Regulatory CD4+CD25+ T cells (Tregs) are defective numerically and functionally in autoimmune hepatitis (AIH). We have investigated and compared the mechanism of action of Tregs in healthy subjects and in AIH patients using Transwell experiments, where Tregs are cultured either in direct contact with or separated from their targets by a semipermeable membrane. We also studied Treg FOXP3 expression and effect on apoptosis. Direct contact is necessary for Tregs to suppress proliferation and IFN-γ production by CD4+CD25− and CD8+ T cells in patients and controls. Moreover, in both, direct contact of Tregs with their targets leads to increased secretion of regulatory cytokines IL-4, IL-10, and TGF-β, suggesting a mechanism of linked immunosuppression. Tregs/CD4+CD25− T cell cocultures lead to similar changes in IFN-γ and IL-10 secretion in patients and controls, whereas increased TGF-β secretion is significantly lower in patients. In contrast, in patients, Tregs/CD8+ T cell cocultures lead to a higher increase of IL-4 secretion. In AIH, Treg FOXP3 expression is lower than in normal subjects. Both in patients and controls, FOXP3 expression is present also in CD4+CD25− T cells, although at a low level and not associated to suppressive function. Both in patients and controls, addition of Tregs does not influence target cell apoptosis, but in AIH, spontaneous apoptosis of CD4+CD25− T cells is reduced. In conclusion, Tregs act through a direct contact with their targets by modifying the cytokine profile and not inducing apoptosis. Deficient CD4+CD25− T cell spontaneous apoptosis may contribute to the development of autoimmunity.

Acetaminophen‐induced acute liver failure (AALF) is associated with innate immunity activation, which contributes to the severity of hepatic injury and clinical outcome. A marked increase in hepatic macrophages (h‐mϕ) is observed in experimental models of AALF, but controversy exists regarding their role, implicating h‐mϕ in both aggravation and resolution of liver injury. The role of h‐mϕ in human AALF is virtually unexplored. We sought to investigate the role of chemokine (C‐C motif) ligand 2 (CCL2) in the recruitment of circulating monocytes to the inflamed liver and to determine how the h‐mϕ infiltrate and liver microenvironment may contribute to tissue repair versus inflammation in AALF. We evaluated circulating monocytes, their chemokine (C‐C motif) receptor 2 (CCR2) expression, and serum CCL2 levels in patients with AALF. Cell subsets and numbers of circulation‐derived (MAC387+) or resident proliferating (CD68/Ki67+) h‐mϕ in hepatic immune infiltrates were determined by immunohistochemistry. Inflammatory cytokine levels were determined in whole and laser microdissected liver tissue by proteome array. In AALF, circulating monocytes were depleted, with the lowest levels observed in patients with adverse outcomes. CCL2 levels were high in AALF serum and hepatic tissue, and circulating monocyte subsets expressed CCR2, suggesting CCL2‐dependent hepatic monocyte recruitment. Significant numbers of both MAC387+ and CD68+ h‐mϕ were found in AALF compared with control liver tissue with a high proportion expressing the proliferation marker Ki67. Levels of CCL2, CCL3, interleukin (IL)‐6, IL‐10, and transforming growth factor‐β1 were significantly elevated in AALF liver tissue relative to chronic liver disease controls. Conclusion: In AALF, the h‐mϕ population is expanded in areas of necrosis, both through proliferation of resident cells and CCL2‐dependent recruitment of circulating monocytes. The presence of h‐mϕ within an anti‐inflammatory/regenerative microenvironment indicates that they are implicated in resolution of inflammation/tissue repair processes during AALF. (HEPATOLOGY 2012)

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Acute liver failure (ALF) shares striking similarities with septic shock where a decrease in HLA-DR expression on monocytes is associated with disease severity and predicts outcome. We investigated monocyte HLA-DR expression in ALF in relation to inflammatory mediator levels and clinical outcome. Monocyte HLA-DR expression was determined in 50 patients with acetaminophen-induced ALF (AALF) and 20 non-acetaminophen-induced ALF (NAALF). AALF patients were divided into dead/transplanted (AALF-NS, n ‫؍‬ 26) and spontaneous survivors (AALF-S, n ‫؍‬ 24). Fifty patients with chronic liver disease (CLD) and 50 healthy volunteers served as controls. Monocyte HLA-DR expression was determined by double-color flow-cytometry with monoclonal antibodies detecting HLA-DR and monocyte specific CD14. Serum levels of interleukin (IL) -4, -6, -10, tumor necrosis factor (TNF)-␣ and interferon (IFN)-␥ were concomitantly measured by ELISA. Compared to healthy volunteers (75%) and CLD (67%) monocyte HLA-DR percentage expression was lower in AALF (15%, P < .001) and NAALF (22 %, P < .001). Compared to AALF-S, AALF-NS had lower monocyte HLA-DR % (11% vs. 36%, P < .001) and higher levels of IL-4, IL-6, IL-10 and TNF-␣ (P < .001). HLA-DR percentage negatively correlated with INR, blood lactate, pH and levels of encephalopathy (r ‫؍‬ ؊0.8 to ؊0.5, P < .01), IL-10 (r ‫؍‬ ؊0.8, P < .0001), TNF-␣ (r ‫؍‬ ؊0.4, P ‫؍‬ .02). HLA-DR percentage level <15% has a 96% sensitivity and 100% specificity and 98% accuracy in predicting poor prognosis. In conclusion, the strong relationship of monocyte HLA-DR expression with indices of disease severity, mediators of inflammation and outcome indicates a key role for this molecule as a biomarker of disease severity and prognosis. (HEPATOLOGY 2006;44:34-43.)

