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Other blood groups. Several other blood group antigens have been identified in humans. Some examples: MN, Duffy, Lewis, Kell. They, too, may sometimes.

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Presentation on theme: "Other blood groups. Several other blood group antigens have been identified in humans. Some examples: MN, Duffy, Lewis, Kell. They, too, may sometimes."— Presentation transcript:

1 Other blood groups

2 Several other blood group antigens have been identified in humans. Some examples: MN, Duffy, Lewis, Kell. They, too, may sometimes cause transfusion reactions and even hemolytic disease of the newborn in cases where there is no ABO or Rh incompatibility.

3 Lewis Blood Group System Le The 7 th blood groud. ABH and Lewis Ag are much related together biochemically. Both have the same basic structure (15 Amino Acids), they are glycoproteins. Lewis Ag: Soluble Ag Production governed by two genes Le a & Le b At birth, there is no Lewis Ag. It takes 3-4 years for the Ags to become strong on the surface of the RBCs.

4 Lewis Ab: Anti Le a Anti Le b Agglutinate blood in saline (IgM), work best at 20 o C, and fix the complement. Do not cause HDN of new born because: Ag not developed yet. IgM, can not cross the placenta.

5 Bombay Phenotype It is an abnormal blood group. Discovered in Bombay in 1952.

6 There are 3 genes, are controlled the synthesis of specific enzymes responsible for addition of single carbohydrate residues: There are 3 genes, are controlled the synthesis of specific enzymes responsible for addition of single carbohydrate residues: N. acetyl Galactoseamin= A antigen. N. acetyl Galactoseamin= A antigen. D.galagtose = B antigen. D.galagtose = B antigen. Fucose = H antigen = O blood group. Fucose = H antigen = O blood group. ? = AB blood group ? = AB blood group ABO system

7 It is important to be cautious in predicting the ABO blood type of children based on the phenotypes of their parents. This is due to the fact that a third antigen (H) on the surface of red cells can prevent the expected ABO blood type from occurring. It is important to be cautious in predicting the ABO blood type of children based on the phenotypes of their parents. This is due to the fact that a third antigen (H) on the surface of red cells can prevent the expected ABO blood type from occurring. Normally, if an A blood type mother has an O type child; the father is expected to be type O or at least to carry the O allele (OO, AO, or BO genotype). Normally, if an A blood type mother has an O type child; the father is expected to be type O or at least to carry the O allele (OO, AO, or BO genotype).

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9 The child has inherited an O allele from both parents. However, an O blood type child can also be born to parents who do not have the O allele if a recessive form of the allele for the H antigen also is inherited from both parents.

10 The H antigen is a precursor to the A and B antigens. For instance, the B allele must be present to produce the B enzyme that modifies the H antigen to become the B antigen. It is the same for the A allele. However, if only recessive alleles for the H antigen are inherited (hh), as in the case above, the H antigen will not be produced. Subsequently, the A and B antigens also will not be produced. The result is an O phenotype by default since a lack of A and B antigens is the O type. The H antigen is a precursor to the A and B antigens. For instance, the B allele must be present to produce the B enzyme that modifies the H antigen to become the B antigen. It is the same for the A allele. However, if only recessive alleles for the H antigen are inherited (hh), as in the case above, the H antigen will not be produced. Subsequently, the A and B antigens also will not be produced. The result is an O phenotype by default since a lack of A and B antigens is the O type. This seemingly impossible phenotype result has been referred to as a Bombay phenotype because it was first described in that Indian city. This seemingly impossible phenotype result has been referred to as a Bombay phenotype because it was first described in that Indian city.

11 There are 2 different terms are used to describe these antigens.: Weiner,s Ag,s ( Rho, rh’, rh”, hr’, and hr” ). Fisher & Race Ags ( D, C, E, c’, and e’ ). The most important Ags in weiner is ( Rho ) The most importnant Ags in fisher and race is ( D ) Antigens of rhesus blood group

12 Rhesus (Rh) blood grouping system Antigens: This is one of the most important blood grouping systems. This is one of the most important blood grouping systems. Named because it was first discovered in rhesus monkeys Named because it was first discovered in rhesus monkeys In 1940 Landsteiner and Wiener showed that antibodies produced against the rhesus monkey RBCs agglutinated RBCs of 85% of a human population. In 1940 Landsteiner and Wiener showed that antibodies produced against the rhesus monkey RBCs agglutinated RBCs of 85% of a human population. The antibodies were directed against a molecule called the rhesus (Rh) antigen, and individuals possessing it were called Rh positive. The antibodies were directed against a molecule called the rhesus (Rh) antigen, and individuals possessing it were called Rh positive. Natural antibodies against the Rh antigens do not occur. Natural antibodies against the Rh antigens do not occur.

13 The gene product is identified as the RhD antigen or D antigen. Rh system is very complex, and our present understanding is based on the Fisher system. Three genes making up Rhesus antigens: C, D, and E, found on chromosome 1, the D Ag is the most important one. There are two possible alleles at each locus: c or C; d or D; and e or E.

14 One haplotype consisting of c/C, d/D, e/E is inherited from each parent, and the resulting Rhesus type of the individual depends on their inherited genotype, this will lead to the following genotypes CDe, cDE, cde, cDe, Cde, cdE, CdE, cde. One haplotype consisting of c/C, d/D, e/E is inherited from each parent, and the resulting Rhesus type of the individual depends on their inherited genotype, this will lead to the following genotypes CDe, cDE, cde, cDe, Cde, cdE, CdE, cde. If an individual's Rh genotype contains at least one of the C, D, E antigens, they are Rhesus positive. If an individual's Rh genotype contains at least one of the C, D, E antigens, they are Rhesus positive. Only individuals with the genotype cde/cde (rr) are Rhesus negative. Only individuals with the genotype cde/cde (rr) are Rhesus negative. The most common Rh antibody is anti-D, but it is possible to form antibodies to c, C, e, and E as well, and to form combinations of antibodies. There is no anti-d. The most common Rh antibody is anti-D, but it is possible to form antibodies to c, C, e, and E as well, and to form combinations of antibodies. There is no anti-d.

15 Other Rh Ags: Cw Ag: Very rare, and can causes HDN, and HTR. G Ag. D u Ag: it is an important Ag, which must be regarded as D Ag. in Nigeria, 8% of the people type as D-, are D u. Very strong Anti- D Ab should be used to detect D u Ag.

16 Antibodies to the Rh system: No naturally occurring. All the Ab are immune IgG Abs. All the six Ags will produce immune Abs when given to people not from the same Rh group. D > c > E > e > C Abs can cause HDN and HTR.

17 In any of the 4 ABO groups, a person can be Rh positive or Rh negative, meaning that a person’s blood can be classified as one of 8 possible types (O+, O-, A+, A-, B+, B-, AB+, AB-).

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