影片連結：https://en.wikipedia.org/wiki/File:Viral_hepatitis.webm
譯者姓名:林欣儀、李姿穎
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Hepatitis, meaning like this inflammation,
of the liver, most commonly comes about because
肝炎，就是肝臟發炎，
通常是因病毒感染引起。
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of a virus. These viruses tend to target the
cells in the liver, and when they get in and
病毒鎖定了肝臟的細胞，
一旦造成感染，
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infect these cells, they tend to cause them
to present these weird and abnormal proteins
受感染的細胞
會排放出異常的蛋白質。
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via their MHC class 1 molecules, and at the
same time, you’ve also got these immune
排放途徑是第一類MHC分子，
身體裡的免疫細胞也會進入肝臟，
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cells infiltrating the liver and trying to
figure out what’s going on, and so the CD8
這時體內免疫細胞也進入肝臟
好查明情況
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positive T cells recognize these abnormal
proteins as a sign that the cells are pretty
若CD8+ T細胞確認蛋白質異常
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much toast, and the hepatocytes go through
cytotoxic killing by the T cells and apoptosis.
就會將細胞毒殺。
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Hepatocytes undergoing apoptosis are sometimes
referred to as Councilman bodies, shown on
組織學上，
凋亡中的肝細胞稱為康氏小體。
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histology here, and this typically takes place
in the portal tracts and lobules of the liver.
通常出現在肝門道與肝小葉。
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This cytotoxic killing of hepatocytes is the
main mechanism behind inflammation of the
免疫系統毒殺受感染的肝細胞
是肝臟發炎的主要原因
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liver, and eventual liver damage in viral
hepatitis! As someone’s hepatitis progresses,
甚至造成病毒性肝炎的嚴重傷害
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we’ll see a couple classic symptoms related
to your immune system mounting an attack,
免疫系統攻擊病毒
會產生各種症狀
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like fever, malaise, and nausea. Additionally
though, patients might have hepatomegaly,
像是發燒、全身不適與反胃。
此外，由於發炎，
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where their liver is abnormally large from
inflammation, which might cause some pain.
病人的肝會異常腫大，
因此可能會疼痛。
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Also, as more and more damage is done to the
liver, the amount of transaminases in their
隨著肝臟不斷受到侵擾
轉胺酶在血液中的數量就會增加。
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blood will increase. Your liver has these
transaminase enzymes so it can do its job
肝臟有了這些轉胺酶，
就開始分解各種胺基酸
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of breaking down various amino acids. Typically
the serum amino transaminase, or the amount
通常血清氨基轉胺酶成分在血液中是非常少的，
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in your blood, is pretty low, but when your
hepatocytes start getting damaged they start
但當肝細胞遭破壞
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leaking these into the blood, so a common
sign is a greater amount of both alanine aminotransferase,
便將胺基轉胺酶排放到血液中
最常見的現象就是
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or ALT, and aspartate aminotransferase, or
AST, typically even though both are elevated,
谷丙轉胺酶(ALT)
天冬胺酸氨基轉移酶(AST)
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ALT will be greater than AST in viral hepatitis
and will also be the last liver enzyme to
雖然兩者的量都會上升
但ALT含量較高，也最難恢復正常
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return to normal. Also, elevated levels of
atypical lymphocytes are common to see with
此外，病毒性肝炎另一常見現象
是非典型淋巴球數量增加
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viral hepatitis, known as atypical lymphocytosis.
The lymphocytes are usually like huge, very
最為熟知的名稱為淋巴球增多症。
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large, due to stimulation from antigens, in
our case the hepatitis virus antigens. Patients
由於受抗原體刺激，
淋巴球會腫得很大，
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often also end up developing jaundice, with
a mix of both conjugated bilirubin and unconjugated
最後形成黃疸
共軛與非共軛膽紅素相混合
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bilirubin. The conjugated bilirubin leaks
out when bile ductules are damaged or destroyed
當一些內部組成的肝細胞死亡時，
膽小管壞死，
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when the hepatocytes die, which make up some
of its lining! Also, since these hepatocytes
共軛膽紅素就會流出來補強外壁
也因為肝細胞死了，
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are dying, you start to lose the ability to
conjugate bilirubin and make it water soluble,
共軛膽紅素會失效、呈水溶性
非共軛膽紅素也是。
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and so you also end up with unconjugated bilirubin
as well. So since there’s both conjugated
因為兩種膽紅素混在血液裡
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and unconjugated bilirubin in the blood, some
of the water soluble conjugated bilirubin
膽紅素呈水溶性，會滲入尿液
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gets filtered into the urine, giving it a
darker color. Another common finding is increased
使其顏色變深。
另一種常見現象是
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urobilinogen in the urine, urobilinogen is
produced when bilirubin is reduced in the
尿液中的尿膽素原增加
原因是膽中的膽紅素減少
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gut by intestinal microbes, usually most of
it’s then reabsorbed and transported back
通常尿膽素會被肝臟再吸收
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to the liver to be converted back to bilirubin,
or bile. If these liver cells aren’t working
或是還原成膽紅素或膽汁
若肝細胞無法正常運作，
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properly, that urobilinogen is redirected
to the kidneys and excreted, so you end up
尿膽素原就透過腎臟排泄掉。
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with more urobilinogen in your urine.
