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Biomedical subjects

G W Duff

Publications and source records attributed to G W Duff.

At least 73 records · Page 4Linked to original sources
PubMed1994

Absence of lentiviral and human T cell leukemia viral sequences in patients with rheumatoid arthritis.

OBJECTIVE: The etiology of rheumatoid arthritis (RA) is unknown, and the possibility that an infectious agent is involved has not been excluded. Lentiviruses can cause chronic arthritis in humans and in animals and have been suggested as candidate agents in RA. We therefore tested for the presence of lentiviruses and also for human T cell leukemia virus type I (HTLV-I)/HTLV-II in cells from patients with RA. METHODS: We used the polymerase chain reaction with degenerate primers designed to recognize highly conserved nucleotide sequences from 5 different pathogenic lentiviruses. This method allowed the detection of at least 1 infected cell/20,000 uninfected cells in control experiments. RESULTS: Testing of synovial cells and blood cells from patients with early RA and patients with established RA did not yield any specific viral product. CONCLUSION: Our results do not support the presence of lentiviruses or HTLV-like sequences in RA.

Adult↗
PubMed1994

Interleukin-1 receptor antagonist gene polymorphism as a disease severity factor in systemic lupus erythematosus.

OBJECTIVE: We have previously described associations between an allele of the interleukin-1 receptor antagonist gene (IL1RN) and several inflammatory diseases. In this study we tested the IL1RN gene as a possible marker in patients with systemic lupus erythematosus (SLE). METHODS: Eighty-one SLE patients and 261 ethnically matched control subjects were genotyped by polymerase chain reaction. RESULTS: We found an increase in both frequency and carriage rate of IL1RN*2 in the SLE group. This association strengthened with extensive disease and particularly with the presence of photosensitivity and discoid skin lesions. CONCLUSION: We describe a novel association between IL1RN*2 and SLE. Carriage of the allele seems to influence severity rather than susceptibility to SLE. We postulate that the association of this polymorphism with disease severity is a widespread feature of common inflammatory and autoimmune diseases.

Base Sequence↗
PubMed1994

A genetic association between systemic lupus erythematosus and tumor necrosis factor alpha.

We have investigated the significance of tumor necrosis factor alpha (TNF-alpha) polymorphism in relation to systemic lupus erythematosus (SLE) and autoantibody production. Typing of HLA-B, -DR and TNF was performed in 81 Caucasian SLE patients and 168 Caucasian controls. The presence of anti-Ro and anti-La antibodies was also determined in patients. The frequency of the TNF2 allele increased in SLE compared with controls [0.24 vs. 0.17, p = 0.04, odds ratio (OR) = 1.6], as did HLA-DR3 (0.25 vs. 0.13, p < 0.01, OR = 2.3) and HLA-B8 (0.23 vs. 0.15, p = 0.02, OR = 2). Although HLA-DR3 showed the strongest disease association, we could not demonstrate association of HLA-DR3 or TNF2 with SLE independently of each other. Within SLE a much stronger association of TNF2 was seen with autoantibody production: anti-Ro antibody (0.39 vs. 0.16, p < 0.001, OR = 3.4) and anti-La antibody (0.43 vs. 0.19, p < 0.001, OR = 3.2). When analyzed independently of each other, however, HLA-DR3 remained significantly associated with autoantibodies, while TNF2 did not. These data suggest that on the B8-DR3 haplotype, TNF-alpha polymorphism may play a role in SLE susceptibility, but it is not primarily associated with autoantibody production.

Autoantibodies↗
PubMed1994

Interleukin 1 receptor antagonist gene polymorphism association with lichen sclerosus.

Cytokines play key roles in immune responses, inflammation and fibrosis. The balance between levels of cytokines, their receptors and specific inhibitors controls inflammatory reactions in tissues. The pathogenesis of lichen sclerosus is unknown but probably involves cytokine mediators such as interleukin 1 (IL-1) and interleukin 1 receptor antagonist (IL-1ra). The IL-1ra is a competitive inhibitor of IL-1 alpha and IL-1 beta, and therefore is a powerful endogenous anti-inflammatory molecule. The gene encoding IL-1ra (designated IL-1RN) has a variable number tandem repeat polymorphism in intron 2. There are five alleles of the gene corresponding to 2, 3, 4, 5 and 6 repeats of an 86-bp sequence. We have determined allele frequencies in a control population and a group of 78 patients with lichen sclerosus. The frequency of one of the alleles is related to increasing disease severity. Thus, IL-1RN may be a candidate gene or severity factor for lichen sclerosus or may possibly be a linked marker to another, as yet undefined, gene.

