Second Patient Cleared of the Virus That Causes AIDS
A man in London has become the second known HIV-positive adult to be cleared of the virus that causes the disease AIDS. The man received a stem cell transplant three years ago. He was treated with anti-retroviral drugs until about 18 months ago. Now, tests show he has no sign of the HIV virus in his blood.
"There is no virus there that we can measure. We can't detect anything," said Ravindra Gupta, a professor and HIV scientist who helped lead a team of doctors treating the man.
The patient's name, nationality or age is not public. He is being called "the London patient" because he was treated in the British capital. A similar identification was given to the first known person cleared of HIV infection more than ten years ago, the "Berlin patient." Both men experienced a similar treatment.
Experts who study AIDS say the success of the Berlin patient and the London patient is very important. Their experiences show that scientists will one day be able to end AIDS.
But experts warn that a cure has not been found. The blood treatments the Berlin and London patients had have failed in other patients. The treatments are also too dangerous, expensive and risky to do for the large number of people who already have the virus that causes AIDS. The United Nations estimates that 37 million people worldwide are living with HIV.
The London patient
The medical story of the London patient begins in 2003. At that time, he was found to have the HIV infection.
Then, in 2016, he developed a kind of cancer that affects the immune system, the part of the body that fights disease. To treat the cancer, the London patient agreed to a treatment called a stem cell transplant.
In the transplant, a healthy donor provides extremely small pieces of his or her body that can create new blood. These are released into the patient's blood system. If the treatment is successful, the patient's body uses the other person's stem cells to build a healthy immune system.
But there was something unusual about the person who gave the London patient stem cells. The giver – or donor – had a natural resistance to HIV. In other words, something about this person's body made it impossible for him or her to become infected with the HIV virus. As a result, when the London patient received the stem cells, his immune system changed and he developed a natural resistance to HIV, too.
The doctors note that the donor's natural resistance to HIV is very rare. Only about 1 percent of people who come from northern European relatives have it. The unusual situation is one reason why this way of treating HIV is not done more often.
But in the case of the London patient, the treatment worked.
Ravindra Gupta notes that the donor's unusual resistance to HIV may not be the only reason the treatment cleared the London patient's infection. He notes that the Berlin patient and the London patient had similar side effects after the treatment. In both cases, the donors' stem cells immediately began to attack the patients' immune cells. The interaction may have helped destroy some of the HIV infection in the patients, Gupta says.
His team plans to use their findings to explore possibilities for future HIV treatment plans. They will present what they have learned so far in the next days in the journal Nature, and at a medical conference in the U.S. city of Seattle, Washington.
I'm Jill Robbins.
1.stem cell 干细胞
Hematopoietic stem cell research is a new subject.
2.so far 迄今为止
So far we haven't been able to find anything, but we're still researching.
3.In other words 换句话说
In other words, the system broke.
4.natural resistance 天然抵抗力
This disease is surprisingly difficult to catch as most people have a natural resistance to it.
5.As a result, when the London patient received the stem cells, his immune system changed and he developed a natural resistance to HIV, too.
As a result 结果
As a result, the bad thing has been turned into a good one.
As a result, industry was overmanned and pen-pushers were everywhere.
6.But in the case of the London patient, the treatment worked.
in the case of 对...而言；至于
In the case of different values, this sum is decreased.
In the case of Hawking, it was for overcoming disability to push the boundaries of science.
伦敦一名男子成为第二位已知的被清除艾滋病毒的艾滋病成年患者 。该男子在3年前接受了干细胞移植手术 。18个月前，他停用了抗逆转录病毒药物的治疗 。现在，经检测他的血液里已经没有艾滋病毒的迹象了 。
教授兼艾滋病毒科学家拉文德拉·古普塔（Ravindra Gupta）协助领导了治疗该男子的医疗团队，他说：“（病人体内）没有检测到病毒，没有发现任何病毒 。”
该患者的姓名、国籍以及年龄都没有公开，他被称为“伦敦患者”，因为他在英国首都（伦敦）接受了治疗 。十多年前，已知首例清除艾滋病毒感染的“柏林患者”也被给予相同的身份 。两名患者都接受了类似治疗 。
但是专家警告称，目前还未找到治愈方法 。“柏林患者”和“伦敦患者”采用的血液治疗方法在其他患者身上失败了 。对于大量已经感染艾滋病毒的患者来说，该疗法也过于危险、昂贵和冒险 。联合国估计全球有3700万人感染了艾滋病毒 。
2003年，“伦敦患者”开始接受治疗 。当时他被发现感染了艾滋病毒 。
2016年，他患上了一种影响免疫系统的癌症，免疫系统能抵御疾病 。为了治疗癌症，“伦敦患者”同意接受“干细胞移植疗法” 。
在移植手术过程中，健康的捐献者会提供体内可创造新血液的极其微小的干细胞 。它们被释放到患者的血液系统中 。如果治疗成功，患者的身体就会通过他人的干细胞来建立一个健康的免疫系统 。
但是，为“伦敦患者”提供干细胞的捐献者情况有些特殊 。该捐献者对艾滋病毒具有天然抵抗力 。也就是说，其特殊的体质导致他（她）很难被艾滋病毒感染 。因此，当“伦敦患者”接受了这些干细胞，他的免疫系统发生了变化，他对艾滋病毒也产生了天然抵抗力 。
医生们指出，捐献者对艾滋病毒的天然抵抗力十分少见 。只有约1%的北欧后裔拥有这种天然抵抗力 。该特殊情况是这种艾滋病毒疗法不常采用的原因之一 。
古普塔指出，捐献者对艾滋病毒的罕见抵抗力或许不是该治疗方法清除“伦敦患者”体内病毒的唯一原因 。他指出，“柏林患者”和“伦敦患者”在治疗后都出现类似的副作用 。在两起病例中，捐献者的干细胞很快就开始攻击患者的免疫细胞 。古普塔表示，这种相互作用可能有助于清除患者体内的部分艾滋病毒感染 。
他的团队计划利用这一研究结果来探索未来艾滋病毒治疗方法的可能性 。他们将在几天后的《自然》杂志以及美国华盛顿州西雅图市的医学会议上展示他们迄今为止的研究成果 。