尿液中尿膽素原也因此增加。
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If symptoms continue or the virus sticks around
for more than 6 months, viral hepatitis goes
症狀延續或是病毒停留
如果超過6個月
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from being called acute to being called chronic
hepatitis. At this point, inflammation mostly
病毒性肝炎就會由急性
演變成更嚴重的慢性肝炎
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happens in the portal tract, and if inflammation
and fibrosis keep persisting, we consider
這種情況下，
發炎的部位大多是在肝門徑。
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that a bad sign, since it might be progressing
to postnecrotic cirrhosis.
若發炎和纖維化的現象持續
就可能變成肝硬化
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Now there are five known flavors or types
of hepatitis virus, that have slightly different
現在共發現五種肝炎病毒
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and unique properties. Hepatitis A is transmitted
through ingestion of contaminated food or
它們各有稍微不同的特質
A型病毒經由食物或水感染
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water, in other words the fecal-oral route,
and is known to be acquired by travelers.
換句話說，就是病從口入，
出門在外的人最容易受害
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Hepatitis A virus, or HAV, is almost always
acute only, and there is essentially no chronic
A型肝炎，或稱HAV，
為急性肝炎，並不會轉變成慢性
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HAV. If we’re talking serological markers,
an HAV-IgM antibody indicates an active infection,
若以血清指標來看，
HAV-IgM抗體表示有感染
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whereas HAV-IgG antibody is a protective antibody
and tells us that there’s been recovery
HAV-IgG抗體是保護性抗體
表示過去的感染已消除
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from HAV or vaccination in the past. Hepatitis
E virus’s actually pretty similar to HAV,
E型病毒和A型非常相似
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with the same route of transmission, oral-fecal,
and is most commonly acquired through undercooked
都是經由口食傳染，尤其是
生食海鮮或是不淨的水所造成
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seafood or contaminated water. It also doesn’t
have much of a chronic state, and HEV-IgM
通常也不會轉變成慢性肝炎
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antibodies tell us there’s an active infection
and HEV-IgG antibody is protective and signals
HEV-IgM抗體表示有感染
HEV-IgG抗體是保護性抗體
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recovery. Two big differences to note though
between these two guys, is that (1) only HAV
表示感染消除，健康恢復
HAV和HEV兩者最大的差異
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has the option for immunization. and (2) HEV
infection for pregnant women can be very serious,
第一，人體只會對HAV有免疫力
第二，HEV對孕婦的影響非常大
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and can lead to acute liver failure, also
sometimes called fulminant hepatitis. Alright
可能造成急性肝衰竭
也稱為猛爆性肝炎
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next on the docket is Hepatis C virus, this
guy is transmitted via the blood, so could
接下來介紹C型肝炎病毒
它簡稱C肝，經由血液傳染
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be from childbirth, intravenous drug abuse,
or unprotected sex. C肝 usually does move
所以生孩子、注射毒品
或是不安全的性行為
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on to chronic hepatitis. There’re a couple
tests that we use to help diagnose C肝, one
都可能會傳染C肝
C肝診斷方法有幾種
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way is by enzyme immunoassay, so we’d screen
for the C肝-IgG antibody, if present, it doesn’t
第一種是用酶免疫測試
來看是否找到C肝抗體
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necessarily confirm acute, chronic, or resolved
infection and it isn’t regarded as a protective
但是即使找到，也不能斷言
是急性、慢性，或是已經痊癒
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antibody like HAV and HEV, to get more specific
confirmation, you might use recombinant immunoblot
C肝抗體不像HAV或HEV
要確診為C肝
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assay which helps confirm C肝, it’s more
specific but less sensitive than the immunoassay,
可以透過重組免疫墨點分析
這種方式也不如免疫分析敏銳
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and clinically doesn’t provide much usefulness
and needs an additional supplemental test
臨床上效用有限
發現陽性反應，還要做其他檢查
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if positive. That said, the gold standard
for C肝 diagnosis is an C肝 RNA test, using
診斷C肝的最準確方式
是C肝 RNA檢測
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PCR or polymerase chain reaction, this method