Alleles↗
PubMed1994

Comparative analysis of the genetic associations of HLA-DR3 and tumour necrosis factor alpha with human IDDM.

Insulin-dependent diabetes mellitus (IDDM) is associated with class II molecules of the MHC on chromosome 6, in particular HLA-DR and -DQ alleles, but a pathogenic role for TNF-alpha in the class III region of the MHC has also been implied. We therefore tested whether there was any independent association between a biallelic TNF polymorphism and IDDM. The TNF2 allele was present in 61 of 114 (54%) IDDM patients compared to 101 of 253 (40%) control subjects (odds ratio 1.73; p < 0.02). Stratification analysis in individuals matched for HLA-DR3 revealed, however, that this association was not independent of HLA-DR3 and is most likely to be a result of linkage disequilibrium between these alleles.

Adult↗
PubMed1994

Novel genetic association between ulcerative colitis and the anti-inflammatory cytokine interleukin-1 receptor antagonist.

BACKGROUND/AIMS: Ulcerative colitis and Crohn's disease have well-recognized familial tendencies, but the genetic basis of this clinical observation remains unknown. The cytokine interleukin-1 receptor antagonist is a potent anti-inflammatory protein that can prevent immune-mediated bowel inflammation in animals. We have previously characterized a polymorphism within the gene for this cytokine and others in the genes for the proinflammatory cytokines interleukin 1 alpha, interleukin 1 beta, and tumor necrosis factor alpha. The aim of this study was to determine whether inflammatory bowel disease was associated with particular alleles of these polymorphic cytokine genes. METHODS: The allelic frequencies of these polymorphic cytokine genes were determined in patients with ulcerative colitis (n = 113), Crohn's disease (n = 78), and healthy controls (n = 261). RESULTS: Allele 2 of interleukin-1 receptor antagonist was significantly over-represented in the ulcerative colitis patients: 35% versus 24% in controls (P = 0.007). Carriage of at least one copy of this allele gave an odds ratio of 2.0 for ulcerative colitis compared with controls. This association with allele 2 of interleukin 1 receptor antagonist was greatest in patients with total colitis and was not seen in Crohn's disease. There were no associations between UC and any of the other cytokine genes examined. CONCLUSIONS: This observation provides evidence that interleukin-1 receptor antagonist may have a role in determining the genetic susceptibility to and pathogenesis of ulcerative colitis.

Adult↗
PubMed1994

Severity of alopecia areata is associated with a polymorphism in the interleukin-1 receptor antagonist gene.

One of the most potent pro-inflammatory mediators is the early-acting cytokine interleukin-1. Its actions are regulated by a structurally related anti-inflammatory cytokine known as the interleukin-1 receptor antagonist. We have previously characterized a DNA polymorphism in this gene (IL-1rn) and have found associations between allele 2 and several chronic inflammatory diseases. In the present study, we tested the frequency of allele 2 of the IL-1rn gene in 90 patients with alopecia areata compared with 261 healthy controls. There was a significant association between allele 2 of the polymorphism and the severity of alopecia areata. The frequency of allele 2 increased from 24.1% in the control population to 25.9% in patchy alopecia areata, 36.1% in alopecia totalis, and 47.2% in alopecia universalis (p = 0.005). This severity association is similar to that found in other epithelial-related diseases, including inflammatory bowel disease, lichen sclerosus, and systemic lupus erythematosus.

Alleles↗
PubMed1994

Cytokines and acute phase proteins in rheumatoid arthritis.

