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B Christensson

Publications and source records attributed to B Christensson.

At least 73 records · Page 4Linked to original sources
PubMed1997

Quantitative assessment of IgG and IgA subclass producing cells in rectal mucosa during shigellosis.

AIMS: To assess quantitatively both the morphological changes in the rectal mucosa and the changes in the relative frequency of IgA and IgG subclass producing cells found in the rectal mucosa during the acute phase of shigellosis and at convalescence. METHODS: Rectal biopsies from 25 Shigella dysenteriae 1 infected patients, 10 Shigella flexneri infected patients, and 40 uninfected controls were studied. Morphological changes in the mucosa were graded. The frequency of IgA and IgG subclass producing cells was assessed. In addition, immunostaining for secretory component in epithelial cells was analysed. RESULTS: Using morphological grading, 20% of the 35 patients studied had advanced inflammation (grade 3) in the acute phase of the disease. At convalescence, grade 1 inflammation was seen in 37% of the patients and in 10% of the controls. In the acute phase, as well as at convalescence, the number of IgA1, IgA2, and IgG2 positive cells was significantly higher than in the controls. The results were related to the histopathological degree of inflammation. CONCLUSIONS: In shigellosis, there is evidence for a prolonged humoral response residing in the mucosa long after the clinical symptoms have resolved, suggesting that shigellosis induces persisting mucosal humoral immune and inflammatory responses, remaining at least until 30 days after the infection.

Adult↗
PubMed1996

Preliminary data on hard metal workers exposure to tungsten oxide fibres.

The first personal exposure data for tungsten oxide fibres, in two hard metal manufacturing industries is presented. Occupational exposure was studied by static and personal measurements during tungsten metal production. Three different initial materials were used, ammonium-paratungstate (APT), blue oxide and tungsten trioxide. In both factories, airborne tungsten oxide fibres were detected both in static and personal samples. Fibre exposure varies for different activities. Charging of raw material, changing the hammer, cleaning-work on the cyclone and the micro-filter were found to be among the most high dusty operations. However, as workers use respirators during cleaning operations, these filters could not be related to personal exposure. The calcination of APT to the blue oxide generates fibrous dust. The raw material imported as blue oxide is also fibrous material and both charging it into the calcination furnace and re-charging it into the reduction furnace generates unnecessarily additional dusty periods. A single reduction-stage is, therefore, preferable. Furthermore, the tungsten trioxide raw material is non-fibrous, therefore, calcination of APT to tungsten trioxide and its reduction to tungsten metal is preferable with respect to minimising workers exposure to tungsten oxide fibres.

Air Pollutants, Occupational↗
PubMed1996

Suicide gene therapy for plasma cell tumors.

Suicide gene therapy for plasma cell tumors was attempted in severe combined immunodeficient (SCID) mice injected with human myeloma cell lines. Initially, a ganciclovir-induced bystander effect was observed in vitro using myeloma cells transduced with a herpes simplex thymidine kinase (HSVtk) gene. Transduced cells injected subcutaneously (SC) into SCID mice could be eradicated by the administration of ganciclovir (GCV). Furthermore, an in vivo bystander effect was noticed when mice received mixtures of HSVtk-positive and nontransduced cells. Unexpectedly, a "distant bystander" effect was observed as tumors in regions inoculated with only nontransduced cells were significantly smaller and had increased frequency of apoptotic figures and decreased mitotic frequency in GCV-treated mice transplanted with HSVtk-positive cells at a different region compared with control mice.

Animals↗
PubMed1996

Prognostic significance of proliferative and apoptotic fractions in low grade follicle center cell-derived non-Hodgkin's lymphomas.

BACKGROUND: The biologic parameters, DNA ploidy and proliferative activity, have been suggested as prognostic factors in non-Hodgkin's lymphoma (NHL). However, reports on the prognostic importance of these factors in follicle center cell-derived (FCC) centroblastic/centrocytic (CB/CC) NHL patients with long follow-up are scarce. METHODS: Apoptotic fractions were quantified in 60 patients with CB/CC NHL by in situ labeling of DNA strand breaks in nuclei [TdT-mediated dUTP/dATP in situ 3'OH--end labeling (TUNEL)]. The findings were related to S-phase and MIB-1 counts, DNA ploidy, and clinical outcome. RESULTS: In CB/CC NHL, the percentages of proliferating and apoptotic cells were lower than in reactive germinal centers (GC; P < 0.05; mean, 0.188 vs 3.263% and 19.05 vs. 69.4% for TUNEL and MIB-1 positive cells in CB/CC and GC, respectively). Significantly higher percentages of MIB-1 and TUNEL positive cells were observed in patients with complete remission when compared with the partial remission / no response group (P < 0.01). The size of proliferative and apoptotic fractions did not correlate with the overall survival of the patients. However, follicular and diffuse growth pattern, elevated serum lactic dehydrogenase, advanced stage, and age indicated a lower probability of 5- and 10-year survival. CONCLUSIONS: The investigation of proliferative and apoptotic fractions in FCC lymphomas may help to define groups of patients to who would benefit from aggressive, high dose therapy protocols and patients to whom less aggressive strategies can be applied safely.

