中英文稿 ?

2008 年，難以置信的事情發(fā)生了： 一名HIV患者被成功治愈?在超過(guò)七千萬(wàn)HIV病例中，這是第一例， 目前為止也是最后一例?我們無(wú)法確切的知道他是如何被治好的?我們可以治愈很多疾病，比如瘧疾與丙肝?但是我們?yōu)楹尾荒苤斡鶫IV？?首先，讓我們來(lái)看HIV病毒是如何感染人類?以及如何發(fā)展成為艾滋病

HIV病毒通過(guò)體液交換傳播?無(wú)保護(hù)的性行為和污染的針頭是傳播的主要原因?幸運(yùn)的是，HIV 無(wú)法通過(guò)空氣、水或者接觸傳播?任何年紀(jì)，性取向，性別和種族的個(gè)體?都有可能感染HIV

一旦進(jìn)入人體，HIV病毒便開(kāi)始感染免疫系統(tǒng)的細(xì)胞?它專門攻擊輔助型T細(xì)胞?這是一種幫助人體抵抗細(xì)菌和真菌感染的細(xì)胞?HIV 是逆轉(zhuǎn)錄病毒?它可以將自己的基因編碼寫(xiě)入被感染細(xì)胞的基因組?指派他們復(fù)制更多的病毒

在HIV感染初期?病毒在輔助性T細(xì)胞中復(fù)制?在這個(gè)過(guò)程中破壞了許多T細(xì)胞?在這個(gè)階段，患者通常有類似流感的癥狀?但不會(huì)有生命危險(xiǎn)?在幾個(gè)月甚至幾年的一段時(shí)期內(nèi)?患者可能看起來(lái)很健康?但病毒持續(xù)復(fù)制，同時(shí)破壞T細(xì)胞?當(dāng)T細(xì)胞數(shù)目過(guò)低?患者將處于致死性感染的危險(xiǎn)中?這種感染在健康的免疫系統(tǒng)中是可以被抵御的?HIV感染的這個(gè)階段被稱作艾滋病

好消息是已經(jīng)有有效的藥物?能夠控制HIV病毒水平，?并防止T細(xì)胞數(shù)目過(guò)低，?從而避免發(fā)展成為艾滋病?如果進(jìn)行抗逆轉(zhuǎn)錄病毒治療，?大部分HIV陽(yáng)性的病人能夠繼續(xù)正常生活?而且也會(huì)減少對(duì)其他人的感染

但目前有兩個(gè)難點(diǎn)?第一，HIV陽(yáng)性病人在有生之年?必須一直服藥?如果停止，HIV會(huì)惡化

那么，這些藥物是如何起作用的？?最常用的那些臨床藥物可以阻止病毒的基因?復(fù)制并合并入宿主細(xì)胞DNA?其他的藥物可以阻止病毒的變異和組裝?使得HIV病毒不能感染體內(nèi)其他細(xì)胞

但是HIV病毒會(huì)藏在目前藥物無(wú)法到達(dá)的地方：?健康T細(xì)胞的DNA中?大部分T細(xì)胞被HIV傳染后迅速死亡?但是很小的一部分?被用作構(gòu)建更多HIV病毒的場(chǎng)所，會(huì)處于休眠?有時(shí)甚至好幾年?因此，即使我們能夠清除感染人體的每一個(gè)HIV病毒?一個(gè)這樣的T細(xì)胞就能激活并且重新傳播病毒

另一個(gè)難點(diǎn)是，并不是世界上的所有人都能獲得?這些能夠挽救他們生命的藥物?在撒哈拉以南非洲， 這個(gè)地區(qū)占全球艾滋病患者的70％以上?2012年，僅有三個(gè)HIV陽(yáng)性患者接受抗逆轉(zhuǎn)錄病毒治療?這個(gè)問(wèn)題很難解決?政治，經(jīng)濟(jì)，文化的障礙?使得有效的預(yù)防和治療變得困難?即使是在美國(guó)，每年HIV奪去超過(guò)10000人的生命

