BLOOD GROUPS BLOOD TRANSFUSION

Blood Groups Systems The cell membrane of the red blood cells contains a variety of agglutinogens which form the basis of blood groups.

Cell Membrane

Blood Group Systems ABO system Rh system M,N system Kell system Lewis system

A B O SYSTEM DEPENDS ON THE PRESENCE OR ABSENCE OF BLOOD GROUP ANTIGENS (AGGLUTINOGENS ) A AND B ON THE SURFACE OF RED CELLS. BLOOD GROUP A HAS A ANTIGEN B HAS B ANTIGEN AB HAS both A AND B ANTIGENS O HAS NONE

A and B antigens are glycoproteins O A B

ANTIBODIES AGAINST AGGLUTINOGENS CALLED AGGLUTININS PRESENT IN PLASMA AGGLUTININ α acts against antigen A AGGLITININ β acts against antigen B

LANDSTEINER’S LAW When a particular blood group antigen is present on the red cells, the plasma does not contain the corresponding antibody. E.g if red cells have antigen A, plasma would not α agglutinin When if a blood group antigen is absent, the plasma always contains the corresponding antibody. Group A person has β agglutinin Group O person has both α and β agglutinins

BLOOD GROUP ANTIGEN AGGLUTININ A A β B B α AB A,B -- O O α,β

BLOOD GROUPS GENETICALLY DETERMINED. In different populations, percentage of different blood groups varies. Europeans have most commonly groups O and A Asians have most commonly group B and O

Antigens A an B develop in intrauterine life Agglutinins appear only after birth due to exposure to various foods and intestinal bacteria.

Secretion of blood group substances Many tissues other than red cells contain the blood group substances, e.g. salivary glands, pancreas, kidney, liver etc Blood group substances secreted in body fluids like saliva, semen, amniotic fluid may be used to identify a criminal, but now DNA test is most specific.

Gene A and B are codominant over gene O BLOOD GROUP (Phenotype) GENO TYPE A A A or A O B B B or B O AB A B O O O ROLE IN PATERNITY DISPUTES : Now DNA test used

Role of BLOOD GROUPS IN BLOOD TRANSFUSION BG( REC) ANTIBODY (REC) Blood Group of DONOR A B AB O A β B α AB O α, β =AGGLUTINATION -- =No agglutination. RC = recipient BLOOD GROUP O Universal DONOR AB Universal RECIPIENT

Normal red cells In saline

Agglutination

Blood clotting Fibrin threads

Rh SYSTEM OF BLOOD GROUPS RED CELLS OF ABOUT 9O % HUMANS CONTAIN Rh ANTIGEN =Rh positive 10 % do not have Rh antigen=Rh negative Rh antibodies not naturally present. (Rh system does not follow Landsteiner law) Only red cells have Rh antigen. No other tissue

Rh antibodies appear in blood if: Rh – individual transfused Rh + blood or Rh – female gives birth to a Rh + baby (i.e. father is Rh+) Three types of Rh antigens C,D and E commonest is D antigen

Genetic transmission of Rh factor Rh + individual may have DD or Dd genotype Rh- individual has dd genotype If the father is Rh + (Dd genotype) and mother Rh-,only half of the children are likely to be Rh +. If father has DD genotype, all the children are Rh+ No way to differentiate DD and Dd genotypes

HEMOLYTIC DISEASE OF THE NEWBORN ( OR) ERYTHROBLASTOSIS FETALIS If father Rh + and mother Rh --, fetus may be Rh + During pregnancy specially during delivery, separation of placenta, some Rh + fetal blood enters maternal circulation. Mother’s tissues develop Rh antibodies (IgG type).

During next pregnancy with a Rh + fetus these antibodies reach fetus through placenta and cause hemolysis of fetal cells -----Severe anemia and jaundice

Result: Fetal death in utero or The baby dies soon after birth or Newborn baby has severe anaemia and jaundice Fetal peripheral blood shows erythroblasts Kernicterus develops if serum bilirubin above 18 m%. Bilirubin deposited in basal ganglia----permanent brain damage

Erythroblastosis (nucleated red cells in peripheral blood)

Treatment: Exchange blood transfusion with ABO compatible Rh– blood PREVENTION: MORE IMPORTANT JUST AFTER FIRST DELIVERY INJECT Rh antibodies to the mother. It destroys Rh + fetal cells before they get implanted in the maternal immunological competent tissues

BLOOD BANK FOR STORAGE OF BLOOD: BLOOD 420 ML 2%DISODIUM CITRATE 100 ML (anticoagulant, lowers blood pH) 15% DEXTROSE 20 ML( nutrient, lactic acid lowers pH) STORE AT 4 o C

A thief broke into a blood bank and became a VAMPIRE

Blood bank

BLOOD TRANSFUSION INDICATIONS : Whole blood transfusion BLOOD LOSS INJURY SURGICAL OPERATION ERYTHROBLASTOSIS FETALIS (EXCHANGE TRANSFUSION)

INDICATIONS BLOOD PRODUCTS Packed cells: Severe anemia Albumin: Severe hypoprotenemia Rh immunoglobulins: Rh – mother Granulocyte concentrate: severe granulocytopenia Platelet concentrate: Severe thrombocytopenia

Changes during storage of blood (effects of low temperature) REDUCED red cell METABOLISM: Sodium- potassium pump activity weak. Intracellular Na+ rises to m Eq / L Extra cellular K + rises to m Eq / L Red cells swollen, greater osmotic fragility. White blood cells and platelets disappear----- short life span. IONIC BALANCE RESTORED HOURS AFTER TRANSFUSION

Precautions SAFEST: INTRAGROUP TRANSFUSION CROSS MATCHING ESSENTIAL FOR ABSOLUTE SAFETY CROSS MATCHING: MATCH CELLS OF DONOR WITH SERUM OF RECIPIENT MATCH SERUM OF DONOR WITH CELLS OF RECIPIENT

DANGERS OF BLOOD TRANSFUSION INFECTIONS : AIDS, HEPATITIS, MALARIA HYPERKALEMIA :( STORED BLOOD WITH HIGH PLASMA K+ USED FOR MANY TRANSFUSIONS) ALKALOSIS : WHEN MANY TRANSFUSIONS, AND KIDNEY FUNCTION POOR( CITRATE METABOLISED TO BICARBONATE NOT EXCRETED) HYPOCALCEMIA: ( MANY TRANSFUSIONS : DUE TO EXCESS OF CITRATE) CIRCULATORY OVERLOAD

INCOMPATIBILITY REACTIONS A.Inapparent hemolysis( slight mismatch) B. Post-transfusion jaundice (transient)

Agglutination

Agglutination: antigen-antibody reaction

Red cell agglutination Rouleaux formation

Effect of red cell agglutination: Capillary blockade

C.Severe incompatibility reaction: (Gross mismatch ) Clumping of red cells--- capillary blockade in vital organs --- death or Severe intravascular hemolysis –-----Hb released into plasma---hemoglobinuria, fall of BP,---- Low GFR-----blockade of renal tubules by precipitation of acid hematin ---acute renal failure ---death Cross matching prior to transfusion : mandatory to avoid mismatch reactions

Renal Tubule

Hemoglobinuria

EFFECTS OF BLOOD DONATION EFFECTS OF BLOOD DONATION ON DONOR : NIL CONTRAINDICATIONS FOR BLOOD DONATION 1. AGE BELOW 18 YEARS OR ABOVE PREGNANCY 3. ANAEMIA 4. HISTORY OF VIRAL HEPATITIS, MALARIA AIDS,