Blood groups By Abdelrahman and Mostafa.pptx

Blood groups

1. Blood groups

2. AGENDA Introduction Principles ​ Blood Groups, Antigens and Antibodies RH factor

3. Introduction Blood transfusions in the past was from the most chaotic medical procedures that had terrible consequences, before the groundbreaking work of Karl Landsteiner in the early 20th century, the intricacies of blood compatibility were a mystery, leading to disastrous outcomes in the realm of blood transfusions. In the pre-Landsteiner era, physicians attempted transfusions with little knowledge of the diverse blood types that exist among individuals. The consequences were often dire, marked by a litany of adverse reactions ranging from severe discomfort to fatal outcomes. This paved the way for immune responses that triggered clotting and hemolysis, wreaking havoc on the circulatory system.

4. The consequences people with wrong blood transfusion had to deal with: Wrong blood transfusions in the past led to severe consequences for individuals, including immediate adverse reactions and long-term health complications. Incompatible transfusions often resulted in Hemolytic reactions, where the immune system attacked and destroyed transfused red blood cells, causing kidney damage, jaundice, and potentially fatal complications. Clotting disorders were another peril( (خطر , with the risk of blood clots forming in vessels, leading to conditions like deep vein thrombosis (تجلط الأوردة) and pulmonary embolism (الانسداد الرئوي) . Acute Hemolytic Transfusion Reactions (AHTR) manifested as a severe, immediate response with symptoms such as fever, nausea (غثيان) , and shock. Delayed immune reactions emerged gradually, contributing to chronic anemia, persistent fatigue, and compromised organ function. Moreover, the transmission of infections, including HIV and hepatitis( (التهاب الكبد .

5. Principles A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). Blood is characterized into different blood groups, based on the presence or absence of these Antigens or Antibodies . The ABO blood group is characterized by two glycolipid antigens, called A and B – depending on whether the RBCs have none, only one or both antigens, blood groups are distinguished as type O, type A, type B, or type AB.

6. But, what are Antigens and Antibodies ?? Antigens are markers that tell your immune system whether something in your body is harmful or not. Antigens are found on viruses, bacteria, tumors and normal cells of your body. Antigens are also called agglutinogens because of their capacity to cause agglutination of RBCs. Antibodies are protective proteins produced by your immune system. They attach to antigens (foreign substances) — such as bacteria, fungi, viruses and toxins — and remove them from your body.

7. Blood grouping (ABO Basics) Determination of ABO blood groups depends upon the immunological reaction between antigen and antibody. Landsteiner Rule: If an antigen is present on a patients red blood cells (RBCs) the corresponding antibody will NOT be present in the patients plasma, under 'normal conditions’.

8. Based on the presence or absence of antigen A and antigen B, blood is divided into four groups: "A, B, AB and 'O' group. Blood having antigen A belongs to 'A' group. This blood has ẞ-antibody in the serum. Blood with antigen B and a-antibody belongs to 'B' group. If both the antigens are present, blood group is called 'AB' group and serum of this group does not contain any antibody. If both antigens are absent, the blood group is called 'O' group and both a and ẞ antibodies are present in the serum.

9. Principles of blood grouping Blood grouping is done on the basis of agglutination. Agglutination means the collection of separate particles like RBCs into clumps or masses. Agglutination occurs if an antigen is mixed with its corresponding antibody which is called isoagglutinin, i.e. occurs when A antigen is mixed with anti-A or when B antigen is mixed with anti-B. It is the thing that made the disasters when we were ignorant about Blood grouping.

10. IMPORTANCE OF ABO GROUPS IN BLOOD TRANSFUSION During blood transfusion, only compatible blood must be used. The one who gives blood is called the 'donor' and the one who receives the blood is called 'recipient While transfusing the blood, antigen of the donor and the antibody of the recipient are considered. Thus, RBC of 'O' group has no antigen and so agglutination does not occur with any other group of blood. So, 'O' group blood can be given to any blood group persons and the people with this blood group are called 'universal donors ’. Plasma of AB group blood has no antibody. This does not cause agglutination of RBC from any other group of blood. People with AB group can receive blood from any blood group persons. So, people with this blood group are called 'universal recipients'.

11. Rh factor In addition to antigens of ABO system, the red cells of humans also contain an additional antigen, called Rh antigen (or Rh factor). There are several varieties of Rh antigen—C, D, E, c, d, and e—but the D antigen is the most common, and antigenically, the most potent( (الأقوى . Therefore, Rh + ve persons are also called D + ve and Rh – ve are called D – ve . Persons whose red cells contain this additional antigen are called “Rh positive” ( Rh +) while those who lack this antigen are called “Rh negative” (Rh –). However, there are no naturally occurring antibodies against Rh (D) antigen. The Rh (D) antigen is not present in body fluids and tissues, but only on red cells.

12. Medical significance of RH factor Although there are no natural anti-Rh antibodies, and they never develop spontaneously, they can be produced only in Rh – ve persons. This can happen in either of 2 ways: In transfusions. When an Rh – ve person receives Rh + ve blood, there is no immediate reaction since there are no antibodies. But during the next few weeks/months, he/she may produce anti-Rh antibodies that will remain in the blood. (Even 0.5 ml of Rh + ve blood is enough to produce immune response). However, if within a few weeks, or even years later, a second Rh + ve blood is injected, the newly donated red cells will be agglutinated, thus resulting in a serious transfusion reaction.

13. In pregnancy. The most common problem due to Rh incompatibility( (عدم توافق may arise when an Rh – ve mother (phenotype dd) carries an Rh + ve fetus( (الجنين . Normally, no direct contact occurs between maternal ) mother related) and fetal bloods. However, if a small amount of Rh + ve blood leaks (at the time of delivery) from the fetus through the placenta into the mother’s blood, the mother’s immune system will start to make anti- Rh antibodies. As a result, some mothers develop high concentration of anti-Rh antibodies during the period following delivery. Therefore, the first-born baby will not be affected. However, during the second and following pregnancies, the mother’s anti-Rh antibodies cross the placental membrane into the fetus where they cause agglutination. The clinical condition that develops in the fetus is called “hemolytic disease of the newborn (HDN)’ or “erythroblastosis fetalis” ( داء كرات الدم الحمراء الجنينية )

14. شكرا لحسن استماعك ساهم في صناعته كلا من: عبدو IT مصطفى مسعد مع السلامة

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