Terazawa Y, Yoshioka K, Kobayashi M, Watanabe K, Ishigami M, Yano M, Takagi K, Kakumu S
Third Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Am J Gastroenterol. 2000 Jul;95(7):1781-7. doi: 10.1111/j.1572-0241.2000.02176.x.
Interferon sensitivity-determining region (ISDR) in nonstructural region 5A of hepatitis C virus (HCV) genotype-1b has been reported to be associated with viral load. Viral load is usually small in the patients with mutant type (four or more amino acid substitutions, compared with HCV-J) and large in those with wild (identical to HCV-J) or intermediate type (from one to three amino acid substitutions). A possible correlation was investigated between mutations in ISDR and alterations of viral load during the course of disease.
The sequences of ISDR were determined in eight patients with significant changes of viral load and in 11 patients without changes.
In two of the eight patients with significant alterations of viral load, ISDR sequences changed significantly. In one patient whose viral load increased after a course of interferon therapy, the number of substitutions, compared with HCV-J, decreased from five to zero or one; the type of ISDR converted from mutant type to wild or intermediate type. In one patient whose viral load decreased significantly after two courses of interferon therapy, the number of substitutions increased from one to six; ISDR changed from intermediate type to mutant type. In the remaining six patients with changes of viral load and in the other 11 patients without changes, the sequences of ISDR did not change significantly.
The mutations in ISDR are one of the viral factors involved in the changes in viral load during the course of disease, although the majority of other factors involved are still unknown.
据报道，丙型肝炎病毒（HCV）1b基因型非结构区5A中的干扰素敏感性决定区（ISDR）与病毒载量相关。突变型患者（与HCV-J相比有四个或更多氨基酸替换）的病毒载量通常较低，而野生型（与HCV-J相同）或中间型（有一至三个氨基酸替换）患者的病毒载量通常较高。研究了疾病过程中ISDR突变与病毒载量变化之间的可能相关性。
测定了8例病毒载量有显著变化的患者和11例病毒载量无变化的患者的ISDR序列。
在8例病毒载量有显著变化的患者中，有2例的ISDR序列发生了显著变化。1例患者在干扰素治疗一个疗程后病毒载量增加，与HCV-J相比，替换数从5个减少到0个或1个；ISDR类型从突变型转变为野生型或中间型。1例患者在两个疗程的干扰素治疗后病毒载量显著下降，替换数从1个增加到6个；ISDR从中间型转变为突变型。其余6例病毒载量有变化的患者和另外11例病毒载量无变化的患者，ISDR序列没有显著变化。
ISDR突变是疾病过程中病毒载量变化所涉及的病毒因素之一，尽管所涉及的大多数其他因素仍不清楚。