但是依然有希望?研究人員比以往任何時(shí)候都接近發(fā)展出真正的治療方法?一項(xiàng)研究涉及?使用一種藥物激活隱含HIV遺傳信息的所有細(xì)胞?這將破壞這些細(xì)胞并且將病毒暴露出來(lái)?接著我們現(xiàn)有的藥物就可以起作用了?另外一種是使用基因工具?將HIV的DNA從細(xì)胞基因組剪切下來(lái)

盡管七千萬(wàn)人中僅有一例治愈?但是一個(gè)總比沒(méi)有好?我們現(xiàn)在清楚治療還是有可能的?這告訴我們將需要什么去擊敗HIV

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In 2008, something incredible happened: a man was cured of HIV.?In over 70 million HIV cases, that was a first and, so far, a last.?We don't yet understand exactly how he was cured.?We can cure people of various diseases, such as malaria and hepatitis C,?so why can't we cure HIV??Well, first let's examine how HIV infects people?and progresses into AIDS.

HIV spreads through exchanges of bodily fluids.?Unprotected sex and contaminated needles are the leading cause of transmission.?It, fortunately, cannot spread through air, water, or casual contact.?Individuals of any age, sexual orientation, gender and race?can contract HIV.

Once inside the body, HIV infects cells that are part of the immune system.?It particularly targets helper T cells,?which help defend the body against bacterial and fungal infections.?HIV is a retrovirus,?which means it can write its genetic code into the genome of infected cells,?co-opting them into making more copies of itself.

During the first stage of HIV infection,?the virus replicates within helper T cells,?destroying many of them in the process.?During this stage, patients often experience flu-like symptoms,?but are typically not yet in mortal danger.?However, for a period ranging from a few months to several years,?during which time the patient may look and feel completely healthy,?the virus continues to replicate and destroy T cells.?When T cell counts drop too low,?patients are in serious danger of contracting deadly infections?that healthy immune systems can normally handle.?This stage of HIV infection is known as AIDS.

The good news is there are drugs that are highly effective?at managing levels of HIV?and preventing T cell counts from getting low enough?for the disease to progress to AIDS.?With antiretroviral therapy,?most HIV-positive people can expect to live long and healthy lives,?and are much less likely to infect others.

However, there are two major catches.?One is that HIV-positive patients must keep taking their drugs?for the rest of their lives.?Without them, the virus can make a deadly comeback.

So, how do these drugs work??The most commonly prescribed ones prevent the viral genome from being copied?and incorporated into a host cell's DNA.?Other drugs prevent the virus from maturing or assembling,?causing HIV to be unable to infect new cells in the body.

But HIV hides out somewhere our current drugs cannot reach it:?inside the DNA of healthy T cells.?Most T cells die shortly after being infected with HIV.?But in a tiny percentage,?the instructions for building more HIV viruses lies dormant,?sometimes for years.?So even if we could wipe out every HIV virus from an infected person's body,?one of those T cells could activate and start spreading the virus again.

The other major catch is that not everyone in the world has access to the therapies?that could save their lives.?In Sub-Saharan Africa, which accounts for over 70% of HIV patients worldwide,?antiretrovirals reached only about one in three HIV-positive patients in 2012.?There is no easy answer to this problem.?A mix of political, economic and cultural barriers?makes effective prevention and treatment difficult.?And even in the U.S., HIV still claims more than 10,000 lives per year.

However, there is ample cause for hope.?Researchers may be closer than ever to developing a true cure.?One research approach involves?using a drug to activate all cells harboring the HIV genetic information.?This would both destroy those cells and flush the virus out into the open,?where our current drugs are effective.?Another is looking to use genetic tools?to cut the HIV DNA out of cells genomes altogether.

And while one cure out of 70 million cases may seem like terrible odds,?one is immeasurably better than zero.?We now know that a cure is possible,?and that may give us what we need to beat HIV for good.

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