John E Hegarty

Publications (27)104.29 Total impact

• Article: Hepatitis C Virus targets the Interferon-α JAK/STAT pathway by promoting proteasomal degradation in immune cells and hepatocytes.

  Nigel J Stevenson, Nollaig M Bourke, Elizabeth J Ryan, Marco Binder, Liam Fanning, James A Johnston, John E Hegarty, Aideen Long, Cliona O'Farrelly
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  ABSTRACT: JAK/STAT signalling is essential for anti-viral immunity, making IFN-α an obvious anti-viral therapeutic. However, many HCV+ patients fail treatment, indicating that the virus blocks successful IFN-α signalling. We found that STAT1 and STAT3 proteins, key components of the IFN-α signalling pathway were reduced in immune cells and hepatocytes from HCV infected patients, and upon HCV expression in Huh7 hepatocytes. However, STAT1 and STAT3 mRNA levels were normal. Mechanistic analysis revealed that in the presence of HCV, STAT3 protein was preferentially ubiquitinated, and degradation was blocked by the proteasomal inhibitor MG132. These findings show that HCV inhibits IFN-α responses in a broad spectrum of cells via proteasomal degradation of JAK/STAT pathway components.
  FEBS letters 04/2013; · 3.54 Impact Factor
• Article: It's a man's world: Does orthotopic liver transplantation in the elderly male confer an additional risk on survival?

  Eoin Slattery, John E Hegarty, P Aiden McCormick
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  ABSTRACT: Orthotopic liver transplantation (OLT) in a well-selected population is a highly successful procedure, with one-year survival rates reported to be as high as 90%. Advanced age is considered to be a contraindication. Survival rates in patients >60 years of age appear to be comparable with those of younger patients. However, little objective data exist on the outcomes of patients >65 years of age undergoing OLT. To review the outcomes of OLT in the Irish National Transplant Unit in patients >65 years of age and to compare outcomes with patients ≤65 years of age. Second, to identify any factors that may provide valuable prognostic information regarding outcomes. Patients >65 years of age who underwent OLT since the inception of the National Liver Unit in 1993 were identified from a prospectively maintained database. Medical records were reviewed. Survival was compared with the overall cohort using the Kaplan-Meier technique. Independent variables between the two groups were assessed using logistic regression analysis. Between January 1993 and December 2009, 551 patients underwent 639 transplants in the Irish National Liver Transplant Unit. Forty-three transplants were performed in 40 patients >65 years of age. Unadjusted one- and three-year survival rates for the elderly cohort were 77.8% and 64.5%, respectively. This compared with 93% and 85%, respectively, in the unselected cohort. Using Kaplan-Meier analysis, a significant benefit in survival was observed in patients ≤65 years of age (P=0.017). Similarly, when adjusted for sex, a significant difference was noted between the groups. Male patients >65 years of age had poorer survival compared with their female counterparts >65 years of age and all patients ≤65 years of age (P=0.02). There was no significant difference between the groups with respect to preoperative variables such as bilirubin, creatinine and sodium levels, and Model for End-stage Liver Disease score. A significant difference was seen in male patients >65 years of age with more than one comorbidity, compared with female patients and male patients ≤65 years of age. Male sex was associated with poorer survival in patients >65 years of age undergoing OLT. Multiple comorbidities in elderly male patients should be considered a relative contraindication in patients being assessed for OLT.
  Canadian journal of gastroenterology = Journal canadien de gastroenterologie 10/2012; 26(10):697-700. · 1.21 Impact Factor
• Article: Elevated circulating osteoprotegerin and reduced matrix-metalloprotease-9 in post-menopausal women with chronic Hepatitis C virus infection.

