W M Howell

Southampton University Hospitals NHS, Southampton, ENG, United Kingdom

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Publications (66)270.35 Total impact

  • Article: HLA DPB1 ALLELES AND SUSCEPTIBILITY TO RHEUMATOID ARTHRITIS
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    ABSTRACT: SUMMARYHLA-DPB1 genotypic and phenotypic frequencies were investigated in a series of 35 adult rheumatoid arthritis (RA) patients and 42 controls. No significant associations between DPB1 alleles and susceptibility to RA were demonstrated, although some non-significant differences in DPB1*0301 and 0401 allele frequencies between patients and controls were observed.
    International Journal of Immunogenetics 04/2007; 18(4):259 - 263. · 1.29 Impact Factor
  • Article: PCR‐SSO TYPING FOR HLA‐DPB ALLELES
    International Journal of Immunogenetics 04/2007; 18(1‐2):81 - 95. · 1.29 Impact Factor
  • Article: HLA and eye disease: a synopsis.
    S V Goverdhan, A J Lotery, W M Howell
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    ABSTRACT: Human leukocyte antigen (HLA) gene products have been implicated in the pathogenesis of an increasing number of eye diseases, mainly inflammatory in nature. This perspective reviews the current hypotheses for why HLA polymorphisms are associated with specific eye diseases. Statistical problems in studies involving HLA associations are discussed, and possible solutions outlined. The relevance of HLA testing in routine ophthalmic practice, its practical and cost implications is also assessed.
    International Journal of Immunogenetics 01/2006; 32(6):333-42. · 1.29 Impact Factor
  • Article: ICAM-1 polymorphisms and development of cutaneous malignant melanoma.
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    ABSTRACT: Tumour growth in cutaneous malignant melanoma (CMM) is mediated by cell adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1). ICAM-1 expression is associated with increasing Breslow thickness of vertical growth-phase tumours and, in patients with stage 1 disease, may be associated with disease free and patient survival. In this study we have investigated whether two single nucleotide polymorphisms (SNPs) in the ICAM-1 gene encoding amino acid substitutions in codons 241 and 469 of the expressed ICAM-1 molecule are associated with susceptibility to and markers of prognosis (including tumour Breslow thickness) in CMM. A total of 164 CMM patients and 264 cancer-free controls were genotyped for these SNPs by the 5' nuclease assay for allelic discrimination (TaqMan). No genotypes showed any significant associations with CMM susceptibility, although there was a non-significant increase in frequency of the ICAM-1 469 AA genotype among CMM patients vs. controls (38.4% vs. 29.9%; P = 0.11). However, the ICAM-1 241 GG genotype was significantly decreased in frequency among patients with primary invasive tumours of greater Breslow thickness (72.5% vs. 91.2%; P = 0.013; OR = 0.25 (0.072-0.85)). These results provide no evidence for a role for the ICAM-1 codon 241 and 469 SNPs in determining susceptibility to CMM, but provide preliminary evidence that the role of ICAM-1 polymorphism in modulating tumour growth in CMM requires further investigation in a larger study group.
    International Journal of Immunogenetics 01/2006; 32(6):367-73. · 1.29 Impact Factor
  • Article: Influence of cytokine and ICAM-1 gene polymorphisms on susceptibility to chronic pancreatitis.
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    ABSTRACT: To test the hypothesis that single nucleotide polymorphisms (SNPs) within genes (or their promoter regions) encoding cytokines, growth factors, and intercellular adhesion molecules modulate the risk of development of chronic pancreatitis (CP). DNA was extracted from peripheral blood leucocytes or formalin fixed, paraffin wax embedded tissue from 53 patients with CP and 266 healthy controls. SNPs within the interleukin 1beta (IL-1beta), IL-6, IL-8, tumour necrosis factor alpha (TNFalpha) and vascular endothelial growth factor (VEGF) gene promoter regions and the transforming growth factor beta1 (TGFbeta1) and intercellular cell adhesion molecule 1 (ICAM-1) genes were genotyped by the amplification refractory mutation system polymerase chain reaction or 5' nuclease (Taqman) techniques. Patient-control comparisons were made using 2 x 2 contingency tables and chi2 analyses. A non-significant decrease in the frequency of the IL-8 -251 AA genotype and a non-significant increase in the frequency of the ICAM-1 +469 GA genotype was seen in patients compared with controls. No associations were identified between SNPs in the promoter regions of the IL-1beta, IL-6, or TNFalpha proinflammatory cytokines genes or the TGFbeta1 and VEGF genes and susceptibility to CP. This preliminary study suggests that genetic polymorphism within several cytokine genes is unlikely to influence susceptibility to CP, but the possible role of IL-8 and ICAM-1 polymorphisms in the development of this disease requires further investigation.
