No abstract

Lamivudine (LAM) is a nucleoside analogue widely used for the treatment of chronic hepatitis B virus (HBV) infection. Emergence of resistant strains with amino acid substitutions in the tyrosine-methionine-aspartate-aspartate (YMDD) motif of reverse transcriptase is a serious problem in patients on LAM therapy. The amount of covalently closed circular DNA in the serum is reported to be higher in patients who develop YMDD mutants than in those without mutants. However, there is no useful serum marker that can predict early emergence of mutants during LAM therapy. Analysis of patients who were treated with entecavir (n ‫؍‬ 7) and LAM (n ‫؍‬ 36) showed some patients had high serum levels of HBV RNA. Median serum levels of HBV RNA were significantly higher in patients in whom the YMDD mutant had emerged within 1 year (n ‫؍‬ 6, 1.688 log copies/ml) than in those in whom the YMDD mutant emerged more than 1 year after treatment (n ‫؍‬ 12, 0.456 log copies/ml, P ‫؍‬ 0.0125) or in whom the YMDD mutant never emerged (n ‫؍‬ 18, 0.688 log copies/ml, P ‫؍‬ 0.039). Our results suggest that HBV RNA is a valuable predictor of early occurrence of viral mutation during LAM therapy. (HEPATOLOGY 2007;45:1179-1186 T he hepatitis B virus (HBV) is a member of the hepadnaviridae family. Worldwide, approximately 350 million people are estimated to be chronically infected with HBV. 1 Patients with chronic HBV infection develop chronic hepatitis, cirrhosis, and hepatocellular carcinoma, accounting for approximately 1 million deaths per year. 2 Recently, inhibitors of reverse transcriptase have been developed and widely used for patients with chronic HBV infection. Lamivudine (LAM), a cytosine nucleoside analogue, was first developed as an antiviral agent against HIV and later was used effectively against HBV because HBV also uses reverse transcriptase for replication. 3,4 Because LAM suppresses HBV replication, patients who are treated with LAM show a decreased level or disappearance of HBV DNA in serum and hepatitis B e antigen, normalization of serum alanine aminotransferase (ALT) level, and histological improvement. [5][6][7][8][9][10][11][12] However, discontinuation of therapy often leads to reactivation of HBV. 6,8,13,14 Therefore, long-term therapy is necessary for many patients with chronic HBV infection. During long-term LAM therapy, drug-resistant mutants with amino acid substitutions in the tyrosine-methionine-aspartate-aspartate (YMDD) motif emerge, resulting in expression of HBV DNA increasing again and in worsening of hepatitis. 6,10,[15][16][17][18] Moreover, some patients develop a severe flare-up of hepatitis that could lead to fatal hepatic failure. Therefore, prediction of the emergence of YMDD mutants is an important issue.In our hunt for useful serum markers to detect the early emergence of YMDD mutants, we noticed some patients who showed a discrepancy in the expression of HBV DNA measured by the transcription-mediated amplifica-

Hepatitis B virus (HBV) infection is associated with increased expression of microRNA-122. Serum microRNA-122 and microRNA-22 levels were analyzed in 198 patients with chronic HBV who underwent liver biopsy and were compared with quantitative measurements of HBsAg, HBeAg, HBV DNA, and other clinical and histological findings. Levels of serum microRNA-122 and microRNA-22 were determined by reverse transcription-TaqMan PCR. Serum levels of microRNA-122 and microRNA-22 were correlated (R(2)  = 0.576; P < 0.001), and both were elevated in chronic HBV patients. Significant linear correlations were found between microRNA-122 or microRNA-22 and HBsAg levels (R(2)  = 0.824, P < 0.001 and R(2)  = 0.394, P < 0.001, respectively) and ALT levels (R(2)  = 0.498, P < 0.001 and R(2)  = 0.528, P < 0.001, respectively). MicroRNA-122 levels were also correlated with HBV DNA titers (R(2)  = 0.694, P < 0.001 and R(2)  = 0.421, P < 0.001). Levels of these microRNAs were significantly higher in HBeAg-positive patients compared to HBeAg-negative patients (P < 0.001 and P < 0.001). MicroRNA-122 levels were also lower in patients with advanced liver fibrosis (P < 0.001) and lower inflammatory activity (P < 0.025). These results suggest that serum micro-RNA levels are significantly associated with multiple aspects of HBV infection. The biological meaning of the correlation between microRNA-122 and HBsAg and should be investigated further.

Chronic HCV-infected patients tend to have vitamin D deficiency, suggesting that vitamin D supplementation may enhance the efficacy of treatment with pegylated interferon (PEG-IFN) and ribavirin (RBV). We therefore assessed the effects of vitamin D supplementation on viral response to PEG-IFN/RBV. Eighty-four patients with HCV genotype 1b were randomized, 42 to oral vitamin D supplementation (1000 IU/day) and 42 to nonsupplementation (control), from week 8 to the end of PEG-IFN/RBV therapy. The primary end point was undetectable HCV RNA at week 24 (viral response [VR]). VR rate at week 24 was significantly higher in the vitamin D than in the control group (78.6% vs 54.8% P = 0.037). Adverse events were similar in both groups. When patients were subdivided by IL28B SNP rs8099917 genotype, those with the TT genotype group showed a significantly higher VR rate at week 24 with than without vitamin D supplementation (86.2% vs 63.3% vs P = 0.044). Although patients with the TG/GG genotype, who were relatively resistant to PEG-IFN treatment, had similar VR rates at week 24 with and without vitamin D supplementation, the decline in viral load from week 8 to week 24 was significantly greater with than without vitamin D supplementation. Multivariate analysis showed that rs8099917 genotype and vitamin D supplementation contributed significantly to VR at week 24. SVR rates were similar in the vitamin D and control groups [64.3% (27/42) vs 50% (21/42), P = 0.19]. Vitamin D supplementation may enhance the effects of PEG-IFN/RBV in HCV genotype 1b-infected patients.

Using an autoimmune hepatitis model of A/J mice which was prepared with immunization by syngeneic crude liver proteins, various influences of neonatal thymectomy were studied by observations of histological liver changes, autoantibody to liver-specific membrane lipoprotein (LSP), delayed-type hypersensitivity (DTH) to LSP, and purified protein derivative (PPD), and suppressor activity to LSP. The liver changes in the thymectomized mice were more intense than those in the non-thymectomized controls. Production of the anti-LSP autoantibodies and positive DTH to syngeneic LSP could be recognized in both groups of the thymectomized mice and the non-thymectomized controls, but the levels of those were higher in the former. In the level of DTH to PPD the thymectomized mice were lower than the non-thymectomized controls. Adoptive transfer experiments showed that suppressor activity to LSP was reduced in the spleen cells of neonatally thymectomized mice. This experiment suggests that neonatal thymectomy is apt to abolish tolerance to LSP on account of depressed suppressor activity to autoantigen, and accordingly liver damage is increased Keywords experimental hepatitis liver-specific membrane lipoprotein neonatal thymectomy suppressor cells