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T Höhler

Publications and source records attributed to T Höhler.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Genetic hemochromatosis and the HFE gene: from molecular genetics to clinical diagnosis].

More than 90% of patients with genetic hemochromatosis carry a characteristic mutation in the HFE-gene (C282Y). HFE modulates the iron uptake by the transferrin receptor. Duodenal crypt cells of HFE-knockout mice show low intracellular iron concentrations which lead to an upregulation of the divalent metal transporter and enhanced iron uptake by duodenal enterocytes. Heterozygosity for the C282Y mutation appears to alter the course of other liver diseases like porphyria cutanea tarda and nonalcoholic steatohepatitis.

Amino Acid Substitution↗
PubMed1999

Hepatocellular carcinoma in a patient with hereditary hemochromatosis and noncirrhotic liver. A case report.

A case of a 62-year-old patient with hereditary hemochromatosis is reported, who developed hepatocellular carcinoma (HCC) in the absence of cirrhosis and other potential risk factors for HCC. Occurrence of HCC in patients with genetic hemochromatosis and noncirrhotic liver is a rare event which has previously been described only six times and appears to be limited to male patients.

Carcinoma, Hepatocellular↗
PubMed1999

Ankylosing spondylitis in monozygotic twins: studies on immunological parameters.

OBJECTIVE: To examine immunological parameters that might explain disease discordance in monozygotic twin pairs with ankylosing spondylitis (AS). METHODS: 11 monozygotic twin pairs (nine with AS, two with undifferentiated spondyloarthropathy) were investigated. The peripheral T cell receptor Vbeta repertoire was investigated using FACS analysis and 14 different Vbeta antibodies. In addition serum samples were tested for antibodies to Klebsiella pneumoniae, Streptococcus pyogenes, Candida albicans, Proteus mirabilis, and Escherichia coli. Peripheral blood lymphocyte reactivity against a number of bacteria was investigated by interferon gamma ELISPOT assays. RESULTS: Twins suffering from AS showed cellular hyporeactivity against K pneumoniae, S pyogenes, C albicans in the ELISPOT assays compared with healthy twins. In contrast with the antibody data, where no significant differences were observed between the two groups, AS concordant twins showed the most pronounced differences in their Vbeta repertoire on CD4+ and CD8+ lymphocytes. CONCLUSIONS: Cellular hyporeactivity of peripheral blood cells to bacterial antigens might reflect defective T cell responses allowing bacterial antigens to persist in diseased patients. There are probably other environmental factors that influence disease concordance.

Adult↗
PubMed1998

Tumor necrosis factor alpha promoter polymorphism at position -238 is associated with chronic active hepatitis C infection.

Tumor necrosis factor alpha (TNF-alpha) is involved in the pathogenesis of chronic hepatitis C virus infection. The gene for TNF-alpha is encoded in the major histocompatibility locus (MHC). Two polymorphisms at positions -308 and -238 in the TNF-alpha promoter region might influence TNF-alpha expression. These promoter polymorphisms have been linked previously to a number of infectious diseases. TNF-alpha promoter polymorphisms at positions -238 and -308 were studied by DNA sequencing and sequence-specific oligonucleotide hybridization in 82 individuals with chronic hepatitis C and 99 control subjects. Subjects had been HLA class I and class II typed in a previous study. The frequency of the TNF238.2 promoter allele was significantly higher in the hepatitis C group (18.7%) compared to the controls (3.5%; P < 0.0001; pcorr < 0.009). No significant differences in the frequency of the TNF308.2 allele were observed between patients and controls. The increased frequency of the TNF238.2 allele could not be explained by linkage disequilibrium to HLA-B or -DR genes. These findings show an association between the TNF238.2 promoter variant and chronic active hepatitis C. They suggest that this polymorphism or a linked gene may be a host factor contributing to the development of chronic active hepatitis C.

Alleles↗
PubMed1998

Association of different tumor necrosis factor alpha promoter allele frequencies with ankylosing spondylitis in HLA-B27 positive individuals.

