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J G Kusters

Publications and source records attributed to J G Kusters.

At least 19 recordsLinked to original sources
PubMed2006

Prednisolone suppresses the function and promotes apoptosis of plasmacytoid dendritic cells.

Organ transplant recipients are highly susceptible to viral infections early after transplantation. Plasmacytoid dendritic cells (PDC) play a major role in antiviral immunity. Therefore, we determined the numbers of circulating PDC after liver transplantation (LTX) and established the effects of immunosuppressive drugs on PDC survival and function. PDC were determined longitudinally in 13 LTX recipients treated with prednisone and cyclosporin or tacrolimus. Purified PDC were cultured with or without clinically relevant concentrations of cyclosporin, tacrolimus or prednisolone. Apoptosis induction was monitored by determination of active caspase-3, nuclear condensation and annexin-V/7AAD staining. After LTX, a 4-fold reduction in the number of circulating PDC was observed (p < 0.01), which recovered partially after discontinuation of prednisone treatment. In vitro, prednisolone induced apoptosis in PDC, while cyclosporin and tacrolimus did not. Higher doses of prednisolone were needed to induce apoptosis in Toll-like receptor (TLR)-stimulated PDC. However, non-apoptosis inducing concentrations of prednisolone suppressed interferon-alpha production, upregulation of co-stimulatory molecules and allo-stimulatory capacity of TLR-stimulated PDC. In conclusion, prednisolone induces apoptosis in PDC, which explains the decline in circulating PDC numbers after transplantation. Moreover, prednisolone suppresses the functions of TLR-stimulated PDC. Therefore, corticosteroid-free immunosuppressive therapy may reduce the number and severity of viral infections after transplantation.

Adult↗
PubMed2006

Different composition of intrahepatic lymphocytes in the immune-tolerance and immune-clearance phase of chronic hepatitis B.

Based on virological and biochemical parameters patients with chronic hepatitis B virus (HBV) are divided into distinct clinical phases: the immune-tolerance phase, the immune-clearance phase, and the inactive carrier state. Unclear is whether these phases have characteristic intrahepatic immune responses. The composition of liver-derived lymphocytes in patients with chronic HBV infection was studied. In 47 patients the composition of liver-derived lymphocytes was analyzed by flow cytometry of fine needle aspiration biopsies of the liver. The proportion natural killer (NK) cells in the liver was significantly higher in immune-tolerant than in immune-clearance patients and inactive carriers. No differences were found in proportion CD4+ T-cells and CD8+ T-cells, in these phases. However, when patients in the immune-clearance phase, with similar alanine transaminase (ALT), were grouped according to viral load, the proportion CD8+ T-cells was higher in those with high viral load. In contrast, the proportion CD4+ T-cells was increased in patients with low HBV-DNA. These differences were absent in the peripheral blood (PB). Intrahepatic HBV-specific CD8+ T-cells were mainly found in immune-clearance patients with low viral load. In conclusion, clear differences in the intrahepatic cellular infiltrate were found between the various clinical phases of chronic HBV infection. These findings are relevant to the design of new, individualized anti-viral strategies.

Adolescent↗
PubMed2006

Does CDX2 expression predict Barrett's metaplasia in oesophageal columnar epithelium without goblet cells?

BACKGROUND: Intestinal metaplasia (Barrett's oesophagus), but not cardiac-type mucosa in columnar-lined oesophagus, is regarded as premalignant. As intestinal metaplasia and cardiac-type mucosa are endoscopically indiscernible, it is difficult to take targeted samples from columnar-lined oesophagus with consequently a risk of having undetected intestinal metaplasia. AIM: To investigate whether the intestinal markers CDX2, MUC2 and villin can predict the presence of undetected intestinal metaplasia in columnar-lined oesophagus. Methods Presence of intestinal metaplasia or cardiac-type mucosa was identified in 122 biopsy sets of columnar-lined oesophagus from 61 patients, collected at two subsequent follow-up upper endoscopies. CDX2, MUC2 and villin expression were determined by immunohistochemistry. RESULTS: All intestinal metaplasia samples (55) were positive for CDX2 and MUC2 and 32 of 55 for villin. CDX2 expression was detected in 23 of 67 (34%) samples with only cardiac-type mucosa. Detection of CDX2 in cardiac-type mucosa increased the likelihood of finding intestinal metaplasia in another biopsy set of columnar-lined oesophagus (odds ratio 3.5, 95% CI = 1.2-10, P = 0.02). MUC2 was positive in 13 of 23 (57%) of CDX2-positive cardiac-type mucosa samples, whereas villin was detected in seven of 23 (30%). CONCLUSIONS: CDX2 expression in cardiac-type mucosa might be able to predict the presence of undetected intestinal metaplasia in columnar-lined oesophagus, and thus may be a putative marker for the presence of intestinal metaplasia in the absence of goblet cells.

