Kobayashi Mariko, Suzuki Fumitaka, Arase Yasuji, Akuta Norio, Suzuki Yoshiyuki, Hosaka Tetsuya, Saitoh Satoshi, Kobayashi Masahiro, Tsubota Akihito, Someya Takashi, Ikeda Kenji, Matsuda Marie, Sato Junko, Kumada Hiromitsu
Research Institute for Hepatology, Toranomon Hospital, 1-3-1 Kajigaya, Takatsu-ku, 213-8587 Kawasaki, Japan.
J Gastroenterol. 2004 Sep;39(9):844-50. doi: 10.1007/s00535-004-1400-3.
Because genotype A of hepatitis B virus (HBV) is not indigenous, there have been only few data on infection with it in Japan.
We examined clinical and virological features of the 66 Japanese patients who admitted Toranomon Hospital in Tokyo, Japan, between 1976 and 2001, who were found to have HBV/A infection. HBV genotype A was classified into subtype A (European type) and A' (South African type) by phylogenetic analysis of the preS1 and preS2 regions, and the S gene sequences.
Of the 66 patients infected with HBV/A, 14 (21%) were asymptomatic carriers, 26 (39%) presented with acute hepatitis, 22 (33%) with chronic hepatitis, and 4 (6%) with liver cirrhosis. HBV/A infection persisted for more than 6 months in 5 of the 26 (19%) patients with acute hepatitis. The frequency of acute hepatitis in patients infected with HBV/A was higher after than before 1991 (2/22 [9%] vs 24/44 [55%]; P < 0.0001). The frequency of nucleotide 1858 of T was higher in asymptomatic carriers than in patients with acute hepatitis in whom infection was resolved (5/14 [36%] vs 0/21 [0%]; P = 0.008). Of the 57 patients for whom subtypes of genotype A were determined, subtype A was identified in 53 (93%) and subtype A' in only 4 (7%). All patients infected with subtype A' were persistently infected with HBV.
HBV/A infection has become more frequent during recent years, predominantly presenting as acute hepatitis, and subtype A' is uncommon in the Tokyo metropolitan area.
由于乙型肝炎病毒（HBV）A基因型并非日本本土基因型，因此日本关于该基因型感染的数据较少。
我们研究了1976年至2001年间入住日本东京虎之门医院且被发现感染HBV/A的66例日本患者的临床和病毒学特征。通过对前S1和前S2区域以及S基因序列进行系统发育分析，将HBV A基因型分为A亚型（欧洲型）和A'亚型（南非型）。
在66例感染HBV/A的患者中，14例（21%）为无症状携带者，26例（39%）表现为急性肝炎，22例（33%）为慢性肝炎，4例（6%）为肝硬化。26例急性肝炎患者中有5例（19%）的HBV/A感染持续超过6个月。1991年以后感染HBV/A的患者中急性肝炎的发生率高于1991年以前（2/22 [9%] 对24/44 [55%]；P < 0.0001）。无症状携带者中核苷酸1858位点T的频率高于感染已清除的急性肝炎患者（5/14 [36%] 对0/21 [0%]；P = 0.008）。在确定了A基因型亚型的57例患者中，53例（93%）为A亚型，仅4例（7%）为A'亚型。所有感染A'亚型的患者均为HBV持续感染。
近年来HBV/A感染变得更加常见，主要表现为急性肝炎，且A'亚型在东京都市区并不常见。