    Journal of Clinical Pathology 07/2005; 58(6):595-9. · 2.31 Impact Factor
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    Article: VEGF polymorphisms and severity of atherosclerosis.
    W M Howell, S Ali, M J Rose-Zerilli, S Ye
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    ABSTRACT: Vascular endothelial growth factor (VEGF) is a potent angiogenic factor, and neovascularisation has been shown to be important in atherosclerotic plaque development. There is some disagreement as to whether VEGF acts as a pro-atherosclerotic or anti-atherosclerotic factor. In the present study we have sought to clarify this by determining genotypes and haplotypes for three reportedly functional VEGF SNPs in a large series of well documented coronary atherosclerosis patients. VEGF -2578, -1154, and -634 single nucleotide polymorphisms were genotyped in 984 subjects from the Southampton Atherosclerosis Study, using the 5' nuclease assay for allelic discrimination (TaqMan). VEGF -2578 genotypes showed a significantly different distribution in patients without myocardial infarction when stratified according to number of diseased arteries. VEGF -2578 was also associated with mean number of stenotic segments in the same patient group. The AA genotype was a risk factor and CC was protective. These associations were significant before and after adjustment for classic risk factors, and were reflected in associations between VEGF haplotypes and the number of diseased arteries and stenotic segments. As VEGF -2578 CC has been provisionally shown to be associated with higher VEGF expression than the AA genotype, these results are consistent with a protective effect for VEGF in atherosclerosis development. Some changes in VEGF -1154 genotype frequencies were also detected, but no significant associations were detected for any one particular genotype. This study provides preliminary evidence that VEGF polymorphism is associated with development of atherosclerosis, possibly via regulation of VEGF expression, supporting a protective effect for VEGF in atherosclerosis. These results require replication in an independent study group, combined with study of additional candidate polymorphisms in the VEGF gene.
    Journal of Medical Genetics 07/2005; 42(6):485-90. · 6.36 Impact Factor
  • Article: An interleukin-10 promoter polymorphism may influence tumor development in renal cell carcinoma.
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    ABSTRACT: Polymorphisms in the promoter of the interleukin-10 (IL-10) gene may influence tumor development by altering the levels of IL-10 present in the serum or tumor microenvironment. In this study we looked for evidence of specific polymorphisms of the IL-10 promoter and whether lymphocyte expression of IL-10 correlates with specific genotypes. Archival, paraffin embedded renal cell carcinoma tissue from 166 patients and 161 controls were genotyped for the IL-10-1082 single nucleotide polymorphism using real-time polymerase chain reaction. IL-10 protein expression in peripheral blood lymphocytes was assessed by standard enzyme-linked immunoassay in 32 patients with renal cancer. Patient-to-control comparisons identified the AA genotype to be significantly greater in patients with renal cell carcinoma (44% vs 30%, p <0.05). However, study of IL-10 protein expression in peripheral blood lymphocytes from patients with renal cancer showed no statistical difference in IL-10 expression among the GG, AA or AG genotypes. We found that there was a significantly larger proportion of patients with renal cell carcinoma with the AA homozygous genotype than in a normal population cohort. This result is in accordance with those in previous studies of prostate cancer and cutaneous malignant melanoma. In contrast to previous studies of other tumor types, no correlation could be established between IL-10-1082 polymorphism and serum IL-10.