OBJECTIVE: To investigate the potential association of tumor necrosis factor alpha (TNFalpha) promoter alleles with ankylosing spondylitis. METHODS: DNA from 141 HLA-B27 positive Caucasian patients with ankylosing spondylitis and 46 B27-positive and 99 B27-negative healthy Caucasian controls was investigated by polymerase chain reaction amplification of the TNFalpha promoter region and subsequent dot-blot analysis with allele-specific oligonucleotides. RESULTS: There was a significant decrease in the promoter alleles TNF-238.2 and TNF-308.2 in the ankylosing spondylitis group (266 wild-type alleles, 16 variant alleles) compared with the B27-positive (75 wildtype promoter alleles, 17 variant alleles; P<0.0004) and the B27-negative (159 wild-type promoter alleles, 39 variant alleles; P< 0.00001) control groups. Positivity for the variant promoter alleles conferred protection and a relative risk of 0.3 to B27-positive individuals. CONCLUSION: These data indicate that allelic variations in the TNFalpha promoter influence disease susceptibility in HLA-B27 positive individuals. This protective effect of variant promoter alleles could be related to differences in TNFalpha production or could reflect the association of different B27 haplotypes with ankylosing spondylitis.

Adolescent↗
PubMed1998

The influence of major histocompatibility complex class II genes and T-cell Vbeta repertoire on response to immunization with HBsAg.

Nonresponsiveness to HBsAg vaccination is observed in 5-10% of vaccine recipients and is possibly caused by a defect in the T helper cell compartment. The immune response to HBsAg is influenced by genes of the major histocompatibility complex. We have investigated MHC class I and class II antigens in 53 adult responders and 73 nonresponders. Results obtained in this first study were tested in a second study with 56 responders and 62 nonresponders from an infant vaccination trial. In addition, the peripheral Vbeta-chain T-cell receptor repertoire was investigated using monoclonal antibodies and flow-cytometry in 26 adult responders and 38 nonresponders. As previously reported, nonresponsiveness to HBsAg vaccination was associated with DRB1*3 and DRB1*7. In addition, DRB1*13 was significantly increased among vaccine responders (35.2% vs 5.4%;p < 0.0001) suggesting an immune response promoting effect for this allele whereas the closely related allele DRB1*14 was associated with nonresponse in the infant study. There was no evidence for a hole in the T cell receptor Vbeta repertoire. In conclusion, in agreement with results obtained in mice there appears to be a hierarchy of DRB1* genes in the HBsAg immune response. The possible differential association of DRB1*13 and DRB1*14 may allow the identification of differences between responsiveness and nonresponsiveness to a few amino acid differences in the beta1-domain of the class II heterodimer.

Adult↗
PubMed1998

Pathogenesis of human leukocyte antigen B27-positive arthritis. Information from clinical materials.

In the spondyloarthropathies human leukocyte antigen (HLA) B27 confers a strong genetic predisposition to the development and to the chronicity of disease after extra-articular infection with certain gram-negative bacteria. The close relationships between infection, HLA-B27, other genetic factors, and the host immune system, however, still are unexplained. HLA-B27-positive arthritis continues to be an area of intensive investigation in basic and clinical research. New animal models with HLA-B27 transgenic mice and rats, as well as recent developments in understanding the processes involved in signal transduction, cytokine production, and human T-lymphocyte activation, contribute to the development of new pathogenic models of the spondyloarthropathies. This article summarizes the current concepts of the cause and pathogenesis of the spondyloarthropathies resulting from studies of clinical materials. The host-microbial interplay in human disease, namely in bacteria-induced reactive arthritis, may eludicate principle disease mechanisms in acute disease and in the development of chronic autoimmune arthritis or ankylosing spondylitis.

Animals↗
PubMed1998

A tumor necrosis factor-alpha (TNF-alpha) promoter polymorphism is associated with chronic hepatitis B infection.