  Kavinderjit S Nanda, Jennifer J Brady, Barbara F Murray, Owen Sullivan, Ursula Fearon, Malachi J McKenna, John E Hegarty, Cliona O'Farrelly, Elizabeth J Ryan
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  ABSTRACT: The failure of the immune response to clear the Hepatitis C virus (HCV) results in chronic inflammation that leads to liver cirrhosis. In general, women have a better prognosis than men and this may be associated with increased levels of anti-inflammatory mediators that are positively regulated by female sex hormones. Our aim was to determine if a cohort of Irish women who acquired infection through administration of HCV genotype 1b-contaminated anti-D immunoglobulin from a single source, had altered levels of circulating cytokine levels compared to women who spontaneously resolved infection, men with HCV infection or age-matched healthy controls. Twenty post-menopausal women and 20 men with chronic HCV infection (genotype 1), 20 post-menopausal women who resolved infection and age and sex-matched controls were recruited for the study. Levels of circulating cytokines were assessed by ELISA. Circulating IL-6, Oncostatin-M, TNF-α, CXCL10, CCL18, VEGF and GM-CSF did not differ between groups. Both men and women with HCV had significantly elevated levels of circulating Osteoprotegerin (OPG). However, male but not female HCV patients had elevated levels of circulating Matrix Metalloprotease-9 (MMP-9). An increased OPG: MMP-9 ratio in the circulation of females compared to males with chronic HCV may help protect against HCV-associated liver disease and explain the slow progress of liver disease in this cohort.
  Cytokine 08/2012; 60(2):328-33. · 3.02 Impact Factor
• Source

  Available from: Cliona O'Farrelly

  Article: Ribavirin enhances IFN-α signalling and MxA expression: a novel immune modulation mechanism during treatment of HCV.

  Nigel J Stevenson, Alison G Murphy, Nollaig M Bourke, Catherine A Keogh, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: The nucleoside analogue Ribavirin significantly increases patient response to IFN-α treatment of HCV, by directly inhibiting viral replication. Recent studies indicate that Ribavirin also regulates immunity and we propose that Ribavirin enhances specific interferon sensitive gene (ISG) expression by amplifying the IFN-α-JAK/STAT pathway. We found that IFN-α-induced STAT1 and STAT3 phosphorylation was increased in hepatocytes co-treated with Ribavirin and IFN-α, compared to IFN-α alone. Ribavirin specifically enhanced IFN-α induced mRNA and protein of the anti-viral mediator MxA, which co-localised with HCV core protein. These novel findings indicate for the first time that Ribavirin, in addition to its viral incorporation, also enhances IFN-α-JAK/STAT signalling, leading to a novel MxA-mediated immuno-modulatory mechanism that may enhance IFN-α anti-viral activity against HCV.
  PLoS ONE 01/2011; 6(11):e27866. · 4.09 Impact Factor
• Article: Interferon-α suppressed granulocyte colony stimulating factor production is reversed by CL097, a TLR7/8 agonist.

  Tariq Tajuddin, Elizabeth J Ryan, Suzanne Norris, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: Neutropenia, a major side-effect of interferon-α (IFN-α) therapy can be effectively treated by the recombinant form of granulocyte colony stimulating factor (G-CSF), an important growth factor for neutrophils. We hypothesized that IFN-α might suppress G-CSF production by peripheral blood mononuclear cells (PBMCs), contributing to the development of neutropenia, and that a toll-like receptor (TLR) agonist might overcome this suppression. Fifty-five patients who were receiving IFN-α/ribavirin combination therapy for chronic hepatitis C virus (HCV) infection were recruited. Absolute neutrophil counts (ANC), monocyte counts and treatment outcome data were recorded. G-CSF levels in the supernatants of PBMCs isolated from the patients and healthy controls were assessed by enzyme-linked immunosorbent assay following 18 h of culture in the absence or presence of IFN- α or the TLR7/8 agonist, CL097. Therapeutic IFN-α caused a significant reduction in neutrophil counts in all patients, with 15 patients requiring therapeutic G-CSF. The reduction in ANC over the course of IFN-α treatment was paralleled by a decrease in the ability of PBMCs to produce G-CSF. In vitro G-CSF production by PBMCs was suppressed in the presence of IFN-α; however, co-incubation with a TLR7/8 agonist significantly enhanced G-CSF secretion by cells obtained both from HCV patients and healthy controls. Suppressed G-CSF production in the presence of IFN-α may contribute to IFN-α-induced neutropenia. However, a TLR7/8 agonist elicits G-CSF secretion even in the presence of IFN-α, suggesting a possible therapeutic role for TLR agonists in treatment of IFN-α-induced neutropenia.
  Journal of Gastroenterology and Hepatology 12/2010; 25(12):1883-90. · 2.87 Impact Factor
• Source

  Available from: Elizabeth Ryan

  Article: Variant in CD209 promoter is associated with severity of liver disease in chronic hepatitis C virus infection.