    The Journal of Urology 04/2005; 173(3):709-12. · 3.75 Impact Factor
  • Article: Cytokine gene polymorphisms and breast cancer susceptibility and prognosis.
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    ABSTRACT: Single nucleotide polymorphisms (SNPs) in the promoter regions of cytokine genes are associated with differential levels of cytokine expression. We hypothesized that these SNPs might influence breast tumour development and progression by affecting the efficiency of the antitumour immune response and/or pathways of angiogenesis. A total of 144 female breast cancer patients and 263 cancer-free population controls were genotyped for the interleukin (IL)-1beta-511 (T/C), IL-6 -174 (G/C), tumour necrosis factor (TNF)-alpha-308 (A/G), IL-10 -1082 (A/G), IL-8 -251 (A/T) and vascular endothelial growth factor (VEGF) -1154 (A/G) SNPs, using amplification refractory mutation system polymerase chain reaction (ARMS-PCR) and TaqMan (Applied Biosystems, Foster City, CA, USA) 5' nuclease assays for allelic discrimination. No significant associations were seen. Patient-control comparisons revealed a non-significant trend for association between the TNF-alpha-308 GG genotype and breast cancer compared to controls (79.7 vs. 68.2%, P = 0.03, Pc = 0.54). Stratification of the patient group according to the Nottingham Prognostic Index and individual prognostic factors revealed trends for association between IL-6 -174 GC and IL-8 -251 AA genotypes and markers of poor prognosis (P = 0.04, Pc = 0.72 and P = 0.02, Pc = 0.36, respectively). There were also trends for associations between VEGF -1154 AG and IL-1beta-511 TC genotypes and markers of good prognosis (P = 0.02, Pc = 0.36 and P = 0.05, Pc = 0.90, respectively). These results suggest that the role of cytokine promoter SNPs in both susceptibility to and prognosis in breast cancer requires further investigation in a larger study.
    European Journal of Immunogenetics 09/2004; 31(4):167-73.
  • Article: Lack of association of HLA class I genes and TNF alpha-308 polymorphism in toluene diisocyanate-induced asthma.
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    ABSTRACT: Toluene diisocyanate (TDI)-induced asthma is a common cause of occupational asthma and it affects 5-15% of the exposed population suggesting an underlying genetic susceptibility. To investigate the role of genetic factors in the development of TDI-induced asthma, we analyzed the distribution of human leukocyte antigen (HLA) class I genes and of tumor necrosis factor (TNF)-alpha A-308G polymorphism in 142 patients with TDI-induced asthma and in 50 asymptomatic exposed subjects. Neither the distribution of HLA class I antigens nor the distribution of TNF-alpha A-308G polymorphism was different between patients with TDI-induced asthma and asymptomatic exposed subjects. These results suggest that HLA class I antigens and TNF-alpha A-308G are not associated with susceptibility or resistance to the development of TDI-induced asthma.
    Allergy 02/2004; 59(1):61-4. · 6.27 Impact Factor
  • Article: Cytokine gene single nucleotide polymorphisms and susceptibility to and prognosis in cutaneous malignant melanoma.
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    ABSTRACT: Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that CMM patients develop an immune response to their tumours, although, in most cases, anti-tumour immune responses are insufficient to abrogate tumour development. Polymorphism in genes regulating the immune response and cell growth may result in increased susceptibility to and/or poorer prognosis in certain individuals. In this study, we addressed whether single nucleotide polymorphisms (SNPs) associated with differential expression of selected pro- and anti-inflammatory cytokines and growth factors [interleukin (IL)-1beta-35 and -511, IL-2 -330, IL-4 -590, IL-6 -174, IL-8 -251, interferon (IFN)-gamma+874 and transforming growth factor (TGF)beta1 +915] or as markers of candidate cytokine genes (IL-12 +1188) are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, tumour regression) in CMM. One hundred and sixty-nine British caucasian CMM patients and 261 controls were included in the study and all SNPs were genotyped by ARMS-PCR. No SNP genotypes or alleles showed significant associations with CMM susceptibility and only the IL-1beta-511 TT genotype was associated with thinner invasive tumours at presentation, as assessed by Breslow thickness at the clinically significant cut-off point of 1.5 mm [occurring in 2/51 (3.9%) thicker vs. 14/78 (17.9%) thinner tumours (P = 0.03; relative risk = 0.29 (95% confidence interval 0.05-0.95)]. These findings suggest that - with the possible exception of IL-1beta- genetic variation associated with differential expression of the selected pro- and anti-inflammatory cytokines is unlikely to play a major role in susceptibility to and prognosis in CMM.
