What is a blood group?• Any variation or polymorphism "having multiple forms". detected in the blood could be considered a blood group, restricted to blood cell surface antigen generally to red cell surface antigen
Nomenclature• The ABO blood group system was discovered by Karl Land Steiner in 1901. Red blood cells or erythrocytes are present in the blood and contain certain proteins on their surface.• These proteins are called antigens.• The plasma which is the liquid part contains antibodies which will attack certain antigens if they are present.• There are various types of red blood cell antigens - the ABO and rhesus types are the most important.• By the time a person is six months old, he naturally will have developed antibodies against the antigens his red blood cells lack.
Blood Group “A”• A blood group individuals will have type A antigens on the surface of red blood cells• And anti-B antibodies in plasma
Blood Group “B”• B blood group individuals will have type B antigens on the surface of red blood cells• And anti-A antibodies in plasma.
Blood group AB• AB blood group are those who will have type A and type B antigens on the surface of red blood cells• And no antibodies to A or B antigens in plasma.
Blood group “O”• O blood group are those who will have neither type A or type B antigens on the surface of red blood cells• but will have anti-A and anti-B antibodies in plasma.
1. The reason for the presence of A and B antibodies in blood is not clearly understood.2. Antibody normally do not developed against unless the body is exposed to the antigen.3. This means, for example, that a person with type A blood should not have type B antibodies unless he has received a transfusion of type B blood, which contain type B anti-gens
• Because people with type A blood (who never have received a transfusion of type B blood) do have type B antibodies,• One possibility is that type A or type B antigens on bacteria or food in the digestive tract stimulate the formation of antibodies against antigens that are different from ones own antigens.• Thus a person with type A blood would produce type B antibodies against the B antigens on the bacteria or food.• In support of this hypothesis is the observation that A and B antibodies are not found in the blood until 2 months after birth
Donor and recipient• A donor is a person who give blood• A recipient is a person who received blood•
• The six possible O 47% combinations of genes, as shown in are OO, OA, OB, AA, A 41% BB, and AB. These combinations of genes are known as B 9% the genotypes, and each person is one of A B3% the six genotypes.
• A general view of the molecular structure of Elizabethkingia meningosepticum N- acetylgalactosaminidase in complex with the NAD+ cofactor (in yellow) and the A antigen on the surface of A type red blood cells. The N- acetylgalactosamine molecule recognized and hydrolyzed by the enzyme appears in red. (Credit: Copyright AFMB - CNRS 2007)
Rhesus factor History of discoveries• The Rhesus system is named after the Rhesus monkey, following experiments by Karl Land steiner and Alexander S. Wiener, which showed that rabbits, when immunised with rhesus monkey red cells, produce an antibody that also agglutinates the red blood cells of many humans. This factor was discovered in 1937 (publishing in 1940)
Rhesus factor• Individuals either have, or do not have, the Rhesus factor (or Rh D antigen) on the surface of their red blood cells.• This is usually indicated by RhD positive (does have the RhD antigen)• or RhD negative (does not have the antigen)• This suffix is often shortened to D pos/D neg, RhD pos/RhD neg, or +/-.• RhD+• or RhD-• In simplest terms, there may be prenatal danger to the fetus when a pregnant woman is RhD-negative and the biological father is RhD-positive.
Hemolytic disease of the newborn• Hemolytic disease of the newborn is also called Erythroblastosis Fetalis. This condition occurs when there is an incompatibility between the blood types of the mother and the baby..• hemolytic comes from two words: hemo (blood) and lysis (destruction) or breaking down of red blood cells• erythroblastosis refers to the making of immature red blood cells• fetalis refers to the fetus
When the condition is caused by the RhD antigen-antibody incompatibility, it is called RhD Hemolytic disease of the newborn (often called Rhesus disease or Rh disease Here, sensitization to Rh D antigens (usually by feto- maternal transfusion during pregnancy) may lead to the production of maternal anti- RhD antibodies which can pass through the placenta. This is of particular importance to RhD negative females because any subsequent pregnancy may be affected by the Rhesus D hemolytic disease of the newborn if the baby is Rh D positive.
• Fetal-maternal hemorrhage can occur due to trauma, abortion, childbirth, ruptures in the placenta during pregnancy, or medical procedures carried out during pregnancy that breach the uterine wall.• In subsequent pregnancies, if there is a similar incompatibility in the fetus, these antibodies are then able to cross the placenta into the fetal bloodstream to attach to the red blood cells and cause hemolysis.• In other words, if a mother has anti-RhD antibodies as a result of previously carrying a RhD-positive fetus, this antibody will only affect a fetus with RhD-positive blood.
• The vast majority of Rh disease is preventable in modern antenatal care by injections of IgG anti- D antibodies (Rh(D) Immune Globulin).• The incidence of Rhesus disease is mathematically related to the frequency of RhD negative individuals in a population, so Rhesus disease is rare in East Asians and Africans,• but more common in Caucasians.
Population dataThe frequency of Rh factor blood types and the RhD neg allele gene differs invarious populations.]Population data for the Rh D factor and the RhD neg allelePopulation Rh(D) Neg Rh(D) PosEuropean Basque approx 35% 65%Caucasian Approx 35 % 65%American Blacks approx 35%16%approx 65%84%93%99%over 7%approx 1%less 1%less 1% 99%over 99%Native American approx 35%16%approx 65%84%93%99%overIndians 7%approx 1%less 1%less 1% 99%over 99%African descent approx 35%16%approx 65%84%93%99%over 7%approx 1%less 1%less 1% 99%over 99%
Symptoms and signs in the Fetus: Enlarged liver, spleen, or heart and fluid buildup in the fetus abdomen seen via ultrasound.• Symptoms and signs in the Newborn: 1. Anemia which creates the newborns pallor (pale appearance). 2. Jaundice or yellow discoloration of the newborns skin, sclera or mucous membrane. This may be evident right after birth or after 24 - 48 hours after birth. This is caused by bilirubin (one of the end products of red blood cell destruction). 3. Enlargement of the newborns liver and spleen. 4. The newborn may have severe edema of the entire body. 5. Dyspnea or difficulty breathing.