  Elizabeth J Ryan, Megan Dring, Cliona M Ryan, Carol McNulty, Nigel J Stevenson, Matthew W Lawless, John Crowe, Niamh Nolan, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: CD209, a c-type lectin expressed by dendritic cells (DCs), acts as a pathogen recognition receptor. A single nucleotide polymorphism (SNP) in the promoter region of CD209 (-336 A/G; rs4804803) affects transcription and is associated with the severity of tuberculosis and dengue fever. Because CD209 binds hepatitis C virus (HCV) glycoprotein-E2, we investigated this SNP in the context of chronic HCV infection. A total of 131 Irish women who had received HCV-contaminated anti-D-immunoglobulin and 79 healthy control subjects were genotyped. We found no association between rs4804803 and the risk of HCV chronicity. However, of those with chronic infection, possession of at least one g-allele was associated with more advanced liver disease, with significantly higher liver fibrosis scores and levels of alanine transaminase (ALT) observed. We conclude that rs4804803, an SNP in the CD209 promoter, contributes to severity of liver disease in chronic HCV infection.
  Human immunology 08/2010; 71(8):829-32. · 2.55 Impact Factor
• Article: Effect of chronic hepatitis C virus infection on bone disease in postmenopausal women.

  Kavinderjit S Nanda, Elizabeth J Ryan, Barbara F Murray, Jennifer J Brady, Malachi J McKenna, Niamh Nolan, Cliona O'Farrelly, John E Hegarty
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  ABSTRACT: Limited data are available on the contribution of chronic HCV infection to the development of bone disease in postmenopausal women. We studied whether women who acquired HCV infection through administration of HCV genotype 1b-contaminated anti-D immunoglobulin from a single source had decreased bone mineral density (BMD) or altered levels of bone turnover markers (BTMs), compared with women who spontaneously resolved infection or age-matched healthy controls. From a cohort of postmenopausal Irish women, we compared BMD, determined by dual-energy x-ray absorptiometry, and a panel of BTMs in 20 women chronically infected with HCV (PCR(+)), 21 women who had spontaneously resolved infection (PCR(-)), and 23 age-matched healthy controls. Levels of BTMs and BMD were similar in PCR(+) and PCR(-) women and healthy age-matched controls. However, there was an increased frequency of fractures in PCR(+) (n = 6) compared with PCR(-) women (n = 0, P = .007). PCR(+) women with fractures were postmenopausal for a longer time (median, 15.5, range, 5-20 years vs 4.5, range, 1-20 years in PCR(+) women without fractures; P = .033), had lower BMD at the hip (0.79, range, 0.77-0.9 g/cm(2) vs 0.96, range, 0.81-1.10 g/cm(2); P = .007), and had a lower body mass index (23.7, range 21.2-28.5 kg/m(2) vs 25.6, range 22.1-36.6 kg/m(2); P = .035). There was no difference in liver disease severity or BTMs in PCR(+) women with or without fractures. Chronic HCV infection did not lead to discernable metabolic bone disease in postmenopausal women, but it might be a risk factor for bone fractures, so preventive measures should be introduced. To view this article's video abstract, go to the AGA's YouTube Channel.
  Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 01/2009; 7(8):894-9. · 5.64 Impact Factor
• Source

  Available from: Barry Moran

  Article: Hepatitis C virus-specific Th17 cells are suppressed by virus-induced TGF-beta.