Adult↗
PubMed2005

Perianal fistulas in Crohn's disease are predominantly colonized by skin flora: implications for antibiotic treatment?

In this study we aimed to determine the microorganisms found in perianal fistulas in Crohn's disease and whether treatment with ciprofloxacin affects these microorganisms. Thirteen patients (males/females, 7/6; median age, 34 years; range, 18-61 years) with fistulas were treated with infliximab, 5 mg/kg intravenously, at weeks 6, 8, and 12 and randomized to double-blind treatment with ciprofloxacin, 500 mg bd (n = 6), or placebo (n = 7) for 12 weeks. Samples were taken at baseline and at weeks 6 and 18. In the ciprofloxacin group 10 different genera of microorganisms were identified, while 13 genera could be identified in the placebo group. Gram-negative enteric floras were present in a small minority. The genera found in patients with perianal fistulas were predominantly gram-positive microorganisms. Therefore, antimicrobial treatment should be directed toward these microorganisms.

Adult↗
PubMed2005

Flow cytometry of fine-needle-aspiration biopsies: a new method to monitor the intrahepatic immunological environment in chronic viral hepatitis.

SUMMARY: Information about the character and grade of the intrahepatic immune response in viral hepatitis is important for the evaluation of disease stage and effect of therapy. Complications like haemorrhage limit the frequent performance of tissue-needle biopsies (TB), and the cells of peripheral blood have to be used as surrogate markers instead. Fine-needle-aspiration biopsy (FNAB) of the liver represents a safe and atraumatic method that allows frequent cytological sampling. Our aim was to investigate whether flow cytometry of FNAB specimens allows co-analysis of phenotype, function and specificity of key populations of liver-infiltrating lymphocytes (LIL). In 20 consecutive patients with chronic viral hepatitis [10 hepatitis B virus (HBV), 10 hepatitis C virus (HCV)], flow cytometry was performed on FNAB cytology, and simultaneously on lymphocytes isolated from a TB and peripheral blood mononuclear cells (PBMC). The ratio of CD8+/CD4+ lymphocytes in FNAB correlated well with LIL from TB (r =0.78, P < 0.05) but differed from PBMC (mean ratio: 2.6, 2.1 and 0.7, respectively). Similarly, a correlation was observed for percentage CD56+ natural killer (NK) cells (mean %: 29.9, 32.3 and 14.5, respectively; r = 0.69, P < 0.05). The percentage of interferon (IFN)-gamma-producing CD3+ lymphocytes in both FNAB and TB was higher than in PBMC (mean %: 41, 44 and 22, respectively; P < 0.05). Furthermore, tetrameric complexes allowed analysis of HBV-specific T cells in FNAB specimens. In conclusion, flow cytometry of FNAB allows easy, atraumatic and reliable analysis of lymphocytes obtained from the intrahepatic compartment. Therefore, the FNAB is a valuable tool in the study of the immunopathology of viral hepatitis, and it may contribute to the improved clinical evaluation of chronic viral liver disease.

Biopsy, Fine-Needle↗
PubMed2005

Hepatitis B immunoglobulins inhibit dendritic cells and T cells and protect against acute rejection after liver transplantation.

The efficacy of anti-viral intravenous immunogobulins (anti-HBs Ig and anti-CMV Ig) in preventing acute rejection after liver transplantation was assessed in a retrospective analysis, and correlated to their effects on immune cells in vitro. HBs Ag-positive liver graft recipients (n = 40) treated prophylactically with anti-HBs Ig had a significantly lower incidence of acute rejection compared with recipients without viral hepatitis (n = 147) (12% vs. 34%; p = 0.012), while the incidence of rejection in HCV-positive recipients (n = 29) was similar to that in the control group. Treatment with anti-CMV Ig (n = 18) did not protect against rejection. In vitro, anti-HBs Ig suppressed functional maturation of and cytokine production by human blood-derived dendritic cells (DC) at concentrations similar to the serum concentrations reached during anti-HBs Ig treatment of liver graft recipients. In addition, anti-HBs Ig inhibited allo-antigen- and lectin-stimulated proliferation of peripheral T cells. Anti-CMV Ig suppressed functional DC-maturation and alloantigen-stimulated T-cell proliferation, but not lectin-driven T-cell proliferation. In conclusion, anti-HBs Ig protects against acute rejection after liver transplantation, probably by functional inhibition of the two principal immune cells involved in allograft rejection, DC and T cells.

