Jr(a) is a high-frequency
antigen found in all
ethnic groups. However, the
clinical significance of the anti-Jr(a) antibody has remained controversial. Most studies have reported mild hemolytic
disease of the
newborn and
fetus (HDNF) in Jr(a)-positive
patients. Recently, fatal cases of HDNF have also been reported. We
report the first case of HDNF caused by anti-Jr(a) alloimmunization in
twins in
Korea. A 33-yr-old nulliparous
woman with no
history of transfusion or
amniocentesis was admitted at the 32nd week of
gestation because of
vaginal bleeding caused by
placenta previa. Anti-Jr(a)
antibodies were detected in a routine
laboratory examination. An
emergency cesarean section was performed at the 34th week of
gestation, and 2
premature infant twins were delivered.
Laboratory examination showed positive
direct antiglobulin test and Jr(a+)
phenotype in the
red blood cells and the presence of anti-Jr(a)
antibodies in the
serum in both
neonates. The
infants underwent
phototherapy for
neonatal jaundice; this was followed by
conservative management. They showed no further
complications and were discharged on the 19th
postpartum day. Preparative management to ensure the availability of Jr(a-)
blood, via autologous donation, and close
fetal monitoring must be performed even in cases of first
pregnancy in Jr(a-)
women.