Adult↗
PubMed1996

Reduction in serum levels of antimitochondrial (M2) antibodies following immunoglobulin therapy in severe combined immunodeficient (SCID) mice reconstituted with lymphocytes from patients with primary biliary cirrhosis (PBC).

The effect of gammaglobulin treatment on autoantibody production was investigated in SCID mice reconstituted with human peripheral blood mononuclear cells (PBMC) obtained from patients with PBC. All reconstituted mice displayed the presence of human antimitochondrial antibodies (alpha M2Ab) of both IgG and IgM types before treatment with human immunoglobulin. Two weeks after i.p. injection of 20 x 10(6) PBMC into SCID mice, i.p. treatment with various preparations of human immunoglobulin was initiated. In control animals treated with saline, serum levels of human alpha M2Ab of the IgG type increased with time, peaking around 4 weeks after reconstitution. In contrast, human IgG autoantibodies rapidly decreased in all animals treated with human IgG. Treatment with a human IgM preparation had no effect on serum levels of alpha M2Ab of the IgG type. The results may suggest that the pronounced reduction of specific IgG autoantibodies was due to an increased catabolism of human IgG, including the autoantibodies, in the gammaglobulin-treated mice. Although the production of human alpha M2Ab in reconstituted mice could be easily shown, PBC-specific liver lesions or bile duct destruction were not observed, irrespective of treatment protocol.

Animals↗
PubMed1996

Flow cytometric quantitation of serum anti-D in pregnancy.

BACKGROUND: The major cause of fetal hemolytic disease is maternal immunization to D in D-incompatible pregnancies. To prevent complications, D-incompatible pregnancies are monitored for the level of maternal anti-D. At present, the monitoring of anti-D levels is performed by the indirect antiglobulin test complemented by quantitation by the technique used in an automated antibody detection and quantitation instrument. STUDY DESIGN AND METHODS: Flow cytometry was used to quantitatively determine the level of anti-D in serum and to analyze the IgG subclass distribution and the presence of IgM anti-D in these samples. The results were compared to the indirect antiglobulin test titer and to the results obtained by the technique used in an automated antibody detection and quantitation instrument. RESULTS: Flow cytometry allowed sensitive and accurate determinations of anti-D levels with low interassay and intra-assay variability, both for serum samples and standard curves. CONCLUSION: Flow cytometry is a simple, rapid, and reliable method for determining the serum levels of D antibodies and their Ig subclass distribution. It is therefore well suited for the monitoring of women during D-incompatible pregnancies.

Female↗
PubMed1996

Changes in the peripheral blood T-Cell receptor V beta repertoire in vivo and in vitro during shigellosis.