  Aileen G Rowan, Jean M Fletcher, Elizabeth J Ryan, Barry Moran, John E Hegarty, Cliona O'Farrelly, Kingston H G Mills
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  ABSTRACT: IL-17-secreting T (Th17) cells play a protective role in certain bacterial infections, but they are major mediators of inflammation and are pathogenic in organ-specific autoimmune diseases. However, human Th17 cells appear to be resistant to suppression by CD4(+)CD25(+)FoxP3(+) regulatory T cells, suggesting that they may be regulated by alternative mechanisms. Herein we show that IL-10 and TGF-beta suppressed IL-17 production by anti-CD3-stimulated PBMC from normal individuals. TGF-beta also suppressed IL-17 production by purified CD4(+) T cells, whereas the inhibitory effect of IL-10 on IL-17 production appears to be mediated predominantly by its effect on APC. An examination of patients infected with hepatitis C virus (HCV) demonstrated that Ag-specific Th17 cells are induced during infection and that these cells are regulated by IL-10 and TGF-beta. PBMC from HCV Ab-positive donors secreted IL-17, IFN-gamma, IL-10, and TGF-beta in response to stimulation with the HCV nonstructural protein 4 (NS4). Furthermore, NS4 induced innate TGF-beta and IL-10 expression by monocytes from normal donors and at higher levels from HCV-infected patients. Neutralization of TGF-beta, and to a lesser extent IL-10, significantly enhanced NS4-specific IL-17 and IFN-gamma production by T cells from HCV-infected donors. Our findings suggest that both HCV-specific Th1 and Th17 cells are suppressed by NS4-induced production of the innate anti-inflammatory cytokines IL-10 and TGF-beta. This may represent a novel immune subversion mechanism by the virus to evade host-protective immune responses. Our findings also suggest that TGF-beta and IL-10 play important roles in constraining the function of Th17 cells in general.
  The Journal of Immunology 11/2008; 181(7):4485-94. · 5.79 Impact Factor
• Article: Identification of Apolipoprotein AI as a serum biomarker of chronic kidney disease in liver transplant recipients, using proteomic techniques.

  Aisling O'Riordan, Olwyn Johnston, Tara McMorrow, Kieran Wynne, Patricia Maguire, John E Hegarty, Aidan McCormick, Alan J Watson, Gerard Cagney, William M Gallagher, Michael P Ryan
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  ABSTRACT: Chronic kidney disease (CKD) is a common complication post-orthotopic liver transplantation (OLT). Development of CKD is detected by monitoring serum urea and creatinine, however disease can occasionally be at an advanced stage before they become abnormal. Therefore, more accurate parameters are required. In order to identify novel biomarkers of CKD, serum was obtained from 47 OLT recipients with CKD (glomerular filtration rate <60 mL/min) and 23 with normal renal function (glomerular filtration rate >90 mL/min). Using the proteomic technique SELDI-TOF-MS, three protein biomarkers (55.6 kDa, 9.5 kDa and 11.4 kDa) were identified that, together, could stratify patients into cases or controls with a sensitivity and specificity of 93.6 and 91.3%, respectively. The area under the curve was 0.94. The primary splitter of the groups at 55.6 kDa was an alternative version of a molecule at 27.8 kDa, which was subsequently identified by 1-D SDS-PAGE and LC-ESI-MS/MS to be Apolipoprotein AI. Protein expression was shown to be reduced in CKD, by both ELISA (p = 0.057) and Western blot analysis (p = 0.003). Apolipoprotein AI is a novel, accurate marker of CKD post-OLT. It does require further validation in a large, more diverse patient population but could potentially improve detection of CKD.
  Proteomics. Clinical applications 09/2008; 2(9):1338-48. · 1.97 Impact Factor
• Article: Lower expression of Nrf2 mRNA in older donor livers: a possible contributor to increased ischemia-reperfusion injury?

  Muhammad B Zaman, Martin O Leonard, Elizabeth J Ryan, Niamh P Nolan, Emir Hoti, Donal Maguire, Hugh Mulcahy, Oscar Traynor, Cormac T Taylor, John E Hegarty, Justin G Geoghegan, Cliona O'Farrelly
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  ABSTRACT: The cellular mechanisms involved in mediating cytoprotection against ischemia-reperfusion (IR) injury are not well understood. In animal models, NF-E2-related factor-2 (Nrf2) protects against IR injury by transcriptional activation of phase II antioxidants. Here, we investigate how the expression of Nrf2 mRNA in human donor livers in the setting of liver transplantation (LT) correlates with the histological damage associated with IR injury and whether or not this influences the outcome of LT. Pairs of biopsies were acquired from 14 donor livers; the first biopsy of each pair was taken at the start of the retrieval operation, prior to the IR phase of LT and the second at the end of transplantation. RNA was extracted from snap frozen tissue and cDNA was prepared. Nrf2 mRNA expression was determined using real-time polymerase chain reaction (PCR). The modified Suzuki scoring system was used for histological grading of IR injury and relevant donor, recipient, and after LT clinical data were compiled. Nrf2 expression was observed in all biopsies, both before and after IR. Some donor organs had greater expression of Nrf2 mRNA before IR injury, and these organs had lower Suzuki scores and better liver functions (ALT) after LT. Donors of livers with greater Nrf2 levels were significantly younger (40.5 yrs, range 28-53 yrs) than those with low Nrf2 levels (55.5 yrs, range 48-61 yrs), P<0.05. Livers from older donors have lower levels of Nrf2 perhaps exposing these organs to more IR-related damage.
  Transplantation 12/2007; 84(10):1272-8. · 4.00 Impact Factor
• Article: Ischaemic complications of Glypressin in liver disease: a case series.

