Cord blood sample with mix field in forward typing

[Mnm]

Any idea as to why this is occurring?

Please see details below:

Newborn

A - O

B- 4+ mixed field

D- 4+

Notes: ABORH repeated, cells washed 8x & incubated at RT for 15 minutes

Mother is O+

No IUT

Peripheral sample - same results

 

Thanks

[Yanxia]

I think this phenomenon is because the B antigens are not well developed on new born baby. BTW, I prefer to use 3+mf to describe it

The reason I don't use 4+mf because 4+ agglutination is a kind of solid agglutination, without free cells .maybe I was wrong, just personal opinion.

Edited October 10, 2017 by yan xia

[Malcolm Needs ☆]

I totally agree with yan xia about the cause of the mixed-field.

A, B and H antigens are not direct gene products (they can't be, as the antigen is a sugar molecule attached to a polysaccharide molecule), whereas the D antigen is a protein, and so is a direct gene product (give or take a few post-translational changes).

The gene products of the ABO and H genes are transferase enzymes (alpha-1-3-(or alpha-1-4)N-acetyl-D-galactosyltransferase for the A antigen, alpha-1-3- (or alpha-1-4)N-galactosyltransferase for the B antigen, and L-fucosyltransferase for the H antigen), and these enzymes are not working at their optimum at birth, and so it is not unusual to see mixed-field in the samples of newborns, particularly if they are premature.

As the Rh antigens are direct gene products, i.e. proteins, mixed-field reactions are birth are very rare indeed, and usually there for a completely different reason.

[exlimey]

10 hours ago, yan xia said:

I think this phenomenon is because the B antigens are not well developed on new born baby. BTW, I prefer to use 3+mf to describe it

The reason I don't use 4+mf because 4+ agglutination is a kind of solid agglutination, without free cells .maybe I was wrong, just personal opinion.

 

2 hours ago, Malcolm Needs said:

I totally agree with yan xia about the cause of the mixed-field.

A, B and H antigens are not direct gene products (they can't be, as the antigen is a sugar molecule attached to a polysaccharide molecule), whereas the D antigen is a protein, and so is a direct gene product (give or take a few post-translational changes).

The gene products of the ABO and H genes are transferase enzymes (alpha-1-3-(or alpha-1-4)N-acetyl-D-galactosyltransferase for the A antigen, alpha-1-3- (or alpha-1-4)N-galactosyltransferase for the B antigen, and L-fucosyltransferase for the H antigen), and these enzymes are not working at their optimum at birth, and so it is not unusual to see mixed-field in the samples of newborns, particularly if they are premature.

As the Rh antigens are direct gene products, i.e. proteins, mixed-field reactions are birth are very rare indeed, and usually there for a completely different reason.

Concur.

[Mnm]

Thanks everyone

[BBKTech]

How would you differentiate from a mf reaction due to contamination from the mother's cells?

[Malcolm Needs ☆]

11 hours ago, BBKTech said:

How would you differentiate from a mf reaction due to contamination from the mother's cells?

You could perform a Kleihauer, and subjectively estimate - but it would be very subjective.