A sequential activation of T cells in peripheral blood during shigello sis has been observer (D. Islam, P.K. Bradham, A. A. Lindberg, and B. Christensson, Infect. Immun 63:2941-2949, 1995). To further investigate the cellular response during the course of Shigella infection, changes in the T-cell receptor (TCR) repertoire in the subsets in blood in patients during shigellosis was that Shigella antigens may modulate the function of T cells carrying TCRs capable of recognizing Shigella-specific epitopes or superantigens. Such a selective preference for T cells expressing certain TCR Vbeta types could lead to the expansion or deletion of these T cells. In the present study of 27 adult male Bangladeshi patients with dysentery (14 cases caused by Shigella Dysenteriae 1 and 13 cases caused by Shigella flexneri), the changes in the TCR Vbeta repertoire of peripheral blood CD4+ and CD8+ T-cell subsets have been analyzed with a panel of nine anti-Vbeta monoclonal antibodies by flow cytometry. Twenty healthy males from Bangladesh and 20 healthy males from Sweden served as controls. Compared with the Bangladeshi controls, the patients had an increased frequency of CD4+T cells expression Vbeta2, Vbeta3, and Vbeta17, with a maximum at day 7 after the onset of disease. The frequency of CD4+T cells expressing Vbeta5.1 was increased only in patients with S. flexneri infection. Peripheral blood T cells from Shigella-infected patients also responded to in vitro stimulation in a TCR Vbeta-specific manner. Stimulation with heat-killed S. dysenteriae 1 and Shiga toxin enhanced the frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, Vbeta13.6, and Vbeta17, especially in samples obtained at day 7. The enhanced frequency of cells expressing Vbeta2, Vbeta3, Vbeta5.1, and Vbeta17 found both in in vivo and in vitro could suggest that in shigellosis antigens or superantigens are presented to the immune system and preferentially activate certain TCR Vbeta types in T-cell subsets. The kinetics of the change in the TCR Vbeta repertoire in blood during shigellosis may indicate that following local activation, the antigen activated T cells can be retrieved in the blood and restimulated in vitro. If confirmed by parallel analysis of T cells in the gut and blood by TCR sequence analysis, the possibility suggested by our findings would facilitate further analysis of the role of cell-mediated immune responses in the pathogenesis of and protection against Shigella infection.

Adult↗
PubMed1996

Absolute identification of muramic acid, at trace levels, in human septic synovial fluids in vivo and absence in aseptic fluids.

This is the first report of a study employing the state-of-the-art technique of gas chromatography-tandem mass spectrometry for absolute identification of muramic acid (a marker for peptidoglycan) at trace levels in a human or animal body fluid or tissue. Daughter mass spectra of synovial fluid muramic acid peaks (> or = 30 ng/ml) were identical to those of pure muramic acid. Absolute chemical identification at this level represents a 1,000-fold increase in sensitivity over previous gas chromatography-mass spectrometry identifications. Muramic acid was positively identified in synovial fluids during infection and was eliminated over time but was absent from aseptic fluids.

Arthritis, Infectious↗
PubMed1996

Persistence of nontypeable Haemophilus influenzae in adenoid macrophages: a putative colonization mechanism.

That nontypeable H. influenzae (NTHI) can reside intracellularly in human adenoid tissue has been suggested by use of in situ hybridization of a fluorescein labelled 16S rRNA-targeted oligonucleotide probe (FISH). Adenoid tissues from 43 children operated on in a clinically infection-free interval were investigated. FISH revealed H. influenzae in macrophage-like cells, located subepithelially in the crypts in all 43 adenoids. Furthermore, H. influenzae was detected in 22/22 adenoids using immunohistochemistry with the monoclonal antibody MAHI-3 recognizing a conserved H. influenzae LPS inner-core region. FISH and staining with monoclonal antibodies against immunophenotypic markers were performed simultaneously in order to characterize the cellular interrelations in this microenvironment. The findings of widespread presence of H. influenzae in cells of which some strongly expressed the CD14 marker of the monocyte/macrophage lineage may correspond to an important aspect of the colonization mechanisms whereby NTHI persists in the nasopharynx of children.

Adenoids↗
PubMed1996

Lack of T-helper lymphocytes in BAL fluid from a HIV-negative patient with recurrent non-tuberculous mycobacterial lung infections.

We describe here a previously healthy, 42 year old, HIV-negative woman. Following a seemingly successful 2-year antimycobacterial regimen for a lung infection caused by Mycobacterium avium/intracellulare she acquired a lung infection caused by M. chelonei. Characterization of alveolar cells from bronchoalveolar lavage fluid using flow cytometry revealed a total lack of T-cell subset CD4+ helper lymphocytes in spite of a normal proportion of the CD3+ and CD4+ T-cells in peripheral blood. The levels of Th2 cytokines such as IL-4, TGF-beta and G-CSF were higher in the patient's alveolar cells than in the cells of 4 healthy controls. This imbalance of cells and cell cytokines may contribute to the patient's susceptibility for non-tuberculous mycobacteria and her failure to eradicate these microorganisms.

Adult↗
PubMed1995

N-nitrosodimethylamine and 7-methylguanine DNA adducts in tissues of rats fed Chinese salted fish.