  Fergal Donnellan, Garret Cullen, John E Hegarty, P Aiden McCormick
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  ABSTRACT: To report three cases of extensive skin necrosis in cirrhotic patients treated with the vasoconstrictor agent terlipressin (Glypressin). We identified three patients who developed skin necrosis and determined any factors, which put them at an increased risk of doing so. Two patients were obese and developed extensive abdominal wall skin necrosis. The third patient had lower limb chronic venous insufficiency and developed extensive necrosis of both lower limbs. With increasing clinical use of terlipressin and an increasing incidence of obesity and non-alcoholic fatty liver disease-related cirrhosis, the incidence of these serious complications is likely to rise. Earlier recognition and treatment may lead to improved outcome.
  British Journal of Clinical Pharmacology 11/2007; 64(4):550-2. · 2.96 Impact Factor
• Article: CD1 expression and CD1-restricted T cell activity in normal and tumour-bearing human liver.

  Tony Kenna, Margaret O'Brien, Andrew E Hogan, Mark A Exley, Steven A Porcelli, John E Hegarty, Cliona O'Farrelly, Derek G Doherty
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  ABSTRACT: CD1d-restricted natural killer T (NKT) cells expressing invariant Valpha14Jalpha18 T cell receptor alpha-chains are abundant in murine liver and are implicated in the control of malignancy, infection and autoimmunity. Invariant NKT cells have potent anti-metastatic effects in mice and phase I clinical trials involving their homologues in humans are ongoing. However, invariant NKT cells are less abundant in human liver ( approximately 0.5% of hepatic T cells) than in murine liver (up to 50%) and it is not known if other hepatic T cells are CD1-restricted. We have examined expression of CD1a, CD1b, CD1c and CD1d mRNA and protein in human liver and evaluated the reactivity of mononuclear cells (MNC) from histologically normal and tumour-bearing human liver specimens against these CD1 isoforms. Messenger RNA for all CD1 isotypes was detectable in all liver samples. CD1c and CD1d were expressed at the protein level by hepatic MNC. CD1d, only, was detectable at the cell surface, but CD1c and CD1d were found at an intracellular location in significant numbers of liver MNC. CD1b was not expressed by MNC from healthy livers but was detectable within MNC in all tumour samples tested. Hepatic T cells exhibited reactivity against C1R cells expressing transfected CD1c and CD1d, but neither CD1a nor CD1b. These cells secreted interferon-gamma (IFN-gamma) but not interleukin-4 (IL-4) upon stimulation. In contrast, similar numbers of peripheral T cells released 13- and 16-fold less IFN-gamma in response to CD1c and CD1d, respectively. CD1c and CD1d expression and T cell reactivity were not altered in tumour-bearing liver specimens compared to histologically normal livers. These data suggest that, in addition to invariant CD1d-restricted NKT cells, autoreactive T cells that recognise CD1c and CD1d and release inflammatory cytokines are abundant in human liver.
  Cancer Immunology and Immunotherapy 05/2007; 56(4):563-72. · 3.70 Impact Factor
• Article: Chronic kidney disease post-liver transplantation.

