Severe hemolytic disease of the newborn caused by JK(b) antibody: Two case reports and literature review

JK(b) antibody rarely causes severe hemolytic disease in the newborn except in 1 case, required blood exchange transfusion but later died of intractable seizure and renal failure. Here we describe 2 cases of JK(b)-induced severe neonatal jaundice requiring blood exchange transfusion with good neurological outcome. CASE PRESENTATION: Two female Chinese, ethnic Han, term infants with severe jaundice were transferred to us at the age of 5- and 4-day with a total bilirubin of 30.9 and 25.9 mg/dL while reticulocyte counts were 3.2% and 2.2%, respectively. Both infants were not the firstborn to their corresponding mothers. Direct and indirect Coombs’ tests were positive, and JK(b) antibody titers were 1:64 (+) for both mothers. Phototherapy was immediately administered, and a blood exchange transfusion was performed within 5 hours of admission. Magnet resonance image showed no evidence of bilirubin-induced brain damage, and no abnormal neurological finding was detected at 6 months of life. CONCLUSION: JK(b) antibody-induced hemolytic disease of the newborn usually leads to a benign course, but severe jaundice requiring blood exchange transfusion may occur. Our cases suggest good outcomes can be achieved in this minor blood group-induced hemolytic disease of the newborn if identified and managed early enough.