Body Parts – Rhesus Factor

Blood is red, it’s sticky and just the sight of it makes a fair proportion of the population go wobbly at the knees. But mixing our blood without matching it can have disastrous, even fatal results.

We all fall into four main blood groups: A, B, AB and O. The types refer to different antigens that sit on the surface of the millions of red blood cells in our bodies. An antigen is a protein that prompts the body to produce an antibody.

If you have blood type A, your plasma carries B antibodies so that if you    come into contact with type-B blood, the antibodies seek and destroy the B red blood cells. Contact between the two blood types can have serious consequences, including kidney failure and shock. People with type AB have both A and B antigens while O type blood have neither.

Austrian pathologist Kal Landsteiner identified the first two red cell antigens, A and B, in 1900. In the 1940s, Land Steiner identified a further class of antigen, the rhesus (Rh) factor, named after the monkeys in which the discovery was made.

Rhesus factor is in the red blood cells of most people, but about 15 percent  of people are rhesus-negative. If you are rhesus-negative and receive rhesus-positive blood, you will produce anti-rhesus antibodies.

The first time is not usually crucial, because by then the donated blood is    diluted. But if you receive further transfusions of Rh-positive blood, the anti-rhesus antibodies will attack the positive blood cells, causing agglutination or   clumping, which can be fatal.

身体构件 – 猕因子（Rhesus factor）

血液呈红色而且黏稠。即使是些微的血液也会使相当比例的人群两腿发颤。但是，如果我们的血液中混入了和它不相匹配的血液，那么将导致灾难性、甚至是致命的后果。.

我们所有人属于四大类血型：A型, B型, AB型和O型。这些血型所指的是存在于人体内数百万血红细胞表面的不同类抗原。每种抗原是一种促进身体产生抗体的蛋白。

如果你是A类血型，同时你的血浆携带B型的抗体，那么如果你接触了B型血，这些抗体就会寻找并且破坏B型血红细胞。这两种血型接触到一起会产生严重的后果，包括肾衰竭和休克。AB血型的人既有A型又有B型抗体，而O型血的人两种抗体都没有。

奥地利的病理学家卡尔•兰德斯泰纳（Karl Landsteiner）于1900年识别出了前两种红细胞抗原，A型和B型。 20世纪40年代，兰德斯泰纳从一些猴子身上进一步识别出一种抗原类型，猕因子, 该名称是以被发现此类抗原的这些猴子命名的。

猕因子存在于大多数人的血红细胞内，但只有15%的人呈猕阴性(rhesus-negative)。如果你是猕阴性并且接受了猕阳性血液，那么你就会产生抗猕（anti-rhesus）抗体。

第一次出现这种情况，后果通常不严重，因为此时所供的血液经过了稀释。但如果你继续接受输入猕阳性血液，抗猕抗体就会攻击阳性红细胞，从而引起致命的凝集。