Cytokines are extracellular signalling glycoproteins that play an important pathological role in rheumatoid arthritis (RA) where they mediate acute inflammation, chronic inflammation and connective tissue destruction. In RA the macrophage-derived cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), tumour necrosis factor (TNF), colony stimulating factors (CSFs) and growth factors play a key role in amplifying and perpetuating inflammation. IL-1 and TNF activate cartilage and bone degrading enzymes, while IL-8 recruits inflammatory cells into the joint. IL-1 and TNF play an important role in the acute phase response in that they potently induce IL-6, itself the major mediator and regulator of hepatic synthesis of acute phase proteins (APPs). The acute phase response is signalled by the rapid elevation of APPs such as C-reactive protein (CRP) and serum amyloid A (SAA) in the blood, and these can be used as good surrogate markers of disease activity. In health, the activity of cytokines such as IL-1 or TNF is checked by inhibitory molecules such as receptor antagonist molecules or soluble receptor molecules. In disease, cytokine activity appears to be relatively unopposed, leading to the recent development of cytokine inhibitory molecules as potential anti-RA therapies. However, while cytokines are mediators of disease, they probably do not provide the initial stimulus for RA to develop, although polymorphisms in TNF, IL-1 and IL-1 receptor antagonist genes which have been recently found may represent important genetic modifying factors of disease severity in RA.

Acute-Phase Proteins↗
PubMed1994

Release of platelet-derived growth factor activity from pig venous arterial grafts.

Intimal smooth muscle cell proliferation and superimposed atheroma are the main causes of late failure of saphenous vein bypass grafts. It has been suggested that these reactions are caused by the production of growth factors from the cells of the vessel wall. To test this hypothesis, we cultured segments of pig venous arterial grafts, removed 1 and 4 weeks after implantation, in serum-free medium for 24 hours. Tissue viability as assessed by adenosine triphosphate concentration was maintained throughout the 24-hour culture period (239 +/- 21 nmol/gm wet weight [standard error of the mean], n = 26, 0 hours; 240 +/- 24 nmol/gm wet weight, n = 17, 24 hours). Cell proliferation occurred and autoradiography showed proliferating cells to be located in the neointimal and medial layers. These cells were identified as smooth muscle cells by means of a monoclonal antibody to alpha-actin. Graft-conditioned media were tested for mitogenic activity by means of a fibroblast proliferation assay. Media conditioned for 24 hours produced significant stimulation of cell growth (284% +/- 30%, n = 17) above that obtained in culture medium alone (100%). This mitogenic activity was inhibited by 61% +/- 9%, n = 8, with a polyclonal-neutralizing antibody to platelet-derived growth factor. Reverse-transcription polymerase chain reaction analysis and Northern blots demonstrated platelet-derived growth factor B messenger ribonucleic acid (mRNA) in vein grafts but not in ungrafted vein. Analysis of graft tissue sections by in situ hybridization demonstrated an abundance of platelet-derived growth factor B mRNA positive cells in the endothelial and neointimal layers, as well as in the endothelial cells of the adventitial vessels. These data constitute direct evidence for active growth factor production within the cells of the vein graft. They also suggest that endogenously produced platelet-derived growth factor may play a role in regulating smooth muscle cell proliferation in this model.

Animals↗
PubMed1993

An allelic polymorphism within the human tumor necrosis factor alpha promoter region is strongly associated with HLA A1, B8, and DR3 alleles.

The tumor necrosis factor (TNF) alpha gene lies within the class III region of the major histocompatibility complex (MHC), telomeric to the class II and centromeric to the class I region. We have recently described the first polymorphism within the human TNF-alpha locus. This is biallelic and lies within the promoter region. Frequency analysis of the TNF-alpha polymorphism, using the polymerase chain reaction and single-stranded conformational polymorphism, in HLA-typed individuals, reveals a very strong association between the uncommon TNF allele and HLA A1, B8, and DR3 alleles. This is the first association between TNF-alpha and other MHC alleles and raises the possibility that the uncommon TNF-alpha allele may contribute to the many autoimmune associations of the A1,B8,DR3 haplotype.

Alleles↗
PubMed1993

Genetic polymorphism of human interleukin-1 alpha.

