| 特集名 | B型肝炎 -- 病態解明と治療の最前線 | |
|---|---|---|
| 題名 | B型肝炎の治療最前線 (4) HBV core関連抗原とB型肝炎治療 | |
| 発刊年月 | 2009年 06月 | |
| 著者 | 田中 榮司 | 信州大学医学部内科学講座第二 |
| 著者 | 松本 晶博 | 信州大学医学部内科学講座第二 |
| 【 要旨 】 | HBcrAg量はHBV DNA量とは異なる観点から核酸アナログ薬の治療効果をモニターすることが可能でありその有用性が検討されている．同治療では血中HBV DNA量が検出感度以下になっても耐性株の出現がみられ，治療を中止すると肝炎が再燃することはまれではない．これは，核酸アナログ薬治療下では，血中HBV DNA量は肝細胞中のウイルス量を正確に反映しないことが原因と考えられる． HBcrAg量は肝細胞中のHBV cccDNA量を反映することが示されており，とくに核酸アナログ薬治療で血中HBVDNA量が検出感度以下になった後もこのcccDNA量を反映するため治療効果のモニターに有用である．実際には，HBcrAg量が十分低下する症例では耐性株の出現はまれである．また，治療中止後の肝炎再燃も軽度であることが多く，治療を中止するときの参考となる． |
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| Theme | Cutting Edge : Pathogenesis and Treatment of Hepatitis B | |
|---|---|---|
| Title | HBV Core-related Antigens and Treatment for Hepatitis B | |
| Author | Eiji Tanaka | Department of Medicine, Shinshu University School of Medicine |
| Author | Akihiro Matsumoto | Department of Medicine, Shinshu University School of Medicine |
| [ Summary ] | Measurement of HBV DNA in the serum is useful for monitoring the anti-viral effects of nucleoside or nucleotide analogue therapy. However, a negative result for HBV DNA does not necessarily indicate a good therapeutic outcome since drug resistance may occur even if HBV DNA levels remain undetectable during therapy. Reactivation of HBV replication may occur after therapy. Recently, a CLEIA was developed for the detection of hepatitis B core-related antigens (HBcrAg). HBcrAg consists of HBV core, e, and p 22cr antigens which are transcribed from the precore/core gene. Although serum HBcrAg levels correlated linearly with those of HBV DNA in natural courses, HBcrAg decreased significantly more slowly than HBV DNA after initiation of lamivudine administration. The clinical significance of HBV DNA and HBcrAg levels was analyzed and it was suggested that HBV DNA measurement was useful for identifying patients who are at high risk of developing lamivudine resistance. HBcrAg measurement was also considered valuable for identifying those who are at low risk. The measurement of HBcrAg was found to be useful for predicting reactivation of hepatitis after cessation of lamivudine administration as well. Elevated levels of HBV cccDNA in hepatocytes are considered to be associated with both more frequent occurrence of lamivudine resistance during lamivudine administration and more severe reactivation of hepatitis after halting lamivudine administration. Thus, a serum marker which reflects HBV cccDNA levels is needed. Results so far, including ours, suggest that serum HBcrAg levels reflect HBV cccDNA in hepatocytes more accurately than serum HBV DNA. |
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