    European Journal of Immunogenetics 01/2004; 30(6):409-14.
  • Article: Influence of vascular endothelial growth factor single nucleotide polymorphisms on tumour development in cutaneous malignant melanoma.
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    ABSTRACT: Vascular endothelial growth factor (VEGF) is a potent regulator of vasculogenesis and tumour angiogenesis. We have investigated whether the VEGF -2578, -1154, +405 and +936 SNPs and associated haplotypes confer susceptibility to and/or influence prognosis in cutaneous malignant melanoma (CMM) skin cancer. A total of 152 CMM patients and 266 controls were genotyped for VEGF promoter SNPs by ARMS-PCR. Strong linkage disequilibrium between the -2578, -1154 and +405 SNPs was detected (association, rho = 0.488-0.965), but not between these SNPs and SNP +936 (association, rho = 0.004-0.130). No SNPs or three SNP haplotypes (-2578, -1154, +405) were significantly associated with CMM, although a number of non-significant trends were observed. However, the VEGF -1154 AA genotype and -2578, -1154, +405 CAC haplotype were both significantly associated with less advanced (Stage 1) disease (P = 0.03). In addition, the VEGF -1154 AA genotype was associated with thinner primary vertical growth phase tumours (P = 0.002), while VEGF -1154 GG was associated with thicker primary tumours (P = 0.02). These preliminary results indicate that VEGF genotype may influence tumour growth in CMM, possibly via the effects of differential VEGF expression on tumour angiogenesis.
    Genes and Immunity 07/2002; 3(4):229-32. · 3.87 Impact Factor
  • Article: Influence of TNFalpha and LTalpha single nucleotide polymorphisms on susceptibility to and prognosis in cutaneous malignant melanoma in the British population.
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    ABSTRACT: Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that increased expression of tumour necrosis factor (TNF) alpha, upregulated by UV exposure, may contribute to tumour escape from the immune response. In this study, we addressed whether single nucleotide polymorphisms (SNPs) in the TNFalpha promoter and lymphotoxin (LT) alpha gene are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, and tumour regression) in CMM. One hundred and forty-six British Caucasian CMM patients and 220 controls were typed for TNFalpha-376, -308 and -238 and LTalpha+252 SNPs by ARMS-PCR. Only the TNFalpha -238 GG (P = 0.05) and GA (P = 0.03) genotypes showed slight, but significant, associations with CMM, while LTalpha+252 AA was associated with a higher mitotic count in vertical growth phase tumours (P = 0.02). Both TNFalpha-238 and LTalpha+252 SNPs showed linkage disequilibrium with HLA-DQB1*0303 and *0301 alleles, variably implicated in CMM susceptibility/prognosis. In addition, TNFalpha-238, -308, LTalpha+252 haplotypes were assigned and compared. The GGA haplotype showed a modest association with CMM (P = 0.04) and with stage of disease (P = 0.03) and initial growth phase in CMM (P = 0.02), but these associations were only significant when P-values were uncorrected. Unlike basal cell carcinoma, these preliminary findings suggest that genetic variation associated with differential TNFalpha and LTalpha production is unlikely to play a major, independent role in susceptibility to, and perhaps prognosis in, CMM.
    European Journal of Immunogenetics 03/2002; 29(1):17-23.
