Possible Anti-Fya,-Fy3 or Anti-Fya,-Fyb???????????????

[missyg]

We have a patient who has the known antibodies: anti-Fya,-C,-K,-Jkb. The patient now has a cold agglutinin and a warm auto antibody. The patient's race is black and phenotypes as Fya and Fyb negative. A 2 X @37C allogeneic adsorption was performed using R1R1 Fya+(cell A), R2R2 Fya-(cell , and rr Fya+(cell C). Given the patient's race, we wouldn't expect them to have an anti-Fyb. However, when the adsorbed sera from cell A and C was tested with Fyb positive cells it reacted 1+. If this were anti-Fy3, we should have expected it to be adsorbed out with the cell A and C and in turn have no reactivity with the Fyb positive cell (as a side note, the Fyb positive cell was negative for all the antigens to the previous known antibodies). All other common alloantibodies have been ruled out. Any ideas what could be causing the reactivity with the Fyb positive cells??????????????? An autoadsorption was also performed supporting the results of the allogeneic adsorption.

Thanks!!

[Malcolm Needs ☆]

If the patient is a genuine FY/FY (that is, he or she does not have the FYB gene and homozygous mutation at the GATA-1 gene), he or she can most certainly produce an anti-Fy3, as well as an anti-Fya.

Personally speaking, I can think of no reason why he or she could not also produce anti-Fyb.

I have never seen this, but that does not mean it cannot happen. Logically speaking, it could.

[missyg]

Thanks!!!!!

[galvania]

Check with enzyme treated red cells. Anti-Fy3 is not destroyed

[Malcolm Needs ☆]

This is true, but make sure that the enzyme you use is ficin, papain, alpha-chymotrypsin or pronase, because both the Fya and Fyb are resistant to treatment with trypsin and sialidase.

The term "Fya and Fyb are destroyed by the action of enzymes" (often used) is inaccurate.

Fy3 is resistant to all of these enzymes.