years (T3) of age, to describe gender differences and the factors which may affect experienced relationship quality. A longitudinal design with repeated measures using the self-reporting questionnaire Quality of Dyadic Relationship, QDR36, which was answered by 258 parents at all three occasions. Data was analysed primarily using Friedman's test and multiple regression analysis. The relationship quality statistically significantly decreased at T2 and then significantly increased again at T3 but not back to the level of origin at T1 (p<0.000). Both sexes showed a similar change over time in the QDR-index. The dimension Dyadic Sensuality statistically significantly decreased at all three occasions (p<0.000) and Dyadic Sexuality showed no significant differences over time but remained at a low level at all three occasions. Sexual Frequency and Contentment decreased at T3 after a small increase at T2. Four covariates of perceived relationship quality at T3 were statistically significant; strained relationship with the child, strained health, Sense of Coherence and strained economy. Cronbach's alpha showed a high reliability (0.95) at T3 and indicates a development of the QDR 36. The results showing low intimacy in the relationship indicate a need of support from professionals, e.g. midwives, to couples with small children, for instance by enhancing communication skills and emphasizing the role of sensuality and sexuality.
    Sexual & reproductive healthcare: official journal of the Swedish Association of Midwives 03/2012; 3(1):21-9. · 1.25 Impact Factor
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    ABSTRACT: We have previously demonstrated that Helicobacter pylori infection is associated with an increased number of CD4(+)CD25(high) regulatory T cells in the gastric and duodenal mucosa. In this study, we determined the number and localization of CD4(+) cells expressing the regulatory T-cell-specific transcription factor FOXP3 in the antrum and duodenum of duodenal ulcer patients, asymptomatic carriers, and uninfected individuals. We also determined gene expression levels of FOXP3 as well as anti- and proinflammatory cytokines before and after H. pylori eradication. Cellular FOXP3 expression was studied by immunofluorescence and flow cytometry, and transcription levels of FOXP3, interleukin (IL)-10, transforming growth factor-beta, CD4, and interferon-gamma were analyzed by real-time reverse transcription-polymerase chain reaction. We found an increased (6-fold) frequency of CD4(+)FOXP3(+) T cells in H. pylori-infected gastric mucosa; interestingly 26% of these cells did not co-express CD25. The increase of FOXP3-expressing T cells in the antrum of infected individuals was dependent on the presence of H. pylori, since eradication therapy resulted in 4-fold lower levels of FOXP3 and IL-10 mRNA in the antrum. Furthermore, higher numbers of CD4(+)FOXP3(+) T cells were found in areas of duodenal gastric metaplasia in the duodenum of duodenal ulcer patients compared to duodenal gastric metaplasia of asymptomatic individuals and healthy mucosa in both patient groups. In duodenal ulcer patients, the CD4(+)FOXP3(+) T cells were more highly associated to aggregates in the duodenal mucosa. The numbers of CD4(+)FOXP3(+) T cells are increased and localized in CD4(+) T-cell aggregates in areas of duodenal gastric metaplasia in duodenal ulcer patients.
    Helicobacter 07/2009; 14(3):192-201. · 3.51 Impact Factor
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    ABSTRACT: Helicobacter pylori is one of the most common bacterial pathogens, infecting up to 50% of the world's population. The host is not able to clear the infection, leading to life-long chronic inflammation with continuous infiltration of lymphocytes and granulocytes. The migration of leukocytes from the blood into inflamed tissue is dependent on adhesion molecules expressed on the vascular endothelium. The aim of this study was to characterize the effect of H. pylori-induced gastritis with regard to the expression of endothelial adhesion molecules in the gastric mucosa and compare this to other types of chronic mucosal inflammations. Our results demonstrate an increased level of expression of the adhesion molecule E-selectin, but not of intracellular adhesion molecule 1, vascular adhesion molecule 1, or vascular adhesion protein 1, in H. pylori-induced gastritis but not in gastritis induced by acetylsalicylic acid or pouchitis. The upregulated E-selectin expression was determined to be localized to the gastric mucosa rather than being a systemic response to the infection. Moreover, the H. pylori type IV secretion system encoded by the cag pathogenicity island (cagPAI) was found to be an important determinant for the upregulation of human endothelial E-selectin expression in vitro, and this process is probably dependent on the CagL protein, mediating binding to alpha5beta1 integrins. Thus, endothelial E-selectin expression induced by H. pylori probably contributes to the large influx of neutrophils and macrophages seen in infected individuals, and our results suggest that this process may be more pronounced in patients infected with cagPAI-positive H. pylori strains and may thereby contribute to tissue damage in these individuals.
