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发表于 2002-3-19 23:30
| Phases of chronic hepatitis B infection
乙肝感染的阶段
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A chronic hepatitis B infection can be thought of as having three phases:-
慢性乙肝感染可分为三个主要阶段:-
1. Immune tolerance.
免疫耐受阶段
In this phase the virus is actively reproducing but only mild liver disease may be present and liver enzymes (e.g. ALT) may be normal and frequently no symptoms are present. HBV DNA is usually high and the "e" antigen is generally present. When infected at an early age this phase of immune tolerance can last for a long time until tolerance to the virus breaks down generally between the ages of 15 to 35 (16).
在这个阶段中， 病毒活跃复制, 肝脏可能有一点损害， 肝脏酶指标（如，ＡＬＴ）一般正常， 病人无病状感觉． ＨＢＶ－ＤＮＡ值通常高， ｅ抗原阳性． 如果是早年，幼年感染（如， 母子,女垂直感染），这个阶段通常可以延续很久直到免疫耐受阶段支持不住的时候－－通常在１５－３５岁的时候．
It is believed that HBV does not kill liver cells directly but it is the
immune systems reaction to infected cells by attacking them that causes cell death and hence liver damage. In this first phase as the immune system is believed to ignore the HBV infection or only recognise it at a low level and so only minimal liver damage occurs.
研究认为乙肝病毒不直接涉及肝脏细胞破坏，是人体免疫系统对感染的肝细胞进行攻击造成细胞死亡，肝脏受损．在这第一阶段，免疫系统不理睬乙肝病毒的感染或者仅仅在很低的限度识别他们的存在故肝脏损伤不厉害．
In adults this phase can be very short and the chronic infection begins with the second phase of immune clearance (12,13).
然而，如果是成年感染，这个阶段可以非常短暂，接下来很快进入免疫清除阶段，第二期，开始了慢性感染恶期．
2. Immune clearance.
免疫清除阶段
In this phase the immune system recognises the virus and attacks infected liver cells. HBV DNA is present but generally in lower levels than in the immune tolerant phase and HBeAg is generally also present. Liver enzymes are elevated, symptoms may be present and liver damage is generally occurring due to liver cell death by the immune system. In this phase HBV replication decreases and spontaneous seroconversion from +HBeAg to +HBeAb can occur
generally preceded by a 'flare' in ALT at a rate of around 2.5% of cases per year (14) although this may be much higher (13).
在这个阶段，免疫系统识别病毒并开始进攻被乙肝感染的肝脏细胞．ＨＢＶ－ＤＮＡ阳性但通常比第一期低，ｅ抗体阳性，酶指标通常高，病人通常感觉有病状，肝脏细胞因为被免疫系统攻击死掉，肝脏有不同程度损伤．此阶段乙肝病毒复制减少，ｅ抗原转换成ｅ抗体，每年感染人中２．５％或更多在不同程度上伴有ＡＬＴ剧增．
Transition from this phase to the non replicative phase may occur quickly or can be a prolonged process. There may also be fluctuations of activity with flares of liver enzymes which correspond to the immune systems attempts to clear the virus and in some cases symptoms of acute hepatitis may be present during these flares.
从此阶段过渡到下一个阶段－－不活动阶段，可能很快，也可能很拖延很久．此阶段通常伴有酶指标的巨幅波动和急性肝炎的症状，这是和免疫系统想请除掉病毒相辅相成．
In the immune clearance phase liver damage is generally occurring at some level and the longer this phase continues the greater the risk of liver disease. Where flares in liver enzymes are observed this corresponds to extensive liver cell death as the immune system destroys infected cells and liver damage is much greater. The appearance of a flare can be a good sign as a flare generally precedes seroconversion from +HBeAg to +HBeAb and transition into the non replicative phase. However where seroconversion does not occur the flare is a bad sign as it implies more extensive liver damage.
