ANALYSES OF HEPATITIS A VIRUS GENOME FROM PATIENTS WITH FULMINANT TYPE A HEPATITIS

甲型肝炎不仅在不发达国家，而且在发达国家仍然存在相当大的问题。目前还没有揭示为什么一些患者会进展为暴发型甲型肝炎，而另一些患者则不会。为了验证甲型肝炎病毒(HAV)的基因组差异是否与临床严重程度有关，我们分析了甲型肝炎患者和急性甲型肝炎患者血清中HAV RNA的全核苷酸序列。我们阐明甲型肝炎的严重程度似乎与甲型肝炎病毒5‘端非翻译区中心附近的替换有关，因为在重型肝炎中只观察到少量的替换，而在自限性急性肝炎中观察到相当多的替换。我们进一步测定了甲型肝炎病毒结构蛋白的序列，并对3例甲型重型肝炎和3例急性甲型肝炎患者的血清进行了检测。通过长反转录-聚合酶链式反应(RT-PCR)扩增出甲型肝炎病毒RNA的结构区和非结构区，分为3188个碱基和4688个碱基，包括结构蛋白区和非结构蛋白区。对每一条扩增产物进行克隆，用全自动测序仪对其结构蛋白序列进行测序。甲型肝炎患者的基因分型均为A型，在5‘非翻译区的结构蛋白序列与急性甲型肝炎无明显差异。我们正在检测甲型肝炎病毒的非结构蛋白序列。

Hepatitis A still possess a considerable problem not only in underdeveloped but also in developed countries. It is not revealed why some patients progress to fulminant hepatitis A and others do not. To examine whether genomic differences of hepatitis A virus (HAV) are responsible for the clinical severity, we are analyzing whole nucleotide sequences of HAV RNA in sera from fulminant and acute hepatitis A patients. We clarified that the severity of hepatitis A appears to be associated with the substitutions near the central part of the 5' nontranslated region of HAV,because in the cases with fulminant hepatitis only a small number of substitutions were observed while in the cases with self limited acute hepatitis considerable numbers of substitutions were observed. We further determined the sequences of structural protein region of HAV.Sera from 3 fulminant and 3 acute hepatitis A patients were examined. Structural region and non-strauctural regions of HAV RNA were amplified by long reverse transcription-polymerase chain reaction (RT-PCR) devided into 3188 bp including structural protein region and 4688 bp including non-structural protein region. Each PCR product was cloned and the nucleotide sequence of structural protein region was sequenced by automated sequencer. The genotypes of examined cases were all genotype1A.There were no such obvious differeces in structural protein region as found in 5' nontranslated region between fulminant and acute hepatitis A.We are now examining the sequences of non-structural protein region of HAV.