  Aisling O'Riordan, Vincent Wong, P Aiden McCormick, John E Hegarty, Alan J Watson
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  ABSTRACT: Renal disease is a recognized complication of orthotopic liver transplantation (OLT). We aimed to determine the incidence of all stages of chronic kidney disease (CKD), as defined in the Kidney Disease Outcomes Quality Initiative Guidelines. We also wanted to determine the risk factors for development of CKD and its impact on patient survival. All patients who underwent cadaveric OLT, from January 1993 until July 2004, were analysed. The glomerular filtration rate (GFR) was determined using the equation developed by the Modification of Diet in Renal Disease Study. Thirty potential risk factors were examined by univariate and multivariate ordinal logistic regression analysis. Kaplan-Meier survival analysis, the log-rank test and Cox regression analysis were performed to evaluate the survival data. A total of 230 patients were included (107 males and 123 females) with a mean age of 47.7 years (4.5-70.35). Mean follow-up was 5.57 years (0.53-16.5). The following was the 10 year cumulative incidence for each stage of CKD: 0/1, 9.61%; 2, 53.71%; 3, 56.77%; 4, 6.11%; 5, 2.62%. Female gender, age, pre-OLT proteinuria, lower GFR from 1 year and higher creatinine from 6 months were associated with progression of CKD. The use of tacrolimus had a favourable impact. A GFR <30 ml/min, the need for re-transplantation and fulminant hepatic failure were all associated with reduced patient survival. Moderate CKD was very prevalent. We identified the risk factors for progression of CKD and also that severe CKD was associated with reduced patient survival.
  Nephrology Dialysis Transplantation 09/2006; 21(9):2630-6. · 3.40 Impact Factor
• Article: Changes in hepatic immunoregulatory cytokines in patients with metastatic colorectal carcinoma: implications for hepatic anti-tumour immunity.

  Anna M Kelly, Lucy Golden-Mason, Oscar Traynor, Justin Geoghegan, Gerry McEntee, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: The hepatic immunological environment, dominated by NK and NKR(+) T cells, seems specialised to respond to malignant challenge. Ineffective immune responses to malignancy are likely determined by factors including alterations in the local cytokine profile. This study examines the cytokine milieu of normal and tumour-bearing liver, quantifying pro-/anti-inflammatory cytokines using modified ELISAs and real-time quantitative PCR. Cytokine protein was localised using immunohistochemistry. We demonstrate an active cytokine environment in normal liver, with high levels of inflammatory and regulatory cytokines. Inflammatory IFN-gamma was increased in tumour-bearing liver (p<0.0001). However, a much greater increase in anti-inflammatory IL-10, produced by non-parenchymal cells (p<0.0005), resulted in a reduced IFN-gamma:IL-10 ratio in tumour-bearing liver (p<0.02). In contrast, immunosuppressive TGF-beta and IL-13 were significantly downregulated (p<0.02). Furthermore, IL-2 was not increased and IL-15 was reduced (p<0.02). The IFN-gamma inducing cytokine, IL-18 was increased in tumour-bearing liver (p<0.02), while pro-inflammatory TNF-alpha was suppressed (p<0.05). These results suggest that, whilst there is a significant inflammatory immune response in tumour-bearing liver, evidenced by increased levels of IFN-gamma, disproportionate increase in IL-10 may be a key factor in facilitating tumour progression. Therapies aimed at antagonising IL-10-mediated immunosuppression may prove a useful strategy in the future treatment of metastatic disease.
  Cytokine 08/2006; 35(3-4):171-9. · 3.02 Impact Factor
• Article: The gallbladder and biliary tract in cystic fibrosis.

  Michael P Curry, John E Hegarty
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  ABSTRACT: Chronic liver disease is a major complication of cystic fibrosis. Its incidence and severity are variable, and diagnosis relies on a combination of clinical evaluation, biochemical testing, and radiologic assessment. Identifying patients who have early disease is critical, and the administration of ursodeoxycholic acid appears to be beneficial. The pathogenesis is incompletely understood, and factors that contribute to the variability in incidence and severity are unknown. Fortunately, only a small proportion of individuals progress to advanced liver disease; however, in this population, there is significant morbidity and impairment in quality of life. Liver transplantation can be performed successfully in patients with end-stage liver disease. Future treatments involve targeted gene therapy and activation of mutant forms of the cystic fibrosis transmembrane conductance regulator.
  Current Gastroenterology Reports 06/2005; 7(2):147-53.
• Source

  Available from: Cliona O'Farrelly

  Article: Distinct subpopulations of gamma delta T cells are present in normal and tumor-bearing human liver.