在免疫清除阶段，多多少少肝脏都会受损，此阶段越长，损害的危险性越厉害．肝脏酶指标的剧增就免疫系统攻击肝脏细胞并造成损害的一个现象．但是酶指标剧增也可能是恢复的，ｅ抗原转换成ｅ抗体的，进入非复制阶段的好现象．然而，如果ｅ抗原不变化，酶指标持续剧增可能是肝脏进一步受损害的象征．
3. Non-replicative - Carrier Phase (Inactive carrier phase)
非复制阶段－带原者阶段（非活动带原者阶段）
The third phase occurs once the majority of liver cells infected with
hepatitis B have been destroyed and active viral replication ceases (or is suppressed) HBsAg is generally still present but HBeAg disappears, HBeAb may appear, liver enzymes normalise and HBV DNA is undetectable by normal methods although it can be detected by PCR indicating a low level of viremia
第三阶段通常发生在大部分被感染肝脏细胞被消灭掉，病毒停止复制（或压抑住）时，ＨＢｓＡｇ还是阳性，ｅ抗原消失，ｅ抗体或许出现，酶指标恢复正常，ＨＢＶ－ＤＮＡ用一般方法测不到（如，斑点杂交法），ＰＣＲ法有可能测到少量病毒复制．
In this phase the extent of liver damage present is dependent on the length of the immune tolerant phase and any periods of reactivation. A person in this state is regarded as a chronic carrier and in remission but there may be present permanent liver damage from the previous phase. (sometimes it can't be dectected or noticed by regular method)
在这个阶段，持续的肝脏损伤和免疫耐受期的长短，病毒反跳阶段有重要关系．患者处于这个阶段可以被认为是恢复中的慢性带原者，但是有可能肝脏在起初的阶段已经被损伤．（有时一般方法查不到）
Transition between the above phases can occur in either direction and there can be periods of immune tolerance can follow periods of immune clearance and periods of immune clearance can occur after entering the non-replicative phase. Moving from a phase into the immune clearance phase with a corresponding increase in liver enzymes and associated liver damage is known as reactivation and these phases of reactivation may be common. (15)
以上各阶段的变化方向不定，可好，可坏．可以从免疫耐受阶段到免疫清除阶段，免疫清除阶段也可能在非复制阶段后发生．从一个阶段进入免疫清除阶段时伴有酶高，肝脏损伤是反跳，反跳是常常发生的事情．
The development of viral mutants can also cause problems in determining the phase of hepatitis B infection and a person may remain in the immune clearance phase even after development of HBeAb. Some viral mutants do not produce the "e" antigen. So if HBeAg is negative, liver enzymes continue to be elevated, and HBV DNA is present, it could indicate the presence of a mutant strain."
病毒变异体的产生也是造成判定感染阶段的困扰，使患者在产生ｅ抗体后可能还处于免疫清除期．有些变异型病毒不产生ｅ抗原，所以，若ｅ抗原阴性，酶指标上升，ＨＢＶ－ＤＮＡ阳性，有可能是产生变异型病毒的想象．
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还有人把３个阶段分成６个时段：
0 - Infection - Acute Phase
1 - Tolerance
2 - Active
3 - Non Replicative
4 - Resolved
5 - Defeated
但是大体上和３阶段一样．
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(12) Realdi G et al. Gastroenterology 1980;79;195-9
(13) Hoofnagle JH et al. Ann Intern Med 1981;94:744-8
(14) Violo LA et al. J Med Virol 1981;8169-75
(15) Mels GC et al. Liver 1994;14:175-81
(16) Title: The Clinical Consequences of Chronic Hepatitis B
Author: Pierre Pare, MC, FRCPC, FACG Source: Hepatitis Update. Issue No.6, August 1996 Clinical News & Views on Hepatitis B and C
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所以无论您的血化验，肝功能，图像监察等有多＂正常＂，对您肝脏真正状况（过去／现在）的了解是最最重要的．
hepatitis-b-onmail-list.com 提供．
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