  • Article: Influence of TNFα and LTα single nucleotide polymorphisms on susceptibility to and prognosis in cutaneous malignant melanoma in the British population
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    ABSTRACT: Cutaneous malignant melanoma (CMM) is a potentially fatal malignancy in which exposure to UV light is the most important risk factor. Several lines of evidence suggest that increased expression of tumour necrosis factor (TNF) α, upregulated by UV exposure, may contribute to tumour escape from the immune response. In this study, we addressed whether single nucleotide polymorphisms (SNPs) in the TNFα promoter and lymphotoxin (LT) α gene are associated with susceptibility to or known prognostic indicators (e.g. initial tumour growth phase, Breslow thickness, mitotic count in vertical growth phase tumours, and tumour regression) in CMM. One hundred and forty-six British Caucasian CMM patients and 220 controls were typed for TNFα−376, −308 and −238 and LTα+252 SNPs by ARMS-PCR. Only the TNFα−238 GG (P = 0.05) and GA (P = 0.03) genotypes showed slight, but significant, associations with CMM, while LTα+252 AA was associated with a higher mitotic count in vertical growth phase tumours (P = 0.02). Both TNFα−238 and LTα+252 SNPs showed linkage disequilibrium with HLA-DQB1*0303 and *0301 alleles, variably implicated in CMM susceptibility/prognosis. In addition, TNFα−238, −308, LTα+252 haplotypes were assigned and compared. The GGA haplotype showed a modest association with CMM (P = 0.04) and with stage of disease (P = 0.03) and initial growth phase in CMM (P = 0.02), but these associations were only significant when P-values were uncorrected. Unlike basal cell carcinoma, these preliminary findings suggest that genetic variation associated with differential TNFα and LTα production is unlikely to play a major, independent role in susceptibility to, and perhaps prognosis in, CMM.
    European Journal of Immunogenetics 02/2002; 29(1):17 - 23.
  • Article: Polymorphisms in matrix metalloproteinase-1, -3, -9, and -12 genes in relation to subarachnoid hemorrhage.
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    ABSTRACT: Intracranial aneurysm, which underlies the vast majority of subarachnoid hemorrhage incidences, has a multifactorial etiology, and the importance of genetic factors is increasingly recognized. Development and rupture of intracranial aneurysms involve degradation and remodeling of the vascular wall matrix in which the matrix metalloproteinases (MMPs) play an important role. The possible impact of MMP gene polymorphisms on susceptibility to intracranial aneurysms is still controversial, with conflicting data from different reported studies. In this study we analyzed 5 different functional promoter polymorphisms in the MMP-1, MMP-3, MMP-9, and MMP-12 genes in a sample of 92 patients with aneurysmal subarachnoid hemorrhage and 158 healthy control subjects, all from southern England. No significant difference was detected between the patient and control groups in genotype distribution of any of the polymorphisms studied. The data do not support the hypothesis that MMP gene variations influence the development of intracranial aneurysms in the population studied.
    Stroke 10/2001; 32(9):2198-202. · 5.73 Impact Factor
  • Article: Modification of T-cell receptor Vbeta repertoire in response to allergen stimulation in peanut allergy.
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    ABSTRACT: Peanut is one of the most common foods causing allergic reactions and is the most common cause of fatal and near-fatal food-related anaphylaxis. Little is known of the immunologic mechanisms that underlie peanut allergy. In this study we examined clonality of the T-cell response (TCR) to peanut in MHC class II identical, peanut allergy-discordant sibling pairs. Four sibling pairs were investigated. The TCR repertoire was analyzed before and after in vitro stimulation of PBMCs with crude peanut or PHA, as control for general/nonspecific reactivity. Eighteen TCR-Vbeta families were examined by flow cytometry. Where significant differences in incidence of particular TCR-Vbeta families were observed, PCR familyspecific cDNA amplification and gene scanning were performed. After stimulation with peanut, no selective expansion of any TCR-Vbeta subpopulation was observed with flow cytometry, in either the peanut-allergic or nonallergic siblings, with the exception of 1 peanut-allergic subject who demonstrated a significant increase of TCR-Vbeta11(+) cells (0.3%-5.9% of the total CD3(+) cells). However, gene scanning revealed predominant single-size PCR products for TCRBV11 in all peanut-allergic subjects after peanut stimulation. TCRBV11 polyclo-nality was observed in allergic and nonallergic subjects before peanut stimulation and in nonallergic subjects after peanut stimulation. In comparison, all subjects, before and after stimulation with peanut, showed polyclonality for TCRBV2. Our results argue for clonal or oligoclonal TCRs to crude peanut and indicate that changes in the TCRBV11 subpopulation are restricted to peanut-allergic subjects after stimulation with crude peanut allergen.