Adult↗
PubMed2004

Monitoring intrahepatic CD8+ T cells by fine-needle aspiration cytology in chronic hepatitis C infection.

Infection of the liver with hepatitis C virus (HCV) causes compartmentalization of CD8+ cytotoxic T cells to the site of disease. These cells are thought to be involved in viral clearance during interferon therapy. The repetitive analysis of the intrahepatic immune response is hampered by the difficulty to obtain the intrahepatic T cells. The fine-needle aspiration biopsy (FNAB) technique was evaluated for its use to obtain liver-derived CD8+ T cells in a minimally invasive way. In 26 chronic HCV patients who were evaluated for Peg-interferon and ribavirin combination therapy, pre-treatment FNABs and peripheral blood specimens were obtained simultaneously with liver tissue biopsies, and CD3+ and CD8+ T cells were quantified by immunocytochemistry. The CD8+/CD3+ ratio was significantly higher in the FNABs than in peripheral blood (P < 0.01), and similar to those in portal areas in the tissue biopsies. A significant correlation was observed between numbers of CD3+CD8+ T lymphocytes in the FNABs and the numbers of CD8+ cells in the lobular fields or in the portal tracts of the liver tissue biopsies, but not with CD3+CD8+ T lymphocytes in peripheral blood. Finally, the ratio of CD8+/CD3+ T lymphocytes in FNABs was significantly higher in those patients who responded rapidly to therapy when compared with slow responders at 4 weeks of treatment (P = 0.02). These findings demonstrate that the intrahepatic T-cell composition is reflected in FNABs, and that the FNAB technique can be used for predicting early virological response to therapy of patients chronically infected with HCV.

Biopsy, Fine-Needle↗
PubMed2004

The homeodomain protein CDX2 is an early marker of Barrett's oesophagus.

BACKGROUND: In Barrett's oesophagus (BO), squamous epithelium is replaced by specialised intestinal epithelium (SIE). Transcription factors associated with intestinal differentiation, such as CDX2, may be involved in BO development. AIM: To investigate CDX2 expression in BO, squamous epithelium, and oesophageal adenocarcinoma (ADC). METHODS: CDX2 expression was assessed in 245 samples-167 biopsies of the columnar lined segment and 38 squamous epithelial biopsies of 39 patients with histologically confirmed BO (10 with ADC). Forty biopsies from 20 patients with reflux oesophagitis (RO) without BO were also evaluated. CDX2 protein was investigated immunohistochemically in 138 biopsies from 16 patients with BO, four with ADC, and 20 with RO. Cdx2 and Muc2 mRNA were detected semiquantitatively using 88 BO biopsies and squamous epithelium from 19 BO patients, and when present from ADC. RESULTS: SIE was present in 53/79 biopsies from the columnar lined segment; CDX2 protein was seen in all epithelial cells, but not in biopsies containing only gastric metaplastic epithelium (26/79), or in squamous epithelium (0/40) of patients with RO. Cdx2 mRNA was detected in all biopsies with goblet cell specific Muc2 transcription-indicative of SIE. Low Cdx2 mRNA expression was seen in 6/19 squamous epithelium samples taken 5 cm above the squamocolumnar junction of BO patients. CONCLUSION: CDX2 protein/mRNA is strongly associated with oesophageal SIE. Cdx2 mRNA was present in the normal appearing squamous epithelium of one third of BO patients, and may precede morphological changes seen in BO. Therefore, pathways that induce Cdx2 transcription in squamous epithelial cells may be important in BO development.

Adenocarcinoma↗
PubMed2004

MUC4 is increased in high grade intraepithelial neoplasia in Barrett's oesophagus and is associated with a proapoptotic Bax to Bcl-2 ratio.