  Tony Kenna, Lucy Golden-Mason, Suzanne Norris, John E Hegarty, Cliona O'Farrelly, Derek G Doherty
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  ABSTRACT: Gamma delta T cells are thought to mediate immune responses at epithelial surfaces. We have quantified and characterized hepatic and peripheral blood gamma delta T cells from 11 normal and 13 unresolved tumor-bearing human liver specimens. gamma delta T cells are enriched in normal liver (6.6% of T cells) relative to matched blood (0.9%; P = 0.008). The majority express CD4(-)CD8(-) phenotypes and many express CD56 and/or CD161. In vitro, hepatic gamma delta T cells can be induced to kill tumor cell lines and release interferon-gamma, tumor necrosis factor-alpha, interleukin-2 and interleukin-4. Analysis of V gamma and V delta chain usage indicated that V delta 3(+) cells are expanded in normal livers (21.2% of gamma delta T cells) compared to blood (0.5%; P = 0.001). Tumor-bearing livers had significant expansions and depletions of gamma delta T cell subsets but normal cytolytic activity. This study identifies novel populations of liver T cells that may play a role in immunity against tumors.
  Clinical Immunology 11/2004; 113(1):56-63. · 4.05 Impact Factor
• Article: Nitric oxide in early ischaemia reperfusion injury during human orthotopic liver transplantation.

  Raghu Varadarajan, Lucy Golden-Mason, Leonie Young, Paul McLoughlin, Niamh Nolan, Gerry McEntee, Oscar Traynor, Justin Geoghegan, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: Altered nitric oxide (NO) metabolism has been shown to contribute to ischemia-reperfusion (IR) injury in animal models. However, similar studies have not been performed in human liver transplantation (LT). In this study, we examined nitrate, nitrite, and nitrosothiols (NOx), NO synthases (endothelial [constitutive] nitric oxide synthase [eNOS] and inducible nitric oxide synthase [iNOS]), and nitrotyrosine in early IR injury after human LT. Paired biopsies were obtained from nine donor livers before cold ischemia (retrieval biopsy) and after reimplantation (reperfusion biopsy). Sections were graded for reperfusion injury using the Suzuki score. NO was detected by chemiluminescence after reduction of NOx. Expression of eNOS and iNOS was by Western blot and reverse transcriptase polymerase chain reaction and peroxynitrite by immunodetection of 3-nitrotyrosine. Reperfusion biopsies showed histologic evidence of injury (median Suzuki score: retrieval 2, reperfusion 6, P=0.008) and neutrophil infiltration. NOx was reduced after reperfusion from 5.41 microM/100 mg (median, range 2.17-13.39 microM) to 3.51 microM (1.45-5.66 microM, P=0.05). eNOS protein was reduced after reperfusion from 0.6 units (median, range 0.45-1 unit) in retrieval biopsies to 0.39 units in reperfusion biopsies (range 0.2-0.79 units, P=0.007). There was no change in eNOS or iNOS mRNA expression or iNOS protein. Western blotting showed increased nitrotyrosine formation after reperfusion, median 0.42 (range 0.16-0.87) units in retrieval biopsies and 0.68 (0.29-1.06) units in reperfusion samples (P=0.007) and localized to periportal regions. iNOS protein may not contribute to early reperfusion injury during human LT. However, reduced NO bioavailability caused by reduced eNOS may contribute significantly to damage at this time point.
  Transplantation 08/2004; 78(2):250-6. · 4.00 Impact Factor
• Article: Adult human liver contains CD8pos T cells with naive phenotype, but is not a site for conventional alpha beta T cell development.

  Lucy Golden-Mason, Daniel C Douek, Richard A Koup, Jacinta Kelly, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: Normal adult human liver (AHL) contains populations of unconventional lymphocytes that have been shown in the mouse to mature locally. The presence of lymphoid progenitors together with IL-7, recombinase-activating gene, and pre-TCR-alpha expression in AHL suggests similar local T cell development activity in humans. Flow cytometry was used to characterize potentially naive hepatic alphabeta-T cells. We looked for evidence of TCR-alphabeta cell development in AHL by quantifying delta deletion TCR excision circles (TRECs) in CD3(pos) populations isolated from the liver and matched blood of eight individuals. Phenotypic analysis of hepatic T cells suggests the presence of Ag-inexperienced populations. TRECs were detected in all blood samples (mean, 164.10 TRECs/ micro g DNA), whereas only two hepatic samples were positive at low levels (59.40 and 1.92). The relatively high level of CD8(pos) T cells in these livers with a naive phenotype suggests that in addition to its role as a graveyard for Ag-specific activated CD8(pos) T cells, naive CD8(pos) T cells may enter the liver without prior activation. The almost complete absence of TRECs suggests that normal AHL is not a site for the development of conventional alphabeta T cells.
  The Journal of Immunology 06/2004; 172(10):5980-5. · 5.79 Impact Factor
• Source

  Available from: Cliona O'Farrelly

  Article: Interleukin 12 (IL-12) is increased in tumour bearing human liver and expands CD8(+) and CD56(+) T cells in vitro but not in vivo.

