Clinical significance of anti‐Jr^a: report of two cases and review of the literature

Abstract

Anti-Jra can be clinically significant as demonstrated by acute hemolysis in the second case. The MMA accurately predicted the clinical outcome of each case and appears to be a useful tool in predicting the biologic behavior of anti-Jra.

Null alleles of ABCG2 encoding the breast cancer resistance protein define the new blood group system Junior

“…who have the Jr(a−) blood type. Anti-Jr a may be responsible for acute hemolytic transfusion reactions 3 but is of particular concern in obstetrics, as it can cause fatal hemolytic disease of the fetus and newborn (HDFN) 4 . In fact, anti-Jr a is usually detected during pregnancy of Jr(a−) mothers, whose Jr(a−) blood type remains ignored until they develop an anti-Jr a induced by the Jr(a+) cells of their fetus.…”

Fatal hemolytic disease of the fetus and newborn associated with anti‐Jra

“…The clinical significance of anti‐Jr a is still not well established because it occurs rarely and has only been evaluated in a few studies. In the setting of incompatible transfusions, no biologic or clinical evidence of hemolysis to mild acute or delayed transfusion reactions have been reported for anti‐Jr a 5,6 . In the obstetric setting, limited data have led to conflicting results.…”

The American Rare Donor Program

“…If units cannot be located in the United States, international registries such as those in Japan can be contacted by the ARDP regarding the availability of units. For example, the Japanese population has the highest frequency of Jr a -negative individuals (∼0.03%) [12,13]. The transfusing physician must understand the limitations imposed by regulatory agencies when rare units are imported into the United States.…”