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The outcome of hepatitis C virus (HCV) infection has been associated with antiviral CD4 T cell response, human leukocyte antigens (HLA) class II genotypes, and ethnicity. However, HLA class II molecules restrict the nature of CD4 T cell response, and HLA distributions differ between ethnic groups. In this study, we asked whether HLA class II genotypes associated with HCV clearance are shared between Caucasian and African Americans and whether they contribute to enhanced antiviral CD4 T cell response. In a cohort of 93 HCV-seropositive subjects from Northeast America with defined ethnicity, virological outcome, and HCV-specific CD4 T cell proliferation, we confirm the previously reported associations between HCV clearance and two HLA types (DQB1*03, DRB1*11) while identifying a new association with DRB3*02. Strikingly, these associations were identified only among Caucasian [DQB1*03: odds ratio (OR), 10.4; P = 0.031, DRB1*11: OR, 7.0, P = 0.019; DRB3*02: OR, 8.3, P = 0.005; DQB1*03–DRB3*02: OR, 13.5, P = 0.001) but not among African American patients. Furthermore, although HLA DQB1*03, DRB1*11, and DRB3*02 genotypes were associated with increased HCV-specific CD4 T cell response in univariate analyses, these associations were lost when controlling for virological outcomes. Conclusion: We conclude that the immunogenetic basis for HCV clearance differs between ethnic groups and that the association between HLA class II and HCV clearance is not directly explained by antiviral CD4 T cell response. (HEPATOLOGY 2008.)

TNF-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in various transformed cell lines but not in almost-normal tissues. It is regulated by 2 death receptors, TRAIL receptor 1 (TRAIL-R1) and TRAIL-R2, and 2 decoy receptors, TRAIL-R3 and TRAIL-R4. We investigated the expression of TRAIL-R– and TRAIL-induced apoptosis in human hepatocellular carcinomas (HCCs). TRAIL-R1, -R2, and -R4 were expressed in 6 HCC cell lines examined, but TRAIL-R3 was expressed in only 2 of the 6 cell lines. In addition, immunohistochemical results revealed a high and prevalent expression of TRAIL-R1 and -R2 in human HCC tissues. Despite the expression of TRAIL-R1 and -R2, all 6 HCC cell lines showed resistance to TRAIL-induced apoptosis with no relation to nuclear factor κ B (NF-κB) levels induced by TRAIL. TRAIL-induced death signal was inhibited with both decreased caspase-8 and caspase-3 activity. However, TRAIL induced significant apoptosis in the presence of a subtoxic level of actinomycin D, indicating that the TRAIL-induced apoptotic pathway is in place in these cell lines. In addition, we found that treatment with conventional chemotherapeutic agents, doxorubicin and camptothecin, dramatically augmented TRAIL-induced cytotoxicity in most of the HCC cell lines. Actinomycin D and camptothecin almost completely suppressed NF-κB induction by TRAIL, whereas doxorubicin had little effect. These results indicate that TRAIL, in combination with chemotherapeutic agents, may have therapeutic potential in the treatment of human HCC. (Hepatology 2000;32:482-490.)

Survivin is a recently described inhibitor of apoptosis. Because suppression of apoptosis is important for carcinogenesis and tumor growth, we investigated the expression and function of survivin in human hepatocellular carcinomas (HCCs). We have shown that 4 HCC cell lines and 7 out of 8 human HCC tissues expressed survivin messenger RNA (mRNA), whereas expression of survivin mRNA was not detected in normal liver and nontumor areas of these tissues using the reverse transcription polymerase chain reaction. Survivin was detected primarily in the nucleus by immunofluorescence staining of HCC cells. In addition, 14 of 20 (70%) HCC tissues showed positive nuclear staining for survivin, whereas nontumor tissues showed little detectable staining by immunohistochemistry. Survivin expression strongly correlated with the proliferation index but not significantly with the apoptosis index in HCC tissues. Therefore, we performed cell cycle analysis after survivin transfection and showed that overexpression of survivin resulted in a decrease in the G(0)/G(1) phase and an increase in the S phase in all 4 HCC cell lines. Furthermore, we have found that survivin interacted with cyclin-dependent kinase 4 (Cdk4) and overexpression of survivin released p21(WAF1/Cip1) (p21) from Cdk4. From these results, we conclude that survivin promotes cell proliferation by interacting with Cdk4 and releasing p21 from Cdk4. This may play an important role in carcinogenesis and progression of human HCCs.