Anti-N in OB patient?

[COTTONBALL]

Greetings fellow BBkers,

 

Need to know your stories/cases on Anti-N.  I know quite a few things about antibodies and I have seen Anti-N at least three times in my 20 years, so would like to hear REAL cases that you have experienced.  Because some techs have never seen certain antibodies, they believe for example, an Anit-N is not possible.  Everything has been ruled out, plus antigrams/panel cells reactions fit Anti-N, perfectly on more than one hospital visit.  Father's sample is not available, plus we are not trying to do any additional work, as Anti-N is usually insignificant, not implicated in HDN, and patient has delivered.  Your input is most appreciated.

 

Kind regards,

 

Connie Cottman, MT(ASCP)SBB^CM

 

 

[Malcolm Needs ☆]

Hi Connie,

 

I have seen many examples of anti-N, but all but a very few of these have been, in effect, auto-anti-N.

 

The reason that the vast majority are autoantibodies is because, although the N antigen is expressed on glycophorin A, there is a part of glycophorin B where the first 29 amino acid residues are identical to those found on the N version of glycophorin A.  The first five of these amino acid residues (Leu-Ser-Thr-Thr-Glu) are identical to the N antigen and constitute the 'N' antigen.  In a way, therefore, all individuals who are M+N-, but have the "normal" glycophorin B structure, including the 'N' antigen, and who produce an anti-N, mus be thought of as producing an auto-anti-N - and this is why anti-N is seldom clinically significant.

 

In theory, individuals who are M+N-, S-s-U- or S-s-Uvar, can produce an alloanti-N that may be clinically significant, and there are a few examples of this that have made the literature.

 

In addition, there is an antithetical antigen to the 'N' antigen, called He (although, in reality, there are quite a few genetic backgrounds to the He antigen, and so, perhaps, they should be called He antigens).  If an individual is, therefore, M+N-, 'N'-, He+, they are also capable of producing a true alloanti-N, which may prove to be clinically significant.

 

All that having been said, last year we experienced a quite nasty delayed haemolytic transfusion reaction in a sickle cell patient who was M+N-, with a normal 'N' antigen, and who had, amongst other non-clinically significant antibodies, an anti-N, and it was this anti-N that appeared to be the culprit for the DHTR.  These findings were confirmed by the International Blood Group Reference Laboratory, and we are now busily writing it up as a Case Study to be published somehwere.

 

Best wishes,

 

Malcolm

[COTTONBALL]

Hi Malcolm,

 

Thanks for the generous amount of information and a very good antigen structure review.  Interesting case that you have, and so I am thinking when you say your patient was M+N-, this means serologically, and normal "N" antigen by molecular or other test.  In your line of work, "seldom" should be used with caution  .  Can't wait to read your story. 

 

Thanks for all that you do.  Regards,

 

Connie Cottman, MT(ASCP)SBB^CM

[Malcolm Needs ☆]

  In your line of work, "seldom" should be used with caution  . 

 

Connie Cottman, MT(ASCP)SBB^CM

 

I agree entirely, but, NOTE, I never said NEVER!!!!!!!!!!!!!.........and never would!

[jsherrie]

As in life.....remember......in blood banking, ANYTHING IS POSSIBLE !!!!!!!!!!!!!!  Never assume.

[ADawson]

Hi Everyone,

Its ironic that the subject of Anti N is surfacing. For the last couple of months we have been dealing with an OB patient, 21 years old with an Anti N & Anti U. How rare is that? Anti U <1% compatible! The physician ordered 2 units. With much effort and over the span of about 4 weeks of searching high and low the Red Cross came through with the units. She delivered and received the units, both she and infant were discharged after about 3 days in good condition.

[Yanxia]

 

All that having been said, last year we experienced a quite nasty delayed haemolytic transfusion reaction in a sickle cell patient who was M+N-, with a normal 'N' antigen, and who had, amongst other non-clinically significant antibodies, an anti-N, and it was this anti-N that appeared to be the culprit for the DHTR.  These findings were confirmed by the International Blood Group Reference Laboratory, and we are now busily writing it up as a Case Study to be published somehwere.

 

Best wishes,

 

Malcolm

Malcolm, does the culprit anti-N appear as auto or all?

Edited July 20, 2013 by shily

[Yanxia]

It seems some wrong on my last post, I edit it here

Malcolm, does the culprit anti-N appear as all or auto?

Edited July 20, 2013 by shily