    Journal of Allergy and Clinical Immunology 07/2001; 107(6):1089-94. · 11.00 Impact Factor
  • Article: IL-10 promoter polymorphisms influence tumour development in cutaneous malignant melanoma.
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    ABSTRACT: Cutaneous malignant melanoma (CMM) is the most serious cutaneous malignancy. CMM patients often develop an immune response to their tumours. Conflicting evidence suggests that IL-10 may contribute to tumour escape from the immune response, but may also have an anti-tumour effect. To distinguish between these models and to determine whether genotypes associated with differential IL-10 expression confer susceptibility to and/or influence prognosis in CMM, 165 CMM patients and 158 controls were genotyped for IL-10 promoter SNPs by ARMS-PCR. The IL-10--1082 AA low expression genotype was increased in incidence among CMM patients (P = 0.04). In addition, IL-10 genotypes showed significant associations with three of four prognostic indicators examined; IL-10--1082 GG (P = 0.02) and -1082, -819 and -592 compound high expression (P = 0.03) genotypes were associated with horizontal (non-invasive) tumour growth; IL-10--1082 AA low expression genotype was associated with more advanced (Stage II-IV) disease (P = 0.04); finally, the IL-10--1082 AA (P = 0.005) and compound low expression (P = 0.009) genotypes were significantly increased in frequency among patients with thicker primary Vertical growth phase tumours. These results indicate that genotypes associated with high levels of IL-10 expression in vitro are protective in CMM, while low expression genotypes are a risk factor for more advanced/poorer prognosis disease and may confer susceptibility to CMM. Although the influence of IL-10 on melanoma development is likely to be complex, these results support recent findings that IL-10 has an anti-tumour effect in CMM, possibly via inhibition of angiogenesis.
    Genes and Immunity 03/2001; 2(1):25-31. · 3.87 Impact Factor
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    Article: Invasiveness of cutaneous malignant melanoma is influenced by matrix metalloproteinase 1 gene polymorphism.
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    ABSTRACT: The matrix metalloproteinases (MMPs) are implicated in connective tissue destruction during cancer invasion and metastasis. A naturally occurring variant arising from the insertion or deletion of a guanine in the promoter of the MMP-1 gene has recently been reported and shown to influence its transcriptional activity in melanoma cells. In this study, MMP-1 genotype was determined in 139 Caucasian patients with cutaneous malignant melanoma. The insertion allele was associated with deep invasive, and therefore poorer-prognosis, primary tumors [(34% of patients with vertical growth phase tumor were homozygous for the insertion allele compared with 17% of patients with horizontal growth phase tumor (P = 0.0333; odds ratio = 2.51)]. These data suggest that the invasiveness of cutaneous malignant melanoma is influenced by variation in the MMP-1 gene promoter that affects MMP-1 expression.
    Cancer Research 03/2001; 61(4):1296-8. · 7.86 Impact Factor
  • Article: Rheumatoid arthritis T cells produce Th1 cytokines in response to stimulation with a novel trispecific antibody directed against CD2, CD3, and CD28.
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    ABSTRACT: Rheumatoid arthritis (RA) T cells respond poorly to conventional mitogens. We have examined the proliferative and cytokine responses of T cells to a synthetic trispecific antibody (Tsab) directed against CD2, CD3, and CD28. In 11 subjects RA T cells proliferated more, and secreted significantly more IL-2, in response to Tsab than did control peripheral blood (PB) cells. Very high levels of IL-2 were produced by 2 patients with aggressive disease. Measurement of intracellular IL-2, IFN-gamma, IL-4, and IL-5 by flow cytometry showed a Th1 pattern of cytokine production in 13 RA and 9 control subjects. We conclude that RA T cells are not irreversibly inactivated, and that spatial arrangement of stimulating molecules may be important in eliciting maximal responses.