Cytokines such as TNF-alpha and interferon gamma (IFN-gamma) are important for the elimination of infected hepatocytes during acute hepatitis B virus (HBV) infection. Two G versus A transitions in the TNF-alpha promoter region at positions -308 and -238 possibly influence TNF-alpha expression. We investigated these TNF-alpha polymorphisms in 71 patients with chronic HBV infection, in 32 subjects that had spontaneously recovered from acute HBV infection, and in 99 healthy controls. The -238 A promoter variant was present in 18 (25%) of 71 patients with chronic HBV infection compared with two (6%) of 32 subjects with acute infection (P<0.04), and seven (7%) of 99 controls (P<0.003). By contrast, the prevalence of the variant at position -308 was similar in all investigated groups. The observed differences could not be explained by linkage disequilibrium to HLA-B or -DRB1* alleles. These findings suggest an association between the TNF-alpha promoter polymorphism at position -238 and the development of chronic HBV infection. This promoter variant appears to be linked to defective viral clearance.

Alleles↗
PubMed1998

Viral and host factors in the prediction of response to interferon-alpha therapy in chronic hepatitis C after long-term follow-up.

Acute infection with hepatitis C virus (HCV) develops into a chronic hepatitis in about 50-70% of patients. Treatment of these patients with interferon-alpha (IFN-alpha) results in a sustained long-term response in only 15-20% but causes numerous unwanted side-effects in a higher percentage of patients. The aim of our study was to define host or viral parameters that would allow identification of responders and non-responders to IFN-alpha prior to the onset of treatment. We studied a group of 87 patients suffering from chronic hepatitis C who were treated with IFN-alpha. After long-term follow-up, 18 patients (21%) showed a sustained response to IFN-alpha therapy (normalization of serum transaminases and loss of viral RNA from serum) for up to 7 years after therapy had ceased. By univariate and multivariate analyses, no host factors were found to be predictive of response to therapy. Neither the degree of inflammation or fibrosis in liver biopsy samples obtained before treatment nor immunogenetic factors (major histocompatibility complex II haplotype and tumour necrosis factor-alpha promoter polymorphism) were associated with response to therapy. In contrast, viral parameters showed a strong association with response to therapy. HCV genotype 3 was found significantly more frequently in responders (P = 0.034), and mean HCV RNA concentration was lower in responders (3.1 x 10(4)) than in non-responders (2.5 x 10(5)) (P = 0.01). By multivariate analysis, both HCV genotype and HCV RNA concentration were independent predictors of response to therapy. However, exact prediction of response to treatment for an individual patient was not possible on the basis of pretreatment viral RNA concentration or viral genotype. The best association with response to therapy was found to be clearance of HCV RNA from serum 3 months after the start of treatment (32 of 34 partial and sustained responders vs 0 of 53 non-responders; P = 0.001). In conclusion, determination of pretreatment viral factors, but not host factors, was significantly correlated with treatment response but did not give an accurate prediction for patients, whereas clearance of HCV RNA from serum after 3 months of therapy was predictive of response to therapy.

Adult↗
PubMed1998

No association between mannose-binding lectin alleles and susceptibility to chronic hepatitis B virus infection in German patients.

Variants of the mannose-binding lectin (MBL) have been shown to be associated with low serum concentrations of the protein and to predispose to bacterial, fungal and viral infections. A recent small study on 33 Caucasian patients had suggested that a mutation at codon 52 of the MBL gene is associated with chronic hepatitis B virus (HBV) infection. Exon 1 of the MBL gene was amplified by PCR in 61 patients with chronic HBV infection, 28 patients with acute infection and in 60 controls. MBL variants were detected by subsequent restriction enzyme digestion and agarose gel electrophoresis. The occurrence of the codon 52 mutation in patients with chronic HBV infection did not differ significantly from that in controls or patients with acute infection (9 vs. 7%), nor were there any significant differences for the codon 54 mutation. The frequency of MBL variants at codon 52 and 54 is not increased in patients with chronic HBV infection. Thus, the previously reported association of MBL deficiency with chronic HBV infection in adults could not be confirmed.

Acute Disease↗
PubMed1997

MHC class II genes influence the susceptibility to chronic active hepatitis C.