Interleukin-1 alpha (IL-1 alpha) has been implicated in the pathogenesis of infectious, autoimmune and inflammatory diseases. There is, however, very little information on the cis-acting sequences involved in IL-1 alpha regulation or whether there is any variation in the structure of the gene. It is known that intron 6 of IL-1 alpha shows a 5 x 46 bp tandem repeat in the genomic sequence. We have studied this region of the gene. Amplification by polymerase chain reaction showed different sized products from different individuals, most being of higher molecular weight than the expected size of 620 bp. Sequencing demonstrated that the polymorphism was due to a variable number of repeats of the 46 bp sequence. This was confirmed by restriction fragment length analysis of genomic DNA. Altogether, 72 unrelated individuals were tested and 6 alleles ranging from 5 to 18 repeats were found, the most frequent allele (62%) containing 9 repeats. This polymorphism may be of interest in gene function, since each repeat contains three potential binding sites for transcriptional factors: an SP1 site, a viral enhancer element and a glucocorticoid-responsive element. The latter, at least, demonstrates site-specific protein binding by electromobility shift assay. The functional significance of the polymorphism and its allelic frequency in inflammatory and autoimmune diseases are currently under investigation.

Base Sequence↗
PubMed1993

No independent association between a tumor necrosis factor-alpha promotor region polymorphism and insulin-dependent diabetes mellitus.

Several studies have implicated tumor necrosis factor (TNF)-alpha in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). In the present study we analyzed the first reported TNF-alpha gene polymorphism in relation to IDDM. We have made frequence analysis and tested in vitro lipopolysaccharide (LPS)-induced TNF-alpha secretion. A significant difference in allele frequency was observed between patients and controls (p = 0.03). However, a very strong association of the uncommon TNF2 allele was observed with the HLA-B8, -DR3 alleles. The relative risk (RR) of TNF2 was 2.2 compared to a RR of 3.1 for DR3. One reason for this difference was the identification of the TNF1 allele on the otherwise strongly IDDM-associated HLA-DR3 haplotype: DQB1*0201, DQA1*0501, DRB1*0301, TNFc2, TNFB*2, TNFa1, TNFb5, B18. Thus, the IDDM-associated TNF2 allele had no DR3-independent value as a disease marker. The LPS-induced TNF-alpha production by human monocytes in relation to genotypes demonstrated that TNF1/2 heterozygous individuals had higher, though not statistically significantly (p = 0.08) levels than TNF1-homozygous subjects. However, this difference was rather small, unlikely to be of biological significance and based on the present material we cannot establish the functional importance of this polymorphism.

Adolescent↗
PubMed1993

Polymorphism in human IL-1 receptor antagonist gene intron 2 is caused by variable numbers of an 86-bp tandem repeat.

We have investigated the polymorphism in intron 2 of the interleukin-1 receptor antagonist gene and identified two new alleles of the system. We have shown that the polymorphism is caused by the variable copy number of an 86-bp sequence, by using the polymerase chain reaction and primers immediately flanking the repeat region, and by direct sequencing. The repeat region contains three potential protein-binding sites and therefore the variable copy number may have functional significance.

Alleles↗
PubMed1993

Polymorphic tandem repeat region in interleukin-1 alpha intron 6.

Analysis of polymerase chain reaction amplified products from the sixth intron of the human interleukin-1 alpha gene reveals a high polymorphism (polymorphism information content = 0.51) in a Caucasian population. Altogether, seven alleles have been defined ranging from 620 to 1220bp. This polymorphism is probably attributable to a variable number of 46-bp tandem repeats, each containing potential regulatory sequences.

Base Sequence↗
PubMed1993

Sequence homologies between hsp60 and autoantigens.

The human heat shock protein (hsp) 60 shares sequence homology with a wide range of autoantigens including those of insulin dependent diabetes mellitus, Hashimoto's thyroiditis, glomerulonephritis, scleroderma, pemphigoid, rheumatoid arthritis, multiple sclerosis, chronic active hepatitis, primary biliary cirrhosis and Addison's disease. Here we show the extent of this homology and suggest that it contributes to autoimmunity through cross-reactivity between hsp60 and tissue-specific proteins containing similar epitope motifs. Differences between individuals in MHC class II may influence the selection of a particular hsp60 epitope and the corresponding target antigen that gives rise to an autoimmune disease.

Autoantigens↗