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DR. MOHAMMED H SAIEMALDAHR Faculty of Applied Medical Science

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Presentation on theme: "DR. MOHAMMED H SAIEMALDAHR Faculty of Applied Medical Science"— Presentation transcript:

1 DR. MOHAMMED H SAIEMALDAHR Faculty of Applied Medical Science
BOMBAY Blood Group DR. MOHAMMED H SAIEMALDAHR BB Faculty of Applied Medical Science MED TECH DEP. drmsaiem

2 The Bombay Phenotypes (Oh)
The H gene appears to be necessary for the formation of A and B Ags. It is very common 99.9% of all individuals have an HH or Hh genotype. The allele h is very rare and does not produce the L-Fucose transferase necessary for formation of the H-Structure. The genotype (hh) or H null is extremely rare and is known as the Bombay Phenotype or Oh. drmsaiem

3 H Antigen The H gene codes for an enzyme (fucosylytranferase) that adds a Fucose to the terminal sugar of a Precursor Substance (PS*). The biochemical structure below constitutes the H Antigen. (h gene is an amorph.) H gene acts on a Precursor substance(PS)* by adding Fucose *PS = oligosaccharide chain attached to either glycosphingo-lipid, Type 2 chain (on RBC) or glycoprotein, Type 1 chain (in secretions) drmsaiem

4 H antigen is the foundation upon which A and B antigens are built.
A and B genes code for enzymes that add an immunodominant sugar to the H antigen. O allele does not code a functional enzyme Greatest Least amount of H O > A2 > B > A2B > A1 > A1B amount of H drmsaiem

5 The Bombay Phenotypes (Oh)
The Bombay Phenotype was first reported by Bhende 1952 in Bombay, India. Bombay cells can not be converted to group A or B by the specific transferases. This support the concept that the H structure serves as the acceptor molecule or precursor substance for the product of the A or B gene -specified tranferases. drmsaiem

6 The Bombay Phenotypes (Oh)
Bombay individuals lack all normal expression of the A, B, or O genes they inherited. The Bombay Phenotype Red Cells are devoid of normal A B, H Ags. Fail to react with anti- A, anti -B , and anti -A,B and anti H. Bombay Serum contains anti-A, -B and anti-H. drmsaiem

7 The Bombay Phenotypes (Oh)
The Bombay anti-H is active over a wide thermal range. It is an IgM antibody that can bind complement and cause red cell lysis. Because the H Ag is common to all ABO blood group, Bombay blood is incompatible with all ABO donors. In routine forward grouping, using anti-A, anti-B, and anti-AB. The Bombay would phenotype as an O blood group. However, transfusing normal group O would cause immediate cell lysis by the potent anti-H of the Bombay individuals. Thus, only blood from another Bombay individual can be transfused to a Bombay recipient. drmsaiem

8 The Bombay Phenotypes (Oh)
Oh (hh) individuals are all non-secretors of ABH substances, because both the H gene and the Se gene must be inherited for the ABH antigens to be found in secretions. drmsaiem

9 The Bombay Phenotypes (Oh)
Proof that individual lacks the H antigen may be accomplished by typing the Bombay phenotype red cells with a products of the plant Ulex Europacus or with sera containing Anti-H activity from which all anti-A, anti-AB activity has been adsorbed (Removal of Abs) This plant lectin provide a much simple and more readily available source of anti-H like activity. Thus this plant must used to determine the presence or absence of the H antigen on the surface of RBCs drmsaiem

10 The Bombay Phenotypes (Oh)
General Characteristics of Bombay Oh (Hnull Phenotypes) 1. Absence of H, A, and B antigens; NO agglutination with anti-A, anti-B, or anti-H lectin 2. Presence of anti-A, anti-B, anti-A,B and a potent wide thermal range of anti-H in the serum 3. A, B, H non-secretor (no A, B, or H substances present in saliva) 4. Absence of α-2-L-fucosyltransferase (H enzyme) in serum and H antigen on red cells drmsaiem

11 The Bombay Phenotypes (Oh)
5- Presence of A or B enzymes in serum 6- Strong reactivity with anti-I reagents (possibly owing to an increase in number of I receptors) 7. A recessive mode of inheritance. 8. Red cells of the Bombay phenotype (Oh will not react with the anti-H lectin (Ulex europaeus) 9. Red cells of the Bombay phenotype (Oh are compatible only with the serum from another Bombay individual. drmsaiem

12 The Bombay Phenotypes (Oh)
The Bombay phenotype can been divided into four different categories that depend on the inheritance of the alleles of H (hh) are responsible for the variable expression of H and in turn A and B antigens. Category I: Classic Bombay This group arises from the inheritance of the hh genotypes. These cells lack all H antigen and react stronger with examples of anti-I. drmsaiem

13 The Bombay Phenotypes (Oh)
Category 2: Deficient Bombay Non –Secretors The red cells of these individuals have a slight amount of ABH antigens that are primarily detected by adsorption and elution (removal of Ab) studies. Category 3: H-Deficient Bombay Secretor Recessive Inheritance These Bombay secretors arise out of the inheritance of a double dose of the recessive gene. drmsaiem

14 The Bombay Phenotypes (Oh)
Category 4: H-Deficient Bombay Secretors Dominant Inheritance These persons inherit H-deficient red cells via a dominant gene; however, they contain normal ABH substance if they are secretors. drmsaiem

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