BACKGROUND/AIMS: Chronic hepatitis C develops in more than 70% of hepatitis C virus infected subjects. Viral factors influence the disease course, but little is known about the importance of host factors. METHODS: Frequencies of major histocompatibility complex (MHC) class I and class II antigens were analyzed in two groups of patients with chronic hepatitis C virus infection and in control subjects. MHC class I typing was done by standard microlymphocytotoxicity assays. DRB1 and DQA1 genotyping was done by PCR based typing methods. RESULTS: DRB1*0301 was found in 26 of 75 patients with chronic hepatitis C virus infection (34.7%) and in 12 of 101 control subjects (11.9%) (relative risk 3.9; p < 0.001). Homozygosity for this allele appeared to confer a stronger risk. In contrast, DRB1*1301 was detected in three subjects with persistent infection (4.0%) compared to 21 control subjects (20.8%) (relative risk 0.2; p < 0.008). This allele was linked with DQA1*0103, which was found in 10 patients (13.3%) compared to 34 control subjects (33.7%) (relative risk 0.31; p < 0.003). An even stronger protective effect was provided by the presence of DRB1*1301 and DQA1*0103 (relative risk 0.08; p < 0.005). These findings were confirmed in a second group of chronic hepatitis C virus infected patients. CONCLUSIONS: The MHC class II allele DRB1*0301 appears to predispose to progression to chronic active hepatitis C, whereas the class II alleles DRB1*1301 and DQA1*0103 appear to provide protection against chronic active infection with hepatitis C virus.

Alleles↗
PubMed1997

HLA-DRB1*1301 and *1302 protect against chronic hepatitis B.

BACKGROUND/AIMS: The outcome of acute hepatitis B infection may be influenced by host factors like the major histocompatibility complex (MHC). We have investigated MHC class I and class II antigens in patients with chronic hepatitis B compared to a healthy control population. To confirm the findings of this first study we performed a second study in a group of subjects who had spontaneously recovered from acute hepatitis B infection. METHODS: Frequencies of MHC class I and class II antigens were analyzed in patients with chronic hepatitis B virus infection and in control subjects. MHC class I typing was done by standard microlymphocytotoxicity assays. DRB1 and DQA1 genotypes were determined by polymerase chain reaction based typing methods. RESULTS: In the first study the class II allele HLA-DRB1*1301-02 was found in 4 of 70 subjects with chronic hepatitis B virus infection (5.7%) compared to 27 of 101 healthy controls (26.7%, relative risk 0.17; p=0.001; p(corr)=0.025). This protective effect of the DRB1*1301-02 allele was confirmed in the second study. Eight of 24 patients (33.3%) who cleared hepatitis B virus spontaneously were positive for DRB1*1301-02 (relative risk of developing chronic infection compared to chronic hepatitis B subjects 0.12; p=0.004). Subtyping confirmed that 1301 and 1302 were both decreased in frequency in patients with chronic hepatitis B. CONCLUSIONS: The MHC class II allele DRB1* 1301-02 is associated with protection from chronic hepatitis B in Caucasian patients.

Adult↗
PubMed1997

A TNF-alpha promoter polymorphism is associated with juvenile onset psoriasis and psoriatic arthritis.

Tumor necrosis factor-alpha is considered to be one of the important mediators in the pathogenesis of psoriasis. A strong association of juvenile onset psoriasis with the major histocompatibility complex encoded HLA-Cw6 antigen has been reported but it is unclear whether Cw6 itself or a closely linked gene is involved in the pathogenesis. This study has focused on the association of promoter polymorphisms of the major histocompatibility complex encoded tumor necrosis factor-alpha gene with psoriasis and psoriatic arthritis. Tumor necrosis factor-alpha promoter polymorphisms were sought by sequence-specific oligonucleotide hybridization and by direct sequencing in Caucasian patients with juvenile onset psoriasis and with psoriatic arthritis and in healthy controls. A mutation at position -238 of the tumor necrosis factor-alpha promoter was present in 23 of 60 patients (38%; p < 0.0001; p[corr] < 0.008) with juvenile onset psoriasis and in 20 of 62 patients (32%; p < 0.0003; p[corr] < 0.03) with psoriatic arthritis, compared with seven of 99 (7%) Caucasian controls. There was a marked increase of homozygotes for this mutation in the psoriasis group. Another mutation at position -308 was found in similar proportions of patients and controls. Our study shows a strong association of the tumor necrosis factor-alpha promoter polymorphism at position -238 with psoriasis and psoriatic arthritis. Our findings suggest that this promoter polymorphism itself or a gene in linkage disequilibrium with tumor necrosis factor-alpha predispose to the development of psoriasis.