Previous studies have demonstrated that rats fed Chinese salted fish developed carcinomas of the nasopharynx and nasal cavity. In the present work the contents of nitrosamines in salted fish from the city of Guangzhou, southern China, and the contents of nitrosamines and possible nitrosamine-induced DNA adducts in organs of rats fed the fish were analysed. Similar levels of N-nitrosodimethylamine (NDMA) were detected in tough and soft salted fish. The NDMA content in steamed fish was higher than in raw fish. In vitro incubation of salted fish with gastric juice significantly increased the level of NDMA. NDMA was found in liver and kidney from rats fed salted fish for 2 years, but no dose-dependence was found between salted fish treatment and NDMA content. The level of 7-methylguanine in rat liver DNA was found to be slightly higher than in DNA from nasopharynx. However, there were no significant differences in the level of 7-methylguanine in DNA samples from rats fed salted fish and rats fed standard diet.

Animals↗
PubMed1995

Peripheral blood cell preparation influences the level of expression of leukocyte cell surface markers as assessed with quantitative multicolor flow cytometry.

We have compared the influence of sample preparation upon the level of surface expression of T, B, and NK cell-related antigens as assessed by flow cytometry. Lysed whole blood (WBL), Ficoll-Paque separated peripheral blood lymphocyte (F-PBL), and frozen peripheral blood lymphocyte (Fr-PBL) were analyzed via single- and multicolor flow cytometry. The percentage of positive cells expressing the individual cell surface markers was not affected by the procedure for preparation of WBL, F-PBL, and Fr-PBL. In contrast, the fluorescence intensity level of individual cell surface markers varied depending on cell preparation. By using Quantum Simply Cellular (QSC) microbeads, the antibody binding capacity (ABC) of single-color stained cells was quantified and compared. The amount of monoclonal antibody (MAb) anti-CD3-FITC bound to Fr-PBL (mean ABC = 137,040) was significantly higher (P < 0.001) that the amounts bound to WBL (mean ABC = 112,410) and F-PBL (mean ABC = 107,738). In multicolor analysis, the fluorescence intensity of CD3-FITC and CD4-FITC was significantly higher on Fr-PBL than on WBL and F-PBL; CD8-PE and CD20-PerCP was significantly higher on WBL. Furthermore, the intensity of CD3 and CD4 was different on T-cell subsets. The intensity of CD3 staining in three-color analysis was lower than with single-color staining using the same fluorochrome. We conclude that particularly the method of cell preparation but also the selection of MAb combinations may influence the level of staining of certain lymphocyte antigens. This may be of relevance in the analysis of cellular activation and regulation of differentiation.

Adult↗
PubMed1995

Antibody response to Staphylococcus aureus collagen binding protein in patients with S. aureus septicaemia and collagen binding properties of corresponding strains.

An ELISA was developed for the detection of IgG antibodies to Staphylococcus aureus collagen binding protein (CnBP) in 95 patients with S. aureus endocarditis, complicated septicaemia with bone and joint involvement or uncomplicated septicaemia and in 95 control patients. Sixty percent of S. aureus-infected patients showed a positive peak anti-CnBP antibody level or a significant rise in titre, or both, during infection, but patients with S. aureus endocarditis or complicated septicaemia could not be differentiated from those with uncomplicated S. aureus septicaemia. The collagen binding capacity of S. aureus strains from 82 of the 95 patients was investigated in a particle agglutination assay and a 125I-labelled assay. All strains bound collagen in the particle agglutination assay as did 68% in the 125I-labelled assay, but there was no correlation between collagen binding of the patient strain and endocarditis, joint or skeletal involvement. An anti-CnBP antibody response was seen in 16 patients infected with a S. aureus strain negative for collagen binding in vitro, indicating in-vivo expression of CnBP.

Adolescent↗
PubMed1995

Immunoglobulin subclass distribution and dynamics of Shigella-specific antibody responses in serum and stool samples in shigellosis.

