The red blood cells contain agglutinogen that can be fused, and the plasma contains lectins of sticking functions in it. There are two kinds of agglutination origin A and B; there are also two kinds of Lectins, anti-A and anti-B. The A and anti-A, B and anti-B are two pairs of enemies, they will “fight” together, and have agglutination when twisted together. If the agglutination origin A input into the blood encounter the anti-B of the patients plasma, the agglutination reaction will take place.The most common early symptoms are fever, most with chills; Other symptoms are including irritability, flush on face or body, chest pain, low back pain, severe cases will be breathing difficulties, low blood pressure, shock, etc.endprint