Recently, I had a case where the blocking antibody was not an anti-D, but rather an anti-B in a case of ABO hemolytic disease of the fetus/newborn HDFN.  The D typing result was weak but the D control in the gel was positive so the result was indeterminate.  DAT was 3+ IgG and anti-B was identified in the eluate (mother was antibody screen negative, regular elution panels (group O cells) were negative.  Some of the actual workup follows:

29/7/20

I cannot emphasize enough proper technique in doing the washing during the elution process.  We are usually concerned about too little washing and thus possibly residual reactions in the last wash.  However, aggressive overwashing may remove the bound antibody resulting in a negative result.

Here is an example of anti-PP1Pk (alias anti-Tja).  The mother’s panel shows an antibody to a high prevalence/incidence antigen with negative autocontrol and no lability at enzyme phase:

The neonate’s DAT was weak positive at polyspecific and IgG monospecific phases.  An eluate was performed.  Here is the result after washing four (4) times:

Since 2 cells in the last wash were very weakly positive, the washing was continued for a total of 9 times with the following results:

Even then there was very weak positivity in one cell, but the eluate was negative.  We had washed away the attached antibodies.

A 31 year old Indian female’s prenatal testing results follow:

ABO Group B—unremarkable pattern

Rh(D) positive by both DVI+ and DVI- reagents by multiple manufacturers, both with gel and tube methods

Extended Rh and Kell:

No reactions for C, c, E, e;  Kell negative

(These results were confirmed by multiple manufacturer’s tube and gel reagents)

Extended Antigen Typings:

From the phenotypic data, we could already rule out anti-H, k, PP1Pk, U, and some unusual MN system variants found in the region.

DAT:  Polyspecific and monospecific IgG, C3b/C3d were all negative.

Antibody Screen:  4+ panreactive

Antibody Panel:  4+ panreactive, autocontrol negative,  also 4+ by enzyme

Clinical Course:

At the time of the prenatal specimen, we informed the clinicians that we did not know the significance of the panreactive antibody.  We recommended screening any blood relatives and autologous blood collection.  We also recommended genotyping of the mother.

Several months later the patient presented in labor with severe fetal hydrops.  The previous workup was repeated and confirmed.  Neither genotyping or autologous collection had been done.  No relatives had the same phenotype, and none were compatible with the mother.

We now knew that the antibody was highly clinically significant and very dangerous.  With the permission of the treating obstetrician, the mother’s blood was used for transfusion of the newborn (washed, irradiated).  Both mother and baby were group B positive.

To date of my departure from HMC Doha, the antibody had not been characterized, but we continued to recommend genotyping and autologous collection from the mother.

This is a presentation from my time at NGHA Riyadh on a strategy for rare RBC types in the Gulf/Middle East region. This is my practical method for dealing with these antibodies.

As regards prophylactic antigen matching, my remarks are based on the antibodies observed in my region. I know that some would match at least Duffy antigens, but emergence of anti-Fya and anti-Fyb have not been common in my practice.

This presentation is from my time at National Guard Health Affairs Riyadh and suggests an algorithm to assess the clinical significance of the reaction. In my opinion, the essence of immunohematology testing is the antiglobulin test so I would spend much time with technical and medical staff, including trainees/fellows (even those not based in transfusion medicine) to make certain they understood how to interpret it.

This is a presentation I gave while working as Head of Transfusion Medicine for Saudi Arabian National Guard Affairs, King Abdulaziz Medical City at Riyadh. I used this strategy there and later at HMC Doha.

Fortunately we had access to rare antisera such as anti-Tja (anti-PP1Pk) which we could purchase from Diamed AG and its successor Biorad. I emphasize that we only sparingly used these rare antisera AFTER ruling out more common high-incidence antibodies.

It is the middle of the night, you only have one blood bank technologist on duty, an urgent request for 6 units of packed PRBCs from a bleeding patient is received. You have units, you have the specimen, but also the unfortunate luck that the antibody screen is positive. There is no previous transfusion history and no previous results. What do you do? They need the blood YESTERDAY!!! The Transfusion Medicine Consultant is called and tells the staff not to release any RBCs until the workup is complete.

The following is taken from my Powerpoint presentation based on this incident. The intended audience is basic-level blood bank technical staff and the clinicians involved in the case: