Here's Another Goodie

[David Saikin]

Prenatal patient I have been following since 2009, A Neg; all testing in gel. 

 

8/2009:  Ortho screening cell 2: 1+; abid: random reactivity, no specificity determined.

 

2/2010:  Only reacts with Ortho R2R2 cells (1+), pt is E neg:  other manufacturer's R2R2 cells are negative:  reported anti-E and discussed with MD.

 

7/2013:  Still only reacts with Ortho R2R2 cells (1+); rec'd RhIg after specimen collected.

 

5/2014:  Ortho cells:  2/3 R2R2 (2+) one R2R2 neg; R1wr cell: 1+.  2 step Papain treatment:  all cells 2+, R2R2 cells 4+, the R1wr cell is 4+, auto ct: neg.   Quotient (Alba) panel:  neat:  all cells negative;  2 step papain treatment:  all D+ cells are 2+mf.  O Neg cord cell is neg neat and with enzyme pretreatment.

 

6/2014:  Ortho panel and Quotient panel:  both negative neat and all D+ cells 2+mf with enzyme pretreatment.

 

My take is that what I thought was anti-E back in 2010 was really just the anti-D developing.  Can't explain the panreactivity found in May.    Is this anti-D clinically significant?  Thought about anti-LW but had no Rh= cord cells to play with (besides, one was negative last month)..

 

Go for it - any ideas, recommendations are welcome.  No complications at delivery for mother and child.  One delivery at a different institution.

[Malcolm Needs ☆]

One thought is that is, and always has been, a very low level anti-D.

 

The number of D antigen sites on R₂R₂ red cells are the highest for all of the "normal" Rh phenotypes, and so these would react more strongly than would, for example, the R1^wr red cell sample, although all D+ red cells will have a "range" of D sites (by that I mean that R₂R₂ red cells from one source might have 33, 000 D sites per red cell, whilst another may only have 25, 000 D sites per red cell.

 

It could also be that one or more of the "R₂R₂" red cells are actually R₂r", which would reduce the number of D sites per red cell.

 

This is just by way of a "first pass" at an answer to your query!