    Scandinavian Journal of Rheumatology 02/2000; 29(5):282-7. · 2.47 Impact Factor
  • Article: HLA class II genotype, HLA-DR B cell surface expression and allergen specific IgE production in atopic and non-atopic members of asthmatic family pedigrees.
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    ABSTRACT: HLA class II polymorphism is variably associated with sensitization to specific allergens, but few convincing HLA associations with asthma or the general state of atopy have been demonstrated. In this study we investigated HLA class II genotype associations with asthma, atopy and specific IgE (sIgE) production to six allergen extracts and six purified major allergens (Der p 1, Der p 2, Fel d 1, Can f 1, Alt a 1 and Phl p 5) in 176 individuals from 20 asthmatic family pedigrees. In selected individuals, cell surface HLA-DR peripheral B-cell expression was correlated with HLA-DRB1 genotype and atopic status. Results showed that HLA-DRB1*08 was negatively associated with asthma (2% vs 17%; Pc = 0.02; OR = 0.08) and atopy (0% vs 16%; Pc = 0.04; OR = 0.1), while DRB1*15 was positively associated with asthma (36% vs 13%; Pc = 0.02; OR = 3.6). Analysis of DRB1 sequences showed that only 29% of individuals with GAG TAC TCT ACG at codons 9-12 in one or both alleles were atopic, compared with 53% of individuals without this sequence (P = 0.002; OR = 0.36). DPA1*0201 was negatively associated with sIgE to both grass pollen mix and Phl p 5 (0% vs 23%; Pc = 0.02; OR = 0.14). A non-significant trend towards higher HLA-DR B-cell expression was seen in both non-atopic and DRB1*08 individuals. In conclusion, this single centre study has demonstrated a number of HLA class II genotype associations with asthma, atopy and sIgE to grass pollen mix and Phl p 5, including hitherto unreported DRB1*08, DRB1 codon 9-12 and DPA1*0201 associations. No significant associations between HLA-DR expression and DRB1 genotype or atopy were demonstrated, although a trend towards higher expression was seen in non-atopic individuals and individuals of DRB1*08 genotype.
    Clinical & Experimental Allergy 01/2000; 29 Suppl 4:35-8. · 5.03 Impact Factor
  • Article: Polymerase chain reaction based human leucocyte antigen genotyping for the investigation of suspected gastrointestinal biopsy contamination.
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    ABSTRACT: Mislabelling or contamination of surgical specimens may lead to diagnostic inaccuracy, particularly within gastrointestinal pathology when multiple small mucosal biopsy specimens are commonly taken, and where a tiny fragment of foreign tissue may be indistinguishable from true biopsy material using histological assessment alone. To assess the utility of polymerase chain reaction (PCR) based human leucocyte antigen (HLA) genotyping techniques for the investigation of potentially mislabelled or contaminated gastrointestinal biopsy specimens. Ten cases (28 samples) in which mislabelling or contamination was suspected, comprising four upper gastrointestinal tract biopsies and six colonoscopic biopsy series. Direct and nested PCR-sequence specific primer (SSP) based HLA class II genotyping was performed on DNA extracted from formalin fixed and paraffin wax embedded tissue (23 samples) or peripheral blood leucocytes (five samples). A full HLA-DRB1 genotype was determined in all 28 samples. In seven cases the HLA-DRB1 genotype of the putative contaminant was different to that of the corresponding reference tissue, confirming different individual origins for the contaminant and reference material. In one case the contaminant tissue was shown to possess the same HLA-DRB1 alleles as a second patient (probable source). In the remaining three cases the same HLA-DRB1 alleles were detected within the potential contaminant and reference tissues. PCR based HLA class II genotyping is a valuable tool for investigating potential contamination or mislabelling within gastrointestinal biopsy specimens and this report has confirmed contamination in seven of ten cases studied.
    Gut 09/1999; 45(2):259-63. · 10.11 Impact Factor