Immunotolerance is maintained by regulatory T cells (Tregs), including CD4 1 CD25 hi , CD8 1 CD28 2 , cd, and CD3 1 CD56 1 [natural killer T (NKT)] cells. CD4 1 CD25 hi cells are impaired in children with autoimmune hepatitis (AIH). Little is known about Tregs in adults with AIH. The aim of this study was to investigate the frequency and function of Treg subsets in adult patients with AIH during periods of active disease and remission. Forty-seven AIH patients (16 with active disease and 31 in remission) and 28 healthy controls were studied. Flow cytometry was used to evaluate surface markers and functionrelated intracellular molecules in cd, CD8 1 CD28 2 , NKT, and CD4 1 CD25 hi cells. CD4 1 CD25 hi T cell function was determined by the ability to suppress proliferation and interferon gamma (IFN-c) production by CD4 1 CD25 2 target cells. Liver forkhead box P3-positive (FOXP3 1 ) cells were sought by immunohistochemistry. In AIH patients, particularly during active disease, CD4 1 CD25 hi T cells were fewer, expressed lower levels of FOXP3, and were less effective at inhibiting target cell proliferation versus healthy controls. Moreover, although the numbers of CD8 1 CD28 2 T cells were similar in AIH patients and healthy controls, NKT cells were numerically reduced, especially during active disease, and produced lower quantities of the immunoregulatory cytokine interleukin-4 versus controls. In contrast, cd T cells in AIH patients were more numerous versus healthy controls and had an inverted Vd1/Vd2 ratio and higher IFN-c and granzyme B production; the latter was correlated to biochemical indices of liver damage. There were few FOXP3 1 cells within the portal tract inflammatory infiltrate. Conclusion: Our data show that the defect in immunoregulation in adult AIH is complex, and cd T cells are likely to be effectors of liver damage. (HEPATOLOGY 2010;52:999-1007) A utoimmune hepatitis (AIH) is an immunemediated liver disease characterized by high levels of aminotransferases and gamma-globulins, circulating autoantibodies, and histological evidence of interface hepatitis. 1-3 Two AIH subsets are conventionally recognized according to their autoantibody profile 4 : type 1 AIH (AIH-1), which is characterized by positivity for anti-nuclear antibody (ANA) and/or

On the basis of historical studies, hepatitis delta virus (HDV) infection is considered uncommon in the United Kingdom (UK) and mainly confined to intravenous drug users. In order to assess the current prevalence of HDV co-infection in patients with chronic hepatitis B (HBV), a retrospective analysis was performed of 962 consecutive HBV-infected adult patients referred to King's College Hospital between January 1st 2000 and March 31st 2006. The 82 subjects positive for HDV antibody (8.5%) had a similar age to those without HDV (median 36 years, interquartile range 30-47, vs. 35 years, 29-43). Excluding non-UK residents, the prevalence of HDV Antibody was 7.1%. Most HDV-infected subjects were born in regions where HDV is endemic, for example, Southern or Eastern Europe (28.1%), Africa (26.8%) or Middle-East (7.3%). Forty one (50%) were considered to have acquired HDV infection via intra-familial transmission but intravenous drug use was still a common route of transmission (24.4%). Comparing HBV/HDV co-infected to HBV mono-infected patients, a higher proportion were hepatitis C antibody positive (25.6% versus 3.8%; odds ratio 8.89, 95% confidence interval 4.4-17.9; P < 0.00001) and more had cirrhosis (26.8% vs. 12.9%; odds ratio 2.64, 95% confidence interval 1.55-4.49; P < 0.0001) but, despite this, the risk of hepatocellular carcinoma was similar (odds ratio 1.34, 95% confidence interval 0.62-2.91). Although HDV infection is reportedly declining in some endemic regions, our data demonstrate a high prevalence in South London. HDV co-infection is associated with increased morbidity and patients with HBV should be tested for HDV infection.

Autoimmune hepatitis type 2 (AIH-2) is a severe organ-specific disorder characterized by liver kidney microsomal antibody type 1 targeting cytochrome P4502D6 (CYP2D6). Growing evidence implicates the involvement of CD8 T cell immune responses in its pathogenesis. We investigated CYP2D6-specific CD8 T cell human leukocyte antigen (HLA)-A2 restricted responses in AIH-2 (20 patients, 11 HLA-A2؉). Binding affinity of CYP2D6 peptides to HLA-A2 was predicted by the algorithm SYFPEITHI and assessed in vivo by T2 cell assays. CD8 T cell interferon (IFN)-␥ production was assessed via intracellular cytokine staining, cytotoxicity via chromium release assay, and frequency of circulating and intrahepatic CYP2D6-specific CD8 T cells via tetramer staining. CYP2D6-specific CD8 T cell reactivity was tested at diagnosis and during treatment and correlated with indices of disease activity. Seven CYP2D6 peptides with high HLA-A2 binding affinity colocalizing with known B cell or CD4 T cell epitopes were selected. Five sequences inducing high levels of IFN-␥ were used for HLA-A2 tetramer construction. Frequency, IFN-␥ production, and cytotoxicity of CYP2D6-specific CD8 T cells were higher at diagnosis than during treatment. Intensity of CYP2D6-specific CD8 T cell responses correlated with disease activity. Immune responses to CYP2D6 245-254 were the strongest both at diagnosis and during treatment. Conclusion: HLA-A2-restricted, CYP2D6-specific CD8 T cell immune responses vary according to disease stage and correlate with hepatocyte damage. CD8 T cell targets on CYP2D6 -in particular CYP2D6 245-254 -may be the focus of novel immune intervention in AIH-2. (HEPATOLOGY 2007;46:472-484.)

The present study combines use of markers for different processes in the development of steatohepatitis. Serum biomarkers, especially CK18 M30, are useful in stratifying disease severity in paediatric NAFLD.