Anti-Jsb (KEL7)

Blood Group: Kell

Common: Very rare. ~100% of people have Jsb antigen.

Causes HDN: Yes
Critical Titer: 
Prior to 1995, anti-Jsb had not been known to cause HDN. Doctors reported a patient with high anti-Jsb titers causing hydrops and death in one pregnancy, followed by a pregnancy treated with multiple IUTs. [2]  In one case, they treated the baby with IUTs with blood donated from the mother [5]. Anti-Jsb can also be treated with erythropoietin (commonly called Epogen) [6].

Anti-Jsb has been known to cause anemia requiring transfusion. This happened in a 6 day old infant who was transfused with blood from his mother in the absence of a suitable donor.[4]

It is difficult to severity with anti-Jsb off of titer. In 2001 a patient presented unexpectedly with severe HDN requiring urgent exchange transfusion. Signs of fetal distress were found at 35 weeks. Despite a previous Jsb+ baby who was unaffected, this pregnancy was severely affected. [3]


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