Re: Anti-D Immunoglobulin prophylaxis and anti-D reagent

From: Ian_DIMMICK@europe.bd.com
Date: Sun Dec 22 2002 - 07:26:31 EST


Dear Emanuel,
          It has been my experience that if anti D is administered to  D-ve
maternal circulation this is very effective in opsonising D+ foetal cells
which are very rapidly taken out of circulation by the reticulo endothelial
system. The absolute kinetics of this however will always depend on the
number of D+ cells in circulation and the concentration of Anti D
administered, the competitive inhibition of Anti D immunoglobulin to your
Anti D monoclonal for detection therefore would be able to be worked out in
vitro quite nicely but I suggest that in Vivo, because of the
aforementioned R.E. system's influence this may end up being a purely
academic exercise, however you are correct in saying they may be "D
Immunoglobulin coated cells" in your sample whereby the biding of the
conjugated antisera may be inhibited , the validity of this percentage will
be directly proportional to the life span of these cells in Vivo.

Ian (Merry Xmas to all of my friends in the flow community , it is cold on
the lake shore this time of year sometimes to jump in is a warming
experience) TB




"Emanuel Raniolo" <emanuel.raniolo@imvs.sa.gov.au> on 18/12/2002 05:50:24

To: cyto-inbox
cc:

Subject:  Anti-D Immunoglobulin prophylaxis and anti-D reagent



Hi Flow People

Could anyone answer my query:
Does prophylactically administerd Anti-D immunoglobulin interfere with
(inhibit) the binding of conjugated anti-D monoclonal antibody reagent on
Rh
D+ fetal red cells in Rh D negative maternal circulation?

Surprisingly, I have not been able to find any reports that have
specifically addressed this subject. Some simple in-vitro co incubation
experiments would probably clarify the issue.

Presumably the maternal reticulo-endothelial system is responsible for the
removal of IgG (anti-D) coated fetal red cells. This mechanism of
destruction is not instantaneous, raising the possibility that coated cells
may be present in the specimen when performing this anti-D flow based assay
for FMH. It is also unclear whether competition for the same red cell
epitopes would occur by Anti-D immunoglobulin (polyclonal) and anti-D
reagent (monoclonal antibody).

Thanking you in anticipation of your responses

Emanuel Raniolo
Cell Analysis & Cryopreservation Laboratory
Department of Haematology
The Queen Elizabeth Hospital Division
The Institute of Medical & Veterinary Science
Woodville, South Australia



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