can detect the virus very early on, as much
這種方法
檢驗聚合酶鏈鎖反應(PCR)
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as 1 to 2 weeks after infection, basically
it detects the levels of viral RNA in the
可在感染後一兩週查出病毒
它檢測血液中病毒RNA的級數
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blood, which tells us the levels of virus
circulating. If RNA levels begin to decrease,
判斷病毒循環的週期
若RNA級數開始下降
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we know the patient’s recovering, if RNA
remains the same, the patient probably has
則可知病人正在康復中
若RNA持平，則可能為慢性C肝
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chronic C肝. Okay, on to hepatitis B, B肝’s
just like C肝 in that it’s contracted via
現在來談B型肝炎，簡稱B肝
B肝和C肝都由血液接觸感染
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blood, so the same routes like childbirth,
unprotected sex, and others. B肝, however,
包括母嬰垂直感染
或是不安全性行為等原因
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only moves on to chronic hepatitis in 20%
of cases overall, but it also depends on the
但B肝僅有20%會變成慢性
但是，跟感染的年紀也有關係
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age that someone gets infected, for example
children less than 6 years old are most likely
六歲以下孩童感染B肝
約50%會轉成慢性肝炎
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to get chronic infections, about 50%, and
that percentage increases as they get younger.
感染年紀越小
轉為慢性肝炎可能性越高
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Also, chronic B肝 is known to be linked to
liver cancer. All these things make B肝 and
慢性B肝也與肝癌有關
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the serology of B肝 a super important concept
to understand, and kind a like hepatitis C
因此B肝血清學極為重要
跟C肝檢驗一樣
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we can use a variety of testing methods, like
PCR, to look for certain markers, especially
我們也可以用PCR等方法
來檢測B肝抗體
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the B肝 antigens. And the presence or absence
of each at different time points tells us different
抗體數量多寡
在不同時間有不同的意義
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things. K so the key marker for an B肝 infection
is the B肝 surface antigen, this is like the
顯示感染B肝的最大指標
是B肝表面抗原
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supervillain in this story, and this evildoer
lives on the surface of the virus, here, and
這就是我們要談的大魔頭
它住在病毒表面
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we can call it HBsAg, meaning Hepatitis B
surface antigen. Another marker though, is
我們稱之為B肝表面抗原
也就是HBsAg
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a core antigen, meaning that these antigens
come from the core of the virus, HBcAg, think
另一個指標是一種核心抗體
存在病毒的核心，叫HBcAg
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of these like the dispensable henchmen that
work inside the villain’s evil factory.
它就像是大魔頭的嘍囉
在它的基地裡工作
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Finally there’s this other antigen called
the ‘e’ antigen, which is secreted by
最後還有一種抗原
e抗原
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infected cells and so is a marker of active
infection, these are like the byproducts of
它由感染的細胞分泌出來
是病毒的活性指標
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the factory and along with viral DNA, that
tell us it’s replicating and infecting.
它就像是毒品工廠的副產品
顯示病毒的繁殖和感染情況
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Alright, so at the onset of infection, during
the acute phase, our surface antigen villain
感染初期，也就是急性期
表面抗原開始出現
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will be positive and it’s layer will be
pumpin’ out both viral DNA and e antigen,
它的表層分泌出病毒DNA
還有e抗原
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at this point the immune system produces IgM
antibodies, which are like your basic police
這時免疫系統會製造出IgM抗體
它就是你的警察部隊
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force, against the core henchmen. These antibodies
hack away at the core antigens and do their
專門對付核心裡的壞蛋
這些抗體對核心抗體全力猛攻
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darndest, but in order to really defeat the
virus, you need to go for the supervillain,
但是想要真的消滅病毒
得打倒大魔頭－表面抗體
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the surface antigen, so the we need a superhero
to go after it, and in this story the IgG
為此目的，我們需要大英雄
我們的大英雄呢…
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antibody for the surface antigen is our superhero.
