Case Study CM
Patient Name: CM
Age: 18 years
Race: African American
Diagnosis: Pregnancy
Medications: Vitamins
Transfusion History: None
Number of Pregnancies: One (current pregnancy)
Case Study CM: Initial Serological Results
Cells vs: / Anti-A / 0
Anti-B / 0
Anti-D / 3+
Serum vs: / A1 cells / 4+
B cells / 4+
DAT: / 0
Screen
Cell / IS / LISS
37oC / IgG
I / 4+ / 4+ / 4+
II / 4+ / 4+ / 4+
III / 4+ / 4+ / 4+

Questions:

  1. What do the patient’s initial serological results suggest?
  2. What would be your next step?

CASE STUDY CM: ANTIBODY IDENTIFICATION
Rh / MNS / P1 / Lewis / Kell / Kidd / Duffy / Serum
D / C / E / c / e / Cw / M / N / S / s / P1 / Lea / Leb / K / k / Jka / Jkb / Fya / Fyb / LISS
IS / 37oC / IgG / CC
1 / + / + / 0 / 0 / + / 0 / 0 / + / + / + / + / 0 / + / + / + / + / + / + / 0 / 4+ / 4+ / 4+
2 / + / 0 / + / + / 0 / 0 / + / 0 / 0 / + / + / 0 / + / 0 / + / + / 0 / + / 0 / 4+ / 4+ / 4+
3 / + / 0 / 0 / + / + / 0 / + / + / 0 / + / 0 / 0 / 0 / 0 / + / + / 0 / 0 / 0 / 4+ / 4+ / 4+
4 / 0 / 0 / 0 / + / + / 0 / 0 / + / + / 0 / 0 / + / 0 / 0 / + / 0 / + / + / + / 4+ / 4+ / 4+
5 / 0 / + / 0 / + / + / 0 / + / 0 / + / + / + / 0 / + / 0 / + / 0 / + / 0 / + / 4+ / 4+ / 4+
6 / 0 / 0 / + / + / + / 0 / + / + / 0 / + / + / + / 0 / 0 / + / + / + / 0 / + / 4+ / 4+ / 4+
Auto / 0 / 0 / 0 / 

Upon close examination, it was observed that the reagent red cells were 4+ agglutinated following the washing phase of the antiglobulin procedure and prior to the addition of the IgG AHG.

  1. What classification of antibody(ies) would be suspected in a patient with the given history and serological results?
  1. What blood group systems should be considered as potentially involved?
  1. What further testing should be completed? Would testing another panel be helpful? Why or why not?
  1. What recommendations would you make to the patient’s physician regarding the management of the pregnancy?

CASE STUDY: CM

  1. CM’s initial serological results indicate that her serum contains an antibody reactive at immediate spin, after the 37oC incubation and at the IgG IAT. At this point an autologous control has not been tested, although a direct antiglobulin test was negative.
  1. The next step would be to test the serum against a panel of reagent red cells including an autologous control. The phase and pattern of reactivity with the panel cells was consistent with the initial antibody screening test. The autologous control was negative, suggesting the presence of an alloantibody rather than an autoantibody.
  1. The phases of the patient’s serum reactivity coupled with the fact that she does not have a history of exposure to foreign red cells antigens suggests the possibility of naturally occurring antibody(ies) rather than immune antibodies.
  1. Blood group systems whose antibodies should be considered include the MNS, P, Lewis, I and H systems.
  1. The single, common antibody specificities directed against M, N, P1, Leaor Lebwould not explain the broad pattern of reactivity obtained with the red cell panel. A combination of the antibodies or a more broadly reactive single antibody could, however, be present.

Typing the patient’s red cells for the common antigens in these systems may suggest possible specificities. Additional antigen phenotyping will probably be useful as well.

Case Study: CM
Patient’s Phenotype:
D+C-E-c+e+, M+N+S-s+, P1+, Le(a+b-), K-, Fy(a-b+), Jk(a-b+)

Given the patient’s phenotype, common antibodies in the MNS, P and Lewis systems do not appear likely. Testing another panel of random reagent red cells would not be helpful at this point because there does not appear to be a simple antibody specificity.

Two blood group systems, the I and H systems, may contain antibodies with a broad pattern of reactivity, reactive at the phases observed with this patient’s serum. Many laboratories would not have anti-I or anti-H on hand to type the patient’s red cells. Testing the patient’s serum against I negative group O cord or adult cells may be used to determine if the patient’s serum contains anti-I. Since the patient’s autologous control is negative, an antibody with I specificity would likely be alloanti-I which may be present in the serum of I negative individuals.

Case CM: Additional Antibody Identification

/ The patient’s serum reacted equally as strong with I negative and I positive red cells.
Saline Suspended /

Serum

Selected Red Cells
I negative adult
I negative cord cells
I

II

III
Auto / IS
4+
4+
4+
4+
4+
0 / 37oC
4+
4+
4+
4+
4+
0 / AHG
4+
4+
4+
4+
4+
0 / CC

A Reference Laboratory will be able to perform the testing necessary to evaluate the possibility of an alloantibody to H or other high-incidence antigens.

Case Study: CM
Patient’s H phenotype: H-

Red cells which type as group O and are H- are known as Oh or having the “Bombay” phenotype. These red cells lack normal ABH antigens and the serum contains anti-A, anti-B, anti-A,B and anti-H. Unlike the anti-H found occasionally in the serum of A1, B and AB individuals, the Bombay anti-H has a wide thermal range of reactivity and is strongly incompatible with all red cells except other Oh red cells.

Case Study: CM

Serum

Selected Red Cells
Oh
Oh
Oh
Oh / IS
0
0
0
0 / 37oC
0
0
0
0 / AHG
0
0
0
0 / CC




In addition to testing the patient’s serum against Oh red cells, the possible presence of additional antibodies was ruled out by the use of alloadsorptions of the patient’s serum onto red cells of known antigenic phenotype.

Case Study CM: Allogeneic Adsorptions
Adsorbed Serum #1 / Adsorbed Serum #2 / Adsorbed Serum #3
Selected Red Cells / IS / LISS
37oC / IgG / CC / IS / LISS
37oC / IgG / CC / IS / LISS
37oC / IgG / CC
I / 0 / 0 / 0 /  / 0 / 0 / 0 /  / 0 / 0 / 0 / 
II / 0 / 0 / 0 /  / 0 / 0 / 0 /  / 0 / 0 / 0 / 
III / 0 / 0 / 0 /  / 0 / 0 / 0 /  / 0 / 0 / 0 / 
(#1) R1R1 adsorbing cells are s-,Fy(a-), Jk(b-)
(#2) R2R2 adsorbing cells are S-K-Jk(a-)
(#3) rr adsorbing cells are S-K-Fy(b-)

No additional antibodies were detected.

Additional testing which was performed:

  • Adsorption onto rabbit erythrocyte stroma reduced the strength of the anti-H but did not eliminate it.
  • DTT (Dithiothreitol) studies showed that although the patient’s anti-H was predominately IgM in nature, an IgG component was present in CM’s serum. The presence of the IgG component raised the issue of potential risk to the fetus.
  1. In the absence of documented case reports of pregnancies involving Oh individuals with IgG anti-H, the patient should be evaluated throughout the course of her pregnancy for signs of possible HDN. The patient should also be evaluated as a candidate for autologous donation and her siblings tested for the Oh phenotype, in an effort to identify compatible blood donors should they be needed.