目的　通过对慢性乙型肝炎不同病型患者S区准种复杂性差异的分析 ,探讨S区准种与疾病活动性的关系。方法　选择HBVDNA阳性患者共 112例 ,其中慢性重型肝炎 (FHF) 6 0例 (同时有肝硬化者 38例 ) ,慢性轻、中型肝炎 (CH) 30例 ,病毒携带者 (ASC) 2 2例 ,采用单链构像多态性(SSCP)和DNA序列分析方法检测HBVS区准种。结果　不同疾病期SSCP条带数不同 ,分别为ASC( 1.4 5± 0 .13) ,CH( 3.70± 0 .2 2 ) ,FHF( 5 .93± 0 .2 4 )。准种复杂性随疾病进展而增加 ,组间比较差异有显著性 ,F =72 .73,P <0 .0 1。HBeAg阳性与HBeAg阴性患者SSCP条带数分别为 3.4 1± 0 .2 7和 5 .2 7± 0 .30 ,两组差异有显著性 (t =4 .5 3,P <0 .0 1)。HBV基因型B、C患者SSCP条带数分别为 4 .71± 2 .36和 3.0 6± 1.76 ,差异有显著性 (t =2 .6 6 ,P <0 .0 1)。 2例重型肝炎患者随访 1年后丙氨酸转氨酶 (ALT)分别由 5 6 7.2U/L、4 6 2 .3U/L降至正常和接近正常 ( 4 2 .8U/L) ,SSCP条带数分别由 9、7条减至 5、2条 ;1例ASC随访 1年SSCP方式仍维持 1条带不变 ,ALT水平高低与SS CP条带数多少相一致。经DNA序列分析 ,证实了SSCP显示的HBV准种性。结论　HBVS基因准种随疾病病情加重而复杂性增加 ,其增加程度与HBeAg阴性、病情轻重及基因型 Objective To analyze the differences of quasispecies complexity in patients with different types of chronic hepatitis B and discuss the relationship between quasispecies and disease activity in patients with chronic hepatitis B. Methods A total of 112 HBVDNA positive patients were selected, including 60 cases of chronic severe hepatitis (FHF), 38 cases of cirrhosis, 30 cases of chronic mild hepatitis and 30 cases of viral hepatitis, Single strand conformation polymorphism (SSCP) and DNA sequence analysis were used to detect HBV quasispecies. Results The numbers of SSCP bands in different disease stages were different, which were ASC (1.4 5 ± 0.13), CH (3.70 ± 0.22) and FHF (5.993 ± 0.24). Quasi-species complexity increases with disease progression, the difference between groups was significant, F = 72.73, P <0.01. The number of SSCP bands in patients with HBeAg-positive and HBeAg-negative were 3.4 1 ± 0.27 and 5.27 ± 0.30, respectively, with significant difference between the two groups (t = 4.33, P <0.01) . The number of SSCP bands in patients with HBV genotype B and C were 4.71 ± 2.36 and 3.06 ± 1.76 respectively, with significant difference (t = 2.66, P <0.01). ALT was decreased from 56.2U / L and 46.23U / L to normal and nearly normal (42.2U / L) in 2 patients with severe hepatitis at one year of follow-up. SSCP bands The numbers were reduced from 9 to 7 to 5 and 2, respectively. One case of ASC was followed up for 1 year and the SSCP mode remained unchanged. The level of ALT was consistent with the number of SS CP bands. DNA sequence analysis confirmed HBV quasispecies exhibited by SSCP. Conclusions The quasi-species of HBVS gene increases with the aggravation of the disease and the complexity of the disease is increased with the degree of HBeAg-negative, the severity and the genotype