1. Red Cell and Platelet Antibodies in Pregnancy
Nicole L. Draper, MD
Assistant Professor, Department of Pathology, University of Colorado
Associate Medical Director, Transfusion Services, University of Colorado Hospital

2. Objectives Identify categories of red cell and platelet antibodies.
Discuss laboratory tests that are used to identify antibodies, and tests that aid in prediction of clinical significance.
Understand the clinical implications of laboratory test interpretations in pregnancy.

3. Red Cell Antibodies

4. Case 1 42-year-old woman, G6P5003 at 13 weeks gestation
First prenatal visit this pregnancy
This baby is with a new partner
Two previous pregnancies had heart defects
Standard prenatal testing today

5. Initial Prenatal Visit
hCG
ABO and Rh type, red cell antibody screen
Hematocrit and MCV
Rubella and varicella immunity
Urine culture
Syphilis, HIV and hepatitis B antigen screening
Cervical cytology
If at risk
Chlamydia, ghonorrhea, hepatitis C
Thyroid function
Cystic fibrosis, Down syndrome, fragile X, hemoglobinopathies

6. Hemolytic Disease of the Fetus/Newborn
Maternal IgG antibodies against paternal antigens on fetal red cells
Fetomaternal hemorrhage
Transfusion
Increased likelihood in the third trimester
Delivery
Increased fetal blood volume
Cytotrophoblast no longer consistently present
Trends in Endocrinology & Metabolism, Volume 22, Issue 5, 2011,

7. HDFN Hemolysis Anemia Bilirubin Kernicterus Ischemia Cardiac Failure
Extramedullary
Hematopoiesis
Decreased
oncotic pressure
Edema

8. Type and Screen Type: A, Rh-negative with anti-B
Kell
Duffy
Kidd
Lewis
MNS
Luth D C c E e K k
Fya
Fyb
Jka
Jkb
Lea
Leb M N S s
Lua
Lub I + II
III AC SP
Common clinically significant antigens are represented
Chosen because of potential for hemolysis
Performed on first prenatal visit

9. Antibody Significance
Cross the placenta (IgG)
Amount of antibody (titer)
Antigen present on fetal RBC’s
Paternal type
I, Le(a), Le(b), P-system, Lu(b), Yt(a), VEL not developed
ABO not well developed
Transfusion Jul;50(7):

10. ABO Antigens & Antibodies
RBC
Antigens A
(AA, AO) B
(BB, BO) AB
(AB)
None
(OO)
Plasma
Antibodies
Anti-B
Anti-A
Anti-A,B

11. Anti-A,B Most common HDFN O mom with A or B baby DAT often negative
ABO antigens few and unbranched
A and B on tissues
Soluble A and B
Mild neonatal jaundice

12. RhIg?
Prevent alloantibody formation with administration of passive anti-D (RhIg)
Antepartum
D-antigen negative (Rh-)
Has not formed an anti-D
Father of the baby is known to be Rh+ or Rh type is unknown
Full-dose 300 μg (1500 IU) administered at 28 weeks gestation or with risk of fetal- maternal hemorrhage

13. RhIg? Postpartum Rh+ platelet transfusions ITP treatment
D-antigen negative (Rh-)
Has not formed an anti-D
Baby is Rh+
Dose calculated
Rh+ platelet transfusions
Transfusion Mar;54(3):650-4
ITP treatment

14. Case 1 Patient reports no recent administration of RhIg
Last pregnancy 9 years ago in Mexico

15. Anti-D IgG antibody that can cross the placenta
Very severe HDFN possible
Anti-D titer of 16 associated with significant fetal anemia

16. Case 1: 13 weeks Anti-D currently too weak to titer Repeat in 1 monthRh
Kell
Duffy
Kidd
Lewis
MNS
Luth D C c E e K k
Fya
Fyb
Jka
Jkb
Lea
Leb M N S s
Lua
Lub
LISS
Ror +
Anti-D currently too weak to titer
Repeat in 1 month

17. Fetus Rh(D)-positive? Circulating cell-free fetal DNA testing FOC type
Fetus is predicted to be female
Fetus is predicted to be Rh(D) positive
FOC type
Heterozygous
~2% have incorrect knowledge of paternity

18. Case 1: 25 weeks Anti-D currently titer of 4 Repeat in 1 month + Rh
Kell
Duffy
Kidd
Lewis
MNS
Luth D C c E e K k
Fya
Fyb
Jka
Jkb
Lea
Leb M N S s
Lua
Lub
LISS
Ror + 3+
Anti-D currently titer of 4
Repeat in 1 month

19. Type and Screen: 33 weeks + Rh Kell Duffy Kidd Lewis MNS Luth I II III
Fya
Fyb
Jka
Jkb
Lea
Leb M N S s
Lua
Lub I + II
III AC SP

20. Antibody ID Panel Rh Kell Duffy Kidd Lewis MNS Luth + 4+ 3+ 1 2 3 4 5C c E e K k
Fya
Fyb
Jka
Jkb
Lea
Leb M N S s
Lua
Lub SP 1 + 4+ 2 3 3+ 4 5 6 7 8 9 AC

21. Case 1: 33 weeks Anti-C too weak to titerRh
Kell
Duffy
Kidd
Lewis
MNS
Luth D C c E e K k
Fya
Fyb
Jka
Jkb
Lea
Leb M N S s
Lua
Lub
LISS
r’r +
Ror 3+
Anti-C too weak to titer
Anti-D currently titer of 256
MCA doppler ultrasound needed