BACKGROUND: Patients with Barrett's oesophagus (BO) are at risk of oesophageal adenocarcinoma. Because the pattern of mucosal mucins changes during neoplastic progression, it may serve as a marker of intraepithelial neoplasia. AIMS: To determine the expression pattern of mucins in neoplastic BO epithelium (high grade dysplasia) and correlate it with the expression of apoptosis markers Bax and Bcl-2. METHODS: Thirty seven patients with BO were studied: 16 without intraepithelial neoplasia, six with high grade intraepithelial neoplasia (HGN), and 15 with infiltrating adenocarcinoma. Biopsies were obtained from squamous epithelium, Barrett's epithelium, and (when present) foci of suspected HGN or adenocarcinoma. MUC1-4, MUC5AC, MUC5B, MUC6, Bax, and Bcl-2 mRNA were determined by semiquantitative RT-PCR. MUC2, MUC5AC, and MUC6 protein was determined by immunoblotting. RESULTS: Mucin expression varied between neoplastic progression stages in BO. Mucin mRNA levels were low in squamous epithelium, except for MUC4, and were at least four times higher in BO and HGN (p<0.001), but less so in adenocarcinoma. MUC4 expression was significantly lower in BO than in normal squamous epithelium, whereas in HGN and adenocarcinoma, levels were significantly higher than in BO (p = 0.037). The Bax:Bcl-2 ratio was increased in HGN compared with BO (p = 0.04). MUC2, MUC5AC, and MUC6 protein values correlated with mRNA data. CONCLUSIONS: Mucin expression varies during the development of oesophageal adenocarcinoma in BO. MUC4 could serve as a tumour marker in this process. In contrast to animal studies, upregulation of MUC4 in HGN is associated with increased apoptosis, suggesting that MUC4 plays a minor role in apoptosis regulation in BO.

Adenocarcinoma↗
PubMed2003

Effect of frequent consumption of a Lactobacillus casei-containing milk drink in Helicobacter pylori-colonized subjects.

BACKGROUND: Several studies have reported inhibitory effects of lactic acid bacteria on bacterial pathogens. AIM: To test whether a drink containing Lactobacillus casei strain Shirota inhibits Helicobacter pylori growth. METHODS: The in vitro growth inhibition of H. pylori was studied when L. casei was added to plates previously inoculated with H. pylori reference strain NCTC 11637. In an intervention study, 14 H. pylori-positive subjects were given Yakult drink (10(8) colony-forming units/mL L. casei) thrice daily during meals for 3 weeks. Six untreated H. pylori-positive subjects served as controls. H. pylori bacterial loads were determined using the 13C-urea breath test, which was performed before and 3 weeks after the start of L. casei supplementation. RESULTS: In vitro, L. casei inhibits H. pylori growth. This effect was stronger with L. casei grown in milk solution than in DeMan-Rogosa-Sharpe medium. No growth inhibition was shown with medium inoculated with lactic acid, Escherichia coli strain DH5alpha or uninoculated medium. Filtration of L. casei culture before incubation with H. pylori completely abolished the inhibitory effect. Urease activity decreased in nine of the 14 (64%) subjects with L. casei supplementation and in two of the six (33%) controls (P = 0.22). CONCLUSIONS: Viable L. casei are required for H. pylori growth inhibition. This does not result from changes in lactic acid concentration. In addition, a slight, but non-significant, trend towards a suppressive effect of L. casei on H. pylori in vivo may exist.

Adult↗
PubMed2002

Helicobacter pylori does not mediate the formation of carcinogenic N-nitrosamines.

BACKGROUND: Both N-nitroso compounds and colonization with Helicobacter pylori represent known risk-factors for the development of gastric cancer. Endogenous formation of N-nitroso compounds is thought to occur predominantly in acidic environments such as the stomach. At neutral pH, bacteria can catalyze the formation of N-nitroso compounds. Based on experiments with a noncarcinogenic N-nitroso compound as end product, and using only a single H. pylori strain, it was recently reported that H. pylori only displays a low nitrosation capacity. As H. pylori is a highly diverse bacterial species, it is reasonable to question the generality of this finding. In this study, several genetically distinct H. pylori strains are tested for their capacity to form carcinogenic N-nitrosamines. MATERIALS AND METHODS: Bacteria were grown in the presence of 0-1000 microM morpholine and nitrite (in a 1 : 1 molar ratio), at pH 7, 5 and 3. RESULTS: Incubation of Neisseria cinerea (positive control) with 500 microM morpholine and 500 microM nitrite, resulted in a significant increase in formation of N-nitrosomorpholine, but there was no significant induction of N-nitrosomorpholine formation by any of the H. pylori strains, at any of the three pH conditions. CONCLUSION: H. pylori does not induce formation of the carcinogenic N-nitrosomorpholine in vitro. The previously reported weak nitrosation capacity of H. pylori is not sufficient to nitrosate the more difficulty nitrosatable morpholine. This probably also holds true for other secondary amines. These results imply that the increased incidence of gastric cancer formation that is associated with gastric colonization by H. pylori is unlikely to result from the direct induced formation of carcinogenic nitrosamines by H. pylori. However, this has to be further confirmed in in vivo studies.

