One must remember that if the mother and infant are ABO incompatible the fetal cells are coated with maternal anti A, Anti B or Anti A,B which are cleared by the maternal circulation very rapidily. This is a protective mechanism against HDN due to Rh + fetal red cells. Russ Wick MT(ASCP)SBB ----- Original Message ----- From: <Ian_DIMMICK@europe.bd.com> To: cyto-inbox Sent: Sunday, December 22, 2002 7:26 AM Subject: Re: Anti-D Immunoglobulin prophylaxis and anti-D reagent > > > 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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