Immune Hematology L Bonstien PhD E J Dann MD
RED BLOOD CELL SURFACE MAMBRANE
BLOOD GROUPS Systems ANTIGENS and Chromosomal Location
ABO system Carbohydrate Antigens ABO Antigens are not unique to RBC.They are present on other cells and in bacteria and plants 80% of humans excrete ABO antigens in their secretions (Secretors) Secretors (of Antigens) = Se/Se, Se/se Non secretors = se/se
Incidence of ABO blood groups in Israeli population שכיחות INCIDECE סוג TYPE שכיחות INCIDECE סוג TYPE 4%-A-A38%+A+A 2%-B-B16%+B+B 1%-AB6%+AB 3%-O-O30%+O+O D- are 15 % of the population less then world prevalence
Possible genotype and Phenotype when the parents are O and A or B
THERE IS A SINGLE SUGAR DIFFERENCE BETWEEN THE A AND B TYPE
Indirect agglutination test known RBC with patient serum
Intra Vascular Hemolysis Due to infusion of A RBC to O recipient
Antigens of Rh system Are encoded by 2 homologous genes RHD and RHCE Transport proteins in the RBC membrane Basic unit is a quartenary complex of 2RhAG +2RhD or 2RhAG+2RhCE D is the significant immunogen cde/cde are D- or rr 15% 32% CDe/cde 17%CDe/Cde 13%cDE/cde 14%CDe/cDE 4%cDE/cDE Other genotype are almost all + There is no d protein it is a null protein
Rh system 15% of caucasian and 5% of black are Rh- 1% of asian popularion are Rh- D+ are marked D and negative are d are Rh+ D/D or D/d, are Rh- d/d
BLOOD TYPING 1.ABO and Rh blood group is determined 2.USE of sera of anti A B sera anti D with patients erythrocytes 3.Use of Pt serum to check for anti A and anti B with known A1 and B RBC 4.Serum is screened for important antibodies by an indirect antiglobulin test on a large panel of antigenically-typed red cells
patient RBC with commercial sera serum Patient Anti A Anti B Anti D A RBC B RBC A+A AB+AB B O+O+
Hoffbrand Petit Moss essential Haematology 4 th edition
IgM antibodies can activate complement and cause intra vascular hemolysis
IgG Antibodies usualy cause extra vascular hemolysis
Direct Anti Globulin Test(Direct Coombs) Anti human globulin helps to complete the reaction in presence of IgG DAT screen for Ab on RBC cells attached in vivo an example hemolitic disease of the newborn Indirect Anti Globulin Test for Ab in the pt serum. The reaction between the Ab and Ag is in vitro anti IgG Coombs reagent is mono specific IgG + anti C 3 Coombs reagent is poly specific
RBC Antibody is attached to Antigen on Erythrocyte surface membrane RBC Adding anti Human Globulin In Vitro Direct Anti Globulin Test(Coombs’)
Indirect Anti Globulin Test (Indirect coombs) survey of acquired antibodies in patient serum
Allo antibodies versus Auto antibodies Allo Ab are antibodiy against antigen from foreign blood Versus auto Ab which react with self Red Blood Cell Ag
Antibodies screening
Indirect Anti Globulin Test
Positive test in Presence of Ag
Direct Anti Globulin Test Aim Detection of Ab on Pt RBC in cases of Hemolysis
A case study A pt with anemia, fatigue, respiratory distress on exertion Lab results anemia and high reticulocyte count Positive Direct Anti Globulin test (DAT) High LDH high billirubin Dg autoimmune hemolytic anemia
Rx steroids, packed red blood cells folic acid
Hemolytic disease of the new born - HDN Appearance of Ab in the blood stream of a pregnant woman against paternal Ag present in fetal blood
HDN IgG Ab that cross the placenta
Ist exposure (Pregnancy)
Second exposure (Second preg) or post infusion of Rh + blood
HDN Rx UVa exposure to decrease levels of un conjugated billirubin Exchange transfusion of blood Direct anti globulin test to fetal blood or new born Indirect globulin test to maternal serum If mother has no Anti D check for other Ag Yta for example
HDN Direct Anti Globulin Test
HDN prevention by injection of anti D (Proginin) 500 iu during pregnancy at week 28 and 34 at birth if baby is having a Rh+ another dose is indicated within 72 hours
Antibodies found in a pt Antibodies in serum Antibodies on RBC Post transfusion+- Post pregnancy+- A new born to mother who carry Ab ++ Auto immune disease possible+
Thank You Uribamba Valley Peru 5/2004