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Faculty of Allied Medical Science

Faculty of Allied Medical Science. Blood Banking (MLBB 201). Lewis and Kell Blood Groups Prof.Dr . Nadia Aly Sadek Blood Bank Director, MRI. Outcomes. By the end of this lecture, the students will be able to: Recognize the Lewis and Kell blood group antigens

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Faculty of Allied Medical Science

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  1. Faculty of Allied Medical Science Blood Banking (MLBB 201)

  2. Lewis and Kell Blood Groups Prof.Dr. Nadia AlySadek Blood Bank Director, MRI

  3. Outcomes • By the end of this lecture, the students will be able to: • Recognize the Lewis and Kell blood group antigens • Know their clinical importance

  4. Lewis antigens are carbohydrate structures carried on glycolipids. They differ from other blood groups in that they are not produced by RBCs , but they become incorporated into the red cell membrane from the plasma.

  5. Types of Lewis antigens There are two main antigens:- 1- Le a 2- Le b There are 4 Lewis phenotypes:- 1- Le (a+b-): only found in ABH non-secretors 2- Le (a-b+): only found in ABH secretors

  6. 3- Le (a+b+) only found in ABH secretors 4- Le (a-b-) RBCs have no Lewis antigens Lewis antibodies are only made by individuals with the Le (a-b-) red cells. They are not clinically significant as they are not active at 37 degrees.

  7. Kell system It includes K (KEL 1) with a frequency of 9% in Northern Europeans and 1.5% in African populations. The k (KEL 2) antigen is of high frequency in all populations. (KEL 3) is found in about 2% of Caucasians but not present in Africans or Japanese.

  8. (KEL 4) is of high frequency in all populations. • (KEL 6) is completely confined to African individuals.

  9. Kell antibodies • These antibodies are clinically significant. They cause severe hemolytic disease of fetus and newborn (HDFN) as well as hemolytic transfusion reactions. • Patients with Kell antibodies should be transfused with antigen-negative blood.

  10. Kell system antibodies are usually IgG and predominantly (IgG1).

  11. Difference between HDFN due to anti-K or anti-D 1. Anti-K HDFN is associated with lower concentrations of amniotic fluid bilirubin concentration than anti-D HDFN. 2. Post- natal hyperbilirubinaemia is not prominent in babies with anti-K.

  12. 3. There is reduced reticulocytosis and normoblast % in the anti-K disease. 4. Kell antigen appears on early erythroid cells much before the Rh antigen. Kell negative girls and women of child-bearing age should receive K- blood transfusion.

  13. Detection of Kell antibodies Anti-K directly agglutinate K+ red cells. -Antiglobulin test is the method of choice for their detection.

  14. Universal Blood group A and B antigens on red cells can be removed, in vitro, by converting them back to the H antigen. This is done by removal of the immunodominant sugar with an appropriate enzyme. They become group O. These enzymes are obtained from bacteria (A-zyme) and green coffee beans (B-zyme).

  15. Study question State true or false:- 1- Lewis antigens are produced by the RBCs 2- Le (a-b+) are only found in ABH secretors 3- Le (a-b-) have antigens on RBCs

  16. Assignments • Plasma Exchange عائشة خضر احمد

  17. Thank You

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