Impact of aging on the development of hepatocellular carcinoma in patients with hepatitis C virus infection in Japan.

BACKGROUND: It is difficult to study the long-term outcome of hepatitis C virus (HCV) infection because chronic infection is often asymptomatic and duration of the disease is prolonged. The clinical outcome of HCV infection remains unclear in patients of advanced age. METHODS: Among 575 patients consecutively diagnosed with hepatocellular carcinoma (HCC) from 1988 to 1999 at Hiroshima University, we examined 430 with HCV. We studied the differences between males and females in the following characteristics: age at first diagnosis of HCC, Child grade, various tumour factors, history of blood transfusion, duration to development of HCC, and history of alcohol intake. RESULTS: The incidence of HCC patients with HCV increased in elderly persons, including female patients. Background liver function was significantly better for female patients (P < 0.001). In both genders, the duration between blood transfusion and diagnosis of HCC was significantly shorter when the patients received blood transfusion at an older age (P < 0.001). In habitual drinkers, the average age at first diagnosis of HCC was significantly younger (P < 0.001), and duration to development of HCC significantly shorter (P < 0.05). The percentage of atomic bomb survivors among HCV-positive HCC patients was significantly higher than that among HCV-negative HCC patients (P < 0.05). CONCLUSIONS: Patients with HCV might exhibit slow disease progression and develop HCC finally with aging regardless of gender. Patients of advanced age with HCV, even female patients, should therefore be closely followed.

Immune-mediated cholangiohepatitis in neonatally thymectomized mice: the role of T cells and analysis of T-cell receptor Vbeta usage.

We have previously reported the induction of immune-mediated cholangiohepatitis following injection of a hybrid recombinant proteins containing the E2 of the pyruvate dehydrogenase (PDC-E2) and the branched-chain keto-acid dehydrogenase (BCOADC-E2) to neonatally thymectomized (Tx) A/J mice. Further, we demonstrated that intrahepatic infiltrating mononuclear cells could transfer pathology to other Tx mice. To further our observations, we examined intrahepatic infiltrating mononuclear cells by flow cytometry and used cell transfer experiments to identify the phenotype involved. Interestingly, following immunization of neonatally Tx A/J mice and immunization with the bihybrid molecule, the number of CD3+infiltrating mononuclear cells were significantly higher (77.8%) compared with the control group. There was a small although not significant increase among intrahepatic infiltrating mononuclear cells and splenic cells of Vbeta 5.1,5.2+, Vbeta7+and Vbeta17+. In addition, Vbeta14+cells accounted for 20.4% of the infiltrating T-cells (P<0.01 vs. the control group). In further experiments, CD3+, CD4+or CD8+cells were isolated and removed from intrahepatic infiltrating mononuclear cells and subpopulations of mononuclear cells transferred to Tx mice. Both CD3+CD4+cells and CD3+CD8+cells are required for development of the lesion, and the damage is mediated by CD3+Vbeta14+cells.

mel-18 negatively regulates cell cycle progression upon B cell antigen receptor stimulation through a cascade leading to c-myc/cdc25.

mel-18 is a mammalian Polycomb group gene encoding a transcriptional repressor with tumor suppressive activity. Overexpression of mel-18 in mice results in cell cycle arrest of B cells upon B cell receptor stimulation with downregulation of c-myc. This phenotype is rescued in mel-18/c-myc double-transgenic mice, suggesting that c-myc locates downstream of mel-18. In mel-18 transgenic mice, the downregulation of cyclins D2 and E; CDK4, -6, and -7; and CDC25A causes the impairment in the activities of cyclin-dependent kinases, resulting in hypophosphorylation of the retinoblastoma protein. In contrast, the upregulation of c-Myc, CDC25, and CDC2/CDK2 kinase activities results in the augmentation of B cell proliferation in mel-18-deficient mice. We therefore propose that mel-18 negatively regulates the cell cycle through a c-myc/cdc25 cascade.

Mammalian Polycomb group genes are categorized as a new type of early response gene induced by B-cell receptor cross-linking.