22. Anti-G? IgG, but not typically clinically significant
Appears to be anti-D and anti-C
Shared epitope
103Ser
Explains D- exposed to D-(C+) blood develops apparent anti-D
Almost all anti-G with anti-D or anti-C
RhIg?
Semin Hematol. 2007 Jan;44(1):42-50

23. Case 1 Not likely anti-G Likely RBC exposure during this pregnancy
Formed anti-D months before anti-C
Very different titer results
No RhIg indicated
Likely RBC exposure during this pregnancy
Anamnestic response for anti-D
New formation or anamnestic response for anti-C

24. MCA Doppler Ultrasound
AJUM November 2010; 13 (4):24-27

25. HDF Treatment Intrauterine transfusion of RBC’s Delivery
ABO compatible with both mother & fetus (usually O-neg)
CMV-safe (LR & CMV-seronegative)
Irradiated
Lacking any antigen for which mom has the corresponding antibody
Hyperpacked (Hct target 85%)
Fresh (<5days)
Hgb S-negative
Delivery
>33weeks

26. Case 1 Baby girl delivered by C-section at 34 weeks
Type A, Rh(D)-positive
C-antigen negative
IgG DAT 3+
Hemoglobin 5.1 g/dL ( )
MCV fL ( )
RDW fL ( )
Max bilirubin 12.3 mg/dL at day 1
Required RBC transfusion, not exchange

27. Case 2 32-year-old woman, G3P2002 at 27 weeks
Transfer to maternal fetal medicine for anti-K
Titer at outside institution of 64
MCA doppler ultrasound with PSV 1.7 MoM
Planned IUT

28. Anti-K
Discrepancy between titer and bilirubin level in amniotic fluid (Berkowitz et al )
Anti-K titer of 2048
Decreased bilirubin between weeks and 24 with development of hydrops

29. Anti-K Inhibits fetal erythropoiesis Causes peripheral hemolysis

30. Anti-K Titer of 8 considered critical MCA Doppler preferred
20% of severely affected infants type as K- with IgM reagent anti-K K K K

31. Case 2 IUT at 27, 28, 30 and 31 weeks gestation
MCA doppler PSV normalized
Delivered baby at 33 weeks

32. Anti-M Usually IgM antibody
Conversion to an IgG occurs rarely – reports in English literature
DTT treatment to determine IgG component
IgG anti-M titer of 32 critical

33. Warm Autoantibody IgG Autoantibodies often exacerbated in pregnancy
Hemolysis in mother?

34. Predicting Anemia DAT Poor predictive value
23% of DAT+ infants required treatment for hyperbilirubinemia
RhIg
ABO incompatibility

35. Platelet Antibodies

36. Case 3
A 19-year-old woman
Diagnosis of immune thrombocytopenic purpura (ITP)
Post splenectomy at age 13
Platelet count typically 30-50x109/L
Wants to conceive, but concerned about how her disease could affect pregnancy

37. ITP Acute Chronic Typically children
Post viral infection, usually upper respiratory
Platelets 5-20
Chronic
20-50 years old
More common in women
Other associated autoimmune diseases
Platelets 5-75
>3mm purpura
<3mm petechiae

38. ITP
Test for antibodies to platelet specific antigens to confirm the diagnosis

39. ITP

40. Fetal/Neonatal Alloimmune Thrombocytopenia
Transplacental transfer of maternal antibodies (anti-HPA-1a most common) against paternal antigens
Mother formed platelet specific antibody after
Exposure to baby blood
Transfusion
Can have moderate (50) to severe (10) thrombocytopenia, risk of intracranial hemorrhage
Previous pregnancy outcome good predictor for future pregnancies
HPA-1a located on GPIIIa.

41. A pregnant patient is diagnosed as having anti-platelet antibodies
A pregnant patient is diagnosed as having anti-platelet antibodies. Assuming her baby needs a platelet transfusion at birth, which of the following donors would be the best source of platelets for the baby?
The mother of the baby
The father of the baby
The baby’s paternal grandfather
The baby’s maternal grandfather
A random, unrelated donor
Transfusion of washed, maternal platelets or platelet-antigen matched platelets

42. Anti-HLA Antibodies
Tested sera from 187 pregnant women for the presence of anti-HLA-A, -B, and -C and anti-B lymphocytes or anti-HLA-DR).
Patients were studied before 20 weeks, between 21 and 30 weeks, and between 31 and 40 weeks' gestation.
No correlation was found between the presence of such antibodies and obstetric complications, fetal wastage, placental weight, or infant birth weight.
Obstet Gynecol. 1981 Apr;57(4):444-6.

43. Platelet Refractory: PRA

44. Summary
Severe fetal hemolysis with anti-D (85%), anti-c (3.5%), anti-K (10%) and anti-E.
IgM antibodies do not cross the placenta A, B, P1, Le(a,b), M, I
Antigens poorly expressed on fetal cells Lu(b), Yt(a), VEL
Titers aid in prediction of fetal hemolysis
Platelet-specific alloantibodies are likely to cause severe thrombocytopenia in fetuses and neonates

45. General References
Moise KJ. Fetal anemia due to non-Rhesus-D red- cell alloimmunization. Seminars in Fetal and Neonatal Medicine (2008) 13,
Rossi’s Principles of Transfusion Medicine, fourth ed.
Transfusion therapy: clinical principles and practice third ed. AABB 2011.
Technical manual, eithteenth ed. AABB 2014.

46. Questions