Adult↗
PubMed1997

No primary association between LMP2 polymorphisms and extraspinal manifestations in spondyloarthropathies.

OBJECTIVE: To investigate the potential role of the HLA-linked LMP2 (low molecular weight protein) gene polymorphisms in conjunction with DR4 and DR7 on extraspinal disease manifestations in HLA-B27 positive patients with spondyloarthropathy. METHODS: 172 patients with spondyloarthropathy, 46 healthy, HLA-B27 positive blood donors, and 99 unrelated controls were typed for HLA-class I and II antigens. LMP2 alleles were determined by polymerase chain reaction and subsequent restriction enzyme digestion. RESULTS: There were statistically non-significant increases of DR4 and DR7 in spondyloarthropathy subjects. However these differences did not relate to specific extraspinal manifestations. There were no significant differences in the LMP2 genotype distribution in the disease groups. All differences in LMP2 genotype frequencies disappeared when correcting for DR4, which was in linkage disequilibrium with the LMP2B allele. CONCLUSIONS: There is no independent association between LMP2 genotypes and the occurrence of uveitis or peripheral arthritis in HLA-B27 positive subjects with spondyloarthropathy. DR4 and DR7 do not contribute to these disease manifestations.

Adolescent↗
PubMed1996

[Enteropathic spondylarthritis in chronic inflammatory bowel diseases: prevalence, manifestation pattern and HLA association].

BACKGROUND: Enteropathic spondylarthropathies (SpA) are the most frequent extraintestinal manifestation of the chronic inflammatory bowel disease (IBD), Crohn's disease (CD) and Ulcerative Colitis (UC). It was the aim of the present study, to analyze a large number of IBD patients for the prevalence and pattern of joint manifestation and the association of SpA with the extend of bowel involvement and HLA-haplotype. PATIENTS AND METHODS: 521 patients (409 CD and 112 UC) were prospectively analyzed over a period of one year. SpA was diagnosed on the basis of an appropriate patient history as well as clinical, radiological and immunoserological parameters. RESULTS: SpA was diagnosed in 10.7% of all CD and 14.4% of all UC patients. In 26.8% of all patients symptoms of SpA occurred prior to and in 14.4% simultaneously with IBD. 28.1% of all patients presented with isolated peripheral arthritis, 26.8% of all patients showed an isolated involvement of the spine or sacroiliic joints and 45.1% of all patients presented with combined involvement. 2/12 UC patients with SpA suffered from rectosigmoiditis, 5/12 from partial colitis and 5/12 had pancolitis. In CD patients with SpA, 8/59 had isolated colitis, 8/59 ileocolitis and 31/59 isolated small bowel involvement. There was a positive correlation between SpA and HLA-B27 (p < 0.01). CONCLUSION: Enteropathic spondylarthropathies are an important extraintestinal manifestation of IBD. Spondylarthropathies occur irrespective of the extend of IBD and frequently become symptomatic prior to IBD. These and recent data describing inflammatory bowel disease in patients with SpA of unknown etiology suggest that both diseases have a common pathogenetic background.

Adult↗
PubMed1996

Fatal cerebellar haemorrhage due to phenprocoumon poisoning.

A 32-year-old patient died of a cerebellar haemorrhage and the blood coagulation analysis before death suggested defective synthesis of vitamin K-dependent clotting factors due to vitamin K deficiency. The post-mortem toxicological examination of different tissues revealed phenprocoumon poisoning as the cause of death. The differential diagnosis of vitamin K deficiency and the toxicology of hydroxycoumarins are discussed.

Adult↗