Antigens, Bacterial↗
PubMed2002

Alterations in penicillin-binding protein 1A confer resistance to beta-lactam antibiotics in Helicobacter pylori.

Most Helicobacter pylori strains are susceptible to amoxicillin, an important component of combination therapies for H. pylori eradication. The isolation and initial characterization of the first reported stable amoxicillin-resistant clinical H. pylori isolate (the Hardenberg strain) have been published previously, but the underlying resistance mechanism was not described. Here we present evidence that the beta-lactam resistance of the Hardenberg strain results from a single amino acid substitution in HP0597, a penicillin-binding protein 1A (PBP1A) homolog of Escherichia coli. Replacement of the wild-type HP0597 (pbp1A) gene of the amoxicillin-sensitive (Amx(s)) H. pylori strain 1061 by the Hardenberg pbp1A gene resulted in a 100-fold increase in the MIC of amoxicillin. Sequence analysis of pbp1A of the Hardenberg strain, the Amx(s) H. pylori strain 1061, and four amoxicillin-resistant (Amx(r)) 1061 transformants revealed a few amino acid substitutions, of which only a single Ser(414)-->Arg substitution was involved in amoxicillin resistance. Although we cannot exclude that mutations in other genes are required for high-level amoxicillin resistance of the Hardenberg strain, this amino acid substitution in PBP1A resulted in an increased MIC of amoxicillin that was almost identical to that for the original Hardenberg strain.

Amoxicillin↗
PubMed2002

Polymorphisms of Helicobacter pylori HP0638 reflect geographic origin and correlate with cagA status.

Since the associations between Helicobacter pylori genotype and disease differ in Asia and the West, we investigated the correlation between HP0638, encoding an outer membrane protein, and potential markers of virulence (cagA, vacA, and iceA). For 109 strains from nine countries, the status of cagA, vacA, and iceA was determined by PCR and/or a line probe assay. We also studied 18 strains from 8 patients (parents and 6 daughters) from a Dutch family and paired strains collected on average 8 years apart from 11 patients. When the HP0638 signal sequences were amplified by PCR and DNA sequence determinations were performed, 89 (96%) of 93 cagA-positive strains had HP0638 in frame, versus none (0%) of 16 cagA-negative strains (P < 0.001). Among strains in which HP0638 was in frame, a six-CT dinucleotide repeat pattern was dominant in Western countries (23 of 33 strains [70%]), while a pattern of three CT repeats with another CT after four T's (3 + 1-CT-repeat pattern) was dominant in East Asia (31 of 46 strains [67%]); however, specific CT repeat patterns did not correlate with clinical outcome. HP0638 phylogenetic trees also showed geographic characters. The HP0638 frame status and CT dinucleotide repeat patterns were identical for 9 of 11 pairs of strains obtained on average 8 years apart from individuals and the 15 strains obtained from the mother and all six daughters. Thus, HP0638 frame status and cagA status are strongly correlated. The CT dinucleotide repeat pattern in the putative HP0638 signal sequence has geographic characters and appears stable in particular patients and families over a period of years. Analysis of HP0638 CT polymorphisms may serve as a new typing system to discriminate H. pylori isolates for epidemiological purposes.

Adult↗
PubMed2001

The role of Helicobacter pylori virulence factors in interleukin production by monocytic cells.

Helicobacter pylori infection results in chronic gastritis, which is initiated by the release of cytokines like interleukin (IL)-12 and IL-8 from mononuclear cells, and IL-8 from gastric epithelial cells. The severity of gastritis is influenced both by host factors and by bacterial factors such as the Cag proteins and the vacuolating cytotoxin VacA. Amounts of IL-12 and IL-8 produced by monocytic THP-1 cells differed considerably between the eight H. pylori isolates tested, but in contrast to H. pylori-induced IL-8 production by gastric epithelial cells, did not correlate to the Cag and VacA types of the strains. Apparently, in addition to Cag and VacA, other bacterial factors determine the extent in which H. pylori induced IL production in monocytes.

Antigens, Bacterial↗