Fatal hemolytic disease of the fetus and newborn associated with anti-Jr.
BACKGROUND
Jr(a) is a high-prevalence red cell (RBC) antigen. The clinical significance of anti-Jr(a) is controversial. When hemolytic disease of the fetus and newborn (HDFN) occurred, most reported cases were clinically mild. We report the first case of fatal HDFN due to anti-Jr(a).


METHODS
A 28-year-old Caucasian woman with transfusion history was monitored at the 29th week of pregnancy (G4P1). An ultrasound scan showed fetal cardiomegaly and hepatomegaly. An antibody directed against a high-prevalence antigen was detected, but without conclusive identification. An emergency cesarean section was performed at the 36th week. The newborn was hydropic and showed severe anemia. Death occurred 30 hours after birth.


METHODS
Serologic methods were performed to investigate the mother's RBCs and serum. An in vitro functional cellular assay and semiquantitative measurement of anti-Jr(a) were used to determine the clinical significance of the antibody.


RESULTS
Anti-Jr(a) was identified in the serum and Jr(a-) phenotype was confirmed. The anti-Jr(a) titer was 1024, with predominant immunoglobulin (Ig)G1 and minor IgG4 subclasses. The functional cellular assay was consistent with an antibody unlikely to cause HDFN. Semiquantitative measurement of anti-Jr(a) showed a reactivity equivalent to a 25 IU per mL (5 microg/mL) concentration of anti-D, a value associated with a significant risk of HDFN.


CONCLUSIONS
This is the first documented case of fatal HDFN due to anti-Jr(a). Therefore, we recommend close monitoring of pregnant women with a high-titer anti-Jr(a), especially those with an incompatible transfusion history and/or multiple pregnancies. This case report provides new arguments about the clinical significance of anti-Jr(a) in the transfusion setting.
Peyrard
Thierry
T
National Reference Laboratory for Blood Groups, the National Institute of Blood Transfusion, INSERM Unit 665, Paris, France. tpeyrard@ints.fr
Pham
Bach-Nga
BN
Arnaud
Lionel
L
Fleutiaux
Sophie
S
Brossard
Yves
Y
Guerin
Bénédicte
B
Desmoulins
Isabelle
I
Rouger
Philippe
P
Le Pennec
Pierre-Yves
PY
D000328:Adult; D001789:Blood Group Antigens / Q000276:immunology*; D017809:Fatal Outcome; D005260:Female; D006461:Hemolysis / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic / Q000276:immunology*
D001789:Blood Group Antigens