    Infection and immunity 06/2009; 77(7):3109-16. · 4.21 Impact Factor
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    ABSTRACT: Gastric adenocarcinoma is closely associated with Helicobacter pylori infection. It is also much more frequent in patients with common variable immunodeficiency or selective IgA-deficiency than in the general population. To investigate a possible link between local antibody production and gastric tumors, we studied gastric B cell infiltration and local IgA production in patients with H. pylori induced gastric adenocarcinomas. These studies showed that total and H. pylori-specific IgA antibody levels were substantially lower in gastric tissue from the cancer patients compared to those from asymptomatic H. pylori carriers. However, serum IgA levels were similar in the cancer patients and asymptomatic carriers. As could be expected, H. pylori infected asymptomatic carriers had considerably increased IgA antibody levels compared to uninfected subjects. We conclude that patients suffering from gastric adenocarcinoma have a dramatically decreased local IgA production in the stomach compared to asymptomatic H. pylori infected individuals.
    Clinical Immunology 03/2009; 131(3):463-71. · 3.77 Impact Factor
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    ABSTRACT: Human Helicobacter pylori infection gives rise to an active chronic gastritis and is a major risk factor for the development of duodenal ulcer disease and gastric adenocarcinoma. The infection is accompanied by a large accumulation of immunoglobulin A (IgA)-secreting cells in the gastric mucosa, and following mucosal immunization only H. pylori-infected volunteers mounted a B-cell response in the gastric mucosa. To identify the signals for recruitment of gastric IgA-secreting cells, we investigated the gastric production of CCL28 (mucosa-associated epithelial chemokine) and CCL25 (thymus-expressed chemokine) in H. pylori-infected and uninfected individuals and the potential of gastric B-cell populations to migrate toward these chemokines. Gastric tissue from H. pylori-infected individuals contained significantly more CCL28 protein and mRNA than that from uninfected individuals, while CCL25 levels remained unchanged. Chemokine-induced migration of gastric lamina propria lymphocytes isolated from patients undergoing gastric resection was then assessed using the Transwell system. IgA-secreting cells and IgA(+) memory B cells from H. pylori-infected tissues migrated toward CCL28 but not CCL25, while the corresponding cells from uninfected patients did not. Furthermore, IgG-secreting cells from H. pylori-infected patients did not migrate to CCL28 but instead to CXCL12 (SDF-1alpha). However, chemokine receptor expression did not correlate to the migratory pattern of the different B-cell populations. These studies are the first to show increased CCL28 production during gastrointestinal infection in humans and provide an explanation for the large influx of IgA-secreting cells to the gastric mucosa in H. pylori-infected individuals.
    Infection and immunity 08/2008; 76(7):3304-11. · 4.21 Impact Factor
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    ABSTRACT: Helicobacter pylori infection induces chronic inflammation in the gastric mucosa with a marked increase in the number of lymphoid follicles consisting of infiltrating B and T cells, neutrophils, dendritic cells (DC) and macrophages. It has been suggested that an accumulation of mature DC in the tissue, resulting from a failure of DC to migrate to lymph nodes, may contribute to this chronic inflammation. Migration of DC to lymph nodes is regulated by chemokine receptor CCR7, expressed on mature DC, and the CCR7 ligands CCL19 and CCL21. In this study we analysed the maturation, in vitro migration and cytokine production of human DC after stimulation with live H. pylori. For comparison, DC responses to non-pathogenic Escherichia coli bacteria were also evaluated. Stimulation with H. pylori induced maturation of DC, i.e. up-regulation of the chemokine receptors CCR7 and CXCR4 and the maturation markers HLA-DR, CD80 and CD86. The H. pylori-stimulated DC also induced CD4(+) T-cell proliferation. DC stimulated with H. pylori secreted significantly more interleukin (IL)-12 compared to DC stimulated with E. coli, while E. coli-stimulated DC secreted more IL-10. Despite low surface expression of CCR7 protein following stimulation with H. pylori compared to E. coli, the DC migrated equally well towards CCL19 after stimulation with both bacteria. Thus, we could not detect any failure in the migration of H. pylori stimulated DC in vitro that may contribute to chronic gastritis in vivo, and our results suggest that H. pylori induces maturation and migration of DC to lymph nodes where they promote T cell responses.
    Microbes and Infection 04/2006; 8(3):841-50. · 2.92 Impact Factor
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    Malin Hansson

Publication Stats

101 Citations
39.45 Total Impact Points

Institutions

  • 2012–2013
    • University of Gothenburg
      • • Department of Microbiology and Immunology
      • • Institute of Health and Care Sciences
      Göteborg, Vaestra Goetaland, Sweden
  • 2008
    • Sahlgrenska University Hospital
      Goeteborg, Västra Götaland, Sweden