At this point, the host enters this spooky
當然就是IgG抗體啦
這時，患者進入病情潛伏期
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phase called the window, where neither the
supervillain or superhero can be detected,
大魔頭也好，大英雄也好
因為它們濃度太低
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because they’re so low, and this can last
from several weeks to months, it’s like
各種動態，我們都難以查覺
潛伏期可能長達數週至數月
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the war’s being waged but we don’t know
who’s coming out on top. The only thing
此時其實雙方已經開戰
只是我們看不見誰佔上風
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you can detect during this stage is the IgM
core antibodies, the police force. At this
這時期所能檢測到的
只有我們的警察部隊---IgM抗體
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point, two things can happen, if the superhero
comes out, the IgG antibodies to the surface
這時，只有兩種可能
一是大英雄IgG出現
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antigen, we’re golden, and this means the
day is saved and we win. The other possibility
表示情況受到控制
也就是危機解除，我們獲勝
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is that the supervillain wins, and surface
antigens are still again detected, there may
另一個可能性是反派獲勝
表面抗原仍然存在
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also be presence of B肝 DNA and e antigen
because it’s now replicating again, the
B肝DNA和e抗原繼續存在
還會繁殖增生
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main point though is that there will not be
the IgG for surface antigens, our superhero.
問題是大英雄IgG不見了
表面抗原就更肆無忌憚了
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Regardless of who wins, the IgM antibodies,
the police force, will be promoted to IgG
不論誰贏，我們的警察部隊IgM
六個月內都會升級成IgG
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by 6 months time, and this does not mean that
the host is protected. So it’s important
這不代表患者可以高枕無憂
所以我們得注意
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to note that we need this surface IgG superhero
to win, but we can have core IgG and still
我們只靠核心抗原IgG還不夠
獲勝關鍵是表面抗原IgG
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lose. If the battle’s lost, the host transitions
into chronic viral hepatitis, defined by it
要是不幸失敗
患者會形成慢性肝炎
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continuing after 6 months. When chronic, the
host could present as “healthy”, and will
就是說六個月後症狀仍持續存在
患者表面會看似健康
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likely have the presence of surface antigen,
core antibody, and no DNA or e antigen, basically
體內有表面抗原、核心抗體
也看不出病毒DNA或e抗原
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saying that the supervillain’s there, it’s
just not replicating, and at this point the
表示大魔頭雖然存在
卻沒有繁殖增生
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host is contagious, but there’s lower risk.
The other option is that they’re infective,
這時患者傳染性通常較低
但是有時候感染性也可能很高
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00:10:52,260 --> 00:10:58,020
meaning the whole villain force is active
along with an overwhelmed police force. This
就是說反派勢力強大
警察部隊無力壓制
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state increases the risk for postnecrotic
cirrhosis and hepatocellular carcinoma. One
這種情況下
肝硬化、肝癌的機率就會大增
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00:11:03,910 --> 00:11:08,370
way to get around this whole fiasco is by
immunization, which skips these steps and
要避免這種情況有一種方法
就是免疫接種
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00:11:08,370 --> 00:11:15,080
gets you right to the IgG superhero antibody
for surface antigen. Alright, last but not
直接讓大英雄表面抗體保護你
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00:11:15,080 --> 00:11:21,130
least, well maybe least, I donno, anyways
Hepatits D virus is a unique in that it NEEDS
最後...可能不是絕對要緊的一點
D型肝炎病毒，得靠 B肝
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00:11:21,130 --> 00:11:30,040
B肝, it can only infect if the host also has
B肝. If it infects at the same time, it’s
只有B肝患者才可能得D型肝炎
兩種病毒可能同時感染
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00:11:30,040 --> 00:11:35,080
called co-infection, if it infects sometime
later, it’s called superinfection, which
若是較晚感染D型
就叫作超級感染了
66
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00:11:35,080 --> 00:11:42,250
is considered to be more severe that co-infection.
If either the IgM or IgG antibody are present,
它比同時感染更為嚴重
只要有IgM或是IgG抗體出現
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00:11:42,250 --> 00:11:55,830
that indicates an active infection, so in
this case the IgG is not a protective antibody.
都表示發生感染現象
這時，IgG抗體就不是保護性抗體