Lewis, I/i, and P1PK Blood Group Systems

Question 1

Of the Lewis system, mention the most important antibodies.

Answer 1

Lea and Leb

Question 2

Describe the physiological characteristics of Lea and Leb.

Answer 2

Found as glycolipids, present in plasma and secretions, and RBC acquire Lewis phenotype. They are indirect gene products, resulting from the specific actions of specific glycosyltransferases

Question 3

Secretors who have the Lewis gene make _____.

Answer 3

Leb

Question 4

Secretors have __ antigen.

Answer 4

H

Question 5

Non-secretors who have the Lewis gene make _____.

Answer 5

Lea

Question 6

What are the inheritance and racial features of the Lewis blood group system?

Answer 6

Ø In terms of inheritance: Le and le genes exist. le is an amorph. Le gene and sese will lead to the phenotype Le (a+b-) (22% of white population; 23% of black population). Le gene and Sese or SeSe gives Le (a-b+), the most common phenotype in the white population (72%), and comprise 55% of the black population. Le (a-b-) is found in 6% of the white population, and the remainder of the black population

Question 7

What genetic setup produces Lewis antibodies?

Answer 7

Le (a-b-)

Question 8

Write a note on the I/i blood group system.

Answer 8

Antigens are found on RBC membrane. Membranes-associated glycoproteins and glycosphingolipids are present. The gene loci encode glycosyltransferases. The i antigen is a precursor of the I antigen; foetal RBC are rich in i antigen. The I antigen develops in the first two years. The i antigen is very rarely found in adults
Anti-I is a common autoantibody, is usually cold-reactive, and an IgM; it is sometimes demonstrated by failure to react with RBC from cord blood, but pre-warming the cells and serum to 37 degrees C will remedy the situation