  Anna M Kelly, Lucy Golden-Mason, Gerry McEntee, Oscar Traynor, Derek G Doherty, John E Hegarty, Cliona O'Farrelly
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  ABSTRACT: Human liver is enriched with CD8(+)T- and CD3(+)CD56(+) natural T (NT)-lymphocytes, important anti-tumour effectors, similar to murine NKTs. IL-12 promotes anti-tumour functions of NKTs. We quantified IL-12 and CD56(+)/CD8(+)T lymphocytes in normal and tumour bearing liver. We also examined the effect of IL-12 on the expansion/activation of peripheral blood cells in vitro. IL-12 was detected in normal (n=13, median 2032 pg/100 mg protein) and increased in tumour bearing liver (n=9, 3678 pg, p< 0.01). Infiltrating monocytes appear to be the principal producers. Culture with IL-12 selectively expanded CD8(+)T and CD3(+)CD56(+)NT cells and polarised their cytokine responses to Th1-type. However, there was no in vivo expansion of these cells in tumour bearing liver. Changes observed in culture required addition of IL-2. We therefore quantified IL-2 in hepatic tissue. IL-2 was detected in normal liver (median 4700 pg/100 mg protein). Surprisingly, there was no increase in tumour-infiltrated liver (4910 pg). The presence of IL-12 may create an environment in healthy liver that promotes the accumulation of CD8(+)T and CD56(+)NT cells. Therefore, the development of metastases in the presence of high levels of IL-12 may be due to an insufficient IL-12 response. Alternatively, lack of IL-2 rather than a defect in IL-12, may be responsible for insufficient expansion/activation of tumour specific cytotoxic T lymphocytes.
  Cytokine 03/2004; 25(6):273-82. · 3.02 Impact Factor
• Article: NKT cells from normal and tumor-bearing human livers are phenotypically and functionally distinct from murine NKT cells.

  Tony Kenna, Lucy Golden-Mason, Steven A Porcelli, Yasuhiko Koezuka, John E Hegarty, Cliona O'Farrelly, Derek G Doherty
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  ABSTRACT: A major group of murine NK T (NKT) cells express an invariant Valpha14Jalpha18 TCR alpha-chain specific for glycolipid Ags presented by CD1d. Murine Valpha14Jalpha18(+) account for 30-50% of hepatic T cells and have potent antitumor activities. We have enumerated and characterized their human counterparts, Valpha24Vbeta11(+) NKT cells, freshly isolated from histologically normal and tumor-bearing livers. In contrast to mice, human NKT cells are found in small numbers in healthy liver (0.5% of CD3(+) cells) and blood (0.02%). In contrast to those in blood, most hepatic Valpha24(+) NKT cells express the Vbeta11 chain. They include CD4(+), CD8(+), and CD4(-)CD8(-) cells, and many express the NK cell markers CD56, CD161, and/or CD69. Importantly, human hepatic Valpha24(+) T cells are potent producers of IFN-gamma and TNF-alpha, but not IL-2 or IL-4, when stimulated pharmacologically or with the NKT cell ligand, alpha-galactosylceramide. Valpha24(+)Vbeta11(+) cell numbers are reduced in tumor-bearing compared with healthy liver (0.1 vs 0.5%; p < 0.04). However, hepatic cells from cancer patients and healthy donors release similar amounts of IFN-gamma in response to alpha-galactosylceramide. These data indicate that hepatic NKT cell repertoires are phenotypically and functionally distinct in humans and mice. Depletions of hepatic NKT cell subpopulations may underlie the susceptibility to metastatic liver disease.
  The Journal of Immunology 09/2003; 171(4):1775-9. · 5.79 Impact Factor