新科学家杂志-血型清除对器官移植的意义

器官移植有多难

器官移植是个医学奇迹也是个难题。

因为病人进行器官移植后，会面临着诸多的并发症。

大家有没有想过这样一个问题：

如果器官捐献者是A型血，而器官接受者是B型血，

那么移植后，会出现什么样的情况呢？

或者换句话：血型对器官移植有什么影响？

克服血型限制对器官移植意义多大

这就是本期《新科学家》杂志New Scientist 里的一篇文章要讲述的问题。

本文标题：

Lung changed to new blood type is a step towards universal donor organs

捐赠肺血型改变，是万能捐赠器官的垫脚石

RESEARCHERS have successfully changed the blood type of a donated human lung by treating it with enzymes, marking an important step towards making universal donor organs.

研究人员通过酶成功地改变了一颗捐赠肺的血型，这标志着人类向万能捐赠器官迈出了重要的一步。

“We still have a way to go to show safety in clinical trials,” says Marcelo Cypel at the University of Toronto, Canada. “But assuming that the results on clinical trials are similar to the results we observed here, this will be a major breakthrough.”

加拿大多伦多大学的马塞洛. 赛派尔说：“为了临床实验的安全性，我们仍有长路要走。

但假设我们的临床实验结果与这里观察到的结果相似，那么这将成为一个重大突破”。

血型与移植反应

Blood types are largely defined by the presence or absence of certain sugar molecules called antigens on the surface of cells. These can occur not just on the cells of the blood itself, but also other tissues, such as those in the lung.

血型的不同主要是由一种生长在细胞表面的被称作抗原的某种糖分子的缺失或者出现造成的。

这种缺失或出现不仅发生在血液表面，还发生在其他组织中，如肺部细胞上。

If an antigen isn’t recognised by the body’s immune system, it will mount an attack on these cells. This leads to the rejection of transplanted organs from a donor with a different blood type.

如果一种抗原没有被身体的免疫系统识别，那么免疫系统就会向这些细胞发起攻击。

这就会导致来自不同血型捐赠者的移植器官发生排异反应。

如何克服血型障碍

People with the most common blood type, O, lack these antigens on their cells, so their organs can be accepted by people with other blood types. If all donor organs could be made type O, for example the lungs from someone with blood type A, this could be a help.

拥有最常见血型O型血的人细胞上缺乏这些抗原，所以他们的器官可以被其他血型的人接受。

如果所有捐赠器官都变成O型，比如来自A型血人的肺变成O型，那就可以了。

To try this, Cypel and his team used a pair of enzymes that are normally found in the human gut to digest sugars. They found that the enzymes removed more than 99 per cent of type A antigens from red blood cells and 97 per cent in lungs from a type A donor in 4 hours. This meant the cells had been effectively changed to blood type O.

为了进行这个尝试，赛派尔和他的团队使用了一对一般能在人体肠道发现的用于消化糖的酶。

他们发现这种酶在4个小时内，将红细胞中99%多的A型抗原清除了，而且来自A型捐赠者的肺部抗原也被去掉了97%。

这说明细胞被有效地变成了O型血。

血型清除实验是如何完成的

After this treatment, the altered lungs were kept alive using a system known as ex-vivo lung perfusion, which supplies organs with nourishing fluid so they are ready for transplantation.

这项操作之后，使用一种被称作体外肺灌注的系统让被变换的肺保持活性。这种系统能给器官提供液体，直到其被移植。

To simulate a transplant, Cypel’s team then added type O blood, which contains antibodies that would attack type A antigens, to the fluid supplying the lungs.

为了激发移植器官，赛派尔的团队将O型血加入到了供养给肺部的液体中。

该O型血中含有能够攻击A型抗原的抗体。

The three treated lungs had minimal antibody damage compared with untreated lungs (Science Translational Medicine, doi.org/gphgf5). “When we perfused the lung with old blood, there was no sign of rejection or organ dysfunction,” says Cypel.

与未经过处理的肺相比，这三个肺的抗体损伤最小。

赛派尔说：“当我们将原先的血液灌注到肺部中时，并没有发现排斥或器官功能障碍的情况。”

Although cells stripped of antigens tend to produce new ones over time, Cypel hopes that the lack of antigens would last long enough for the body to get through the perilous first few days and weeks after a transplant. The team now intends to test the procedure in animals.

尽管被去除了抗原的细胞还会随着时间推移产生新的抗原，但赛派尔说他希望这些抗原缺失的时间能让患者安全渡过移植后最初几天和几周的凶险阶段。

该团队现在打算在动物身上进行这一流程的测试。

血型清除方法到底可行与否

The study only looked at the effects of a simulated transplantation over the short term, which isn’t enough time to assess whether the resurfaced antigens could eventually have a negative effect, says Jasvir Parmar at Royal Papworth Hospital, Cambridge, UK. “We can’t[yet] say whether re-exposure of these antigens or the changes that come with that are going to be deleterious in the long run or not,” he says.

该研究只对短期模拟移植的效果进行了研究，而对于重新出现的抗原最终带来的负面影响的评估时间不足。

英国剑桥皇家帕普沃思医院的Jasvir Parmar说“我们现在还不能说这些再次出现的抗原或随着移植而产生的变化在长期来看是有害的。”