Severe haemolytic disease of the newborn due to anti-Js']Jsb

A case of anti-Js(b) in pregnancy was associated with unexpectedly severe haemolytic disease of the newborn, requiring urgent exchange transfusion. Clinical signs of fetal distress were evident at 35 weeks of gestation in a sixth pregnancy. A Js(b+) baby from a previous pregnancy had been unaffected. This case report illustrates the difficulties of predicting severity on the basis of anti-Js(b) titre, and highlights issues relating to the problems of using reconstituted frozen red cells from the rare red cell bank for exchange transfusion.