To assess the humoral immunological responses at the subclass level in shigellosis, specific antibody responses against Shigella dysenteriae 1 lipopolysaccharide (LPS), S. flexneri Y LPS, invasion plasmid-coded protein antigens (Ipa), and Shiga toxin were analyzed. Antibody responses of 41 patients with S. dysenteriae 1 infection (SDIP) and 15 patients with S. flexneri infection (SFIP) were compared with those of controls (n = 40). The levels of total immunoglobulin G (IgG), IgA, IgM, and albumin in serum and stool samples were analyzed. In addition, total IgA (t-IgA), secretory IgA (s-IgA), and antigen-specific s-IgA in fecal samples were analyzed to evaluate the specificities and magnitudes of the mucosal immune responses. By comparing the relative increases in optical density for each IgG subclass separately, it was determined that the anti-LPS (homologous) response initially increased in the order IgG2 > IgG1 > IgG3 > IgG4 and that this order changed to IgG2 > IgG3 > IgG1 > IgG4 later in the disease. The IgG subclass response against protein antigens initially showed the order IgG1 > IgG3 > IgG2 > IgG4, which changed to IgG3 > IgG1 > IgG2 > IgG4 later in the disease. A significant increase in the proportion of IgA2 among t-IgA compared with that in controls was seen in both SDIP and SFIP, while significant changes in the proportions of IgG1 and IgG2 among t-IgG compared with controls was seen only in SDIP. The anti-LPS IgA2 response was more prominent in SDIP than in SFIP. We found an early peak of antigen-specific s-IgA in fecal samples, with a shorter duration than the corresponding response in serum samples. The simultaneous increase of serum IgA, fecal t-IgA, and s-IgA in SDIP compared with those in SFIP suggests that there is a massive increase in the local IgA production, giving an increase in systemic IgA concomitant with an extensive gut mucosal inflammation leading to an increased loss of albumin, IgG, and IgA with a high ratio of t-IgA to s-IgA.

Adhesins, Bacterial↗
PubMed1995

Shigella infection induces cellular activation of T and B cells and distinct species-related changes in peripheral blood lymphocyte subsets during the course of the disease.

Immunophenotypic changes in peripheral blood lymphocytes (T, B, and NK cells) in patients during shigellosis was characterized by using triple-color flow cytometry. Eleven Shigella dysenteriae 1-infected adult patients (SDIP), 11 Shigella flexneri-infected adult patients (SFIP), 15 age- and sex-matched healthy controls from Bangladesh (C-B), and 15 healthy volunteers from Sweden (V-S) were studied. In SDIP and SFIP, a significant increase in the CD45RO+ cells in both CD4+ and CD8+ T cells were seen. We found evidence for sequential T-cell activation, as shown by increased proportions of CD25 and CD4+ cells; HLA-DR and CD38 on CD8+ cells, and CD54 on CD4+ and CD8+ cells. We found differences in the lymphocyte activation and subset patterns related to the infecting Shigella species. Thus, a decrease in CD45 expression was seen in SFIP; this decrease progressed further during the disease. The proportions of NK cells (CD56+ cells) and CD3- CD8+ cells out of the total CD8+ cells were increased in SFIP but not in SDIP. The CD3+ CD8+ CD57+ T-cell subset was significantly lower in SDIP than in C-B. The proportion of B-lymphocyte-expressing activation markers CD80 and CD23 was higher in patients than in C-B. There was a significant increase in the proportion of CD4+ T cells and a significant decrease in the percentages of total B cells, the CD3+ CD8+ CD57+ T-cell subset, and the CD56+ CD16+ NK-cell subset for V-S compared with C-B. Our results indicate that distinct subset changes and activation patterns are elicited in SDIP compared with SFIP and also that the degree of activation is related to disease severity. In addition, a common sequence of cell activation was seen during the disease course. The difference in the subset patterns seen in C-B and V-S may be related to differences in the levels or spectra of infectious agents in the environment.

ADP-ribosyl Cyclase↗
PubMed1995

In situ analysis of the immune microenvironment of the adenoid in children with and without secretory otitis media.

Using monoclonal antibodies and immunohistochemistry, we compared adenoid tissue from 35 children with or without secretory otitis media. Numerous cells infiltrating the reticular crypt epithelium expressed HLA-DR, as did < 10% of the epithelial cells. Of the antigen-presenting cells, CD1a+ dendritic cells showed intraindividual and interindividual variations; CD68+ macrophages and CD22+ B cells were uniformly distributed. The relative frequencies of CD4+ and CD8+ cells were 6.6 +/- 2.0 versus 2.3 +/- 1.2 (p < .001) in the reticular crypt epithelium and 18 +/- 4.5 versus 1.5 +/- 0.9 (p < .001) in the germinal centers. The IL-2 receptor was expressed on < 0.1% of CD3+ T cells. Over 90% of intraepithelial CD3+ T cells were of the CD45RO+ memory phenotype. The proliferation marker Ki67 was almost exclusively found in the germinal centers. That the analyzed parameters showed a similar pattern in both clinical groups suggests that the presence of secretory otitis media may not correlate to specific alterations in the immune microenvironment of the adenoid.

Adenoids↗