IgM Blood Groups (Lewis)

Natural Occurring Antibodies

Natural Occurring Antibodies

Antibody created after exposure of non human material. AB goes away once exposure is done

Non-natural occurring antibodies

ABs created due to exposure of human to human cell transfer. (RBCs). ABs never go away

Lewis system characteristics

Not intrinsic to RBCs (protein that sits outside)

Type 1 glycosphingolipids

Passively absorbed into RBC membrane from plasma

Lewis antibodies are produced by _ and secreted _

Tissue cells; body fluids

Le(a+b=) frequency

22% whites 23% blacks

Le(a=b+) frequency

72% whites 55% blacks

Le(a=b=) frequency

6% whites 22% blacks

Lewis system gene and chromosome

FUT3 gene and Chromosome 19

Lewis phenotypes result from

Interaction of 2 fucosyltransferase encoded by independent genes on chromosome 19

Production of Lewis depends on

The inheritance of Lewis (Le)

Amount of Lewis antigen detectable on the RBC is influenced by

ABO genes

Lewis antigens produced in saliva are

Glycoproteins

Lewis cell-bound antigens absorbed from plasma are

Glycolipids

Lewis antigens are not expressed on

Cord cells or mother’s RBCs during pregnancy

Enzyme treatment _

Enhances reaction (resistant)

Lewis development pathway if the child inherits Le and Se genes

(a=b=) at birth> (a+b+) after 10 days > (a=b+) after 6 years

First Le to develop in a newborn

Le(a) ; fucosyltransferase is more active than Se. Type 1 chains are likely to be Le(a)

As secretor status activity increases in babies

Type 1 chains will convert to Type 1H where Le(b) is detected

Presence of Le ag on red cells is determined by

Secretor status

Lewis antigen with out the secretor gene (sese)

Le (a) (a+b=)

Lewis antigen w secretor gene (Se)

Le (b) (a=b+)

lele genotype caused by

Mutation in the Le gene (FUT3)

Most Lewis antibodies are found in

Le(a=b+) individuals

Most common antibody produced by Le(a=b=)

anti Le a (20% of a=b+)

Anti-Le a characteristics

IgM, can activate complements, cause intra and extra vascular hemolysis, does not cause HDFN

Anti Le a can be _ and associated with _

Naturally occurring; increased susceptibility to infections by Candida and E.coli

Anti-Le a can be neutralized using

Lewis substances in plasma or saliva

IgM form of anti le a

Sometimes reacts at 37 but mostly IgG, can bind complement. That causes hemolysis

IgG form of anti le a

Does not bind red cells

Anti le b characteristics

Not as common or strong as anti a, usually produced by an (a=b=) person, can find complement , not usually made by (a+b=)

Le(b) and H antigens are receptors for

H. pylori

Le b and H1 are common receptors for

Norwalk virus

Lewis secretor inhibition test

Manufactured soluble Le antigen is added to pt plasma with Le antibody. Add this to red cells with known Le RBC antigen. Mix and spin. No agglutination is +.

When is the Lewis secretor inhibition done

When a pt has a possible antibody but it does not show up very well.

When is an ABO secretor inhibition done

To determine if the pt is a secretor