Polycomb group (PcG) genes were initially described in Drosophila melanogaster as regulators of the homeobox gene. Four mammalian homologues, mel-18, bmi-1, M33 and rae-28, are analyzed in this study. They not only regulate mammalian homeotic genes by analogy with their Drosophila counterparts, but also have some influence on the growth and differentiation of B lymphocytes. Here we report that these four mammalian PcG genes are rapidly induced after antigen-receptor cross-linking in B cells. Thus we would like to propose that mammalian PcG genes can be categorized as a new type of immediate early gene.

Experimental hepatitis in neonatally thymectomized mice: transfer of disease and the role of T cells.

Using neonatally A/J thymectomized mice, we have produced chronic hepatitis by administration of sublethal doses of Propionibacterium acnes and lipopolysaccharide (LPS). Our goal in this unique model was to evaluate the effector cell population required to generate chronic hepatitis by transferring spleen cells or splenic subpopulations derived from donor thymectomized mice with chronic hepatitis into congenic recipient nonimmunized thymectomized or sham-thymectomized animals. Several key observations were made regarding the ability to induce and to transfer disease. First, an inflammatory liver injury in neonatally thymectomized (NTx) mice was readily generated using sublethal doses of P. acnes and LPS. Second, the lesions were persistent and associated with the production of autoantibodies to liver-specific lipoprotein and anti-nuclear antibodies. Third, these features were not found in comparably injected nonthymectomized control A/J mice. Fourth, the same liver injury was transferred to neonatally thymectomized but otherwise naive mice by the transfer of donor spleen cells from affected mice previously induced to develop experimental hepatitis. Fifth, the transfer of this liver injury could not be achieved using T-cell-depleted spleen cells. Deletion of CD4+ T cells or CD8+ T cells by sensitized spleen cells resulted in suppression of the transferred liver injury. In contrast, transfer of nylon wool adherent splenic T cells induced severe hepatitis. These data suggest that the chronic liver injury induced in NTx mice by administration of P. acnes and LPS involves a breakdown in tolerance accompanied by the appearance of autoantibodies and that nylon wool adherent CD4+ and CD8+ T cells play important roles in the modulation of liver injury.

Induction of autoimmune hepatitis and autoantibodies to liver antigens by neonatal thymectomy in mice.

We examined development of autoimmune hepatitis in neonatally thymectomized C3H/HeN mice and tried to characterize the nature of liver antigens recognized by the autoantibodies at the molecular level. Autoantibodies to crude liver proteins detected by ELISA were found in 12(67%) of 18 mice thymectomized 2 days after birth. However, autoantibodies were not detected in mice thymectomized 7 days after birth. The autoantibodies mainly consisted of IgG and reached the maximum level 8 weeks after birth. Hepatic inflammation, mononuclear cell infiltration in the portal area, was seen in 5 (28%) of 18 mice thymectomized 2 days after birth, but not in mice thymectomized 7 days after birth. Most infiltrating cells were Thy-1+ lymphocytes. The serum autoantibody level to crude liver proteins in mice with hepatitis was much higher than that in mice without hepatitis. We fractionated crude liver proteins by a Sepharose 6B column and examined the reactivity against the autoantibodies. The autoantibodies of three of five mice with hepatitis reacted with th approximately 150kD liver proteins other than liver-specific protein (LSP). By Western immunoblotting of SCS-PAGE using LSP and fractionated liver proteins, we found that the molecular weights of the target antigens were 52kD in LSP and 150kD (strong band), 138, 128, 120 and 110kD (weak band) in fractionated liver proteins other than LSP. This 150-kD target molecule in crude liver proteins was found only in liver. These results indicate that hepatitis and autoantibodies to liver proteins are induced spontaneously by neonatal thymectomy in mice, and the candidates of autoantigen in this hepatitis model are 52-kD protein in LSP and 150-kD liver proteins different from LSP. Still more, we regard the 150-kD molecule as a new autoantigen related to hepatitis.