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Macrophages recognize lipopolysaccharide (LPS) by Toll-like receptor 4 and activate inflammatory responses by inducing expression of various genes. TLR4 activates intracellular signaling pathways via TIR domain containing adaptor molecules, MyD88, and Toll/IL-1 domain containing adaptor inducing IFN-beta (TRIF). Although macrophages lacking MyD88 or TRIF showed impaired cytokine production, activation of intracellular signaling molecules still occurred in response to LPS in these cells. In the present study, we implemented cDNA microarrays to investigate the contribution of MyD88 and TRIF in gene expression induced by LPS stimulation. Whereas wild-type macrophages induced 148 genes in response to LPS, macrophages lacking both MyD88 and TRIF did not upregulate any genes in response to LPS. Surprisingly, 80 LPS-inducible genes were redundantly regulated by either MyD88 or TRIF. In contrast, proinflammatory cytokines and chemokines were critically regulated by MyD88 or TRIF alone. Genes critically regulated by MyD88 alone tend to be induced quickly after LPS stimulation and regulated by mRNA stability as well as transcription. Genes known to be induced by type I interferons were simply dependent on TRIF for their expression. Taken together, MyD88 and TRIF play both redundant and distinct roles in LPS-induced gene expression.

Background/aims: Interferon monotherapy for patients with chronic hepatitis C has been suboptimal. We studied the effect of the combination therapy of an initial high-dose of interferon and amantadine., Methodology: We investigated the virological response of 20 patients with naive chronic hepatitis C with a high viral load of the genotype 1b virus. Seven patients were administered 6MU of interferon-beta once daily for 6 weeks and then thrice weekly for 20 weeks, and 13 were administered 6 MU of interferon-beta daily for 4 or 6 weeks and then 10 MU of natural interferon-alpha thrice weekly for 22 or 20 weeks. All patients were treated with amantadine hydrochloride (100 mg/day) for 26 weeks during interferon administration., Results: The complete response, transient response and no response rate were 15.0%, 60.0%, and 25%, respectively. After daily administration of interferon-beta intravenously, 19 patients (95.0%) showed negative tests for serum HCV-RNA by the polymerase chain reaction method. At the end of treatment, the serum HCV-RNA was not detected in any patients treated with daily interferon-beta and intermittent interferon-alpha with amantadine. At 6-month follow-up, three patients had eradicated HCV-RNA, who were in the group of daily interferon-beta and intermittent interferon-alpha with amantadine. In the patients treated with daily interferon-beta and intermittent interferon-alpha with amantadine, the complete response, transient response and no response rates were 23.1%,-76.9% and 0%, respectively., Conclusions: These findings suggest that the combination of an initial high-dose interferon and amantadine shows promising effects on the eradication of HCV-RNA in the chronic hepatitis C patients with a high viral load of the genotype 1b virus.

Background/aims: The effect of interferon treatment for chronic hepatitis C patients with genotype 1b virus has been suboptimal. We studied the effect of the combination therapy of interferon and amantadine on patients with a high serum viral load of genotype 1b virus., Methodology: We studied the virological response of naive chronic hepatitis C patients with a high viral load of genotype 1b virus (4.5 log copies/50 microL or 100 kcopies/mL and higher) during interferon and amantadine administration for 6 months and 6 months after the end of treatment. Twenty patients were treated with interferon alone (natural interferon-beta 6 MU daily for 6 weeks and thrice-a-week for 20 weeks) for 26 weeks. Eleven patients were treated with the combination therapy of interferon and amantadine hydrochloride (100 mg orally daily) for 26 weeks., Results: After daily administration of interferon-beta intravenously once a day for 6 weeks, all patients showed the negative tests of serum HCV-RNA by polymerase-chain-reaction methods by the combination therapy, while 13 patients (65.0%) showed the negative tests by interferon alone (p = 0.0257). At the end of treatment, serum HCV-RNA were not detected in 54.5% of patients treated with interferon and amantadine, while it was detected in 50.0% of patients treated with interferon alone. At 6 months follow-up, only one patient (9.1%) could eradicate HCV-RNA in patients with interferon and amantadine, while no patient could with interferon monotherapy (not significantly)., Conclusions: Amantadine hydrochloride has the additive effects to interferon treatment on the virological responses of serum HCV-RNA during a co-administration, although the combination therapy has not shown a significantly promising effect on the eradication of HCV-RNA in the patients with chronic hepatitis C with a high viral load of genotype 1b virus.